The Science of
Conservation Biology
As the name of the organization suggests, the mission of Western Wildlife Conservancy (WWC) is to conserve native wildlife. However, it is more than this because we also do what we can to protect animals from various anthropogenic harms, such as animal-automobile collisions, trapping, and hunting, where the primary motive of the hunter is to obtain a trophy. To do this, we engage in both direct action and education. We believe that if people become educated about conservation issues, they will do more on behalf of conservation.
‘Conserve’ is a term applicable to species and populations of a species, not to individual organisms. For that, the word ‘protect’ is more appropriate. Therefore, our mission is to both conserve and protect native wildlife from individual organisms to populations of organisms, communities of organisms and ecosystems.
Conservation biology is a relatively new branch of the biological sciences, having emerged in the 1980s. Its most important founder is Michael Soulé, who published a seminal paper on the subject in 1985, titled “What is Conservation Biology?” In this paper, Soulé presents the foundational principles of the science, including two sets of postulates: “…a functional, or mechanistic, set and an ethical, or normative, set.” Here it is mainly the functional postulates – the science – that concerns us. There are two main functional postulates.
1. Natural biological communities are integrated. Because many species in natural ecosystems coevolved and are interdependent, and also because many species are highly specialized and so depend upon very specific habitats, the extinction of one species, such as a keystone species like the beaver, can result in the loss of many other species. Thus, it is important to “keep all the parts” of an ecosystem.
2. Size is important. If an ecosystem is too small, as tends to happen with habitat fragmentation, at some point, the ecosystem no longer functions properly—in the words of Soulé: “. . . many ecological processes and patterns (including succession, nutrient cycling, and density-dependent phenomena) are interrupted or fail altogether where the system is too small.”
As reflected in these postulates, conservation biology is holistic in two senses. First, it is rooted in the foundational sciences of evolution and ecology, which concern biological systems entire. Second, it is interdisciplinary, bringing many sciences and disciplines to bear on a particular problem. Regarding conservation biology, Michael Soulé stated, “Its goal is to provide principles and tools for preserving biological diversity.” It is a crisis discipline requiring art and intuition and the application of many other sciences, such as ecology, island biogeography and population genetics, to practical problems.
Before elaborating further on the functional postulates, we will do well to first recognize the need for wildlife protection and conservation. We begin by noting that Earth is rapidly losing biodiversity. Entire species of organisms are disappearing at an accelerating rate. Granted, species extinction is as much a part of nature as is species genesis: a species comes into existence through the processes of evolution and eventually goes out of existence (becomes extinct) in the natural course of things. Nothing lasts forever. In fact, if we wish to use one word that best characterizes the physical universe, including the genesis and extinction of species, that word will be ‘change’. Everything is always in the process of changing. By contrast, the terms ‘conserve’ and protect’ suggest active resistance to change, so one might well wonder why anyone should bother to resist the inevitable.
There is a need for conservation biology because human beings are now so rapidly changing the earth—its atmosphere, land, water and biota—that many species can no longer be sustained and are being unnaturally extinguished before their time. In fact, the rate of extinction is now so high—some say 1,000, perhaps even 1,000,000 times the natural rate—that we are well into the sixth great extinction episode in the history of life on Earth. The distinguishing feature of this particular extinction episode is that one species in particular is causing it: Homo sapiens! Our view is that we ought not engage in the unnecessary destruction of what is good and beautiful and should do what we can to restore what we have damaged. This is where conservation biology comes in.
Many human activities contribute to species extinction, but the main one is alteration of wildlife habitat. Essentially, habitat alteration is habitat destruction for a species if it cannot survive in the altered habitat. Think of cities and farms and dams as examples of human-altered habitats. Highly altered habitats such as these are replacing the natural habitats of myriad species in ways that are harmful to them.
Habitat alteration not only degrades habitat for various species, thereby making life harder for individual members of the species, but also results in habitat fragmentation: even remaining patches of “wild” habitat, where native plants and animals are still able to live, are cut off from each other by the creation of altered habitats, thus making it difficult or impossible for plants and animals to move between patches. The consequence of this—especially in the case of animals, and particularly large ones that require lots of room—is that individual organisms in one habitat patch are isolated from, and so unable to breed with, similarly isolated organisms in other habitat patches. This is a problem because isolated habitat patches tend to be relatively small so that the number of members of a species supported by it will inevitably be smaller than in larger unfragmented habitats, resulting in a smaller gene pool, thus making the population less robust and more vulnerable to extinction due to climatic changes, diseases, and other natural disturbances. The bottom line is that these isolated smaller populations are each more susceptible to extinction than the original larger population was. This in turn makes total extinction of a species more probable as, one by one, the smaller populations die out. In this connection, it would be remiss not to point out that anthropogenic climate change compounds the problem of habitat alteration across the globe, making the prospect of mass extinction all the more dire.
The science of conservation biology is designed to remedy these two problems (habitat degradation and habitat fragmentation) by restoring and protecting “wild” habitats and by linking them together with corridors of functional wildlife habitat to create what is referred to as a “wildlands network.” A well-designed wildlands network will function to promote and maintain genetically connected populations of native species The result is a “metapopulation” of the species. An example of how this works would be to connect the greater Yellowstone population of grizzly bears with the Glacier National Park population of grizzly bears by means of protected travel corridors that enable bears to move between the two populations. In this case, some of the connecting movement corridors might also be large enough to themselves support smaller populations of grizzly bears.
A useful way to remember the basics of conservation biology is by the acronym CCC, which stands for cores, corridors, and carnivores. In our example above, the cores are the greater Yellowstone and Glacier National Park. The corridors are represented by the several mountain ranges that connect the cores—the Centennial Range, for example. Ideally, these lands should be surrounded by a “buffer zone” where human activity and habitat alteration are accommodated at a level that still affords adequate protection to the animals.
The reason for focusing on large carnivores is threefold: (1) historically, they have been the historical victims of much persecution, as in the case of both wolves and grizzly bears, which were nearly driven to extinction in the 48 contiguous states; (2) they are “umbrella” species, which means that they require lots of room so that by protecting the habitat they need to survive we automatically protect habitat for a great number of other native species; and (3) they are “keystone” species, which means that many other species of plant and animal are dependent upon their presence.
Keystone species are particularly important because, like the keystone of an arch, their persistence is necessary for the persistence of many other species and for maintaining the functionality of the ecosystem they all inhabit. Two of the best examples of keystone species are the beaver and the prairie dog, which are the foundations of entire ecosystems. Apex predators such as wolves and grizzlies are highly interactive with other species and so also typically perform a keystone function.
From the foregoing, we can see that “rewilding” must be a primary aim of conservation biology. That is, where possible, the goal is to return habitat to an earlier, more wild condition that existed prior to major human-caused disturbances. Good examples of rewilding are the reintroduction of beavers, prairie dogs, wolves and grizzlies to former habitats combined with restrictions on human activities that might adversely affect them.