Post-white-nose syndrome bat communities in the National Capital Region: Part 1—final report

Deeley, Sabrina; Freeze, Samuel; Rohrbaugh, Lindsay

doi:10.36967/nrr-2287867

White-nose syndrome (WNS) has caused large population decreases for several hibernating species in eastern North America. Our objectives were to document the existing bat communities, determine how bat communities have changed since the onset of WNS, document migration activity, document hibernacula use, identify day-roosting habits of WNS-impacted species, and provide ongoing monitoring recommendations within the National Park Service (NPS) National Capital Region (NCR). We surveyed the region between 2016 and 2018 using active acoustic recording, passive acoustic recording, mist netting, crevice searches, and radio-telemetry tracking. Using passive acoustic monitoring, software identified calls and nights with presence (based on United States Fish and Wildlife Service standards) from all species for which we surveyed, including the Federally Endangered Indiana (Myotis sodalis) and Threatened northern long-eared (Myotis septentrionalis) bats. Our active acoustic methods duplicated sampling techniques and locations previously surveyed 2003 – 2004. Comparing the two datasets, we determined that the bat communities have significantly changed since WNS. There were significant decreases in the number of echolocation calls recorded for the WNS-impacted Indiana bat, little brown bat (Myotis lucifugus), and tri-colored bat (Perimyotis subflavus). We also documented an increase in the number of echolocation calls for the big brown bat (Eptesicus fuscus). With passive acoustic sampling, we identified the presence of 12 bat species within the NCR: big brown, eastern red (Lasiurus borealis), eastern small-footed (Myotis leibii), evening (Nycticeius humeralis), hoary bat (Lasiurus cinereus), little brown, Mexican free-tailed (Tadarida brasiliensis), northern long-eared, silver-haired (Lasionycteris noctivagans), southeastern myotis (Myotis austroriparius), and tri-colored bats. We documented presence relative to sampling intensity at each sample site, identifying that the western end of the Chesapeake and Ohio Canal National Historical Park (CHOH) had the highest recorded bat diversity and numbers of occupied nights for species highly-impacted by WNS. Our netting surveys verified the continued presence of species highly-impacted by WNS: eastern small-footed bat, little brown bat, northern long-eared bat, and tri-colored bat. However, compared to pre-WNS surveys in the NCR units, we documented a significant reduction in distribution and abundance, measured by both acoustic monitoring and physical capture, of the little brown, northern long-eared, and tricolored bats. Within Rock Creek Park (ROCR) and Prince William Forest Park (PRWI), the northern long-eared bat populations appear to be persisting. Their day-roosting ecology appears relatively unchanged in terms of forest type/condition and day-roost type/condition post-WNS when compared to pre-WNS observations in the mid-Atlantic region. Additionally, we documented a potential tri-colored bat maternity colony location within private property adjacent to CHOH.

Post-white-nose syndrome bat communities in the National Capital Region: Part 1—final report

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