Public lands are important areas of habitat for wildlife, including invertebrates. In the U.S. the federal government manages roughly 640 million acres of public lands, most of which are National Parks, National Forests, Bureau of Land Management areas, and U.S. Fish and Wildlife Service lands. Much of this land is in the western U.S., as demonstrated by the map below. These lands serve multiple purposes–including recreation, resource extraction, ecosystem service provision, and habitat protection–but their role as habitat for wild bees has often been overlooked.

So just how important are these lands to bees? The Bumble Bee Watch (BBW) database can give us a window into this question. Since 2014, BBW users have submitted more than 250,000 bumble bee observations to the platform, both through formal surveys in our Bumble Bee Atlas projects (active in 20 U.S. states) and incidental or casual observations across North America. These observations take place in all sorts of places, from backyard gardens to cities and wilderness areas.

Our data show that approximately 37% of all of these observations took place on U.S. federal lands, making these lands integral to our collective efforts to understand the status of native bumble bees. The graph below shows that federal lands are particularly important as bee habitat in western United States.

So how do the many uses of our public lands affect bee habitat and populations? We can glimpse these impacts by comparing Bumble Bee Atlas surveys on the various federal lands ownerships to each other and to those conducted on private and other land jurisdictions. Using records from our Bumble Bee Atlas program, one pattern that we see in the data is that the land managed by different agencies appears to have a different capacity for the numbers and types of bumble bees they support. For example, we have found that U.S. Forest Service lands generally have more species than other jurisdictions. Interestingly, U.S. Forest Service lands also had the highest number of bees per survey. We don’t know exactly what is driving these differences, but it’s likely a combination of differing geographical patterns of land acquisition across the agencies, varying ecosystem types, and differences in habitat management practices. The graph below uses box plots* to make this comparison, with the white squares representing means or averages.

*Explanation of box plots: A boxplot represents a set of data records by showing the median value (vertical black line in box), the interquartile range, in which 75% of the records occur (the colored box), and the range in which 95% of the values occur (the horizontal lines extending from box, i.e. whiskers). We have added white squares to signify the mean (average) value for each set of records in this plot.

Not surprisingly, our federal lands are also important refuges for our most imperiled bumble bee species. Below we see a selection of six rare bumble bee species and the number of times they were observed on federal and other lands. Generally, these lands provide important habitat for these species, some of which are the objects of concerted efforts to recover their populations. Species with more western distributions (e.g., western bumble bee, Bombus occidentalis) are disproportionately found on federal lands, while eastern species (e.g., the rusty-patched bumble bee, B. affinis) have been observed primarily on private and other lands.