Category Archives: Biodiversity

Trends in endangered species listings

To list or not to list?

That’s the key question facing the U.S. Fish and Wildlife Service when it comes to endangered species.  More than 1,300 plants and animals have been granted federal protection and these so-called listed species are embroiled in practically every Western environmental issue. The Endangered Species Act (ESA) has real teeth and it’s often the biggest hammer in environmentalists’ toolbox.

In this set of slides, I show where federally protected species live and review the history of ESA listings.

Trends in endangered species listings from EcoWest on Vimeo.

Endangered species are found throughout the country, but they tend to be concentrated in a few hotspots. The graphic below, from NatureServe, depicts how many listed threatened and endangered species are found in each county. Hawaii, the Pacific Coast, the Southwest, Appalachia, and Florida stand out for their large number of listed species, but many U.S. counties, especially in the Midwest, have no threatened or endangered species.

Species map

The number of listed species might seem like a useful barometer for tracking the status of biodiversity, but it’s an imperfect metric at best. Species are supposed to be added to the list solely on the basis of science and biologists’ assessment of their imperilment, even if doing so would derail development or impose steep economic costs. In reality, several studies have found that politics frequently intrudes in the listing process. See, for example, my book Endangered: Biodiversity on the Brink, and a 1990 book by Richard Tobin (no relation),  The Expendable Future: U.S. Politics and the Protection of Biological Diversity.

In its first term, the Obama administration has listed more species per year than George W. Bush’s administration, but considerably fewer than during the Clinton administration. Looking at the rate of species listings says as much about the political appetite for such regulatory moves as it does about the status of the nation’s biodiversity.

The ESA gives citizens the ability to petition the federal government to add a new species to the list and some environmental groups, such as the Center for Biological Diversity and WildEarth Guardians, frequently make these requests. Fish and Wildlife is obligated to evaluate these petitions and decide whether a species should be listed, but with limited resources the agency can only process so many petitions. ESA opponents in Congress and elsewhere have figured out that by limiting this listing budget, they can constrict the pipeline of new species gaining federal protection.

Candidates in regulatory purgatory

The result is a gaping loophole that allows the government to declare a species’ listing as biologically “warranted but precluded” by budget constraints. Fish and Wildlife is only supposed to use this exception if “expeditious progress is being made to add qualified species” to the endangered club. In reality, the exception has become an all-too-convenient way for the government to abdicate its responsibilities under the ESA. I liken it to creating a long, slow-moving line for species to get aboard our legislative Noah’s Ark.

At least 24 species have blinked out while in the listing pipeline and the backlog of candidate species was the subject of recent litigation.  The Obama administration has made some progress in reducing the number of candidates from about 250 at the start of his first term to 192 in November 2012. Candidate species, like listed species, are found throughout the country, but they’re concentrated in Western and Southern states.

The number of listed species is bound to keep rising because only 20 have been declared recovered and no longer in need of ESA protection. In 18 cases, the government decided the original listing was in error, often because of taxonomic changes or the discovery of new populations. A species protected by the ESA has been declared extinct only nine times over the past four decades, which is pretty impressive given that many plants and animals only receive ESA protection after they’ve been driven to the brink.


Data sources

Fish and Wildlife’s ESA site is the go-to source for information on endangered species. I’ve also found Precious Heritage: The Status of Biodiversity in the United States to be an extremely helpful resource. The Nature Conservancy and NatureServe make some of the book’s figures available here.

If you’d like to explore some of this data further, I’ve built a state-by-state dashboard that shows the number of listed, candidate, and extinct species.

EcoWest’s mission is to analyze, visualize, and share data on environmental trends in the North American West. Please subscribe to our RSS feed, opt-in for email updates, or follow us on Twitter.

Mapping the real tweets: eBird’s animations of U.S. species

eBird, a real-time online birding checklist, has produced some fascinating animated maps showing week-by-week occurrences of U.S. species. Below is the animation for the Swainson’s hawk, the most migratory of American hawks.

ebird map

The patterns in the animations struck me as similar to the video of satellite imagery we recently posted which showed how the snowpack, vegetation, and wildfires expand and contract in North America every year.

The eBird website has maps for dozens of other species, but the one above  is especially interesting because it helps illustrate how the hawk has developed an entirely new migratory strategy to take advantage of habitat changes in its range. Here’s how eBird describes what’s happening:

A fascinating pattern can be seen by concentrating on the Central Valley of California. The occurrence of Swainson’s Hawks here has been changing in recent years, as the species appears to have taken advantage of the large areas of agriculture that have become available to them within the last century. This year-round animation shows that Swainson’s Hawks arrive here in early March, more than a month earlier than those arriving on the Great Plains. Swainson’s Hawks feed largely on grasshoppers in summer, and the more temperate climate of the Pacific Coast may permit them to return earlier here (a few even winter in California now). But it also seems likely that these birds are not traveling as far south in winter as the more easterly population. Within the past 20-30 years, Swainson’s Hawks have started wintering in the northern hemisphere, and they now occur regularly in winter in Panama, coastal west Mexico, and southern Baja California–all areas that were forest or desert historically, but have recently been cleared and irrigated for agriculture. With hundreds of birds now wintering in the southern Baja California Peninsula, and an increasingly large late February and March migratory passage in southeastern California, it seems likely that these Pacific Swainson’s Hawks are using these new habitats in both summer and winter, and have rapidly evolved a new migratory strategy to take advantage of them.

Another interesting aspect of eBird is that it relies on the efforts of thousands of volunteer birders around the country to collect the data needed to create these visualizations.

Here’s an overview of eBird:

A real-time, online checklist program, eBird has revolutionized the way that the birding community reports and accesses information about birds. Launched in 2002 by the Cornell Lab of Ornithology and National Audubon Society, eBird provides rich data sources for basic information on bird abundance and distribution at a variety of spatial and temporal scales.

eBird’s goal is to maximize the utility and accessibility of the vast numbers of bird observations made each year by recreational and professional bird watchers. It is amassing one of the largest and fastest growing biodiversity data resources in existence. For example, in January 2010, participants reported more than 1.5 million bird observations across North America!

EcoWest’s mission is to analyze, visualize, and share data on environmental trends in the North American West. Please subscribe to our RSS feed, opt-in for email updates, follow us on Twitter, or like us on Facebook.