A map shows where biodiversity is most at risk in America
By Catrin Einhorn and Nadja Popovich
Let your eyes wander to the areas of a map that deepen into red. They are the places in the lower 48 United States most likely to have plants and animals at high risk of global extinction.
It’s the most detailed map of its kind so far. Animals like the black-footed ferret and California condor are represented, but so are groups often left out of such analyses: species of bees, butterflies, fish, mussels, crayfish and flowering plants. Not included are gray wolves, grizzly bears and other wildlife not at risk of global extinction.
Maps like these offer a valuable tool to officials and conservationists who are scrambling to protect biodiversity. That work is critical, because scientists say humans are speeding extinction at a disastrous pace.
“There are hundreds of species known to be globally critically imperiled or imperiled in this country that have no protection under federal law and often no protection under state law,” said Healy Hamilton, chief scientist at NatureServe, a nonprofit conservation research group that led the analysis behind the map.
By highlighting areas where land is permanently protected for biodiversity, you can see where the habitats of imperiled species are outside conservation zones.
About 13% of the United States is permanently protected and managed primarily for biodiversity, according to the U.S. Geological Survey. The Biden administration has set a goal to conserve and restore 30% of U.S. lands and waters by 2030. It’s part of a larger global push, known as 30x30, to protect more land and water worldwide.
The analysis found that the habitats of hundreds of imperiled species were entirely outside conservation zones.
There is the Cassia crossbill, a finch with a twisty beak found in a single county in Idaho. There’s the tiny patch-nosed salamander in northern Georgia and across the border in South Carolina. And there’s the star cactus, which resembles a green sand dollar with a bright yellow bloom. It exists in only two locations, one in southern Texas and the other in northern Mexico.
Even when species are protected under federal or state laws, they are typically more vulnerable outside lands that are managed to protect biodiversity, Hamilton said. Officials may not know where they are. Private landowners may be reluctant to report them or allow surveys for fear of the restrictions that could follow if they are found.
To identify concentrations of imperiled biodiversity, the scientists created models for more than 2,200 species based on where they are known to exist and their habitat needs. The research, published in the journal Ecological Applications, and the related maps were a partnership among NatureServe and its network of state partners, geographic mapping platform Esri and the Nature Conservancy.
It is one of many efforts to measure biodiversity in the United States and around the world. Some include a much larger number of species. Others note features like potential wildlife corridors.
According to Walter Jetz, an ecologist who leads Yale University’s biodiversity mapping efforts, it’s essential that policymakers make data-driven decisions about which areas to protect. Otherwise “you might gain a large percentage of area protected, but you have done very little in actually safeguarding species.”
Many conservationists also emphasize that the places with the most imperiled species aren’t the only important ones to safeguard.
“Species that are now abundant aren’t going to be if we don’t protect some of these other habitats,” said Brian O’Donnell, director of Campaign for Nature, a coalition of conservation groups.
California is leading the way in tackling some of these challenges. It has more land under biodiversity protection than any other of the lower 48 states, but it’s also home to high concentrations of imperiled species that live outside those areas.
Aquatic biodiversity in the southeast
The Southeastern United States has a high concentration of freshwater mussels, those humble mollusks that help keep streams and rivers clean by filtering water. But they are one of the most imperiled wildlife groups in the United States. Last year, officials announced that eight species had gone extinct.
Just one small section of the Escambia River, which flows through the Florida Panhandle, is home to two imperiled mussel species, along with a turtle and crayfish also at risk of extinction.
Rivers and streams can be hard to protect, because their ecosystems are often degraded by infrastructure like dams, which disrupt natural water flow. Pesticides and erosion from human activity make matters worse.
Vulnerable species on public lands
It’s sometimes assumed that wildlife in national forests is automatically protected. Imperiled species are supposed to be, but that can be tricky depending on what the land is used for. Logging, mining and grazing are allowed on a significant share of public lands, including much of the Lincoln National Forest in southern New Mexico.
About 1 square kilometer of the forest was estimated to host a cluster of imperiled species, including a rabbit, a bee and several plants. So, it’s critical for officials to know where imperiled species exist.
Fast-growing urban areas
Across the continental United States, private land makes up almost 70% of areas with important concentrations of unprotected imperiled species, the researchers found.
The Texas Hill Country region southwest of Austin, growing fast and with little protected land, is one example. Despite pressure from housing developments and groundwater depletion, habitat for six imperiled species — a warbler, a bat, two salamanders and two plants — still exists.
The geographic precision now available, Hamilton said, can allow private individuals and conservation groups to focus more accurately on preventing extinctions. The researchers cited a variety of approaches, like tax incentives, to encourage the protection of certain species on private land.