US protected lands mismatch biodiversity priorities

Abstract

Because habitat loss is the main cause of extinction, where and how much society chooses to protect is vital for saving species. The United States is well positioned economically and politically to pursue habitat conservation should it be a societal goal. We assessed the US protected area portfolio with respect to biodiversity in the country. New synthesis maps for terrestrial vertebrates, freshwater fish, and trees permit comparison with protected areas to identify priorities for future conservation investment. Although the total area protected is substantial, its geographic configuration is nearly the opposite of patterns of endemism within the country. Most protected lands are in the West, whereas the vulnerable species are largely in the Southeast. Private land protections are significant, but they are not concentrated where the priorities are. To adequately protect the nation's unique biodiversity, we recommend specific areas deserving additional protection, some of them including public lands, but many others requiring private investment.

Keywords: conservation priorities; endemism; extinction; protected areas; range size.

Fig. 1.

Biodiversity of the lower continental United States and priority areas for individual taxa. Total richness is the number of all species within the taxonomic group. Endemics are species whose entire range is within the lower 48 states. Priorities map the sum of individual species’ priority scores across the taxon.

Fig. 2.

Small-ranged and threatened species. Globally small-ranged are those species with ranges smaller than the global median for that taxon. USA small-ranged are those species with ranges smaller than the median for the species in the lower 48 states. IUCN Threatened are species considered vulnerable, endangered, or critically endangered on the IUCN Red List.

Fig. 3.

Protection status and ownership of lands in the lower 48 states. (A) Existing protected areas colored by IUCN category (41). (B) Ownership status of public, private, and Native American lands.

Fig. 4.

Summed priority scores across all taxa and recommended priority areas to expand conservation: 1, Middle to southern Blue Ridge Mountains; 2, Sierra Nevada Mountains, particularly the southern section; 3, California Coast Ranges; 4, Tennessee, Alabama, and northern Georgia watersheds; 5, Florida panhandle; 6, Florida Keys; 7, Klamath Mountains, primarily along the border of Oregon and California; 8) South-Central Texas around Austin and San Antonio; 9, Channel Islands of California.