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The Kaspari Lab

The ten principles of ecology.

   Posted on July 17, 2017 by pheidole

   5 Comments

I have been teaching a course called “Principles of Ecology” at OU since 1996. It was a traditional two one-hour lecture, one three-hour lab for most of those years. In 2013, I decided to flip the course, converting the lectures to workshops, and asking students to do more reading outside of class. The goal is to allow for more hands on “learning by doing” activities in the workshops, and to more tightly linked lab and fieldwork to workshop data analysis and interpretation. All in all it has been an exciting, often unnerving, but very satisfying transformation. One that is ongoing.

All along it occurred to me that the title of our course strongly implies that there is a finite number of useful principles that our students should internalize. Moreover, if the list and the principles themselves are sufficiently pithy, we should be able to cover them at the beginning of the course, rather than unveil them, one after the other, as the course proceeds. The advantage there would be that students get the big picture early, allowing us to revisit and recombine different suites of principles to build and explore new concepts and ideas. That’s the idea, at least.

I had two inspirations for this venture. One was Eugene Odum’s classic “Fundamentals of Ecology”, the famous “yellow book” that was the go-to text for much of ecology’s early years. Odum organized the book around chapters with titles that begin “Principles and concepts pertaining to….” (e.g., “Limiting factors).  He would then carve each chapter into a series of expositions each with a “Statement”, followed by an “Explanation” followed by “Examples”. I just love Odum’s book and this organization because it fits so well how I organize my own thoughts. I recommend finding a used copy. It holds up remarkably well.

The second inspiration was Meghan Duffy’s and colleagues’ recent discussion of how to organize an Intro Bio version of Ecology. I think I lifted Principle 2 and 4 directly from that blogpost. Lots of good pedagogy there.

So here is my working list of the Ten Principles of Ecology, stated first as tweet-worthy statement, followed by a short explanation of each. The idea is that my 48 students will be seeing this the first week of class and we will sample, expand on, and recombine them throughout the rest of the semester.  I realize every ecologist is different, and that this lays bare my own intellectual DNA on the subject. None-the-less, I’d love to see more lists like this.

Also, has anyone else tried a similar approach to structuring their class?  That is, start with the big picture, then backfill? I’d love to hear about it.

1. Evolution organizes ecological systems into hierarchies.

Individual organisms combine into populations, populations combine into species, species combine into higher taxa like genera and phyla. Each can be characterized by its abundance and diversity (number of kinds) in a given ecosystem or study plot. How and why abundance and diversity vary in time and space is the basic question of ecology.

2. The sun is the ultimate source of energy for most ecosystems.

Life runs on the carbon-rich sugars produced by photosynthesis; every ecosystem’s sugar output depends on how much solar energy and precipitation it receives.

3. Organisms are chemical machines that run on energy.

The laws of chemistry and physics limit the ways each organism makes a living and provide a basic framework for ecology. The supply of chemical elements and the sugars needed to fuel their assembly into organisms limit the abundance and diversity of life.

4. Chemical nutrients cycle repeatedly while energy flows through an ecosystem.

The atoms of elements like C, N, P, and Na go back and forth from spending time in living to spending time in dead parts of an ecosystem. But the photons of solar energy can be used only once before they are lost to the universe.

5. dN/dt=B-X+I

The rate that a population’s abundance in a given area increases or decreases reflects the balance of its births, deaths, and net migration into the area. Individuals with features that improve their ability to survive (i.e., not die) and make copies of themselves will tend to increase in that population.

6. dS/dt=D-X+I

The rate that the diversity of species in an area changes reflects the balance of the number of new forms that arise, those that go extinct, and those that migrate into the area. Individuals and species that have features allowing them to survive and reproduce in a local environment will tend to persist there.

7. Organisms interact—do things to each other—in ways that influence their abundance.

Individual organisms can eat one another, compete for shared resources, and help each other survive. Each pair of species in an ecosystem can be characterized by the kind and strength of these interactions, measured as their contribution to dN/dt.

8. Ecosystems are organized into webs of interactions.

The abundance of a population is influenced by the chains of interactions that connect it to the other species in its ecosystem. This often leads to complex behavior, and a key challenge in ecology is to determine what patterns of abundance and diversity can be predicted.

9. Human populations have an outsized role in competing with, preying upon, and helping other organisms.

Humans are one of millions of species embedded in Earth’s ecosystems. The ability of humans to change the planet, abetted by our large population size and technological prowess, increases our ability to shape the biosphere’s future. Humans, through principles 1-8, are currently changing the climate, re-arranging its chemistry, decreasing populations of food, moving around its species, and decreasing its diversity.

10. Ecosystems provide essential services to human populations.

These include products like timber, fiber and food, regulating water and air quality, and cultural benefits like recreation. A key goal of ecology is to use principles 1-9 to preserve ecosystem services.

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5 Comments on “ The Ten Principles of Ecology ”

Pingback: Friday links: the Great Emu War, world’s oldest bar graph, 10 principles of ecology, and more | Dynamic Ecology

Love the post! One thing I’ve been wondering is whether anyone has used Mark Vellend’s book as a way of restructuring how they teach about ecology. He argues that, because we tend to focus on lower level processes in ecology, students end up thinking that there isn’t a strong conceptual foundation underlying ecology.

Ecology is such a grab bag of climatology, geology, chemistry, history, and biology, I find it impossible to get my head around it without some big structure on which to arrange all the concepts. Principle #6, which we introduced (I think) in our AmNat 2003 paper ( http://bit.ly/2fFZNn1 ), is about as “proto-Vellend” as you can find in the literature.

More generally, you raise the important pedological issue of facts–>theory or theory–>facts. I don’t know if most UG students worry about Vellend’s “strong conceptual foundation”, but they do want a useful study outline. I think the 10 Principles approach, introduced early, then backfilled with the natural history, with frequent returns to the big picture, is the most satisfying way to go, and “chunks” the material in a relatable way.

This leads to a question for you. Ecology textbooks tend to be as singular as their authors. Do you use a text? If so, how? I am sorely tempted for the first two weeks of class to have students find an example of each of the 10 principles in their assigned textbook, and use the two hours of workshop each week to review their discoveries in class. Emphasize “tempted”. The problem with the first week of class is that is when you set it’s tone. Experimenting too much with form too early is risky.

Pingback: “The Ten Principles of Ecology” by Mike Kaspari – The Cypress Creek Ecological Restoration Project

Thanks Mike. I follow Molles pretty closely, and rely on the big picture of his 8 levels of Ecology introduced early. Of course tge poibt being that levels are constantly integrated to address ecological questions. Your structure via 10 big questions might demonstrate that integration nicely. I particularly like 9 and 10 and how integral they have become to 1-8.

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How The Four Laws of Ecology Help You Solve Problems

Ecology is the study of relationships and processes linking living things to the physical and chemical environment.  Exciting, right?

In the 1971 book The Closing Circle , Barry Commoner gives us a clear and understandable example of what ecology really means , while being one of the first to sound the alarm on the impending environmental crisis. (Although Rachel Caron’s Silent Spring certainly holds the mantle for implanting ecological thought into the popular consciousness.)

Commoner’s life was devoted to helping people see the benefits of ecological thinking :

Ecology has not yet explicitly developed the kind of cohesive, simplifying generalizations exemplified by, say, the laws of physics. Nevertheless there are a number of generalizations that are already evident in what we now know about the ecosphere and that can be organized into a kind of informal set of laws of ecology.

He goes on to lay out  four basic and inescapable laws of ecology (which nicely complement Garett Hardin’s Three Filters ). The principles describe a beautiful web of life on earth.

The First Law of Ecology: Everything Is Connected to Everything Else

It reflects the existence of the elaborate network of interconnections in the ecosphere: among different living organisms, and between populations, species, and individual organisms and their physicochemical surroundings. The single fact that an ecosystem consists of multiple interconnected parts, which act on one another, has some surprising consequences. Our ability to picture the behavior of such systems has been helped considerably by the development, even more recent than ecology, of the science of cybernetics. We owe the basic concept, and the word itself, to the inventive mind of the late Norbert Wiener. The word “cybernetics” derives from the Greek word for helmsman; it is concerned with cycles of events that steer, or govern, the behavior of a system. The helmsman is part of a system that also includes the compass, the rudder, and the ship, If the ship veers off the chosen compass course, the change shows up in the movement of the compass needle. Observed and interpreted by the helmsman this event determines a subsequent one: the helmsman turns the rudder, which swings the ship back to its original course. When this happens, the compass needle returns to its original, on-course position and the cycle is complete. If the helmsman turns the rudder too far in response to a small deflection of the compass needle, the excess swing of the ship shows up in the compass—which signals the helmsman to correct his overreaction by an opposite movement. Thus the operation of this cycle stabilizes the course of the ship. In quite a similar way, stabilizing cybernetic relations are built into an ecological cycle. Consider, for example, the fresh water ecological cycle: fish-organic waste-bacteria of decay inorganic products—algae—fish. Suppose that due to unusually warm summer weather there is a rapid growth of algae. This depletes the supply of inorganic nutrients so that two sectors of the cycle, algae and nutrients, are out of balance, but in opposite directions. The operation of the ecological cycle, like that of the ship, soon brings the situation back into balance. For the excess in algae increases the ease with which fish can feed on them; this reduces the algae population, increases fish waste production, and eventually leads to an increased level of nutrients when the waste decays. Thus, the levels of algae and nutrients tend to return to their original balanced position. In such cybernetic systems the course is not maintained by rigid control, but flexibility. Thus the ship does not move unwaveringly on its path, but actually follows it in a wavelike motion that swings equally to both sides of the true course. The frequency of these swings depends on the relative speeds of the various steps in the cycle, such as the rate at which ships responds to the rudder. Ecological systems exhibit similar cycles, although these are often obscured by the effects of daily or seasonal variations in weather and environmental agents. […] The dynamic behavior of a cybernetic system—for example, the frequency of its natural oscillations, the speed with which it responds to external changes, and its overall rate of operation, depends on the relative rates of its constituent steps. In the ship system, the compass needle swings in fractions of a second; the helmsman’s reaction takes some seconds; the ship responds over a time of minutes. These different reaction times interact to produce, for example, the ship’s characteristic oscillation frequency around its true course. […] Ecosystems differ considerably in their rate characteristics and therefore vary a great deal in the speed with which they react to changed situations or approach the point of collapse. […] The amount of stress which an ecosystem can absorb before it is driven to collapse is also a result of its various interconnections and their relative speeds of response. The more complex the ecosystem, the more successfully it can resist a stress. … Most ecosystems are so complex that the cycles are not simple circular paths, but are crisscrossed with branches to form a network or a fabric of interconnections. Like a net, in which each knot is connected to others by several strands, such a fabric can resist collapse better than a simple, unbranched circle of threads—which if cut anywhere breaks down as a whole. Environmental pollution is often a sign that ecological links have been cut and that the ecosystem has been artificially simplified and made more vulnerable to stress and to final collapse. The feedback characteristics of ecosystems result in amplification and intensification processes of considerable magnitude. For example, the fact that in food chains small organisms are eaten by bigger ones and the latter by still bigger ones inevitably results in the concentration of certain environmental constituents in the bodies of the largest organisms at the top of the food chain. Smaller organisms always exhibit much higher metabolic rates than larger ones, so that the amount of their food which is oxidized relative to the amount incorporated into the body of the organism is thereby greater. Consequently, an animal at the top of the food chain depends on the consumption of an enormously greater mass of the bodies of organisms lower down in the food chain. Therefore, any non-metabolized material present in the lower organisms of this chain will become concentrated in the body of the top one. … All this results from a simple fact about ecosystems—everything is connected to everything else: the system is stabilized by its dynamic self-compensating properties; those same properties, if overstressed, can lead to a dramatic collapse; the complexity of the ecological network and its intrinsic rate of turnover determine how much it can be stressed, and for how long, without collapsing; the ecological network is an amplifier, so that a small perturbation in one network may have large, distant, long-delayed effects.

The Second Law of Ecology: Everything Must go Somewhere

This is, of course, simply a somewhat informal restatement of a basic law of physics—that matter is indestructible. Applied to ecology, the law emphasizes that in nature there is no such thing as “waste.” In every natural system, what is excreted by one organism as waste is taken up by another as food. Animals release carbon dioxide as a respiratory waste; this is an essential nutrient for green plants. Plants excrete oxygen, which is used by animals. Animal organic wastes nourish the bacteria of decay. Their wastes, inorganic materials such as nitrate, phosphate, and carbon dioxide, become algal nutrients. A persistent effort to answer the question “Where does it go?” can yield a surprising amount of valuable information about an ecosystem. Consider, for example, the fate of a household item which contains mercury—a substance with serious environmental effects that have just recently surfaced. A dry-cell battery containing mercury is purchased, used to the point of exhaustion, and then “thrown out.” But where does it really go? First it is placed in a container of rubbish; this is collected and taken to an incinerator. Here the mercury is heated; this produces mercury vapor which is emitted by the incinerator stack, and mercury vapor is toxic. Mercury vapor is carried by the wind, eventually brought to earth in rain or snow. Entering a mountain lake, let us say, the mercury condenses and sinks to the bottom. Here it is acted on by bacteria which convert it to methyl mercury. This is soluble and taken up by fish; since it is not metabolized, the mercury accumulates in the organs and flesh of the fish. The fish is caught and eaten by a man and the mercury becomes deposited in his organs, where it might be harmful. And so on. This is an effective way to trace out an ecological path. It is also an excellent way to counteract the prevalent notion that something which is regarded as useless simply “goes away” when it is discarded. Nothing “goes away”; it is simply transferred from place to place, converted from one molecular form to another, acting on the life processes of any organism in which it becomes, for a time, lodged. One of the chief reasons for the present environmental crisis is that great amounts of materials have been extracted from the earth, converted into new forms, and discharged into the environment without taking into account that “everything has to go somewhere.” The result, too often, is the accumulation of harmful amounts of material in places where, in nature, they do not belong.

The Third Law of Ecology: Nature Knows Best

In my experience this principle is likely to encounter considerable resistance, for it appears to contradict a deeply held idea about the unique competence of human beings. One of the most pervasive features of modern technology is the notion that it is intended to “improve on nature”—to provide food, clothing, shelter, and means of communication and expression which are superior to those available to man in nature. Stated baldly, the third law of ecology holds that any major man-made change in a natural system is likely to be detrimental to that system. This is a rather extreme claim; nevertheless I believe it has a good deal of merit if understood in a properly defined context. I have found it useful to explain this principle by means of an analogy. Suppose you were to open the back of your watch, close your eyes, and poke a pencil into the exposed works. The almost certain result would be damage to the watch. Nevertheless, this result is not absolutely certain. There is some finite possibility that the watch was out of adjustment and that the random thrust of the pencil happened to make the precise change needed to improve it. However, this outcome is exceedingly improbable. The question at issue is: why? The answer is self-evident: there is a very considerable amount of what technologists now call “research and development” (or, more familiarly, “R & D”) behind the watch. This means that over the years numerous watchmakers, each taught by a predecessor, have tried out a huge variety of detailed arrangements of watch works, have discarded those that are not compatible with the over-all operation of the system and retained the better features. In effect, the watch mechanism, as it now exists, represents a very restricted selection, from among an enormous variety of possible arrangements of component parts, of a singular organization of the watch works. Any random change made in the watch is likely to fall into the very large class of inconsistent, or harmful, arrangements which have been tried out in past watch-making experience and discarded. One might say, as a law of watches, that “the watchmaker knows best,” There is a close, and very meaningful, analogy in biological systems. It is possible to induce a certain range of random, inherited changes in a living thing by treating it with an agent, such as x-irradiation, that increases the frequency of mutations. Generally, exposure to x-rays increases the frequency of all mutations which have been observed, albeit very infrequently, in nature and can therefore be regarded as possible changes. What is significant, for our purpose, is the universal observation that when mutation frequency is enhanced by x-rays or other means, nearly all the mutations are harmful to the organisms and the great majority so damaging as to kill the organism before it is fully formed.

The Fourth Law of Ecology: There Is No Such Thing as a Free Lunch

In my experience, this idea has proven so illuminating for environmental problems that I have borrowed it from its original source, economics. The “law” derives from a story that economists like to tell about an oil-rich potentate who decided that his new wealth needed the guidance of economic science. Accordingly he ordered his advisers, on pain of death, to produce a set of volumes containing all the wisdom of economics. When the tomes arrived, the potentate was impatient and again issued an order—to reduce all the knowledge of economics to a single volume. The story goes on in this vein, as such stories will, until the advisers are required, if they are to survive, to reduce the totality of economic science to a single sentence. This is the origin of the “free lunch” law. In ecology, as in economics, the law is intended to warn that every gain is won at some cost. In a way, this ecological law embodies the previous three laws. Because the global ecosystem is a connected whole, in which nothing can be gained or lost and which is not subject to over-all improvement, anything extracted from it by human effort must be replaced. Payment of this price cannot be avoided; it can only be delayed. The present environmental crisis is a warning that we have delayed nearly too long.

Lest you feel these are all scientific, Commoner ends by referring you to classic literature:

“ A great deal about the interplay of the physical  features of the environment and the creatures that inhabit it can be learned from Moby Dick.”

Still Interested?  Check these related posts out:

Garrett Hardin on the Three Filters Needed to Think About Problems  — “The goal of these mental filters, then, is to understand reality by improving our ability to judge the statements of experts, promoters, and persuaders of all kinds.”

The Effect of Scale in Social Science, or Why Utopia Doesn’t Work — Why can’t a mouse be the size of an elephant? Weclome to the effect of scale on values.

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

2 Principles of Ecology

Jean Brainard

The Science of Ecology

Ecology is the study of how living things interact with each other and with their environment. It is a major branch of biology, but has areas of overlap with geography, geology, climatology, environmental science, and other sciences. This chapter introduces fundamental concepts in ecology related to organisms and the environment.

The Importance of Energy

Energy is defined as the ability move things, do work, or transfer heat, and comes in various forms, including light, heat, and electricity. There is Low-quality energy that comes in dispersed forms and high quality energy comes in condensed forms. Thermodynamics is the study of energy and the laws of thermodynamics, as you already learned about them, can be applied to energy flow in ecosystems. Remember: The first law of thermodynamics, or, the conservation of energy principle, states that energy may change from one form to another, but the total amount of energy will remain constant. That is to say that energy is not destroyed or created; it just changes form. For example, when wood is burned, the energy that was stored in the wood is not lost. It is given off as heat, smoke, and ash. The final amount of energy is the same just in new forms. The second law of thermodynamics is also important to environmental science and states that disorganization, or entropy, increases in natural systems through any spontaneous process. This means that as energy is used it is degraded to lower forms of energy.

These two laws are important to environmental science in the following ways: 1. First, and very important: we live in a closed system, the Earth’s ecosphere. Nearly all of the organisms on Earth obtain their energy from the sun, and the sun composes the primary level of most ecosystem food chains, save a few deep-water thermal vents and some geyser bacteria. Since energy is neither created nor destroyed, as stated by the first law of thermodynamics, we can conclude that other than the sun’s energy, the energy present is what we have to work with, including the food you live on 2. Second, when humans use non-renewable resources (such as oil) they are converting them into less-useful energy, as stated by the second law of thermodynamics. When those energy sources are depleted, they are gone. Use of these energy sources often also releases different elements back into the environment. For example, the combustion of oil releases carbon back into the air, and this offsets the carbon cycle ( which you learn about ). This helps contribute to climate change.

What these examples attempt to illustrate is that there are inputs and outputs to all energy types, and also benefits and costs to each kind. and each is controlled and limited within the laws of both ecology and thermodynamics.

Organisms and the Environment

Organisms are individual living things. Despite their tremendous diversity, all organisms have the same basic needs: energy and matter. These must be obtained from the environment. Therefore, organisms are not closed systems.  They depend on and are influenced by their environment. The environment includes two types of factors: abiotic and biotic. 1. Abiotic factors are the nonliving aspects of the environment. They include factors such as sunlight, soil, temperature, and water. 2. Biotic factors are the living aspects of the environment. They consist of other organisms, including members of the same and different species.

Levels of Organization Ecologists study organisms and their environments at different levels. The most inclusive level is the biosphere. The biosphere consists of all the organisms on planet Earth and the areas where they live. It occurs in a very thin layer of the planet, extending from about 11,000 meters below sea level to 15,000 meters above sea level. An image of the biosphere is shown in Figure 2.1. Different colors on the map indicate the numbers of food-producing organisms in different parts of the biosphere. Ecological issues that might be investigated at the biosphere level include ocean pollution, air pollution, and global climate change.

FIGURE 2.1 – Image of the biosphere

Ecologists also study organisms and their environments at the population level. A population consists of organisms of the same species that live in the same area and interact with one another. You will read more about populations in the Populations chapter. Important ecological issues at the population level include: • rapid growth of the human population, which has led to overpopulation and environmental damage; • rapid decline in populations of many nonhuman species, which has led to the extinction of numerous species. Another level at which ecologists study organisms and their environments is the community level. A community consists of populations of different species that live in the same area and interact with one another. For example, populations of coyotes and rabbits might interact in a grassland community. Coyotes hunt down and eat rabbits for food, so the two species have a predator-prey relationship. Ecological issues at the community level include how changes in the size of one population affect other populations. The Populations chapter discusses population interactions in communities in detail.

The Ecosystem

An ecosystem is a unit of nature and the focus of study in ecology. It consists of all the biotic and abiotic factors in an area and their interactions. Ecosystems can vary in size. A lake could be considered an ecosystem. So could a dead log on a forest floor. Both the lake and log contain a variety of species that interact with each other and with abiotic factors. Another example of an ecosystem is pictured in Figure 2.2.

FIGURE 2.2 – Desert Ecosystem. What are some of the biotic and abiotic factors in this desert ecosystem?

When it comes to energy, ecosystems are not closed. They need constant inputs of energy. Most ecosystems get energy from sunlight. A small minority get energy from chemical compounds. Unlike energy, matter is not constantly added to ecosystems. Instead, it is recycled. Water and elements such as carbon and nitrogen are used over and over again.

Niche One of the most important concepts associated with the ecosystem is the niche. A niche refers to the role of a species in its ecosystem. It includes all the ways that the species interacts with the biotic and abiotic factors of the environment. Two important aspects of a species’ niche are the food it eats and how the food is obtained. Look at Figure 2.3. It shows pictures of birds that occupy different niches. Each species eats a different type of food and obtains the food in a different way.

FIGURE 2.3 – Bird Niches. Each of these species of birds has a beak that suits it for its niche. For example, the long slender beak of the nectarivore allows it to sip liquid nectar from flowers. The short sturdy beak of the granivore allows it to crush hard, tough grains.

Habitat Another aspect of a species’ niche is its habitat. The habitat is the physical environment in which a species lives and to which it is adapted. A habitat’s features are determined mainly by abiotic factors such as temperature and rainfall. These factors also influence the traits of the organisms that live there. Consider a habitat with very low temperatures. Mammals that live in the habitat must have insulation to help them stay warm. Otherwise, their body temperature will drop to a level that is too low for survival. Species that live in these habitats have evolved fur, blubber, and other traits that provide insulation in order for them to survive in the cold. Human destruction of habitats is the major factor causing other species to decrease and become endangered or go extinct. Small habitats can support only small populations of organisms. Small populations are more susceptible to being wiped out by catastrophic events from which a large population could bounce back. More than 1,200 species face extinction during the next century due mostly to habitat loss and climate change.

Flow of Energy: Producers and Consumers

Energy enters ecosystems in the form of sunlight or chemical compounds. Some organisms use this energy to make food. Other organisms get energy by eating the food.

Producers Producers are organisms that produce food for themselves and other organisms. They use energy and simple inorganic molecules to make organic compounds. The stability of producers is vital to ecosystems because all organisms need organic molecules. Producers are also called autotrophs. There are two basic types of autotrophs: photoautotrophs and chemoautotrophs. 1. Photoautotrophs use energy from sunlight to make food by photosynthesis. They include plants, algae, and certain bacteria (see Figure 2.6). 2. Chemoautotrophs use energy from chemical compounds to make food by chemosynthesis. They include some bacteria and also archaea. Archaea are microorganisms that resemble bacteria.

Chemoautotrophs In some places where life is found on Earth, there is not enough light to provide energy for photosynthesis. In these places, producers called chemoautotrophs use the energy stored in chemical compounds to make organic molecules by chemosynthesis. Chemosynthesis is the process by which carbon dioxide and water are converted to carbohydrates. Instead of using energy from sunlight, chemoautotrophs use energy from the oxidation of inorganic compounds, such as hydrogen sulfide (H2S). Oxidation is an energy-releasing chemical reaction in which a molecule, atom, or ion loses electrons. Chemoautotrophs include bacteria called nitrifying bacteria, which live underground in soil. They oxidize nitrogen-containing compounds and change them to a form that plants can use. Chemoautotrophs also include archaea. Archaea are a domain of microorganisms that resemble bacteria. Most archaea live in extreme environments, such as around hydrothermal vents in the deep ocean. Hot water containing hydrogen sulfide and other toxic substances escapes from the ocean floor at these vents, creating a hostile environment for most organisms. Near the vents, archaea cover the sea floor or live in or on the bodies of other organisms, such as tube worms. In these ecosystems, archaea use the toxic chemicals released from the vents to produce organic compounds. The organic compounds can then be used by other organisms, including tube worms. Archaea are able to sustain thriving communities, like the one shown in Figure 2.4, even in these hostile environments. Some chemosynthetic bacteria live around deep-ocean vents known as “black smokers.” Compounds such as hydrogen sulfide, which flow out of the vents from Earth’s interior, are used by the bacteria for energy to make food. Consumers that depend on these bacteria to produce food for them include giant tubeworms, like these pictured in Figure 2.5. Why do bacteria that live deep below the ocean’s surface rely on chemical compounds instead of sunlight for energy to make food?

FIGURE 2.4 – Red tube worms, each containing millions of archaea microorganisms, grow in a cluster around a hydrothermal vent in the deep ocean floor. Archaea produce food for themselves (and for the tube worms) by chemosynthesis.

FIGURE 2.5 – Tubeworms deep in the Gulf of Mexico get their energy from chemosynthetic bacteria. The bacteria actually live inside the worms.

Photoautotrophs Phototautotrophs are organisms that use energy from sunlight to make food by photosynthesis. Photosynthesis is the process by which carbon dioxide and water are converted to glucose and oxygen, using sunlight for energy. Glucose, a carbohydrate, is an organic compound that can be used by autotrophs and other organisms for energy. As shown in Figure below, photoautotrophs include plants, algae, and certain bacteria. Plants are the most important photoautotrophs in land-based, or terrestrial, ecosystems. There is great variation in the plant kingdom. Plants include organisms as different as trees, grasses, mosses, and ferns. Nonetheless, all plants are eukaryotes that contain chloroplasts, the cellular “machinery” needed for photosynthesis. Algae are photoautotrophs found in most ecosystems, but they generally are more important in water-based, or aquatic, ecosystems. Like plants, algae are eukaryotes that contain chloroplasts for photosynthesis. Algae include single-celled eukaryotes, such as diatoms, as well as multicellular eukaryotes, such as seaweed. Photoautotrophic bacteria, called cyanobacteria, are also important producers in aquatic ecosystems. Cyanobacteria were formerly called blue-green algae, but they are now classified as bacteria. Other photosynthetic bacteria, including purple photosynthetic bacteria, are producers in terrestrial as well as aquatic ecosystems. Both cyanobacteria and algae make up phytoplankton. Phytoplankton refers to all the tiny photoautotrophs found on or near the surface of a body of water. Phytoplankton usually is the primary producer in aquatic ecosystems.

Figure 2.6 – Different types of photoautotrophs are important in different ecosystems.

Consumers Consumers are organisms that depend on the producers (phototrophs or chemotrophs) organisms for food. They take in organic molecules by essentially “eating” other living things. They include all animals and fungi. (Fungi don’t really “eat”; they absorb nutrients from other organisms.) They also include many bacteria and even a few plants, such as the pitcher plant in Figure below. Consumers are also called heterotrophs. Heterotrophs are classified by what they eat:

• Herbivores  consume producers such as plants or algae. They are a necessary link between producers and other consumers. Examples include deer, rabbits, and mice.
• Carnivores  consume animals. Examples include lions, polar bears, hawks, frogs, salmon, and spiders. Carnivores that are unable to digest plants and must eat only animals are called obligate carnivores. Other carnivores can digest plants but do not commonly eat them.
• Omnivores  consume both plants and animals. They include humans, pigs, brown bears, gulls, crows, and some species of fish.

FIGURE 2.7 – Pitcher Plant. Virtually all plants are producers. This pitcher plant is an exception. It consumes insects. It traps them in a substance that digests them and absorbs the nutrients.

Decomposers When organisms die, they leave behind energy and matter in their remains. Decomposers break down the remains and other wastes and release simple inorganic molecules back to the environment. Producers can then use the molecules to make new organic compounds. The stability of decomposers is essential to every ecosystem. Decomposers are classified by the type of organic matter they break down:

• Scavengers  consume the soft tissues of dead animals. Examples of scavengers include vultures, raccoons, and blowflies.
• Detritivores  consume  detritus —the dead leaves, animal feces, and other organic debris that collects on the soil or at the bottom of a body of water. On land, detritivores include earthworms, millipedes, and dung beetles (see  Figure 2.8). In water, detritivores include “bottom feeders” such as sea cucumbers and catfish.
• Saprotrophs  are the final step in decomposition. They feed on any remaining organic matter that is left after other decomposers do their work. Saprotrophs include fungi and single-celled protozoa. Fungi are the only organisms that can decompose wood.

FIGURE 2.8 – Dung Beetle. This dung beetle is rolling a ball of feces to its nest to feed its young.

Food Chains and Food Webs

Food chains and food webs are diagrams that represent feeding relationships. They show who eats whom. In this way, they model how energy and matter move through ecosystems.

Food Chains A food chain represents a single pathway through which energy and matter flow through an ecosystem. An example is shown in Figure 2.9. Food chains are generally simpler than what really happens in nature. Most organisms consume—and are consumed by—more than one species.

FIGURE 2.9 – This food chain includes producers and consumers. How could you add decomposers to the food chain?

Food Webs A food web represents multiple pathways through which energy and matter flow through an ecosystem. It includes many intersecting food chains. It demonstrates that most organisms eat, and are eaten, by more than one species. An example is shown in Figure 2.10.

FIGURE 2.10 – Food Web. This food web consists of several different food chains. Which organisms are producers in all of the food chains included in the food web?

Trophic Levels The feeding positions in a food chain or web are called trophic levels. The different trophic levels are defined in Table 1.1. Examples are also given in the table. All food chains and webs have at least two or three trophic levels. Generally, there are a maximum of four trophic levels.

Many consumers feed at more than one trophic level. Humans, for example, are primary consumers when they eat plants such as vegetables. They are secondary consumers when they eat cows. They are tertiary consumers when they eat salmon.

Trophic Levels and Energy Transfer The different feeding positions in a food chain or web are called trophic levels. The first trophic level consists of producers, the second of primary consumers, the third of secondary consumers, and so on. There usually are no more than four or five trophic levels in a food chain or web. Humans may fall into second, third, and fourth trophic levels of food chains or webs. They eat producers such as grain, primary consumers such as cows, and tertiary consumers such as salmon. Energy is passed up the food chain from one trophic level to the next. However, only about 10 percent of the total energy stored in organisms at one trophic level is actually transferred to organisms at the next trophic level. The rest of the energy is used for metabolic processes or lost to the environment as heat. As a result, less energy is available to organisms at each successive trophic level. This explains why there are rarely more than four or five trophic levels. The amount of energy at different trophic levels can be represented by an energy pyramid like the one in Figure 2.11.

FIGURE 1.11 – This pyramid shows the total energy stored in organisms at each trophic level in an ecosystem. Starting with primary consumers, each trophic level in the food chain has only 10 percent of the energy of the level below it. The pyramid makes it clear why there can be only a limited number of trophic levels in a food chain or web.

FIGURE 2.12 – Ecological Pyramid. This pyramid shows how energy and biomass decrease from lower to higher trophic levels. Assume that producers in this pyramid have 1,000,000 kilocalories of energy. How much energy is available to primary consumers?

Community Interactions

Biomes as different as grasslands and estuaries share something extremely important. They have populations of interacting species. Moreover, species interact in the same basic ways in all biomes. For example, all biomes have some species that prey on other species for food. Species interactions are important biotic factors in ecological systems. The focus of study of species interactions is the community.

What Is a Community? In ecology, a community is the biotic component of an ecosystem. It consists of populations of different species that live in the same area and interact with one another. Like abiotic factors, such as climate or water depth, species interactions in communities are important biotic factors in natural selection. The interactions help shape the evolution of the interacting species. Three major types of community interactions are predation, competition, and symbiosis.

Predation Predation is a relationship in which members of one species (the predator) consume members of other species (the prey). The lions and cape buffalo in Figure 2.13 are classic examples of predators and prey. In addition to the lions, there is another predator in this figure. Can you find it? The other predator is the cape buffalo. Like the lion, it consumes prey species, in this case species of grasses. Predator-prey relationships account for most energy transfers in food chains and webs.

FIGURE 2.13 – An adult male lion and a lion cub feed on the carcass of a South African cape buffalo.

Types of Predators The lions in Figure 2.13 are true predators. In true predation, the predator kills its prey. Some true predators, like lions, catch large prey and then dismember and chew the prey before eating it. Other true predators catch small prey and swallow it whole. For example, snakes swallow mice whole.

Some predators are not true predators because they do not kill their prey. Instead, they graze on their prey. In grazing, a predator eats part of its prey but rarely kills it. For example, deer graze on plants but do not usually kill them. Animals may also be “grazed” upon. For example, female mosquitoes suck tiny amounts of blood from animals but do not harm them, although they can transmit disease.

Predation and Populations True predators help control the size of prey populations. This is especially true when a predator preys on just one species. Generally, the predator-prey relationship keeps the population size of both species in balance. This is shown in Figure 2.14. Every change in population size of one species is followed by a corresponding change in the population size of the other species. Generally, predator-prey populations keep fluctuating in this way as long as there is no outside interference.

FIGURE 2.14 As the prey population increases, the predator population starts to rise. With more predators, the prey population starts to decrease, which, in turn, causes the predator population to decline. This pattern keeps repeating. There is always a slight lag between changes in one population and changes in the other population.

Some predator species are known as keystone species, because they play such an important role in their community. Introduction or removal of a keystone species has a drastic effect on its prey population. This, in turn, affects populations of many other species in the community. For example, some sea star species are keystone species in coral reef communities. The sea stars prey on mussels and sea urchins, which have no other natural predators. If sea stars are removed from a coral reef community, mussel and sea urchin populations would have explosive growth, which in turn would drive out most other species and destroy the reef community. Sometimes humans deliberately introduce predators into an area to control pests. This is called biological pest control. One of the earliest pests controlled in this way was a type of insect, called a scale insect. The scale insect was accidentally introduced into California from Australia in the late 1800s. It had no natural predators in California and was destroying the state’s citrus trees. Then, its natural predator in Australia, a type of beetle, was introduced into California in an effort to control the scale insect. Within a few years, the insect was completely controlled by the predator. Unfortunately, biological pest control does not always work this well. Pest populations often rebound after a period of decline.

Adaptations to Predation Both predators and prey have adaptations to predation. Predator adaptations help them capture prey. Prey adaptations help them avoid predators. A common adaptation in both predator and prey species is camouflage, or disguise. One way of using camouflage is to blend in with the background. Several examples are shown in Figure 2.15. Another way of using camouflage is to look like a different, more dangerous animal. Using appearance to “mimic” another animal is called mimicry. Figure 2.16 shows an example of mimicry. The moth in the figure has markings on its wings that look like the eyes of an owl. When a predator comes near, the moth suddenly displays the markings. This startles the predator and gives the moth time to fly away.

FIGURE 2.15 – Can you see the crab in the photo on the left? It is camouflaged with algae. The preying mantis in the middle photo looks just like the dead leaves in the background. The stripes on the zebras in the right photo blend the animals together, making it hard to see where one zebra ends and another begins.

Some prey species have adaptations that are the opposite of camouflage. They have bright colors or other highly noticeable traits that serve as a warning for their predators to stay away. For example, some of the most colorful butterflies are poisonous to birds, so birds have learned to avoid eating them. By being so colorful, the butterflies are more likely to be noticed—and avoided—by their predators.

FIGURE 2.16 – The moth on the left mimics the owl on the right.

Predation, Natural Selection, and Co-evolution Adaptations to predation come about through natural selection (see the Evolution in Populations chapter). When a prey organism avoids a predator, it has higher fitness than members of the same species that were killed by the predator. The organism survives longer and may produce more offspring. As a result, traits that helped the prey organism avoid the predator gradually become more common in the prey population. Evolution of traits in the prey species leads to evolution of corresponding traits in the predator species. This is called co-evolution. In co-evolution, each species is an important factor in the natural selection of the other species. Predator-prey co-evolution is illustrated by rough-skinned newts and common garter snakes, both shown in Figure 2.17. Through natural selection, newts evolved the ability to produce a strong toxin. In response, garter snakes evolved the ability to resist the toxin, so they could still safely prey upon newts. Then, newts evolved the ability to produce higher levels of toxin. This was followed by garter snakes evolving resistance to the higher levels. In short, the predator-prey relationship led to an evolutionary “arms race,” resulting in extremely high levels of toxin in newts.

FIGURE 2.17 – The rough-skinned newt on the left is highly toxic to other organisms. Common garter snakes, like the one on the right, have evolved resistance to the toxin.

Competition Competition is a relationship between organisms that strive for the same limited resources. The resources might be food, nesting sites, or territory. Two different types of competition are intraspecific and interspecific competition.

• Intraspecific competition  occurs between members of the same species. For example, two male birds of the same species might compete for mates in the same territory. Intraspecific competition is a necessary factor in natural selection. It leads to adaptive changes in a species through time (see the  Evolution in Populations  chapter).
• Interspecific competition  occurs between members of different species. For example, two predator species might compete for the same prey. Interspecific competition takes place in communities of interacting species. It is the type of competition referred to in the rest of this section.

Interspecific Competition and Extinction When populations of different species in a community depend on the same resources, there may not be enough resources to go around. If one species has a disadvantage, such as more predators, it may get fewer of the necessary resources. As a result, members of that species are less likely to survive, and the species will have a higher death rate than the other species. Fewer offspring will be produced and the species may eventually die out in the area. In nature, interspecific competition has often led to the extinction of species. Many other extinctions have occurred when humans introduced new species into areas where they had no predators. For example, rabbits were introduced into Australia in the mid-1800s for sport hunting. Rabbits had no predators in Australia and quickly spread throughout the continent. Many species of Australian mammals could not successfully compete with rabbits and went extinct.

Interspecific Competition and Specialization Another possible outcome of interspecific competition is the evolution of traits that create distinct differences among the competing species. Through natural selection, competing species can become more specialized. This allows them to live together without competing for the same resources. An example is the anolis lizard. Many species of anolis live and prey on insects in tropical rainforests. Competition among the different species led to the evolution of specializations. Some anolis evolved specializations to prey on insects in leaf litter on the forest floor. Others evolved specializations to prey on insects on the branches of trees. This allowed the different species of anolis to co-exist without competing.

Symbiotic Relationships Symbiosis is a close association between two species in which at least one species benefits. For the other species, the outcome of the association may be positive, negative, or neutral. There are three basic types of symbiotic relationships: mutualism, commensalism, and parasitism.

Mutualism  is a symbiotic relationship in which both species benefit. Lichen is a good example. A lichen is not a single organism but a fungus and an alga. The fungus absorbs water from air and minerals from rock or soil. The alga uses the water and minerals to make food for itself and the fungus. Another example involves goby fish and shrimp (see  Figure 2.17 ). The nearly blind shrimp and the fish spend most of their time together. The shrimp maintains a burrow in the sand in which both the goby and the shrimp live. When a predator comes near, the fish touches the shrimp with its tail as a warning. Then, both fish and shrimp retreat to the burrow until the predator is gone. Each gains from this mutualistic relationship: the shrimp gets a warning of approaching danger, and the fish gets a safe home and a place to lay its eggs. Co-evolution often occurs in species involved in mutualistic relationships. Many examples are provided by flowering plants and the species that pollinate them. Plants have evolved flowers with traits that promote pollination by particular species. Pollinator species, in turn, have evolved traits that help them obtain pollen or nectar from certain species of flowers.

Figure 2.17: The multicolored shrimp in the front and the green goby fish behind it have a mutualistic relationship. The shrimp shares its burrow with the fish, and the fish warns the shrimp when predators are near. Both species benefit from the relationship.

Comensalism  is a symbiotic relationship in which one species benefits while the other species is not affected. In commensalism, one animal typically uses another for a purpose other than food. For example, mites attach themselves to larger flying insects to get a “free ride,” and hermit crabs use the shells of dead snails for shelter. Co-evolution explains some commensal relationships. An example is the human species and some of the species of bacteria that live inside humans. Through natural selection, many species of bacteria have evolved the ability to live inside the human body without harming it.

Parasitism is a symbiotic relationship in which one species (the parasite) benefits while the other species (the host) is harmed. Some parasites live on the surface of their host. Others live inside their host, entering through a break in the skin or in food or water. For example, roundworms are parasites of the human intestine. The worms produce huge numbers of eggs, which are passed in the host’s feces to the environment. Other humans may be infected by swallowing the eggs in contaminated food or water. This usually happens only in places with poor sanitation. Some parasites eventually kill their host. However, most parasites do not. Parasitism in which the host is not killed is a successful way of life and very common in nature. About half of all animal species are parasitic in at least one stage of their lifecycle. Many plants and fungi are parasitic during some stages, as well. Not surprisingly, most animals are hosts to one or more parasites. Species in parastic relationships are likely to undergo co-evolution. Host species evolve defenses against parasites, and parasites evolve ways to evade host defenses. For example, many plants have evolved toxins that poison plant parasites such as fungi and bacteria. The microscopic parasite that causes malaria in humans has evolved a way to evade the human immune system. It hides out in the host’s blood cells or liver where the immune system cannot find it.

Principles of Ecology Copyright © by Jean Brainard is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License , except where otherwise noted.

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• Corpus ID: 154308980

The Basic Principles of Deep Ecology

• A. Naess , Geprge Sessions
• Published 2 October 1986
• Environmental Science, Philosophy

46 Citations

The hope-sparking gloominess in offill’s weather and greengrass’s the high house in the perspective of naess’s theory of deep ecology, gaia, psyche and deep ecology., the green movement: implications for animals, the relevance of deep ecological principles in aquatic crisis: a philosophical analysis, bruno latour: new challenges and inspirations in political ecology, a critical inquiry into ecological visions of ancient india versus, modern west, a view from deep ecology, exploring the historical roots of environmental and ecological accounting from the dawn of human consciousness, uniting ecocentric and animal ethics: combining non-anthropocentric approaches in conservation and the care of domestic animals, ecological sustainability from a legal philosophy perspective, 2 references, the nature and possibility of an environmental ethic, related papers.

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A Collection of Essays by Arne Naess

The deep ecology movement: some philosophical aspects, by arne naess.

Here, Naess tries to make the case why even the more modest aims of what he calls “shallow environmentalism” have a need for deep ecology. The Eight Basic Principles of Deep Ecology are presented and carefully elaborated in this text from 1986. On basis of a number of key terms and slogans that figured in the environmental debate at the time, Naess further aims to clarify the contrast between the shallow and the deep.

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Self-Realization in Mixed Communities of Human Beings, Bears, Sheep, and Wolves

In this article from 1979, Naess carefully dissects how the different interests of species can still be met in a concrete case where they are clearly antagonistic. With that he throws himself in the often heated debate in many Nordic countries, about how much space humans, in their self-chosen role of managers of nature, should allow to predators in wilderness and rural areas.

The Shallow and the Deep, Long-Range Ecology Movement: A Summary

In the early 1970s, Naess identified an important new development. To him, the emergence of ecologists from their former relative obscurity marked a turning point in our scientific communities. He saw that their message got twisted and misused. A shallow, but rather powerful movement and a deep, but less influential movement seemed to be competing for the public’s attention. Here, in this text from 1973, Naess presents what he sees as the main differences between the two.

The Heart of the Forest

When developers make a road through a forest, the amount of square meters that is taken for this might be small. Naess, however, would argue that such a road may well go through the heart of this forest. When one gets deeper and deeper into a forest, he suggests in this short text from 1997, one may get the spontaneous experience of being deep in the forest. If you then hit the road, feeling completely disappears.

Beautiful Action: Its Function in the Ecological Crisis

In efforts to counteract the current ecological crisis, Naess looks for actions that may be politically more effective than those depending on a sense of ethical obligation to act in ecologically responsible ways. One could also encourage – perhaps with more chance of having a lasting impact – the performance of what Immanuel Kant called “beautiful actions.” Such actions stem from people’s inclination and inner satisfaction to behave in such ways. An article from 1993.

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An Example of a Place: Tvergastein

In this article from 1992, Naess describes how Tvergastein, the mountain hut at which he wrote many of his books and articles, came to be his “home,” a place where he developed a strong bond and internal relation to the environment. Here he learned deep lessons which encouraged him to articulate his own Ecosophy T, whereby the T is shorthand for Tvergastein.

A Note on the Prehistory and History of the Deep Ecology Movement

The deep ecology movement did not appear like a bolt out of the blue. In this article from 1991, Arne Naess traces its history, mentioning the publication of Rachel Carson’s Silent Spring in 1963 as a defining moment. Forerunners can also be found much earlier, for example in Romanticism from the time of Goethe. More recent developments within cultural anthropology also had a key influence.

Metaphysics of the Treeline

Throughout his life, Naess felt a mythopoetic connection with the space that opens up, when one moves beyond the treeline. Naess contrasts subordinate gestalts, that is, lesser forms of what is real, with higher-order gestalts such as the contrast between high and low, and dark and light. Movement towards treeline – from low and dark, to high and light – strengthens the contrast. Being at treeline becomes an experience of reaching supreme freedom. A text from 1989.

Intrinsic Value: Will the Defenders of Nature Please Rise

By attributing intrinsic value to nonhuman beings, supporters of the deep ecology movement accept the maxim that no living being should be treated merely as a means. For them, it is the ecosphere, the whole planet, Gaia, that is the basic unit. In this text from 1985, Arne Naess argues that every being has intrinsic value.

Arne Naess Essays & Articles

Arne Naess (1912-2009) Photo: Doug Tompkins

Essays and articles, arne naess essays & articles.

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Marine Conservation

Find out more..., essays on wildlife conservation.

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MarineBio is proud to present Essays on Wildlife Conservation written and edited by Dr. Peter Moyle, et al. for an introductory course on wildlife conservation taught at the University of California, Davis.

The essays were written for students who are not only biology majors and are broad in scope. These chapters provide an introduction to the history of wildlife in North America, biodiversity, natural selection, conservation biology, ecology, conservation legislation, alien species, wildlife and pollution, and things we can all do to save wildlife. We think you will find that they are not only fascinating to read but also very useful toward understanding the myriad of issues concerning conservation efforts today.

If you do use these readings, please inform Dr. Moyle ( [email protected] ). If you significantly modify the essays, please provide Dr. Moyle with an electronic copy of your final version (or a link to it). Comments and corrections are always welcome.

These particular essays are copyrighted by the Regents, University of California, but the only stipulation I have about their use for non-profit purposes is that their source be acknowledged.

About Peter Moyle, PhD. Peter Moyle  has been studying the ecology and conservation of freshwater and estuarine fishes in California for over 30 years. He has documented the declining status of many native species in California as well as the invasions of alien species. The interactions among native and alien species in environments with varying degrees of disturbance have provided the basis for his ecological studies. Dr. Moyle served as member of the Sierra Nevada Ecosystem Project science team (1994-1996), developing strategies for the conservation of fish, amphibians, and watersheds in the mountain range that forms the state’s backbone (and main source of water). He is currently a member of the Independent Science Board for the CALFED Ecosystem Restoration Program, which advises a consortium of state and federal agencies on restoration activities for the Sacramento-San Joaquin watershed, one of the largest aquatic restoration projects ever attempted. He is author/coauthor of over 150 scientific papers and 5 books. For those of you who fish, keep an aquarium or just admire fish for what they are, he shamelessly recommends his  Fish: an enthusiast’s guide , a cheap paperback published by University of California Press. The completely revised and updated version of his book  Inland Fishes of California  was recently published by the Press as well (2002). He is a professor of fish biology in the  Department of Wildlife, Fish, and Conservation Biology, University of California, Davis , where he teaches basic courses in ichthyology, wildlife conservation and watershed ecology.

Edited by  Peter Moyle  & Douglas Kelt

Foreword: A Reader on Wildlife Conservation

JULY 2004 Peter Moyle

The dodo was a large flightless pigeon that once inhabited the remote island of Mauritius. It was clubbed into extinction by sailors in the 17th century for food and sport. The dodo is remembered today mainly as a symbol of stupidity: it was too dumb to get out of the way of humans and was therefore wiped out. Unfortunately, most species sharing this island planet with us are dodos. They cannot get out of the way of human “progress” and will be beaten to extinction unless we actively protect them and their habitats. The essays that follow attempt to demonstrate why this last statement is true and also describe how humans and other forms of life are interdependent. They also provide some ethical and practical tools you can use to help improve the situation. If you choose not to be consciously involved in the conservation of forms of life other than your own, you should at least be aware that by doing nothing you are still having an impact on the biota of this planet. The water you drink, the food you eat, the land you live on, and the air you pollute were all obtained at the expense of other creatures. The decisions we make today on how we are going to share these resources will determine which other species will inhabit Earth for the indefinite future.

The course for which this reader was written, WFC 10, has been taught at the University of California Davis since about 1970. The change in subject matter over the short period of time since its inception reflects the change in the attitudes towards wild vertebrates (wildlife) of biologists, wildlife managers and the public. The earliest versions of the course were concerned primarily with economically important species such as deer, ducks, trout, and salmon and how to manage them to provide maximum harvest. Endangered species and environmental degradation were discussed only as a minor component of the lectures. Gradually the emphasis has shifted. The management of economically important species of wildlife is still discussed in the course but in the context of a concern for the preservation of all wildlife, from the most obscure species of small fish to spectacular predators like mountain lions. The course does focus on vertebrates as the traditional “wildlife”, but vertebrates should be regarded mainly as the forms of life with which we have the most empathy, being vertebrates ourselves. The conservation problems we are having with vertebrates are problems we are having with all forms of life and their interactions with each other (biodiversity). The conservation of biodiversity is the subject of a new, rapidly growing field called Conservation Biology. Conservation Biology gets its theory from ecology and the social sciences, its applied orientation from traditional wildlife and wildland management, and its ethics and energy from the environmental movement. This course is now in many respects a course in conservation biology, emphasizing vertebrates.

The essays in this electronic book have the following progression. The first two essays deal with the history of human-wildlife interactions. These are followed by a series of essays on basic biogeography, ecology, and evolution. The remaining essays deal with conservation problems and how to solve them. The final essay is about what you can do at a personal level to affect positive change. To round out these readings, various published papers, book chapters, essays, and other materials are used.

ACKNOWLEDGEMENTS The first versions of many of these essays were produced in graduate seminar in textbook writing in 1990, by Dianne Leonard, Robert J. Meese, Tim F. Ginnett, Anitra Pawley, Anne Brasher, Steve Ellsworth, Michael Brown, and Jay Davis. The chapters have gone through several major revisions since that time. Douglas Kelt, who also teaches this WFC 10, has provided input on many aspects of the course and wrote the chapter on biogeography. Mary Orland helped to produce this particular version, as a postdoctoral scholar funded through the endowment for the President’s Chair in Undergraduate Education, co-held in 2003-2006 by myself and Jeffrey Mount of Geology. I am also appreciative of the many graduate student teaching assistants and undergraduate students who read the chapters and pointed out errors of commission and omission, thus helping to make these essays into dynamic documents. Further comments are always welcome.

Coexisting with our environment and the awe inspiring wildlife that inhabits it seems to be in short supply today. The threats to both just keep on coming, loss of habitat, trophy hunting chemical use etc. We must not bury our head in our hands however, taking action and not just tweeting something is important. We can all find something to do to help.

We couldn’t agree more. If you haven’t already, you might check out our facebook group at https://www.facebook.com/groups/marinebio/ where there are many of us that feel the same way. Stay safe.      

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A Guide to Writing the Perfect Ecology Research Essay

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Ecological Literacy: Teaching the Next Generation About Sustainable Development

Bioneers | Published: September 3, 2019 Environmental Education Article

As societies search for ways to become more sustainable, Fritjof Capra suggests incorporating the same principles on which nature’s ecosystems operate. In his essay, “Speaking Nature’s Language: Principles for Sustainability” from the book Ecological Literacy , he leaves a blueprint for building a more resilient world on the foundation of natural concepts, such as interdependence and diversity. This essay advocates a shift in thinking to a more holistic view of living systems: taking into account the collective interactions between the parts of the whole, instead of just the parts themselves.

Following is an excerpt from  Ecological Literacy by Fritjof Capra, David Orr, Michael Stone and Zenobia Barlow, including an introduction and Capra’s essay.

If anyone has learned to speak nature’s language, it is Fritjof Capra. A founding director of the Center for Ecoliteracy and currently chair of its board, he has distinguished himself over the past forty years as a scientist, systems theorist, and explorer of the philosophical and social ramifications of contemporary science.

Introducing him to an overflow audience at a Bioneers Conference plenary, Kenny Ausubel said, “One of Fritjof Capra’s greatest gifts is his ability to digest enormous amounts of information from highly complex, wide-ranging fields of inquiry. Not only does he explain them elegantly and clearly, but he distills their essence and sees their implications. Because he’s a credentialed scientist who did his time with particle accelerators all over Europe and the United States, Fritjof never overstates his case or lapses into wishful thinking.”

After receiving his Ph.D. in theoretical physics from the University of Vienna in 1966, Capra did research in particle physics at the University of Paris, the University of California at Santa Cruz, the Stanford Linear Accelerator Center, Imperial College of the University of London, and the Lawrence Berkeley Laboratory at the University of California. He also taught at UC Santa Cruz, UC Berkeley, and San Francisco State University.

He is the author of five international bestsellers: The Tao of Physics (1975), The Turning Point (1982), Uncommon Wisdom (1988), The Web of Life (1996), and The Hidden Connections (2002). He coauthored Green Politics (1984), Belonging to the Universe (1991), and EcoManagement (1993), and coedited Steering Business Toward Sustainability (1995).

He is on the faculty of Schumacher College, an international center for ecological studies in England, frequently gives management seminars for top executives, and lectures widely to lay and professional audiences in Europe, Asia, and North and South America. He is an enormously popular speaker, addressing audiences of thousands, switching easily between German, French, English, Italian, and Spanish. The Center for Ecoliteracy’s single greatest source of inquiries is people from as far away as Brazil and India who find the CEL website by linking from Capra’s.

This essay distills thinking that has inspired the Center for Ecoliteracy and served as its intellectual touchstone for a decade.

AS I DISCUSSED IN THE PREFACE to this book, we can design sustainable societies by modeling them after nature’s ecosystems. To understand ecosystems’ principles of organization, which have evolved over billions of years, we need to learn the basic principles of ecology—the language of nature, if you will. The most useful framework for understanding ecology today is the theory of living systems, which is still emerging and whose roots include organismic biology, gestalt psychology, general system theory, and complexity theory (or nonlinear dynamics). For more discussion of the theory of living systems and its implications, please see my book The Hidden Connections .

What is a living system? When we walk out into nature, living systems are what we see. First, every living organism , from the smallest bacterium to all the varieties of plants and animals, including humans, is a living system. Second, the parts of living systems are themselves living systems. A leaf is a living system. A muscle is a living system. Every cell in our bodies is a living system. Third, communities of organisms , including both ecosystems and human social systems such as families, schools, and other human communities, are living systems.

Thinking in terms of complex systems is now at the very forefront of science. It is also very like the ancient thinking that enabled traditional peoples to sustain themselves for thousands of years. But although the modern version of this intellectual tradition is almost a hundred years old, it has still not taken hold in our mainstream culture. I’ve thought quite a lot about why people find systems thinking so difficult and have concluded that there are two main reasons. One is that living systems are nonlinear—they’re networks—while our whole scientific tradition is based on linear thinking—chains of cause and effect.

In linear thinking, when something works, more of the same will always be better. For instance, a “healthy” economy will show strong, indefinite economic growth. But successful living systems are highly nonlinear. They don’t maximize their variables; they optimize them. When something is good, more of the same will not necessarily be better, because things go in cycles, not along straight lines. The point is not to be efficient, but to be sustainable. Quality, not quantity, counts.

We also find systems thinking difficult because we live in a culture that is materialist in both its values and its fundamental worldview. For example, most biologists will tell you that the essence of life lies in the macromolecules— the DNA, proteins, enzymes, and other material structures in living cells. Systems theory tells us that knowledge of these molecules is, of course, very important, but the essence of life does not lie in the molecules. It lies in the patterns and processes through which those molecules interact. You can’t take a photograph of the web of life because it is nonmaterial—a network of relationships.

Perceptual Shifts

Because living systems are nonlinear and rooted in patterns of relationships, understanding the principles of ecology requires a new way of seeing the world and of thinking—in terms of relationships, connectedness, and context —that goes against the grain of traditional Western science and education. Such “contextual” or “systemic” thinking involves several shifts of perception:

From the parts to the whole. Living systems are integrated wholes whose properties cannot be reduced to those of their smaller parts. Their “systemic” properties are properties of the whole that none of the parts has.

From objects to relationships. An ecosystem is not just a collection of species, but is a community. Communities, whether ecosystems or human systems, are characterized by sets, or networks, of relationships. In the systems view, the “objects” of study are networks of relationships, embedded in larger networks. In practice, organizations designed according to this ecological principle are more likely than other organizations to feature relationship-based processes such as cooperation and decision-making by consensus.

From objective knowledge to contextual knowledge. The shift of focus from the parts to the whole implies a shift from analytical thinking to contextual thinking. The properties of the parts are not intrinsic, but can be understood only within the context of the whole. Since explaining things in terms of their contexts means explaining them in terms of their environments, all systems thinking is environmental thinking.

From quantity to quality. Understanding relationships is not easy, especially for those of us educated within a scientific framework, because Western science has always maintained that only the things that can be measured and quantified can be expressed in scientific models. It’s often been implied that phenomena that can be measured and quantified are more important—and maybe even that what cannot be measured and quantified doesn’t exist at all. Relationships and context, however, cannot be put on a scale or measured with a ruler.

From structure to process. Systems develop and evolve. Thus the understanding of living structures is inextricably linked to understanding renewal, change, and transformation.

From contents to patterns. When we draw maps of relationships, we discover certain configurations of relationships that appear again and again. We call these configurations “patterns.” Instead of focusing on what a living system is made of, we study its patterns.

Here we discover a tension between two approaches to the study of nature that has characterized Western science and philosophy throughout the ages. One approach begins with the question: What is it made of? Traditionally, this has been called the study of matter. The other approach begins with the question: What is the pattern? And this, since Greek times, has been called the study of form.

In the West, most of the time, the study of matter has dominated in science. But late in the twentieth century, the study of form came to the fore again, with the emergence of systems thinking. Chaos and complexity theory are essentially theories of patterns. The so-called strange attractors of chaos theory are visual patterns that represent the dynamics of a certain chaotic system. The fractals of fractal geometry are visual patterns. In fact, the whole new mathematics of complexity is essentially the mathematics of patterns.

Some Implications for Education

Because the study of patterns requires visualizing and mapping, every time that the study of pattern has been in the forefront, artists have contributed significantly to the advancement of science. In Western science the two most famous examples are Leonardo da Vinci, whose whole scientific work during the Renaissance could be seen as a study of patterns, and the eighteenth-century German poet Goethe, who made significant contributions to biology through his study of patterns.

This opens the door for educators’ integrating the arts into the curriculum. Whether we talk about literature and poetry, the visual arts, music, or the performing arts, there’s hardly anything more effective than art for developing and refining a child’s natural ability to recognize and express patterns.

Because all living systems share sets of common properties and principles of organization, systems thinking can be applied to integrate heretofore fragmented academic disciplines. Biologists, psychologists, economists, anthropologists, and other specialists all deal with living systems. Because they share a set of common principles, these disciplines can share a common framework.

We can also apply the shifts to human communities, where these principles could be called principles of community. Of course there are many differences between ecosystems and human communities. Not everything we need to teach can be learned from ecosystems. Ecosystems do not manifest the level of human consciousness and culture that emerged with language among primates and then came to flourish in evolution with the human species.

Sustainability in the Language of Nature

By applying systems thinking to the multiple relationships interlinking the members of the earth household, we can identify core concepts that describe the patterns and processes by which nature sustains life. These concepts, the starting point for designing sustainable communities, may be called principles of ecology, principles of sustainability, principles of community, or even the basic facts of life. We need curricula that teach our children these fundamental facts of life.

These closely related concepts are different aspects of a single fundamental pattern of organization: nature sustains life by creating and nurturing communities. Among the most important of these concepts, recognized from observing hundreds of ecosystems, are “networks,” “nested systems,” “interdependence,” “diversity,” “cycles,” “flows,” “development,” and “dynamic balance.”

Because members of an ecological community derive their essential properties, and in fact their very existence, from their relationships, sustainability is not an individual property, but a property of an entire network.

At the Center for Ecoliteracy, we understand that solving problems in an enduring way requires bringing the people addressing parts of the problem together in networks of support and conversation. Our watershed restoration work, for example (see “‘It Changed Everything We Thought We Could Do’” in Part III), began with one class of fourth-graders concerned about an endangered species of shrimp, but the work continues today because it evolved into a network that includes students, teachers, parents, funders, ranchers, design and construction professionals, NGOs, and government bodies. Each part of the network makes its own contribution to the project, the efforts of each are enhanced by the work of all, and the network has the resilience to keep the project alive even when individual members leave or move on.

Nested Systems

At all scales of nature, we find living systems nesting within other living systems—networks within networks. Although the same basic principles of organization operate at each scale, the different systems represent levels of differing complexity.

Students working on the Shrimp Project, for example, discovered that the shrimp inhabit pools that are part of a creek within a larger watershed. The creek flows into an estuary that is part of a national marine sanctuary, which is included in a larger bioregion. Events at one level of the system affect the sustainability of the systems embedded in the other levels.

Within social systems such as schools, the individual child’s learning experiences are shaped by what happens in the classroom, which is nested within the school, which is embedded in the school district and then in the surrounding school systems, ecosystems, and political systems. At each level phenomena exhibit properties that do not exist at lower levels. Choosing strategies to affect those systems requires simultaneously addressing the multiple levels and recognizing which strategies are appropriate for different levels. For instance (see “Sustainability—A New Item on the Lunch Menu” in Part IV), the Center recognized that changing schools’ food systems required moving from working with individual schools to working at the district level and then to the larger educational and economic systems in which districts are nested.

Interdependence

The sustainability of individual populations and the sustainability of the entire ecosystem are interdependent. No individual organism can exist in isolation. Animals depend on the photosynthesis of plants for their energy needs; plants depend on the carbon dioxide produced by animals and on the nitrogen fixed by bacteria at their roots. Together, plants, animals, and microorganisms regulate the entire biosphere and maintain the conditions conducive to life.

Sustainability always involves a whole community. This is the profound lesson we need to learn from nature. The exchanges of energy and resources in an ecosystem are sustained by pervasive cooperation. Life did not take over the planet by combat but by cooperation, partnership, and networking. The Center for Ecoliteracy has supported schools such as Mary E. Silveira (see “Leadership and the Learning Community” in Part III) that recognize and celebrate interdependence.

The role of diversity is closely connected with systems’ network structures. A diverse ecosystem will be resilient because it contains many species with overlapping ecological functions that can partially replace one another. When a particular species is destroyed by a severe disturbance so that a link in the network is broken, a diverse community will be able to survive and reorganize itself because other links can at least partially fulfill the function of the destroyed species. The more complex the network’s patterns of interconnections are, the more resilient it will be.

On the other hand, in communities lacking diversity, such as monocrop agriculture devoted to a single species of corn or wheat, a pest to which that species is vulnerable can threaten the entire ecosystem.

In human communities ethnic and cultural diversity may play the same role as does biodiversity in an ecosystem. Diversity means many different relationships, many different approaches to the same problem. At the Center for Ecoliteracy, we have discovered that there is no “one-size-fits-all” sustainability curriculum. We encourage and support multiple approaches to any issue, with different people in different places adapting the teaching of principles of ecology to differing and changing situations.

Matter cycles continually through the web of life. Water, the oxygen in the air, and all the nutrients are continually recycled. Communities of organisms have evolved over billions of years, using and recycling the same molecules of minerals, water, and air. Mutual dependence is much more existential in ecosystems than in social systems because the members of an ecosystem actually eat one another. Ecologists recognized this from the very beginning of ecology. They focused on feeding relations and discovered the concept of the food chain that we still use today. But then they realized that those are not linear chains but cycles, because the bigger organisms are eaten eventually by the decomposer organisms, the insects and bacteria, and so matter cycles through an ecosystem. An ecosystem generates no waste. One species’ waste becomes another species’ food. As I noted in the preface, one reason for the Center’s enthusiasm for school gardens is the opportunity that gardens afford for even very young children to experience nature’s cycles.

The lesson for human communities is obvious. A conflict between economics and ecology arises because nature is cyclical, while industrial processes are linear. Businesses transform resources into products plus waste, and sell the products to consumers, who discard more waste after consuming the products. The ecological principle “waste equals food” means that— if an industrial system is to be sustainable—all manufactured products and materials, as well as the wastes generated in the manufacturing processes, must eventually provide nourishment for something new. In such a sustainable industrial system, the total outflow of each organization—its products and wastes—would be perceived and treated as resources cycling through the system.

All living systems, from organisms through ecosystems, are open systems. Solar energy, transformed into chemical energy by the photosynthesis of green plants, drives most ecological cycles, but energy itself does not cycle. As it is converted from one form of energy to another (for instance, as the chemical energy stored in petroleum is converted into mechanical energy to drive the pistons of an automobile), some of it—often much of it—inevitably flows out and is dispersed as heat. We are therefore dependent on a constant inflow of energy.

A sustainable society would use only as much energy as it could capture from the sun—by reducing its energy demands, using energy more efficiently, and capturing the flow of solar energy more effectively through solar heating, photovoltaic electricity, wind, hydropower, biomass, and other forms of energy that are renewable, efficient, and environmentally benign. Among the complex reasons that the Center for Ecoliteracy promotes farm-to-school food programs (see “Rethinking School Lunch” in Part IV) is that buying food grown close by reduces the unrenewable energy that is required to ship tons of food over thousands of miles to supply school lunches.

Development

All living systems develop, and all development invokes learning. During its development, an ecosystem passes through a series of successive stages, from a rapidly growing, changing, and expanding pioneer community to slower ecological cycles and a more stable fully exploited ecosystem. Each stage in this ecological succession represents a distinctive community in its own right.

At the species level, development and learning are manifested as the creative unfolding of life through evolution. In an ecosystem, evolution is not limited to the gradual adaptation of organisms to their environment, because the environment is itself a network of living organisms capable of adaptation and creativity.

Individuals and environment adapt to one another—they coevolve in an ongoing dance. Because development and coevolution are nonlinear, we can never fully predict or control how the processes that we start will turn out. Small changes can have profound effects. For instance, growing their own food in a school garden can open students to the delight of tasting fresh healthy food, which can create an opportunity to change school menus, which can create a systemwide market for fresh food, which can help sustain local family farms.

On the other hand, nonlinear processes can lead to unanticipated disasters, as occurred with DDT and the development of “superorganisms” resistant to antibiotics, and as some scientists fear could happen with genetic modification of organisms. A sustainable society will exercise caution about committing itself to practices with unknown outcomes. In “The Slow School” (in Part I), Maurice Holt describes the unforeseen consequences of schools’ wholesale commitment to standards-measurement techniques derived from manufacturing and industry.

Dynamic Balance

All ecological cycles act as feedback loops, so that the ecological community continually regulates and organizes itself. When one link in an ecological cycle is disturbed, the entire cycle brings the situation back into balance, and since environmental changes and disturbances happen all the time, ecological cycles continually fluctuate.

These ecological fluctuations take place between tolerance limits, so there is always the danger that the whole system will collapse when a fluctuation goes beyond those limits and the system can no longer compensate for it. The same is true of human communities. Lack of flexibility manifests itself as stress. Temporary stress is essential to life, but prolonged stress is harmful and destructive to the system. These considerations lead to the important realization that managing a social system—a company, a city, or an economy—means finding the optimal values for the system’s variables. Trying to maximize any single variable instead of optimizing it will invariably lead to the destruction of the system as a whole.

Every living system also occasionally encounters points of instability (in human terms, points of crisis or of confusion), out of which new structures, forms, and patterns spontaneously emerge. This spontaneous emergence of order is one of life’s hallmarks and is where we see that creativity is inherent in life at all levels.

One of the most valuable skills for utilizing ecological understanding is the ability to recognize when the time is right for the emergence of new forms and patterns. For example, out of frustration with the failure of piecemeal hunger intervention to have much long-term impact, “community food security” programs are emerging across the country. This movement addresses the overall systems—from energy and transportation to government commodities purchasing to the effect of media on children’s food preferences—that permit communities to meet (or prevent them from meeting) their needs for nutritious, safe, acceptable food.

It is no exaggeration to say that the survival of humanity will depend on our ability in the coming decades to understand these principles of ecology and to live accordingly. Nature demonstrates that sustainable systems are possible. The best of modern science is teaching us to recognize the processes by which these systems maintain themselves. It is up to us to learn to apply these principles and to create systems of education through which coming generations can learn the principles and learn to design societies that honor and complement them.

Excerpted from Ecological Literacy by Fritjof Capra, David Orr, Michael Stone and Zenobia Barlow.

Learn more from Fritjof Capra here. Explore more Bioneers content on environmental education here.

• The Spark of a Green Chemistry Education Grassroots Movement Ignites at Bioneers
• Climate Justice: Youth in the Vanguard
• Biochar: An Ancient Method of Healing Modern Soils

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Theoretical Ecology: Principles and Applications (3)

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Robert May's seminal book has played a central role in the development of ecological science. Originally published in 1976, this influential text has overseen the transition of ecology from an observational and descriptive subject to one with a solid conceptual core. Indeed, it is a testament to its influence that a great deal of the novel material presented in the earlier editions has now been incorporated into standard undergraduate textbooks. It is now a quarter of a century since the publication of the second edition, and a thorough revision is timely. Theoretical Ecology provides a succinct, up-to-date overview of the field set in the context of applications, thereby bridging the traditional division of theory and practice. It describes the recent advances in our understanding of how interacting populations of plants and animals change over time and space, in response to natural or human-created disturbance. In an integrated way, initial chapters give an account of the basic principles governing the structure, function, and temporal and spatial dynamics of populations and communities of plants and animals. Later chapters outline applications of these ideas to practical issues including fisheries, infectious diseases, tomorrow's food supplies, climate change, and conservation biology. Throughout the book, emphasis is placed on questions which as yet remain unanswered. The editors have invited the top scientists in the field to collaborate with the next generation of theoretical ecologists. The result is an accessible, advanced textbook suitable for senior undergraduate and graduate level students as well as researchers in the fields of ecology, mathematical biology, environmental and resources management. It will also be of interest to the general reader seeking a better understanding of a range of global environmental problems.

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Agroecological principles and elements and their implications for transitioning to sustainable food systems. A review

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• Volume 40 , article number  40 , ( 2020 )

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• Alexander Wezel   ORCID: orcid.org/0000-0001-5088-5087 1 ,
• Barbara Gemmill Herren 2 ,
• Rachel Bezner Kerr 3 ,
• Edmundo Barrios 4 ,
• André Luiz Rodrigues Gonçalves 5 &
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There is consensus that the global food system is not delivering good nutrition for all and is causing environmental degradation and loss of biodiversity, such that a profound transformation is needed to meet the challenges of persistent malnutrition and rural poverty, aggravated by the growing consequences of climate change. Agroecological approaches have gained prominence in scientific, agricultural and political discourse in recent years, suggesting pathways to transform agricultural and food systems that address these issues. Here we present an extensive literature review of concepts, definitions and principles of agroecology, and their historical evolution, considering the three manifestations of agroecology as a science, a set of practices and a social movement; and relate them to the recent dialogue establishing a set of ten iconic elements of agroecology that have emerged from a global multi-stakeholder consultation and synthesis process. Based on this, a consolidated list of principles is developed and discussed in the context of presenting transition pathways to more sustainable food systems. The major outcomes of this paper are as follows. (1) Definition of 13 consolidated agroecological principles: recycling; input reduction; soil health; animal health; biodiversity; synergy; economic diversification; co-creation of knowledge; social values and diets; fairness; connectivity; land and natural resource governance; participation. (2) Confirmation that these principles are well aligned and complementary to the 10 elements of agroecology developed by FAO but articulate requirements of soil and animal health more explicitly and distinguish between biodiversity and economic diversification. (3) Clarification that application of these generic principles can generate diverse pathways for incremental and transformational change towards more sustainable farming and food systems. (4) Identification of four key entry points associated with the elements: diversity; circular and solidarity economy; co-creation and sharing of knowledge; and, responsible governance to enable plausible pathways of transformative change towards sustainable agriculture and food systems.

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1 Introduction

There is consensus that the global food system is not delivering as needed on several key metrics, including rates of hunger and malnutrition, decent agricultural livelihoods and the environmental impact of agriculture (HLPE 2019 ). A profound transformation is needed at multiple scales to meet the interacting challenges of increased pressure and competition over renewable resources, persistent malnutrition, rural poverty, increased power and concentration of agricultural and food industries, growing consequences of climatic change and alarming losses of biodiversity (FAO 2018a ; IPBES 2019 ; IPCC 2019 ). While there is strong evidence that a major transformation in what food is consumed and how it is produced, processed, transported and distributed is needed to meet Sustainable Development Goal 2 (SDG2) to ‘end hunger and all forms of malnutrition’ by 2030, there has been less agreement on how to achieve this change (HLPE 2019 ). Five years ago, a major consensus building process came to fruition with international agreement on a set of 17 Sustainable Development Goals (SDGs) and 169 targets to guide an integrated plan of action applicable to all developed and developing countries (UN 2015 ). With respect to SDG2, sustainability in agriculture was identified as a priority, integral to addressing the grand challenge of attaining food security and healthy nutrition for all. This consensus acknowledges the need to address aspects that go well beyond a simple metric of productivity, embracing environmental and socially progressive outcomes (Caron et al. 2018 ; Pretty et al. 2018 ; Tittonell 2014 ). Tackling transitions to sustainable food and agricultural systems thus requires a long-term perspective and holistic approaches of the kind embodied in agroecological approaches that are increasingly recognised as having potential to facilitate the transformative change in agriculture required to meet the SDGs (FAO 2019 ).

Agroecology is a dynamic concept that has gained prominence in scientific, agricultural and political discourse in recent years (IAASTD 2009 ; IPES-Food 2016 ), with the United Nations (UN) Special Rapporteur on the Right to Food highlighting agroecology as a viable approach to progress towards global food security and nutrition (De Schutter 2010 ). In September 2014, the Food and Agriculture Organization of the UN (FAO) organised an International Symposium on Agroecology for Food Security and Nutrition, followed in 2015 by three regional meetings in Latin America, Africa and Asia (FAO 2015a , b , 2016 ), a further three regional meetings in 2016 in Latin America, China and Europe, and the most recent in 2017 in North Africa (FAO 2018b ). A second International Symposium was convened by FAO in April 2018 entitled Agroecology: Scaling Up Agroecology to achieve the Sustainable Development Goals (FAO 2018c ).

Although much more visible in the last 20 years, agroecology has a long history (Wezel and Soldat 2009 ). Since the first use of the term in the early twentieth century, its meanings, definitions, interpretations and approaches have evolved. Recently, there has been a proliferation of definitions of agroecology as different institutions and countries define it in ways that reflect their concerns and priorities. These definitions recognise the transdisciplinary nature of an agroecological approach which embraces science, a set of practices and a social movement (Agroecology Europe 2017 ; Méndez et al. 2013 ; Wezel et al. 2009 ) and the application of the concept to whole agri-food systems from food production through to consumption and all that goes on in between (Francis et al. 2003 ).

As a science, commonly used definitions are as follows: (i) the integrative study of the ecology of the entire food system, encompassing ecological, economic and social dimensions (Francis et al. 2003 ) or in brief, the ecology of the food system, (ii) the application of ecological concepts and principles to the design and management of sustainable food systems (Gliessman 2007 ); and more recently (iii) the integration of research, education, action and change that brings sustainability to all parts of the food system: ecological, economic and social (Gliessman 2018 ).

As a set of agricultural practices, agroecology seeks ways to improve agricultural systems by harnessing natural processes, creating beneficial biological interactions and synergies amongst the components of agroecosystems (Gliessman 1990 ), minimizing synthetic and toxic external inputs and using ecological processes and ecosystem services for the development and implementation of agricultural practices (Wezel et al. 2014 ) (Fig.  1 ).

Agroecological practices and production systems. Diversity-rich garden production in central Kenya (left—Photo A. Wezel); Multipurpose legume intercrops (pigeonpea and groundnut) next to maize fields in Malawi (right—Photo R. Bezner Kerr)

Social movements propose agroecology as a solution to modern crises such as climate change and malnutrition, contrasting with the dominant industrial agricultural model based on the use of external inputs. The aim is to transform agriculture to build locally relevant food systems that strengthen the economic viability of rural areas based on short marketing chains, and both fair and safe food production. This involves supporting diverse forms of smallholder food production and family farming, farmers and rural communities, food sovereignty, local knowledge, social justice, local identity and culture, and indigenous rights for seeds and breeds (Altieri and Toledo 2011 ; Nyéléni 2015 ; Rosset et al. 2011 ) (Fig.  2 ). This political dimension of agroecology is becoming increasingly prominent (Gonzalez de Molina 2013 ; Toledo and Barrera-Bassols 2017 ). In this respect, there has been significant debate in recent years regarding how to define, interpret and pursue agroecology, with civil society voices linking agroecology to food sovereignty while often member state representatives have a contrasting position of agroecology as compatible with their view of sustainable intensification focused on approaches to increase production per unit of land to achieve food security.

Market situation with locally produced and marketed products. Clockwise: Organic street market in Porto Alegre, Rio Grande do Sul, Brazil, showing with diversity of products and based on short commercialisation circuit (photo K. Höök); Traditional and locally marketed dairy products in eastern Uzbekistan (photo A. Wezel); Locally produced vegetable and fruits in southern France (photo A. Wezel)

Although the explicit definitions stated above reflect articulations in line with the three constituent manifestations of agroecology: a science, a set of practices and a social movement, there are interlinkages between and a co-evolution amongst these manifestations that together constitute a holistic approach (Agroecology Europe 2017 ; Gliessman 2018 ). This concurs with agroecology being increasingly described as a transdisciplinary, participatory and action-oriented approach (Méndez et al. 2013 ; Gliessman 2018 ) across ecological, agricultural, food, nutritional and social sciences.

2 Methods and processes to define principles

The results presented here are based on consolidating outcomes from two initiatives. The first was carried out under the auspices of FAO to define and document a set of constituent elements of agroecology that can serve to frame and structure FAO Member Countries’ engagement with this area of work (FAO 2018c ). The second involved an extensive literature review related to the concepts, definitions and principles of agroecology considering the three manifestations of agroecology as a science, a set of practices and a social movement.

Principles of agroecology were analysed in terms of their historical evolution from the beginning of the nineteenth century up to the present time. Based on this, a consolidated set of principles was developed through a three-stage iterative process involving their selection (from the literature), articulation (in line with a defined notion of what constitutes a principle) and combination (to arrive at the smallest set of non-repetitious principles that captured what was articulated in the literature). This was done in the framework of the preparation of the High Level Panel of Experts (HLPE) report for the Committee on World Food Security (CFS) on ‘Agroecological and other innovative approaches for sustainable agriculture and food systems that enhance food security and nutrition’ (HLPE 2019 ). This review process of principles involved an open electronic consultation on an initial draft and peer review of the resulting revision. The two parallel processes (FAO and HLPE), rather than competing with each other, have informed one another, having somewhat different aims, in that the HLPE report developed the scientific basis for a set of recommendations to policy-makers, while the elements of FAO are designed to structure and operationalise the assistance that FAO provides to Member Countries on agroecology, from practice to policy.

It has also to be noted that the authors of this article participated in either one or both of the FAO and HLPE processes and through this gained understanding of the issues and insights that have contributed to this article.

The HLPE report was intended to inform policy discussions and increase understanding of the ways in which agroecology can be used by civil society, governments, the private sector and other groups to address global food security and nutrition through developing sustainable food systems. To synthesise the wide range of different publications that articulate an increasing number of principles, the HLPE project team consolidated existing literature on agroecological principles into a parsimonious list of 13 statements. The consolidation mainly involved reducing the number of principles from four major sources (CIDSE 2018 ; Dumont et al. 2016 ; FAO 2018d ; Nicholls et al. 2016 ) to a minimum, non-repetitive list by combining and reformulating them to conform to the notion of a principle as an explicit normative or causative statement that can be used to guide decision-making, action or behaviour (Patton 2018 ).

The 10 elements of agroecology, on the other hand, resulted from a multi-stakeholder consultation process intended to build a framework to be optimised and adapted to local contexts (Barrios et al. 2020 ). It was developed between 2015 and 2019 through a process involving three main phases:

Information gathering: An analysis was undertaken to combine the fundamental scientific literature on agroecology that includes the five principles of agroecology (Altieri 1995 ) and the five levels of agroecological transition (Gliessman 2015 ) enriched by articulation of elements in the presentations within the First International Symposium on Agroecology for Food Security and Nutrition (FAO 2015a ) and the seven FAO multi-stakeholder regional and international meetings on agroecology conducted between 2015 and 2017 (see FAO 2018b for a summary of these meetings). More than 1400 participants representing 170 Member Countries and nearly 500 organisations working at local, national, regional and international levels were involved in these meetings. The selection of funded meeting participants sought to balance and diversify stakeholder representation in terms of gender and nationality.

Synthesis: Led by FAO experts from diverse disciplinary backgrounds with contributions from invited external agroecologists, a synthesis exercise was carried out that identified common elements from the information gathering phase and to cluster them. An initial coherent structure with fives elements emerged as central ecological features of agroecology (Tittonell 2015 ). In addition to these features, regional meetings expressed strong calls for reinforcing social and political aspects of agroecology. Thus, an additional five elements were added.

Approval by FAO: The 10 Elements of Agroecology framework (FAO 2018d ) was launched at the Second FAO International Symposium on Agroecology held in April 2018 (FAO 2018c ). In December 2019, following a review, revision and clearance process through FAO’s governing bodies, the 10 Elements of Agroecology were approved by the 197 Members of the Food and Agriculture Organization of the United Nations to guide FAO’s vision on Agroecology (FAO 2019 ).

On the basis of this process and consultation, FAO made a deliberate decision not to attempt to define the principles of agroecology, which they considered had been done by many knowledgeable practitioners, but rather to identify a set of salient ‘elements’ that can guide intergovernmental work in support of agroecological transitions towards sustainable agriculture and food systems.

3 Evolution of principles of agroecology

During its historical evolution, agroecology has expanded from the field, farm and agroecosystem scale to encompass, since the 2000s, the whole food system (Fig.  3 ) (Wezel et al. 2009 ). A broadening of topics covered along with the different manifestations of agroecology (science, practice and social movements) occurred over the decades and was reflected in an increasing number and diversity of principles.

Historical evolution of agroecology and its principles. a Disciplinary basis of principles articulated within agroecology. b Scales (adapted from Wezel et al. 2009 ). c Aspects, showing the emergence of the three manifestations of agroecology (science, practice and social movement) with key topics and the nature and scope of research (adapted from Silici 2014 , based on Wezel et al. 2009 and Wezel and Soldat 2009 ). Note that indigenous knowledge and practice predate the 1980s as well as older forms of indigenous agroecology that existed prior to the formal sciences

Several different sets of agroecological principles can be found in the scientific literature—Reijntjes et al. ( 1992 ), Altieri ( 1995 ), Altieri and Nicolls ( 2005 ), Stassart et al. ( 2012 ), Dumont et al. ( 2013 ), Nicholls et al. ( 2016 )—that are summarised in Migliorini and Wezel et al. ( 2018 ), and more recently by CIDSE ( 2018 ), FAO ( 2018d ) and INKOTA ( 2019 ). The latter two speak about elements of agroecology as guiding the practical implementation of agroecology. These different principles contain both normative aspects that assert values (e.g. food systems should be equitable) and causative aspects, as in scientific usage, that explain relationships (e.g. more biodiverse agricultural systems are likely to be more resilient), and are applied at different scales (e.g. field, farm, landscape or whole food system) or to different dimensions of food systems such as production or governance (HLPE 2019 ). Today, agroecology is associated with a set of principles for agricultural and ecological management of agri-food systems as well as some wider ranging socio-economic, cultural and political principles. These latter principles have emerged only recently in the literature, arising from the activity of social movements which use agroecology as a key foundation of their work (Fig. 3a ).

It is argued by many that so-called industrial agricultural systems require systemic change to become sustainable and to address food security and nutrition (FSN), and that simply implementing some practices and changing some technologies are not sufficient, rather the application of agroecological principles and a redesign of farming systems is required (IPES-Food 2016 ; Nicholls et al. 2016 ). Some of these principles refer more specifically to the promotion of ecological processes and services including soil, water, air and biodiversity aspects (Nicholls et al. 2016 ). They include the following: (i) recycling of biomass; (ii) enhancement of functional biodiversity; (iii) provision of favourable soil conditions for plant growth; (iv) minimisation of losses; (v) diversification of species and genetic resources in the agroecosystem; and (vi) enhancement of beneficial biological interactions and synergies. The principles of Nicholls et al. ( 2016 ) are based on five principles previously articulated by Reijntjes et al. ( 1992 ) in relation to low-external-input and sustainable agriculture. For agroecological practices involving animals, Dumont et al. ( 2013 ) added other more specific animal production principles of (i) adopting management practices aiming to improve animal health and (ii) enhancing diversity within animal production systems to strengthen their resilience. Peeters and Wezel ( 2017 ) defined agroecological principles specifically for grass-based farming systems. Stassart et al. ( 2012 ) and Dumont et al. ( 2016 ) added further socio-economic principles for agroecology relating to social equity, democratic governance, creating collective knowledge, financial independence, market access and autonomy, and diversity of knowledge and experience.

CIDSE (Coopération Internationale pour le Développement et la Solidarité) ( 2018 ) also developed, together with different civil society organisations, a set of principles of agroecology. They grouped the different principles into four categories: environmental, socio-cultural, economic and political. Some of these principles refer to the demand and visions of many civil society organisations and their quest to support smallholder and family farming and sustainable livelihoods in the Global South with fair production and market conditions. Similarly, the network of INKOTA (Information, Koordination, Tagungen) (2019) defined 10 co-equal elements to best exploit the potential of agroecology which highlighted elements related to rights, participation, control over livelihoods and voice in decision-making.

FAO ( 2018d ) first described the 10 elements of agroecology which are diversity, co-creation of knowledge, synergies, efficiency, recycling, resilience, human and social values, culture and food traditions, responsible governance, and circular and solidarity economy (for more details see Barrios et al. 2020 ).

In the interest of bringing these many perspectives on agroecology principles to a confluence, the HLPE ( 2019 ) report synthesised the wide range of different publications that articulate an increasing number of principles, existing statements of principles and elements, and consolidated them into a list of 13 principles (Table 1 ) which comprise both normative and causative statements.

All principles correspond to one or more of the FAO elements (Table 1 ). All of the FAO elements correspond to principles, while resilience has additional attributes as an expected outcome in terms of system performance from the application of the principles, rather than being a principle itself. The principles are explicit about ensuring soil and animal health whereas these aspects are embedded in the elaboration around several elements and the principles distinguish biodiversity and economic diversification that are conflated in the single element of diversity. Whereas the consolidated principles are articulated as actionable statements containing normative (e.g. ensure animal health and welfare) and causative (e.g. greater participation in decision-making supports decentralised governance and local adaptive management) aspects, the FAO elements are different in nature from one another. For example, the elements resilience and efficiency are measurable system properties or outcomes, whereas the elements responsible governance as well as circular and solidarity economy relate to how food systems should be governed and improved. Efficiency is a broad concept relating outputs to inputs, so that many different efficiencies can be envisaged and in agriculture, increasing one efficiency ratio such as yield per unit of land or labour has often been associated with reduction in other efficiencies such as yield per unit of fossil fuel input or biodiversity loss (Sinclair 2017 ). A key feature of the consolidated principles is that while they are generically formulated, in practice, they are locally applied, generating a diversity of agroecological practice suited to local circumstances (Sinclair et al. 2019 ). In this regard, co-creation of knowledge, embracing equitable involvement of a range of stakeholders and especially the local knowledge of farmers in developing locally adapted practice, is central to both the set of consolidated principles and the FAO elements and a key tenet of transdisciplinary science in an agricultural context (Sinclair and Coe 2019 ).

4 Principles related to food security and nutrition

An important question for sustainable development based on agroecology, particularly in countries of the Global South, is how the agroecological principles relate to FSN. If they are applied, six out of the 13 (2, 5, 7, 10, 11, 13) could be expected to make a direct contribution to FSN, whereas for seven (1, 3, 4, 6, 8, 9, 12), impacts would be less direct. For example, reducing the dependency on purchased inputs (2) can reduce food insecurity especially for small-scale food producers. This is because less money is spent on buying inputs and so there is less reliance on credit, and therefore, potentially more resources to buy food (Hwang et al. 2016 ; Kangmennaang et al. 2017 ; Snapp et al. 2010 ) although potential trade-offs might exist, since depending on quantity and type of inputs, crop yields could be affected negatively, and thus increase food insecurity. Alternatively, some agroecological practices could involve more labour that if disproportionately done by women could worsen children’s nutritional status unless gender relations within households were appropriately addressed (Bezner Kerr et al. 2019a ). Higher labour requirements could also mean increased employment opportunities both in agriculture and agri-food businesses, as one review found for diversified farming systems (Garibaldi and Pérez-Méndez 2019 ). These trade-offs need to be considered in the specific food system context that they occur. An important positive impact on FSN can be expected through applying the principle of economic diversification (7) with higher diversity of on-farm incomes to ensure greater financial independence and more resilience to price volatility (Kanmennang et al. 2017 ). Application of the social values and dietary principle (9) impact nutrition directly, supported by maintaining and enhancing biodiversity (5) on fields and farms (Bellon et al. 2016 ; Bezner Kerr et al. 2019b ; Demeke et al. 2017 ; Jones et al. 2014 ; Lachat et al. 2018 ; Powell et al. 2015 ).

A just food system (Pimbert and Lemke 2018 ) addresses wages and working conditions within it (principle 10—fairness) creating a direct link to FSN. Improved livelihoods for farm labourers, producers, small-scale distributors, market intermediaries, entrepreneurs and processors may enable them to achieve higher incomes and, therefore, purchase food. Increased proximity of producers and consumers and re-embedded local food systems (principle 11—connectivity) may contribute to improving local economies. For example, producers can profit from getting a higher share of revenue if less is taken by intermediaries over a long supply chain for marketing and distribution of produce. Also, local food enterprises and retailers can increase their price margins and become better linked and known to local consumers. Local food efforts that do not, however, address systemic issues of low wages and incomes, often linked to other issues such as systemic racism, can also reinforce and widen inequities in access to fresh, local food (Alkon and Agyeman 2011 ). An important point here is that producers can respond more effectively to the food needs and demand of local consumers, but addressing questions of fairness is critical. This latter point is strongly supported by social organisations which foster greater participation and decision-making (or agency) of food producers and consumers (principle 13—participation).

The other seven principles are more indirectly linked to FSN. For instance, principles 1 (recycling), 3 (soil health) and 4 (animal health) support optimizing and securing agricultural production and therefore also potentially food security. While critically relevant to food security, particularly in regions with low agricultural yields, recent research documents that they are not sufficient on their own. These studies have noted that for agroecology to significantly impact food security and nutrition and generate sustainable diets, power inequalities must be addressed within food systems at multiple scales (Bezner Kerr et al. 2019a , b ; Mier y Teran Gimenez Cacho et al. 2018 ; Pimbert and Lemke 2018 ). In this respect, horizontal sharing and co-creation of knowledge (principle 8—co-creation of knowledge) are important (Bezner Kerr et al. 2018 ; Mier y Teran Gimenez Cacho et al. 2018 ).

5 Transitions to more sustainable food systems

A sustainable transition occurs where there is fundamental change in a system both temporally (over a period of time) and spatially (occurring in a specific territorial location) (Marsden 2013 ). Transitions include political, socio-cultural, economic, environmental and technological shifts in rules, practices, institutions and values, leading to more sustainable modes of production and consumption (Marsden 2013 ; Pitt and Jones 2016 ). To examine sustainable transitions, a multi-level perspective has been used, to consider how dynamic processes and interactions across scales can support whole-system transformative change (Geels 2010 ; Smith et al. 2010 ), but also what issues of power relations drive changes or establish ‘lock-ins’ (IPES-Food 2018 ; Leach et al. 2020 ). Some transitions begin at a small scale, a ‘niche’ or protected space in which farmer cooperatives, social movements, businesses, local government or other groups experiment with and adapt alternative ways of doing things (Geels 2010 ; Hinrichs 2014 ). These small-scale changes may foster alternative models of food systems which are either marginalised, get absorbed by, or challenge, the dominant system (Brunori et al. 2011 ; Elzen et al. 2017 ; Levidow et al. 2014 ). The HLPE report ( 2019 ) found that to effectively address food security and nutrition, discrete techniques or innovations and incremental interventions are not sufficient to bring about the food system transformations that are needed. The report finds that innovation for sustainable food systems requires (i) inclusive and participatory forms of innovation governance; (ii) information and knowledge co-production and sharing amongst communities and networks; and (iii) responsible innovation that steers innovation towards social issues. Examples of collaborative efforts to initiate transformative change include democratically designed ‘innovation platforms’, where stakeholders are brought together to coordinate amongst themselves the development of technical, social and institutional innovations (Tittonell et al. 2016 ). Food retail, consumption and production practices can be shifted over time through a dynamic interaction between innovations in food production, enterprises, social movement advocacy, policy and cultural change (Hinrichs 2014 ; Spaargaren 2011 ). There are clear challenges in making and keeping such processes inclusive—given that they are at the nexus of power imbalances between innovators and those guarding the stability of an existing system. In addition, social and political institutions can create pathways or ‘lock-ins’ which prevent transitions from occurring (IPES 2016 , 2018 ; Smith and Stirling 2010 ).

The transition pathway framework of Gliessman ( 2007 , 2016 ) comprises five different levels (Fig.  4 ). In this framework, assuming transition from an industrial or green revolution form of agriculture towards more sustainable food systems, agroecological transition pathways often begin with a major underlying focus on resource use efficiency. Agroecology addresses resource use efficiency through practices that reduce or eliminate the use of costly, scarce, or environmentally damaging inputs, thus related primarily to the principle of input reduction, but also recycling. At the second level of transition, substitution of conventional inputs that have negative impacts on the environment is envisaged, replacing them by making use of co-existing biota (such as the plant microbiome or natural enemies of pests) to improve plant nutrient uptake, stress tolerance and defences against pests and diseases (Singh et al. 2018 ). Whereas levels 1 and 2 are incremental, levels 3 to 5 are transformational. Level 3 is based on the redesign of farming systems to increase system diversity, improve soil and animal health, enhance diversification and recycling, reduce inputs, and increase synergies on farms and across landscapes. An example is the enhancement of diversity in farm structure and management with diversified rotations, multiple cropping, agroforestry and the (re-)integration of animals and crops. There is a strong focus on managing interactions amongst components, for example through the strategic use of crop residues as mulch or animal feed. Transition levels 4 and 5 broaden the focus to encompass the whole food system. Level 4 establishes a close relationship between people who grow the food and the people who eat it. Pathways are the development of direct sales and new alternative food networks, from farmers’ markets, to community supported agriculture, to other direct marketing arrangements that aim to be fairer and more just. Finally, level 5 involves building a new global food system that is not only sustainable but also helps restore and protect Earth’s life-support systems. This food system is based on participation, localness, fairness and justice, which are important human rights ‘building blocks’ of food security and nutrition (HLPE 2019 ).

Transition levels towards sustainable food systems and related consolidated principles of agroecology. The ovals on the right correspond to the agroecological principles from Table 1 . Principles 1–7 (lower right hand side) relate primarily to the agroecosystem scale whereas 9–13 (upper right hand side) to the food system with co-creation of knowledge central across scales. Note: Levels adapted from Gliessman ( 2007 ). Levels 1 and 2 are incremental, levels 3–5 transformational. Arrows show major influences amongst principles

Through the transition levels towards sustainable food systems, agroecology presents multiple pathways for the transformation of farming and food systems co-created to suit different local contexts, based on a social-ecological systems approach (see also Elzen et al. 2017 ; IPES-Food 2016 ). To move forward with these transitions, many factors, parameters and issues must be considered as there is a diversity of situations, with multiple pathways of agroecological transition towards more sustainable food systems, depending of the starting points, the context and the engagement with markets. The role of civil society, social movements and consumer organisations is critical to ensure transitions. Social movements such as La Vía Campesina at the global scale, and national members such as the Brazilian Landless Workers Movement (MST), are important actors contributing to debates around transition to sustainable food systems, with their varyingly political, civil societies’ and peasants’ views on agroecology as a means to distinguish their practices and vision for food system transformation from those that are supported by agri-food corporations and more mainstream institutions (Giraldo and Rosset 2018 ). These social movement actors have played a crucial role in raising the political dimensions of agroecology, providing alternative models for food systems and emphasizing the need for more systemic changes to occur, such as through grassroots farmer-to-farmer networks (Val et al. 2019 ).

The strong involvement of policy- and decision-makers at local, regional, national and supra-national levels, as well as farmer organisations, supply chain actors and agro-industry is required to facilitate an agroecological transition (IPES-Food 2018 ). The interaction and synergies between context-specific, local knowledge and academic science as well as social and institutional innovation all play a critical role in catalysing and supporting an ‘epistemic’ transition (Elzen et al. 2017 ). This includes creating stronger markets for agroecologically grown foods, developing social solidarity economies, pushing for agroecological procurement by institutions, shifting public awareness and developing inclusive governance mechanisms that support an agroecological transition. One study of how to transition Europe to agroecological systems in 10 years, for example, focused the initial transition discussion on reducing pesticides, supporting diversification of landscapes and shifting diets towards more fruits and vegetables and lowering meat consumption (Poux and Aubert 2018 ). In contrast, Brazilian social movements supporting agroecological transitions have focused on land access and developing local and fair agroecology markets with participatory guarantee systems, while in Senegal, agroecological transitions have focused on the formation of ecovillages and soil management (Ilieva and Hernandez 2018 ).

One of the major challenges to transformative change in agriculture is the difficulty of designing differentiated paths for food and agricultural systems transformation that respond to local and national expectations (Caron et al. 2018 ). In addition to the five levels described above, the FAO agroecology framework recognises all 10 elements as potential entry points for transformative change towards sustainable food and agricultural systems and the facilitative role of visual narratives and nexus analysis (Barrios et al. 2020 ). Four key entry points are identified in Fig.  5 in clock-wise direction and short narratives used to describe plausible transition pathways. First, the Diversity entry point: diversification is central to facing climate change as well as nutrition challenges because variations in agricultural use and management of plant and animal diversity can have important impacts on the adaptive capacity of agricultural systems to climate change as well as on their contribution to nutritious and healthy diets.

Four key entry points in FAO’s 10 elements of agroecology framework to build transformative change pathways towards sustainable food and agricultural systems (Adapted from FAO 2018d )

Second, Circular and Solidarity Economy : changing food consumption patterns can have major impact on markets at different scales. The increasing demand for diversified, nutritious and safer food by consumers would support cleaner production, shorter-value chains, diversified markets and green jobs. These changes would require changes in the supply side through diversified agricultural systems that, in addition to contributing a broader range of products, reduce the need for external inputs as a result of greater resource use efficiency. Third, the Co-creation and Sharing of Knowledge entry point: promoting educational curricula at all levels to support agroecological transitions is fundamental to raise awareness and to encourage improvements in linking knowledge to action. This involves the development of capacities for holistic or systems thinking to face the increasing complexities of an interconnected world where disciplinary or sectoral approaches have had limited success. Fourth, the Responsible Governance entry point: transparent, accountable and inclusive governance mechanisms are necessary to create an enabling environment that supports producers to transform their systems following agroecological concepts, principles and practices. By fostering market-systems that allow for small and medium scale food enterprises, responsible governance also supports local and regional food systems. Furthermore, the transformative impact of multiple entry points can be greater through the promotion of concurrent transitions taking place via different entry points in the same territory adapted to contextual variations across the territory.

6 Conclusions

Agroecological principles have evolved in recent years to encompass social and cultural aspects of whole food systems in addition to those related to agricultural practice at field, farm and landscape scales. A consolidated set of 13 principles constructed from the literature on agroecology as manifest as a science, a set of practices and a social movement (HLPE 2019 ) were found to be well aligned and complementary to the 10 elements of agroecology developed by FAO. The principles, while generically formulated are locally applied, generating diverse, locally adapted agroecological practice through co-creation of knowledge with stakeholders. The principles are relevant both to transitioning agricultural and food systems to achieving global food and nutrition security and to building resilience of agriculture by adapting to climate change.

A further question is the implication for having this enlarged number of agroecology principles on future research. Currently, much of the research carried out related to agroecology focuses more on the first five principles and the first two food systems transformation levels of ‘increased efficiency’ and ‘substitution’ (e.g. for Europe see Wezel et al. ( 2018 ). To fully embrace the systems approach and a holistic view, future agroecology research needs to include much more interdisciplinary and transdisciplinary work and consider multiple entry-points and transition trajectories, in particular including social, cultural, political and economic issues. The core principle of co-creation of knowledge requires a very different approach to research: one that places farmers and stakeholders at the centre of defining research questions and developing solutions alongside scientists. Furthermore, to transition to a just and inclusive food system will require changes in economic policies that support local and regional food systems, raising questions of how to address power dynamics in order to shift the dominant narrative (Anderson et al. 2020 ). The social and political principles of participation, fairness, connectivity and land and natural resource governance all highlight the need for research and advocacy related to these changes, required for a true transformation of food systems to be resilient, equitable and sustainable.

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Acknowledgements

We thank Mary Ann Augustin, Dilfuza Egamberdieva, Oluwole Abiodun Fatunbi, Abid Hussain, Florence Mtambanengwe and Nathanael Pingault for their support, inputs and constructive discussion for developing the 13 principles of agroecology. We are grateful to the CFS (Committee on World Food Security) and the CGIAR Research Programme on Forests, Trees and Agroforestry for supporting the work as well as the McKnight Foundation for supporting the development of the FAO’s 10 elements of agroecology framework.

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Barbara Gemmill Herren

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Rachel Bezner Kerr

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Edmundo Barrios

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Wezel, A., Herren, B.G., Kerr, R.B. et al. Agroecological principles and elements and their implications for transitioning to sustainable food systems. A review. Agron. Sustain. Dev. 40 , 40 (2020). https://doi.org/10.1007/s13593-020-00646-z

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Home — Essay Samples — Environment — Natural Environment — Analysis Of What Ecology Is

Analysis of What Ecology is

• Categories: Natural Environment

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Words: 447 |

Published: Feb 12, 2019

Words: 447 | Page: 1 | 3 min read

Works Cited

• Odum, E. P. (2020). Fundamentals of Ecology. Cengage Learning.
• Begon, M., Townsend, C. R., & Harper, J. L. (2006). Ecology: From individuals to ecosystems. Wiley.
• Smith, R. L., & Smith, T. M. (2014). Elements of ecology. Pearson.
• Pimm, S. L. (2001). The world according to Pimm: a scientist audits the earth. McGraw-Hill.
• Krebs, C. J. (2019). Ecology: The experimental analysis of distribution and abundance. Pearson.
• Ricklefs, R. E., & Miller, G. L. (2000). Ecology. Macmillan.
• Gurevitch, J., Scheiner, S. M., & Fox, G. A. (2006). The ecology of plants. Sinauer Associates.
• Keddy, P. A. (2007). Plants and vegetation: Origins, processes, consequences. Cambridge University Press.
• Turner, M. G. (2019). Landscape ecology in theory and practice: Pattern and process. Springer.
• Levin, S. A. (1992). The problem of pattern and scale in ecology: The Robert H. MacArthur Award lecture. Ecology, 73(6), 1943-1967.

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Essay On Principles Of Ecology

Type of paper: Essay

Topic: Education , Environment , Discipline , Study , Ecology , Population , Life , World

Words: 1400

Published: 01/30/2020

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Ecology is the scientific discipline that brings together facets of other disciplines. It is the study of organisms and their environment and the relationship between the two. In this it overlaps into disciplines such as environmental science and biology among others. R. J. Putman and S. D. Wratten in their book “Principles of Ecology” note that ecology as a term has taken on a number of meanings. “Human ecology” is sometimes used as a political term to describe an individual’s relationship to a society. As the earth is a varied places of numerous and changing environments that hosts millions of diverse and evolving species, it is a field that always has much to learn. This essay endeavors to explore the basic tenets or principles of ecology. Ecology is closely related to environmental studies. There are plenty of diversity even within the discipline. From statistical ecologists, marine ecologists, environmental ecologists, and many other subjects share or borrow terms with ecology. What is interesting is what differentiates them as their own paths of study. It is a matter of focus. Ecology is concerned with a number of factors that environmental studies does not. Ecologists put their focus on studying (general) a particular population within a particular area, and environmental studies is more concerned with the area. Further, this will be elaborated with more detail. Putman and Wratten’s work does a good job of providing uniform, textbook definitions within the science of Ecology. According to them there are five basic things that an Ecologist concerns him/herself with. These are “1) explaining different life processes and understanding these lead to adaption to an environment. 2) Distribution of organism, 3) the movement of material and energy through living communities 4) the successional development of ecosystems and 5) the abundance and distribution of biodiversity.” (Putman, Wratten, 1984). “The Environment” is a fluid concept. Broadly speaking it can mean a very large area. It could also be an area as small as beneath a stone. Generally geographical areas are differentiated through a set of “physicochemical characteristics such as soil composition, climate, and mineral deposit in the area. (Putman, Wratten 1984). The “biosphere” is a way of viewing the earth as one single environment. Or it could be called the sum of all environments. It is not the entire earth, but the parts of the earth that are livable. This includes mountains with bacteria living beneath the snow and warm jets of underwater springs miles below the surface of the ocean where species have found their “niche” and managed to survive despite harsh conditions. There are two factors to consider when talking about the environment: Abiotic and biotic. Abiotic are non-living components to an environment and biotic is the opposite, the living organisms inhabiting a place. Much work is done on the study of macro and micro environments and their effect upon organisms living in them. Brian A. Mauer, James H. Brown and Renee D. Rustler have collaborated on research in evolutionary biology with strong ecological connection regarding how a particular macro-environment contributes the evolution of body size in a population. (Mauer, Brown, Rustler, 1990). Distribution of the organism likewise is an important consideration for any Ecologist studying the patterns of behavior and place within an environment of a species. Ecologists are equally concerned with diversity, or difference between members of a same group, which often times relates to distribution. I,e., members of the same species living remote from other populations tend to develop differently due to their distribution. Terms that are related to population distribution are population growth, life history and population dynamics. Population growth Population growth can be either positive or negative. Meaning, a population could be increasing (a positive growth) or it could even be decreasing (a negative growth). This is the term that ecologists calculate in order to make predictions about future populations. A good illustrating example of these terms in action can be achieved by analyzing an ecological study conducted by Gerald S. Wilkinson and Jason M. South, both researchers from The University of Maryland. The study is called “Life history, ecology and longevity in bats.” The study’s goal was to explain the phenomenon that bats have been observed to live up to three times as long as other similar non-flying mammals. The biological paper looked at a number of ecological factors, “we selected six life history and ecological factors to use in a comparative analysis of longevity among 64 bat species.” (Wilkison, South 2002). The study looked at five individual life histories for bat that had been known to be outliers in the data and live to thirty years. It compared this against known data. The life histories are not scientific like math is, but they give a good specific example of at least one member of a particular species. It then cross-referenced scientifically the average lifespan of bats that with species of non-flying mammals of similar size in order to have a standard of comparison. Ecological study of these other species provided the study with the numbers with which to run the math. The third principle as set by Putman and Wratten is “the movement of material and energy through living communities.” Movements of energy throughout an environment are crucial in understanding what conditions species within the environment are subject to. Energy is transferred to an environment in both gradual and dramatic, sometimes catastrophic ways. A slow natural process that brings energies to an environment is sunlight, which to different degrees touches almost every ecosystem on earth. An exception are certain species of micro organisms who survives of underwater ocean springs. Water, a resource in a community, is also a source of energy at times. If that water, for instance, was falling from a waterfall. There are also wind, fire; or the potential for a fire, amongst others. Ecological succession, the forth pillar established by Putman and Wratten, They write, “Communities shift and alter in composition even when in equilibrium.” This change, that effects the entire population community and results from the general pattern within the species is known as Ecological Succession. The final principle of ecology explored in this essay is the abundance and distribution of biodiversity. Abundance relates to amount of species, the density of their distributions and ecologists arrive at conclusions using this and other factors to determine the relative health of a species. The title of David Hamilton Wright from University of Georgia illustrates how this terminology is used within the discipline. His study, “Correlations between incidence and abundance are expected by chance” explored the relationship between distribution and abundance of species. This illuminates one sub-discipline within ecology, statistical ecology, in which uses math and data gathered by field ecologists and compiles it to make both deductive and inductive conclusions. Ecology is a growing discipline. Only since the middle part of the 20th century did it gane prominence and then respect as an important branch of biology. The reason for this is not difficult to intuit. As we grow in knowledge and awareness as a species on one planet in a large universe, we realize more that life exists in a delicate balance that has evolved over millions of years. Disrupting this balance creates grave problems for other species and for our own. The concept of extinction that a species can simply cease to exist has only become understood recently. A great illustration of this is the Dodo bird. Human arrived on an island where they had not learned to fear man, and then the European explorers clubbed them all to death not knowing that this was the only place they existed on the entire planet. Global Warming becoming a serious issue of the twenty-first century has also brought questions of ecological concern to the table of political debates. Understanding how species change is important in order to understand if changes in the climate are causing disruptions in specie populations. Given our growing knowledge of biology and realization that the more we learn about the world, environments and species around us the better we can protect ourselves as a species and preserve life on earth likely going to continue to make ecology a growing subject of study for biologists everywhere.

Putman, Rory, and Stephen D. Wratten.Principles of ecology. Berkeley: University of California Press, 1984. Print. Wilkinson, Gerald. "Life history, ecology and longevity in bats." Aging Cell 1 (2002): 124-131. Print.

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Literary Theory and Criticism

Home › Eco Criticism › Ecocriticism: An Essay

Ecocriticism: An Essay

By NASRULLAH MAMBROL on November 27, 2016 • ( 3 )

Ecocriticism is the study of literature and environment from an interdisciplinary point of view where all sciences come together to analyze the environment and brainstorm possible solutions for the correction of the contemporary environmental situation. Ecocriticism was officially heralded by the publication of two seminal works, both published in the mid-1990s: The Ecocriticism Reader , edited by Cheryll Glotfelty and Harold Fromm , and The Environmental Imagination, by Lawrence Buell.

Ecocriticism investigates the relation between humans and the natural world in literature. It deals with how environmental issues, cultural issues concerning the environment and attitudes towards nature are presented and analyzed. One of the main goals in ecocriticism is to study how individuals in society behave and react in relation to nature and ecological aspects. This form of criticism has gained a lot of attention during recent years due to higher social emphasis on environmental destruction and increased technology. It is hence a fresh way of analyzing and interpreting literary texts, which brings new dimensions to the field of literary and theoritical studies. Ecocriticism is an intentionally broad approach that is known by a number of other designations, including “green (cultural) studies”, “ecopoetics”, and “environmental literary criticism.”

Western thought has often held a more or less utilitarian attitude to nature —nature is for serving human needs. However, after the eighteenth century, there emerged many voices that demanded a revaluation of the relationship between man and environment, and man’s view of nature. Arne Naess , a Norwegian philosopher, developed the notion of “Deep Ecology” which emphasizes the basic interconnectedness of all life forms and natural features, and presents a symbiotic and holistic world-view rather than an anthropocentric one.

Earlier theories in literary and cultural studies focussed on issue of class, race, gender, region are criteria and “subjects”of critical analysis. The late twentieth century has woken up to a new threat: ecological disaster. The most important environmental problems that humankind faces as a whole are: nuclear war, depletion of valuable natural resources, population explosion, proliferation of exploitative technologies, conquest of space preliminary to using it as a garbage dump, pollution, extinction of species (though not a human problem) among others. In such a context, literary and cultural theory has begun to address the issue as a part of academic discourse. Numerous green movements have sprung up all over the world, and some have even gained representations in the governments.

Large scale debates over “dumping,” North versus South environmentalism (the necessary differences between the en-vironmentalism of the developed and technologically advanced richer nations—the North, and the poorer, subsistence environmentalism of the developing or “Third World”—the South). Donald Worster ‘s Nature’s Economy (1977) became a textbook for the study of ecological thought down the ages. The historian Arnold Toynbee recorded the effect of human civilisation upon the land and nature in his monumental, Mankind and Mother Earth (1976). Environmental issues and landscape use were also the concern of the Annales School of historians , especially Braudel and Febvre. The work of environmental historians has been pathbreaking too. Rich-ard Grove et al’s massive Nature and the Orient (1998), David Arnold and Ramachandra Guha’s Nature, Culture, Imperialism (1995) have been significant work in the environmental history of India and Southeast Asia. Ramachandra Guha is of course the most important environmental historian writing from India today.

Various versions of environmentalism developed.Deep ecology and ecofeminism were two important developments. These new ideas questioned the notion of “development” and “modernity,” and argued that all Western notions in science, philosophy, politics were “anthropocentric” (human-centred) and “androcentric”(Man/male-centred). Technology, medical science with its animal testing, the cosmetic and fashion industry all came in for scrutiny from environmentalists. Deep ecology, for instance, stressed on a “biocentric” view (as seen in the name of the environmentalist group, “ Earth First! !”).

Ecocriticism is the result of this new consciousness: that very soon, there will be nothing beautiful (or safe) in nature to discourse about, unless we are very careful.

Ecocritics ask questions such as: (1) How is nature represented in the novel/poem/play ? (2) What role does the physical-geographical setting play in the structure of the novel? (3) How do our metaphors of the land influence the way we treat it? That is, what is the link between pedagogic or creative practice and actual political, sociocultural and ethical behaviour towards the land and other non-human life forms? (4) How is science —in the form of genetic engineering, technologies of reproduction, sexualities—open to critical scrutiny terms of the effects of science upon the land?

The essential assumptions, ideas and methods of ecocritics may be summed up as follows. (1) Ecocritics believe that human culture is related to the physical world. (2) Ecocriticism assumes that all life forms are interlinked. Ecocriticism expands the notion of “the world” to include the entire ecosphere. (3) Moreover, there is a definite link between nature and culture, where the literary treatment, representation and “thematisation” of land and nature influence actions on the land. (4) Joseph Meeker in an early work, The Comedy of Survival: Studies in Literary Ecology (1972) used the term “literary ecology” to refer to “the study of biological themes and relationships which appear in literary works. It is simultaneously an attempt to discover what roles have been played by literature in the ecology of the human species.” (5) William Rueckert is believed to have coined the term “ecocriticism” in 1978, which he defines as “the application of ecology and ecological concepts to the study of literature.”

Source: Literary Theory Today,Pramod K Nair

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Categories: Eco Criticism

Tags: Annales School , Arne Naess , Arnold Toynbee , Cheryll Glotfelty , Deep Ecology , Earth First! , Ecocriticism , green studies , Harold Fromm , Literary Theory , Mankind and Mother Earth , Nature and the Orient , Nature's Economy , The Comedy of Survival: Studies in Literary Ecology , The Ecocriticism Reader , The Environmental Imagination

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Ecology Essay Ideas

• Writing Essays
• Writing Research Papers
• English Grammar
• M.Ed., Education Administration, University of Georgia
• B.A., History, Armstrong State University

Ecology is the study of the interactions and reciprocal influence of living organisms within a specific environment. It's usually taught in the context of biology, though some high schools also offer courses in Environmental Science which includes topics in ecology.

Ecology Topics to Choose From

Topics within the field can range broadly, so your choices of topics are practically endless! The list below may help you generate your own ideas for a research paper or essay.

Research Topics

• How are new predators introduced into an area? Where has this happened in the United States?
• How is the ecosystem of your backyard different from the ecosystem of another person's backyard ecosystem?
• How is a desert ecosystem different from a forest ecosystem?
• What is the history and impact of manure?
• How are different types of manure good or bad?
• How has the popularity of sushi impacted the earth?
• What trends in eating habits have impacted our environment?
• What hosts and parasites exist in your home?
• Pick five products from your refrigerator, including the packaging. How long would it take for the products to decay in the earth?
• How are trees affected by acid rain?
• How do you build an ecovillage?
• How clean is the air in your town?
• What is the soil from your yard made of?
• Why are coral reefs important?
• Explain the ecosystem of a cave. How could that system be disturbed?
• Explain how rotting wood impacts the earth and people.
• What ten things could you recycle in your home?
• How is recycled paper made?
• How much carbon dioxide is released into the air every day because of fuel consumption in cars? How could this be reduced?
• How much paper is thrown away in your town every day? How could we use paper that is thrown away?
• How could each family save water?
• How does discarded motor oil affect the environment?
• How can we increase the use of public transportation? How would that help the environment?
• Pick an endangered species. What could make it go extinct? What could save this species from extinction?
• What species have been discovered within the past year?
• How could the human race become extinct? Describe a scenario.
• How does a local factory affect the environment?
• How do ecosystems improve water quality?

Topics for Opinion Papers

There is a great deal of controversy about topics that link ecology and public policy. If you enjoy writing papers that take a point of view , consider some of these:

• What impact is climate change having on our local ecology?
• Should the United States ban the use of plastics to protect delicate ecosystems?
• Should new laws be enacted to limit the use of energy produced by fossil fuels?
• How far should human beings go to protect ecologies where endangered species live?
• Is there ever a time when natural ecology should be sacrificed for human needs?
• Should scientists bring back an extinct animal? What animals would you bring back and why?
• If scientists brought back the saber-toothed tiger, how might it impact the environment?
• 67 Causal Essay Topics to Consider
• 501 Topic Suggestions for Writing Essays and Speeches
• Topical Organization Essay
• 100 Persuasive Essay Topics
• Personal Essay Topics
• List of Topics for How-to Essays
• How to Write a Narrative Essay or Speech (With Topic Ideas)
• Cause and Effect Essay Topics
• 50 Argumentative Essay Topics
• Practice in Supporting a Topic Sentence with Specific Details
• Black History Essay Topics
• Writing a Descriptive Essay
• Essay Writing Contests for Students
• How to Write a Great Process Essay
• 12 Interesting Ethical Topics for Essay Papers
• Write a Compare and Contrast Essay

• Glossary old

Where Are We Now?

• 23 Major Findings
• Why Biodiversity Matters
• Who is Biodiversity BC?
• What's Being Done

Ecological Concepts, Principles and Application to Conservation

• Taking Nature's Pulse: The Status of Biodiversity in British Columbia
• Biodiversity Atlas of British Columbia
• Call to Action

Biodiversity BC has prepared two key science documents, a report on Ecological Concepts, Principles and Application to Conservation and Taking Nature's Pulse: The Status of Biodiversity in British Columbia . These reports are designed to support action and planning by providing a primer on biodiversity (setting out the concepts and principles of biodiversity conservation and restoration) and clarifying the current status of biodiversity in B.C.

The report on Ecological Concepts, Principles and Application to Conservation was released in July 2008 and is an overview document that will:

• guide the development of Taking Nature's Pulse , and,
• assist in providing the context for others to identify and assess options and priorities.

How We Developed the "Ecological Principles" Report

The report on Ecological Concepts, Principles and Application to Conservation was prepared under the direction of Biodiversity BC's Technical Subcommittee, whose members include representatives of conservation organizations and the B.C. government.

There is general agreement among experts that prevention is the key to the conservation of biodiversity. It costs far more to repair damage to biodiversity than it does to incorporate biodiversity conservation into planning and development. The key to prevention is understanding the ecological concepts and principles of biodiversity and how to apply this understanding to the conservation of biodiversity.

The Value of Biodiversity

Biodiversity refers to the variety of species and ecosystems that have co-evolved over thousands of years and the complex ecological processes that link them together and sustain the whole. As the name suggests, biological diversity includes diversity within species (genetic diversity), diversity between species and diversity of ecosystems.

There is an obvious relationship between healthy ecosystems and human well-being. Biodiversity is far more than the natural capital for B.C.'s resource-based economy. Species diversity is the source of food, building materials, energy and medicines and of services such a pollination, waste assimilation and water filtration. Genetic diversity within species makes possible the commercial breeding of higher-yield and disease-resistant plants and animals, and allows for adaptation to changing climatic conditions. Ecosystem diversity, in addition to fostering species and genetic diversity, enhances our quality of life through recreation, aesthetic enjoyment, and spiritual enrichment opportunities.

Biodiversity Attributes

Each of these three components of biodiversity is analyzed according to composition, structure and function.

• Composition describes the parts of each biodiversity component in a given area (e.g., habitat types, species present, genetic populations within species).
• Structure refers to the physical characteristics supporting that composition (e.g., size of habitats, forest canopy structure, etc).
• Function means the ecological and evolutionary processes affecting life within that structure (e.g., natural disturbances, predator-prey relationships, species adaptation over time).

The impacts on biodiversity of human activities such as urban development, resource extraction, construction of transportation corridors and pollution, and the climatic effects of greenhouse gas emissions can accelerate rates of species extinction and reduce the productivity of ecosystems. This, in turn, risks the loss of the economic and social benefits that biodiversity produces.

Biodiversity Concepts

Our understanding of ecosystems and how best to manage them is summarized in the following concepts:

• Levels of biological organization : Plants and animals and their supporting natural systems are sustained by dynamic ecological patterns and processes at all levels of biological organization (genes, species, populations, communities, ecosystems, landscapes and regions). These range from very small scale (processes shaping the life-cycle of leaves) to very large scale (climatic processes) and all are interdependent.
• Native species : Native plants, animals, fungi and microbes, evolving together over thousands of years, are the foundation of the natural systems that sustain biological diversity. Individual native species can be displaced not only by human activity but also by the invasion of non-native species such as the American bullfrogs in Vancouver Island lakes.
• Keystone species : Some species like salmon and sea otters have effects on their biological communities disproportionate to their abundance and biomass. Keystone ecosystems (such as riparian areas) and keystone processes (such as wildfire and pollination by insects) are equally vital.
• Population viability thresholds : Impacts such as loss of habitat can reduce the survival viability of a population or species.
• Ecological resilience : Ecosystems can absorb disturbance or stress and remain within their natural variability. However, too much disturbance can lead to ecosystem collapse.
• Disturbances : Natural events such as wildfire or human-induced events such as urban development change the existing condition of an ecosystem, and may put its survival at risk.
• Natural range of variability : The naturally occurring variation over time of the composition and structure found in an ecosystem represents the range of conditions occurring over hundreds of years prior to industrial-scale society.
• Connectivity/fragmentation : The degree to which ecosystems are linked internally as well as to one another to form an integrated network is essential to support the movement and adaptation of species; breaks in these links through human activity can have adverse impacts on biodiversity.

Ecosystem management concepts

The following ecosystem management concepts provide a framework for planning biodiversity conservation:

• Coarse- and Fine-filter approach : Conserving representative samples of all the ecological communities in a region (Coarse-filter) can facilitate conservation of the majority of species. Species, ecosystems and features that "fall through" the Coarse-filter (e.g., species that depend on a specific habitat feature) need to be conserved by a Fine-filter approach such as protecting wildlife trees.
• Adaptive management : Management decisions can be improved over time by learning from experience.
• Ecosystem-based management : An ecosystem-based approach, which maintains key characteristics of ecosystems in a way that sustains species and ecological processes but also supports some human intervention for economic or social purposes.
• Risk : Ecosystem management decisions consider the likelihood of an event occurring and the probable magnitude of the consequences if it does occur, weighing the expected risks against the expected benefits of the decision.
• Protected areas : Areas of land and/or water dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources.

Ecological Principles

The following ecological principles describe the assumptions needed to plan actions for conserving biodiversity:

• Protection of species and species subdivisions will support biodiversity.
• Maintaining habitat is fundamental to conserving species.
• Large areas usually contain more species than smaller areas with similar habitat.
• "All things are connected" but the nature and strength of the connection varies.
• Disturbances shape the characteristics of populations, communities and ecosystems.
• Climate change will increasingly influence all types of ecosystems

Applying Ecological Concepts and Principles in Biodiversity Conservation

These ecological concepts and principles are closely inter-related, and they must be applied in harmony with one another. The following applications are based on Coarse- and Fine-filter considerations:

• Use both filters: Use a Coarse-filter to create a network of representative protected areas and manage surrounding areas in a way that most closely emulates natural processes. Use a Fine-filter to fill in the gaps by conserving ecosystems, features and species not adequately protected through the coarse filter approach.
• Represent all native ecosystem types in a system of protected areas.
• Retain large contiguous or connected areas that sustain natural ecological processes.
• Maintain or emulate natural ecological processes.
• Manage for adaptability in response to environmental change.
• Maintain viable populations of all native species in natural patterns of abundance and distribution.
• Preserve rare landscape elements, critical habitats and features, and associated species.
• Minimize the introduction and spread of invasive alien species.

In Conclusion

The ecological concepts and principles, and their application to conserve biodiversity described in this document are intended to provide a science-based starting point for the action on biodiversity conservation.

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Add a method, remove a method, edit datasets, on the compliance of self-sovereign identity with gdpr principles: a critical review.

5 Sep 2024  ·  Abubakar-Sadiq Shehu · Edit social preview

Identity Management Systems (IdMs) have complemented how users are identified, authenticated, and authorised on e-services. Among the methods used for this purpose are traditional IdMs (isolated, centralised and federated) that mostly rely on identity providers (IdPs) to broker trust between a user and service-providers (SPs). An IdP also identifies and authenticates a user on-behalf of the SP, who then determines the authorisation of the user. In these processes, both SP and IdP collect, process or store private users' data, which can be prone to breach. One approach to address the data breach is to relieve the IdP, and return control and storage of personal data to the owner. Self-sovereign identity (SSI) was introduced as an IdM model to reduce the possibility of data breaches by offering control of personal data to the owner. SSI is a decentralised IdM, where the data owner has sovereign control of personal data stored in their digital wallet. Since SSI is an emerging technology, its components and methods require careful evaluation. This paper provides an evolution to IdMs and reviews the state-of-the-art SSI frameworks. We explored articles in the literature that reviewed blockchain solutions for General Data Protection Regulation (GDPR). We systematically searched recent SSI and blockchain proposals, evaluated the compliance of the retrieved documents with the GDPR privacy principles, and discussed their potentials, constraints, and limitations. This work identifies potential research gaps and opportunities.

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