WASHINGTON (CN) – The U.S. Fish and Wildlife Service proposed the rusty patched bumble bee, an important pollinator, for endangered status under the Endangered Species Act Thursday. The bee, once prevalent in over 28 eastern and Midwestern states and 2 Canadian provinces, is now distributed in a mere eight percent of its former range due to pesticide use, disease and climate change. From 378 U.S. counties and 2 provinces, the bees are now found in only 41 counties and 1 province.
“As pollinators, rusty patched bumble bees contribute to our food security and the healthy functioning of our ecosystems. Bumble bees are keystone species in most ecosystems, necessary not only for native wildflower reproduction, but also for creating seeds and fruits that feed wildlife as diverse as songbirds and grizzly bears,” the agency said.
The listing proposal is in response to a petition filed in 2013 on behalf of the rusty patched bumble bee by the Xerces Society for Invertebrate Conservation. The group then filed a lawsuit against the Service in 2014 because the petition review had not been completed in the 90-day period required by the Endangered Species Act (ESA). In a settlement agreement, the agency committed to publishing the 90-day finding by September 2015 and the 12-month finding by the end of September 2016, which was published Thursday as part of the listing proposal.
This bee “has at least two threats for which existing regulatory mechanisms are inadequate to protect them, the widespread use of toxic insecticides whose toxicity to native bees were not adequately considered in the pesticide approval process and the distribution of commercial bumble bees within the range of the rusty patched bumble bee that are not required to be free of pathogens. Listing the rusty patched bumble bee under the ESA will require that its needs be considered when federal actions, like the registration of new pesticides, are taken,” Xerces Senior Conservation Biologist Rich Hatfield said.
Though the diseases that affect bees are not well understood, it has been documented that several bumble bee species started to decline at the same time that commercially-bred bumblebees were declining. It is speculated that a spillover of pathogens from commercially bred bees has spread to wild colonies, but it does not fully explain the problem, the agency said.
The bumble bees nest in the ground and may be susceptible to accumulated pesticides in the soil. Herbicides also reduce the available flowering plants the bees need to survive, and intensive farming practices, where one crop dominates the landscape, reduce crop diversity, shorten flowering times, and remove the shrubby hedgerows that are used to separate smaller fields of crops that are also an important source of flowering plant diversity.
Climate change is also affecting the bees in various ways, such as creating a mismatch in flowering times and the bees’ life cycle, reducing nesting areas due to flooding, and increasing stress from over-heating due to higher temperatures.
The now widely separated small populations of rusty patched bumble bees continue to shrink, and inbreeding is contributing to the extinction risk. “As population numbers decrease, there is an increased chance of related individuals mating, which results in an increase in the proportion of the population made up of sterile males. In this way, successful reproduction is further reduced and an extinction spiral occurs as proportionally fewer and fewer females and fertile males are produced,” the agency said. “Due to the size of the current populations, some may no longer persist and others are likely already quasi-extirpated (the level at which a population will go extinct, although it is not yet at zero individuals).”
The agency encourages those who want to help the bees to plant gardens, to landscape with native species, to eliminate the use of pesticides and herbicides and to leave some areas untilled for nesting sites.
The Xerces Society encourages citizen scientists to participate in its online Bumble Bee Watch, a developing database of sightings and observations for bumble bee species in the U.S. and Canada.
Comments and information on the listing proposal are due Nov. 21, and requests for public hearings are due in writing by Nov. 7.
Cover photo by Dan Mullen
Information on closeup photos (2nd and 3rd photos): Sam Droege of the United States Geological Survey Bee Inventory and Monitoring Lab noted in the Flicker photo posting: “T’ai Roulston and his identification triggerman Skyler Burrows stopped by the lab this week to work on some tricky bee ids and brought this Bombus affinis in from Sky Meadows State Park at the edge of the Blue Ridge in N. Virginia to have its picture taken. 20 years ago this would be no big deal as this species was common, but populations have subsequently tanked and the last ones see alive East of the Great Lakes were found in New England in 2009 (and only 1). So there is hope that populations persist and may claw their way back from their punishment by introduced microcreatures. Collected as part of a joint Smithsonian/Front Royal Blandy Experiment Station/ UVA project to look at meadow restoration.”
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