A new study led by the University of Wisconsin-Madison has developed detailed maps of bird biodiversity across the entire United States in order to help conservation managers focus their efforts in areas where they are more likely to help endangered bird populations.
Since many resources previously available to conservation managers – such as species range maps – are both too broad and not rigorously tested for accuracy, the new maps focus on individual counties or forests rather than on whole states or regions, and are based on both detailed observations of birds and various environmental factors that affect bird ranges, such as forest cover or temperature levels in specific areas.
“With these maps, managers have a tool they didn’t have before that allows them to get both a broad perspective as well as information at the level of detail that’s necessary for their action plans,” said study co-author Anna Pidgeon, a professor of Forest and Wildlife Ecology at UW-Madison.
“Across the world we’re seeing huge species losses. In North America, three billion birds have been lost since 1970. This is across virtually all habitat types,” added study lead author Kathleen Carroll, a postdoctoral researcher in Wildlife Conservation at the same university. “And we’re seeing a disconnect between what scientists produce for conservation and how that translates to boots-on-the-ground management.”
In order to address these problems, Dr. Carroll and her colleagues produced data-driven maps of bird biodiversity by extrapolating observations of birds from scientific surveys to mile-by-mile predictions of where specific species actually live. The predictions were based on factors such as rainfall, forest coverage, or the extent of human influence on the environment, such as the presence of urban areas or farms.
The scientists clustered individual species by habitat, diet, behavior, or conservation status, grouping them in “guilds” such as fruit eaters or forest dwellers. The final maps cover 19 different guilds at resolutions of 0.5, 2.5, and 5 kilometers. According to the researchers, the 2.5 km resolution maps provided the best balance of accuracy and usefulness for realistic conservation needs.
“We see this being really applicable for things like forest management action plans for the U.S. Forest Service,” explained Dr. Carroll. “They can pull up these maps for a group of interest, and they can get a very clear indication of what areas where they might want to limit human use.” In addition, these maps could also help private land conservancies decide where to prioritize their frequently limited resources to maximize biodiversity protection.
The researchers plan to extend their analyses down to individual species instead of guilds made up of different species in order to help conservation managers aiming to protect specific species improve their work.