Separating the effects of water quality and urbanization on temperate insectivorous bats at the landscape scale.

Many local scale studies have shown that bats respond to water quality degradation or urbanization in a species-specific manner. However, few have separated the effects of urbanization versus water quality degradation on bats, in single city or single watershed case studies. Across North Carolina, USA, we used the standardized North American Bat Monitoring Program mobile transect protocol to survey bat activity in 2015 and 2016 at 41 sites. We collected statewide water quality and urban land cover data to disentangle the effects of urbanization and water quality degradation on bats at the landscape scale. We found that statewide, water quality degradation and urbanization were not correlated. We found that bats responded to water quality degradation and urbanization independently at the landscape scale. and negatively responded to water quality degradation. and positively responded to water quality degradation. did not respond to water quality degradation but was more active in more urbanized areas. positively responded to urbanization and was less active in areas with degraded water quality. We show that bat-water quality relationships found at the local scale are evident at a landscape scale. We confirm that bats are useful bioindicators for both urbanization and water quality degradation. We suggest that water quality can be used to predict the presence of bat species of conservation concern, such as , in areas where it has not been studied locally.