D3518: A snapshot of pollinators inhabiting U.S. Army Corps of Engineers project areas in the Ouachita Mountains, Arkansas

The U.S. Army Corps of Engineers (USACE) manages over 12 million acres of land and water over 43 states, including millions of acres of terrestrial habitat surrounding flood control and navigation projects. Outlined in the 2014 Presidential Memorandum Creating a Federal Strategy to Promote the Health of Honey Bees and Other Pollinators is a mandate for USACE to implement conservation practices for pollinator habitat improvement. USACE Conservation Biologists in the Little Rock District have taken the important step of funding Level II inventories of pollinators and plants to better understand existing conditions as well as improve pollinator habitat by developing best management practices. In an August 2023 survey of pollinators at two USACE project areas (Blue Mountain Lake and Nimrod Lake) within the Ouachita Mountain Level III Ecoregion, almost 2000 specimens representing 84 insect families in 9 orders were collected. A combination of active and passive gear types were used to maximize sampling efficiency during a 4-day window. Family diversity was highest in malaise samples (N=54) and during timed sweepnetting (N=50). Malaise traps also captured larger abundances of insects than any other gear used (N=1240 individuals).  While a 4-day sampling effort represents merely a snapshot of the total insect diversity at these locations, several notable taxa were encountered, including Trachusa dorsalis (Hymenoptera: Megachilidae) and a potentially undescribed species in the genus Myzinum (Hymenoptera: Thynnidae). This survey provides invaluable baseline data on which to provide habitat management recommendations, monitor communities, and to ensure the future success of pollinator populations.