The US Could Save its Unique Wildlife
by Protecting 9 Areas

The United States has one of the oldest systems for protecting wilderness in its many forms in the world. There’s just one problem: in general, protected areas in the US were designated to protect landscapes, not biodiversity. Sure, the biodiversity within those landscapes often benefits from living inside a protected space, but many of the species most in need of protection live elsewhere. The basic mismatch is that most of the country’s protected lands are in the West, while most of the vulnerable species are in the Southeast. That’s the result of a new analysis published this week in PNAS.

Researcher Clinton N. Jenkins from Brazil’s Instituto de Pesquisas Ecológicas, together with colleagues from NOAA, Duke University, and the University of Maryland, set about comparing the United States’ current map of protected areas with data on the conservation status of terrestrial vertebrates, freshwater fish, and trees, in order to identify future conservation priorities.

They began by noting the distinction between species richness and species in need of conservation efforts. Wide-ranging species like coyotes or raccoon, for example, tend to dominate species richness trends, but many are designated as species of least concern. Vulnerable species, on the other hand, tend to have small geographic ranges (and are by definition more rare), or are anatomically large but sparsely distributed, and in many cases (like wolves) are locally extirpated and subject to persecution where they persist. To make the greatest impact on US biodiversity, Jenkins needed to identify landscapes high in species richness that also contained the greatest number of vulnerable species. An area high in biodiversity itself is not necessarily worthy of protection if all the species there are thought of as species of “least concern.”

Next, they classified which vulnerable species were endemics. These are species’ whose entire range falls within the United States. That means the US has the unique ability to protect them from extinction. 70% of amphibians and 68% of freshwater fish considered by the study were US endemics, followed by 30% of reptiles, 29% of trees, 28% of mammals, and 3% of birds. The highest levels of endemism, for all taxa, were in the Southeast.

In all cases, their areas of greatest need fell outside of protected lands, which generally come in one of two flavors.

Most publicly owned lands (at the local, state, or federal levels) are in the West, where landscapes are less suited to agriculture and development. Even still, while enjoying some measure of protection, the majority of those places are subject to extractive industries like logging, mining, or grazing.

In the Midwest and in the East, most land is unprotected and privately owned. In those places, the main tools for conservation are easements, rather than federally owned lands. “The partial data [that currently exist] suggest that much of the land thus far protected is not ideally positioned for biodiversity conservation,” write the researchers.

For example, 22.6% of the documented easement area is in Maine and Montana. Together, the two states cover just 6% of the total area of the lower 48 states, and have “almost no endemism or small-ranged species.” Southeastern states that have high rates of endemism, like Tennessee, Kentucky, North Carolina, South Carolina, Mississippi, Alabama, Georgia, contain only 7.8% of the country’s easement area. “It appears that private land protection efforts, similar to public protected areas, are not prioritizing the most endemic-rich areas of the country, or at least are having less success in those areas,” conclude the researchers.

By calculating the ratio of the proportion of a species’ range that is currently unprotected to the species’ entire known range, the researchers created a “priority score.” As a species’ range size decreases, the score increases. That pattern is supported by empirical data: as a species’ range becomes smaller, its risk of extinction grows. Likewise, if a species’ range is mostly contained within protected areas, the score goes down, because they are already being reasonably well protected, at least theoretically.

After combining all that data, nine “priority areas” emerged. Protecting these places would disproportionately protect US biodiversity in places currently not protected:
(1) Blue Ridge Mountains (salamanders, fish, trees)
(2) Sierra Nevada Mountains (amphibians, trees)
(3) California Coast (trees, amphibians, mammals)
(4) Tennessee, Alabama, and northern Georgia watersheds (fish, reptiles, amphibians)
(5) Florida panhandle (trees, fish, reptiles)
(6) Florida Keys (trees)
(7) Klamath Mountains (trees, amphibians, fish)
(8) South-Central Texas, particularly Austin & San Antonio areas (amphibians, fish, reptiles)
(9) California’s Channel Islands (trees, reptiles, mammals)