Abstract

The availability and accessibility of water resources are important factors influencing bat presence in urban areas. Bats access water sources on the wing and may not be able to access water sources with smaller surface areas or those obstructed by clutter. To address this, we conducted a study to assess the extent to which variation in available water surface area influenced the abundance of bat activity and the diversity of species present in an urban area. We surveyed six study sites in Tarrant County, Texas in 2023 and 2024 using a thermal camera to record the total duration bats were present and the number of observed drinking events and an acoustic detector to record the number of bat calls, number of drinking buzzes, and number of species during each survey. We also used a drone to assess water surface area metrics including the fundamental and realized surface areas, maximum patch sizes, and longest stretches of continuous area. Comparing each of these independent variables with each dependent variable, we determined that decreasing length of available surface area resulted in a corresponding decrease in bat activity and diversity. In particular, we observed a reduction in drinking activity, the primary indicator of water resource use. In other words, we found that as water sources dried up and increased in clutter the length of the available surface area prevented or deterred bats from accessing as a drinking resource. Therefore, effective management of water sources in urban areas must include the removal of any clutter to improve the accessibility of water sources for bats and encourage a diversity of urban wildlife.