Endangered Ecosystems:
A Status Report on America's Vanishing Habitat and Wildlife
by Reed F. Noss and Robert L. Peters

December 20, 1995


*This critically important paper has sadly

 been removed from the Defenders web site.

Upon contact they offered no valid reason for why and

seemed evasive about the paper's present location.*

If possible, please make copies of it and disperse it to

those who are concerned with our Environment.

circa 2000 - Defenders of Wildlife



Recently discovered complete version of this paper here:

Endangered Ecosystems: A Status Report

Robert L. Peters is a former Defenders of Wildlife conservation biologist who holds a Ph.D. from Stanford, coedited Global Warming and Biological Diversity. Reed F. Noss, editor of Conservation Biology and science director of the Wildlands Project, was the coauthor of Saving Nature's Legacy, sponsored by Defenders of Wildlife.

Executive Summary

Since the time of European colonization, millions of acres of North America's natural ecosystems have been destroyed, degraded and replaced by agriculture and concrete. Iowa's tallgrass prairies, once habitat for wolves and buffalo, are now fields of corn. California's golden bear, a subspecies of grizzly, can now be found only on the state flag. The native wildflowers and bunchgrasses of California have dwindled and the hills are now covered with wild wheat, thistles and mustard from Europe and Asia. The entire south Florida landscape, including the Everglades and pine rockland habitat for endangered Key deer, is so seriously degraded that we have identified this entire area as the most endangered ecosystem in the nation.

The magnitude of decline is staggering. For example, the nation has lost 117 million acres of wetlands - more than 50 percent of what was here when Europeans arrived; the Northwest has lost 25 million acres - 90 percent - of its ancient forest; California alone has lost 22 million acres of native grasslands. What little untouched natural landscape remains is becoming increasingly fragmented. Our national forests alone contain nearly 360,000 miles of roads, more than eight times as much as the Interstate Highway System. In the West, 270 million acres of public rangeland are affected by livestock grazing - nine of every ten acres. Although some loss of ecosystems is an unavoidable price of development, the destruction has advanced far beyond what is necessary, because of poor planning, emphasis on short-term economic gain and misplaced government priorities.

The ultimate driving force behind this degradation is America's population, which is growing by 2.6 million every year, equivalent to a city the size of Chicago. Total U.S. population grew nearly 10 percent between 1982 and 1992, with some states like Florida and Nevada growing by more than 25 percent (Table 11). All these people require living space, clean water to drink, farms to supply their food and timber to build their houses. Because Americans consume so much more energy, food and raw materials than the average global citizen, their impact on natural ecosystems is immense. The result is that wild America has been pushed to the wall.

Throughout the nation, ecosystem destruction is increasing. "Reclamation" of wetlands for agriculture continues in the midwestern states. New congressional initiatives would accelerate destruction of wetlands, which are essential breeding habitat for waterfowl. Livestock grazing on damaged western lands continues. Logging in the Pacific Northwest and Alaska is eliminating what little old-growth forest remains, including ancient redwood ecosystems. Residential development in California and other western states is destroying grasslands, chaparral and vernal pools, home to fairy shrimp and other endangered species. Along the coasts, America's continuing love affair with living near the sea drives a building boom that is making hundreds of additional species candidates for federal protection.

What will the future be like if these trends continue? Without dramatic changes in our patterns of land and resource use, more ecosystems will become fragmented and degraded or disappear along with the wildlife they support. The remaining wild lands will be replaced by vast stretches of residential sprawl, factory farms, and tree plantations. In southern California, most of the natural ecosystems along the coast have already been converted to housing and developers are hungrily eyeing Camp Pendleton Marine Corps Base, the largest remnant of coastal green space. Because Florida is so developed, the Florida panther and the state's subspecies of black bear have been pushed into areas so small that a predominant cause of mortality is motor vehicle collisions. Both animals could disappear if new roads like the proposed State Road 40 and widening of U.S. 19 are allowed to chop up remaining habitat. In the Southwest, all riparian ecosystems are under extreme pressure. Some rivers, such as the lower Gila in Arizona, have been largely pumped dry and the native riparian ecosystems have been destroyed. As western states continue to grow, the demand for water will increase, putting the Gila, Colorado and other rivers at still greater risk.

Overview of Findings

Our study emphasizes that extensive habitat destruction is reaching the point where the nation faces the loss of hundreds of natural ecosystems, including California's ancient redwood forests, longleaf pine forests in the Southeast, beach dune habitats along the East Coast, and even subterranean communities of blind fish and crustaceans in Tennessee caves. Used in this sense, the term "ecosystem" means a characteristic community of interdependent plants, animals and microorganisms associated with particular kinds of soil, temperature, rainfall and disturbance patterns. Thus, the redwood ecosystem can be found in patches throughout northern California wherever soil, weather and fire frequency are suitable.

Of the hundreds of imperiled ecosystems, this report identifies the 21 most-endangered ecosystems based on four factors (See Table 4). Ecosystems rank high on Defenders of Wildlife's risk scale if they have been greatly reduced since Europeans settled North America, if they are now very small, if they have many imperiled species, and/or if the continued threat to their existence is high. For example, southern California coastal sage scrub ranks high - in the top ten - because it has been much reduced by development, because it harbors many endangered species and because bulldozers are steadily chewing up what remains. Other most-endangered ecosystems on our list are the south Florida landscape, longleaf pine forests and savannas (grassland with scattered trees), tallgrass prairie, Hawaiian dry forests, old-growth forests of the Pacific Northwest and midwestern wetlands. Note that although we identify these most-endangered ecosystems as having the greatest risk of disappearing, and they therefore deserve high priority for conservation, conservation organizations or agencies might give equal or greater priority to ecosystems not identified here. In order to set their priorities, conservation organizations need to consider not only risk of disappearance but also ecological importance, political and economic opportunities for conservation and other factors.

In acres lost to other land uses since European settlement, the most reduced ecosystems are prairies and other grasslands, savannas (for example, oak savannas in the Midwest) and some forests and wetlands. Table 1 of our report lists 27 ecosystem types that have lost more than 98 percent of their original extent, including spruce-fir forest in the southern Appalachians, pine rockland habitat in south Florida, wet and mesic coastal prairies in Louisiana, sedge meadows in Wisconsin, and Palouse prairie in the Pacific Northwest.

In many ecosystems, what little remains has been largely degraded. Poorly managed grazing on western public lands has resulted in loss of native grasses and other plants and has contributed to the imperilment of at least 340 species that are listed as endangered or threatened or are candidates for listing.2 Suppression of natural fires has caused gradual deterioration of fire-dependent terrestrial and wetland communities such as prairies, barrens, southern canebrakes and longleaf pine and ponderosa pine forests. Fire suppression in longleaf pine forests causes invasion by hardwood trees and a major change in the species composition of the forest.

Aquatic ecosystems have been severely degraded by dams, channelization and pollution. Between 90 and 98 percent of the nation's streams are in bad enough shape to be ineligible for federal designation as wild and scenic rivers, and more than 80 percent of the nation's fish communities are considered degraded because of decline or loss of native species and introduction of exotics. Of Arizona's 30 existing native freshwater fishes, all but one are either threatened, endangered or a candidate for listing under the Endangered Species Act. The Mobile River Basin in Alabama was once home to more than 30 mussels and 130 snails found nowhere else in the world. Today more than half the mussels and nearly a quarter of the snails are extinct.

Besides identifying which ecosystems are most endangered, Defenders determined which states are experiencing the greatest threats to their ecosystems and associated wildlife. States were ranked according to how many endangered ecosystems they contain, how many rare species they have and how much development is occurring. The ten states with the greatest overall risk of ecosystem loss are Florida, followed by California and Hawaii (tied), Georgia, North Carolina and Texas (tied), South Carolina and Virginia (tied), and finally Alabama and Tennessee (tied) (See maps; Table 5).

Most of these states are experiencing rapid growth. In Florida, for example, the amount of developed land increased 35 percent in the decade from 1982 to 1992. If this rate of increase were to continue for the next 70 years, all developable land in the state, including agricultural land, would be covered by houses and concrete. While this is not likely to happen, this statistic illustrates the frantic, unsustainable pace of Florida's current growth. Our Development Threat Index shows that development pressures are greatest in the Southeast and Southwest and parts of the East Coast (See Map 6). States with the highest development scores are Florida and New Jersey (tied), Delaware and Maryland (tied), Massachusetts and Rhode Island (tied), and California, Connecticut, Georgia, North Carolina, New Hampshire, South Carolina and Virginia (tied).

Our study shows that all 50 states have serious problems, even those ranking relatively low in overall risk. Iowa, for example, falls in the bottom third of states based on overall risk to ecosystems, largely because it has low rates of population and development growth and relatively few large urban centers. Yet agriculture has gobbled up 95 percent of Iowa's original 40 million acres of forests, prairies and wetlands, and much of what remains is degraded. Seventy native Iowa plant and animal species have vanished from the state, including wild bison and black bear, wolf, cougar, elk, trumpeter swan, greater prairie chicken, sandhill crane, long-billed curlew and burrowing owl. Iowa lists more than 200 plants and animals as endangered or threatened.

Alaska, which falls at the bottom of Defenders' state rankings, nonetheless contains many ecosystems under duress, including the belt of ancient temperate rainforest stretching from the Kodiak Archipelago southeast along the Gulf of Alaska to the Alaska panhandle. This rainforest is one of the last refuges for many vulnerable species, among them the brown bear, Alexander Archipelago wolf, Queen Charlotte goshawk and marbled murrelet. Also at risk is the Arctic National Wildlife Refuge's coastal plain, where some members of Congress want to allow oil drilling. The plain is the calving ground of one of the continent's largest caribou herds.

Ironically, many states are steadily losing the very ecosystems that make them attractive places to live and to visit. Florida, Defenders' top state in terms of risk to ecosystems, draws new residents and an immense number of tourists specifically because of the natural beauty of the coral reefs, the Everglades marshes and wildlife and the state's other natural ecosystems. Yet the impact of these people is enormous. More than half of Florida's wetlands have been lost to drainage and development, including more than 65 percent of the 3,900-square-mile Kissimmee-Okeechobee-Everglades system. Agriculture and development have interrupted vital water flow across the Everglades and loaded the water with phosphorus and nitrogen, stimulating the growth of dense stands of cattails that choke out sawgrass and other water bird habitat. The Everglades' wading-bird flocks, once estimated at more than 2.5 million birds, have declined by 90 percent since the last century. This unacceptable condition is recognized in a new report by the Commission on a Sustainable South Florida appointed by Governor J. Lawton Chiles that recommends redirecting growth away from the Everglades and other ecologically valuable places because tourism, drinking water and the fishing industry all depend on a healthy natural environment.

Why Care About Ecosystems?

As Governor Chiles's commission concluded, there are economic reasons to save ecosystems. In Florida and elsewhere, people pay handsomely to live and play in natural surroundings. They want to see natural forests with a full complement of birds, flowers, and other wild things, not species-poor plantations of genetically identical pine trees. In Hawaii, they want to see colorful native birds and flowers, not fields of grass and cattle.

Moreover, natural ecosystems provide people with what are known as ecosystem services, including building of fertile soil, purifying both the water and air, and providing flood control. Loss of these services has real although often hidden costs. For example, natural forests on mountain slopes can absorb twice as much water as do plantation forests, slowing runoff and erosion and preventing downstream flooding. Wetlands, estuaries and other aquatic systems provide free sewage treatment. The New York Bight, a 2,000-square-mile embayment at the mouth of the Hudson River, biologically treats the waste produced by 20 million people in the New York metropolitan area. If this biological filter is damaged by excessive pollution, as seems to be occurring, the cost of replacing these services with mechanical and chemical treatment facilities will run into billions of dollars.

Healthy ecosystems also are essential for species to survive. As ecosystems unravel, the species they sustain become candidates for the endangered list. Most of the 956 U.S. threatened and endangered plant and animal species and the 3,902 candidates for listing are in trouble because of habitat loss. Loss of perhaps 99 percent of Atlantic white cedar swamps has caused endangerment of the green Hessel's hairstreak butterfly, a species whose larvae can feed only on the cedar leaves. The imperiled buck moth of the northeastern states is dwindling along with the vanishing pine barrens. If habitat destruction continues, we can expect the number of threatened and endangered species to skyrocket. By waiting until ecosystems are so deteriorated that their component species are in danger of extinction, society incurs huge social and economic costs. This leads to conflict between those people eager to save our living heritage and developers and other exploitive interests.

What Must Be Done?

The challenge is to make our national endeavors less invasive, destructive and wasteful, so that there is room for both humans and nature. Curbing excessive human population growth and its consumption of resources should be a top priority, but even if we are not fully successful much can be done today to reduce the impacts of economic development on natural ecosystems and thereby improve the quality of life for us and our descendants. We can conserve, recycle and reuse natural resources such as wood products. We can restructure government subsidies to discourage methods of ranching, farming and logging that are environmentally destructive and promote those that are beneficial. We can pass zoning ordinances to slow sprawl and promote communities where neighbors live closer together. We can direct further development to lands that already have been ecologically degraded and away from the last unspoiled natural landscapes and we can restore those already degraded.

Making such fundamental changes will require help from government on all levels as well as from industry, developers, scientific institutions, philanthropic foundations, conservation organizations and individual citizens. Because most land-use decisions are made by local government, local efforts to protect natural lands can have tremendous cumulative impact. State and federal initiatives can focus on large-scale patterns of land and resource use, economic incentives and coordinated scientific programs.

It is imperative that the public and policymakers begin to take action. Defenders makes the following recommendations for conserving our nation's ecosystems:

Make ecosystem conservation a national goal. All sectors of society must make ecosystem conservation a high priority. We must provide better education about the importance of ecosystems, provide more resources for their conservation, and provide adequate protective legislation. Natural ecosystem protection should be given first priority on the nation's public lands.
Maintain and strengthen existing environmental laws. We must defeat current efforts in Congress to rollback existing environmental laws that promote ecosystem conservation, among them the National Forest Management Act, Clean Air Act, Clean Water Act, Tongass Timber Reform Act and Endangered Species Act. Congress should also look for opportunities to strengthen the ecosystem protection provisions of the National Forest Management Act, the enabling legislation of the National Wildlife Refuge System and other appropriate legislation.
Reform policies that harm ecosystems. We should eliminate or reform government laws and subsidies that support harmful resource use, including those permitting hardrock mining and petroleum drilling in ecologically sensitive areas, old-growth timber sales, below-market fees for grazing on ecologically degraded or sensitive federal lands, and subsidies for agricultural commodities like corn and soybeans that encourage conversion of wetlands and hedgerows to crop production. As a supplement to traditional regulatory approaches, we should use economic incentives and other creative techniques to encourage landowners to manage their lands in ways that sustain natural ecosystems.
Improve scientific knowledge about ecosystems. We must improve the knowledge base for making informed management decisions. A key need is a robust national scientific agency, such as the National Biological Service, that has the financial and technical capability to spearhead a national effort to map ecosystems, identify ecosystems at risk, organize ecological research and provide the scientific tools for proper conservation and management.
Develop appropriate management plans for whole ecosystems using "ecosystem management." Planning and management should take place on large geographic scales that consider the needs of entire ecosystems, not just pieces. All public and private land managers with jurisdiction over an ecosystem should cooperate and base their joint plans on the best available conservation science, including consideration of disturbance regimes* and minimum viable population sizes** for key species. Because ecosystems are so complex and in many cases exceed our ability to understand them completely, managers should use "adaptive management," meaning that managed ecosystems should be continuously monitored so that timely action can be taken to correct for faulty management or changing conditions.

Overview of Report Structure

Our report begins in Section 1 with a status review of the nation's ecosystems, identifying which ones are substantially reduced in area, rare, contain the most endangered species, and/or face the greatest threats from humans. A survey of threats is placed in Appendix A. We also present a list of the nation's 21 most-endangered ecosystems, case studies for which are in Appendix B. In Section 2 we present our assessment of how high the risk to ecosystems is in each state, and in Section 3 we present five state case studies - Florida, California, Hawaii, New York and Iowa. We chose states that represent different regions of the country, and we took a historical approach to illustrate how past land-use patterns have affected composition and distribution of ecosystems. Finally, we make recommendations for acquiring better information on the status of ecosystems and for protecting and restoring them.

* A disturbance regime is the specific type, size and frequency of disturbance that occurs in an ecosystem. In longleaf pine forests the historical disturbance regime was characterized by frequent low intensity fires over large areas.

** A minimum viable population size (MVP) is the minimum number of individuals necessary to ensure that a population survives over some specific period of time, given known causes of mortality, genetic characteristics, demographic makeup and other factors. MVPs generally considered necessary for long-term survival of large mammals are in the range of 500 to 1,000 individuals.



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