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The Science Behind Continental-Scale Conservation

Effective conservation and ecological restoration needs to be done on multiple scales: local, ecosystem, regional, and continental. In recent years, conservation biologists, including many Rewilding Institute Fellows, have conducted the research and developed the concepts that underlie the need for doing conservation and restoration on a continental scale.

Of course, work needs to continue on smaller scales as well. Because nearly all other conservation groups work on these other scales, The Rewilding Institute was established to emphasize continental-scale conservation in North America. The following areas of work are the foundation for continental-scale conservation.

Clicking on a topic will take you to a page with a more detailed discussion and links to resources, including books and papers. Among the books, Rewilding North America covers all of these topics and Continental Conservation covers most of them—both are available directly from TRI. Other books may be ordered directly from Amazon from this website. All it takes is a click.

Key articles, whether peer-reviewed or popular, are listed under each topic in four categories: (1) Those in PDF form that can be downloaded; (2) those that are available in listed books; (3) those that are available from a link to another site; and (4) those we cannot yet offer electronically, but for which we give a full citation. (Note: This part of the website is still under construction. Unfortunately, many scientific journals do not seem to be interested in making papers available for educational purposes and thus will not allow us to offer PDFs from this website. We will add downloadable articles as we receive permission to offer them. We also will add articles when we can figure out other ways to make them available to you. We are currently creating PDFs for many articles from Wild Earth journal and will list them as soon as the PDFs are available.)

For some topics, we also provide links to longer reports. Please suggest other books, papers, and reports on these subjects so we can make this resource more comprehensive.

General Books:

Rewilding North America: A Vision for Conservation in the 21st Century by Dave Foreman (Island Press 2004). Order from The Rewilding Institute.

(R) Continental Conservation: Scientific Foundations of Regional Reserve Networks edited by Michael E. Soulè and John Terborgh (Island Press 1999).

Saving Nature’s Legacy: Protecting and Restoring Biodiversity by Reed F. Noss and Allen Y. Cooperrider (Island Press 1994). Order from Amazon.

Hope’s Horizon: Three Visions for Healing the American Land by Chip Ward (Island Press 2004). Order from Amazon.

Conservation Biology: An Evolutionary-Ecological Perspective edited by Michael E. Soulè and Bruce A. Wilcox (Sinauer 1980). Order from Amazon.

Conservation Biology: The Science of Scarcity and Diversity edited by Michael E. Soulè (Sinauer 1986). Order from Amazon.

Sky Islands Wildlands Network Conservation Plan by Dave Foreman et al. (The Wildlands Project 2000). Available from Kim Vacariu, The Wildlands Project, at 520-884-0875 or ki*@wi**************.org.

New Mexico Highlands Wildlands Network Vision by Dave Foreman et al. (The Wildlands Project 2003). CD only available from Kim Vacariu, The Wildlands Project, at 520-884-0875 or ki*@wi**************.org.

Southern Rockies Wildlands Network Vision: A Science-based Approach to Rewilding the Southern Rockies by Brian Miller et al. (Colorado Mountain Club Press 2003). Order from Amazon. Or from www.RestoreTheRockies.org.

More will be added from time to time. Other books, articles, and reports are listed under each topic.

These topics are listed more or less in the order in which they should be viewed. For example, Rewilding is more understandable after reading Top-Down Regulation.

Top-down Regulation

Research around the world over the last several decades has shown that large carnivores are vital for ecosystem integrity through their top-down regulation of other species. When top predators are removed, negative effects reverberate down the trophic levels (food chain) of an ecosystem. When big hunters are restored, the ecosystem begins to heal. Regional- and continental-scale conservation strategies need to emphasize the top-down role of large carnivores.


Michael Soulè developed the ecological restoration approach of rewilding in the mid-1990s. Large carnivores need big, wild, roadless areas of habitat for security from humans and to fulfill their survival needs. Few protected areas in North America or anywhere in the world are large enough to stand alone as habitats, therefore core habitats need to be linked by wildlife movement corridors or landscape permeability. Thus, the “Three Cs” of rewilding are: Carnivores, Cores, and Connectivity.

Ecologically Effective Populations

Recovery goals for threatened and endangered species have historically been based on restoring only minimal populations large enough to prevent genetic extinction. New work by Michael Soulè and other researchers argues that goals instead should seek to reestablish ecologically effective populations for highly interactive species. Highly interactive species, formerly called keystone or foundation species, are those that have a disproportionately large effect on ecosystems. Ecologically effective populations are populations large enough so that a species, such as a large carnivore, is able to exercise its top-down regulation of the ecosystem.

Ecological and Evolutionary Processes

Once upon a time, land managers believed that natural disturbance events, such as fire, were bad and should be prevented. Now we know that these natural ecological and evolutionary processes are vital for land health and need to be maintained or restored to wildlands. The most important processes for restoration are wildfire, predation, and hydrology (stream flooding, etc.).

Core Protected Areas

Research and experience clearly show that many species need large core protected areas that are roadless or mostly so. Sensitive species, including many carnivores, are vulnerable to human persecution and disruption. Preventing motorized access is the best way to reduce such human impacts. A regional conservation strategy without wilderness (roadless areas) is not serious.

Landscape Permeability

Habitat fragmentation is widely recognized as one of the leading causes of extinction. Since the mid-1980s, conservation area design in general and wildlands network design in particular have emphasized the importance of protecting and restoring corridors or linkages between core protected areas for the secure movement of various species. Corridors and linkages on the local and regional scales become landscape permeability on the continental scale.


Just as wildlife-movement linkages are an essential part of local and regional-scale conservation planning, MegaLinkages are essential to continental-scale conservation. Four MegaLinkages—Arctic-Boreal, Pacific, Spine of the Continent, and Appalachian—make up the North American Wildlands Network proposed by The Rewilding Institute and other groups.

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