If you live in a city you may not realize that urban populations of bats are all around you. But Liza Lehrer and Shannon Pederson, who work on urban bats, know that bats are common in cities, even if you don’t always see them.
Lehrer started off by describing how bats are under threat due to white-nose syndrome and this could have large consequences for the ecosystem since bats provide services such as pollination and eating insects. But bats can thrive in cities–places like Austin, TX have large bat colonies and ALAN can attract insets which provide food for bats. Lehrer asked, how are bats using the urban core? Using passive acoustic monitoring systems Lehrer set up nine rural and 14 urban sites around Chicago. These acoustic systems recorded over 56,000 calls from seven bat species. Preliminary results suggest that distance to water had a strong effect of four of the seven species. Additionally, for four species, abundance decreased as sound pressure level increased.
Pederson looked at bats in Northern Virginia, Washington DC, Maryland and Delaware and asked (1) Do bats utilize highly urbanized areas? (2) How do different species use urban space? (3) What landscape features are important for bats? Pederson described the necessity of using multiple factors to define “urban” which included Census data, percent impervious surface cover, percent forest cover, and percent open space. Using full spectrum detectors, which are able to record sound from multiple species at once, Pederson found that high-intensity urban areas had only one fewer species compared to medium-intensity and low-intensity areas. Pederson also found that high-intensity urban areas were dominated by the big brown bat and many variables are important for bat presence.
Taken together, these talks provide insight into the multiple ways urbanization is shaping the ecology and evolution of bat species.
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