Data from: Insectivorous bat occupancy is mediated by drought and agricultural land use in a highly modified ecoregion

Abstract Aim California’s Central Valley, one of the most productive
agricultural regions worldwide, is home to a high number of at-risk
species due to habitat conversion. Amplifying the issue, the Central
Valley faces severe droughts, creating water scarcity in surrounding
natural areas. At least 14 insectivorous bat species live in this region,
and prior studies show mixed results regarding the impact of agriculture
and drought on bats. The aim of this study was to investigate how bats use
agricultural areas during drought. Location Central Valley, California,
United States Methods We deployed ultrasonic acoustic detectors at 274
sites from March through July of 2016, the final year of an extreme
drought, and 2017, one of the wettest years on record. We identified bats
to species, used single-species occupancy models including biologically
relevant covariates, and created spatial projections of ecoregion-wide
occupancy for each species. Results We modelled occupancy for eight bat
species. Long-distance migrants in the study area contracted their
geographic range during the drought, while resident species did not. Five
of the eight bats in this analysis were more likely to occupy areas with
orchard crop cover. Lastly, arid-adapted bats used cultivated landscapes
during the drought but retracted their range after the drought ended. Main
Conclusions Migratory bats appeared to shift occupancy more during drought
than resident bats, possibly because of lower roost fidelity.
Additionally, the effects of drought on some bat species in the Central
Valley may be buffered by agricultural landscapes acting as drought
refugia. Overall, this study demonstrates the benefits of broad-scale
acoustic studies which can serve as a tool to track changing bat
distributions on the landscape and provide baseline occupancy for
acoustically detectable species.