US protects lands nobody wants

Despite covering approximately 164,000 square miles (420,000 square kilometers), the US’s arrangement of nature reserves fails to encompass the full range of the nation’s biodiversity with as many as one third of vegetation types not found within protected lands, says the leader of the team responsible for the research, J. Michael Scott of the US Geological Survey.

Scott’s team examined the distribution of ecological zones in comparison to the location of national parks, national forests, national wildlife refuges, and designated wilderness areas, Indian reservations, county parks, and other areas having permanent protection from conversion of natural land cover in the lower 48 states. “The current network of nature reserves in the coterminous United States is the result of lands being set aside, not in accordance with a well-thought-out ecological plan, but rather because the lands lacked value for commercial uses, human habitation, or because of scenic or recreational value,” argues Scott. “These ‘lands nobody wanted’ don’t come close to representing the natural variation found in the US.”

The researchers divided the lower 48 states into three broad ecological domains: eastern humid domain, western humid temperate, and dry temperate domains. They then combined soil productivity data with elevation and land management information to identify 35 potential soil and elevation classes. After breaking down the US landscape by soil productivity, elevation, and broad ecological zones, the authors show that nature reserves are predominantly located in middle to high elevations in areas with less productive soils. For example, they found that 63% of the nature reserves have soil productivity classifications of four and five, the two poorest classifications on a scale of one to five. The richest soils tend to be at lower elevations, and these areas are often more developed for agricultural use, timber production, and residential development.

The research team contends that by disproportionately locating reserves in higher elevations with poor soil productivity, entire species of plants and animals which reside in lower and more fertile areas are left largely unprotected. One example of this is that although the greatest numbers of amphibian and reptile species in the western United States are found below 2000 meters, many reserves are confined to higher elevations.

In order for the US’s biodiversity to be preserved for future generations, the authors of the research point out that the private sector must be encouraged to protect plant and animal species outside of designated reserves. “Past experience indicates that involving the private sector in creative strategies such as conservation easements, tax incentives, and other methods, can provide habitat crucial to US species,” says Scott.

There are signs that policy makers are heeding this call, Scott says, as the recently passed Refuge Improvement Act of 2000 calls upon the US Fish and Wildlife Service’s National Wildlife Refuge System to be representative of the nation’s ecosystems, giving the agency the authority to take measures to ensure better representation of species not currently enjoying protection as public lands.

The research appears in the August edition of Ecological Applications, published by the Ecological Society of America (ESA).