National Parks Do Little To Protect U.S. Biodiversity

But an article in the August edition of Ecological Applications says they are not accomplishing a critical task: preserving the biodiversity of plant and animal species present in the lower-48 states. The research demonstrates that despite covering approximately 168,000 square miles, America's protected lands fail to encompass the full range of the nation's biodiversity.

Some earlier studies found that as much as one third of vegetation types are not found within nature reserves.

This study 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.

Their conclusion: nature reserves are unevenly distributed across ecological zones, and therefore preserve only a small portion of the plants and animals that call America home.

"The current network of nature reserves... 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 J. Michael Scott, primary investigator for the study. "These 'lands nobody wanted' don't come close to representing the natural variation found in the U.S."

The authors found that nature reserves are predominantly located in middle to high elevations in areas with less productive soils. For example, they found that 63 percent of the nature reserves have low quality soil. The richest soils tend to be at lower elevations, and these areas are often more developed for agricultural use, timber production, and residential development.

Since reserves are in higher elevations with poor soil, entire species of plants and animals who reside in lower and more fertile areas are left largely unprotected. For example, past studies have shown that the greatest numbers of amphibian and reptile species in the western United States are found below 1000 feet, while many reserves are confined to higher elevations.

This poses a challenge: In order for America's biodiversity to be preserved for future generations, the authors 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 U.S. species," says Scott.