AUTHORS: Katie Fitzgerald, Marcus Jorgensen, Diana Hews, Cory Suski, and Joy O’Keefe
ABSTRACT: Forest management practices aim to improve natural landscapes and provide critical habitat, but their effects on wildlife health are not well understood. This study used non-invasive techniques to quantify health by measuring hair cortisol, a stress hormone, and body mass, in four common bat species in northeastern Missouri. We sampled across three non-managed forests and three managed forests, where small-scale treatments such as girdling, thinning, and prescribed burns were applied. Sampling occurred before and after the application of these treatments, which were implemented in 2022 (sampling 2019-2023). Post-treatment, Indiana bats from managed forests had significantly lower cortisol than those from non-managed forests, while evening bats and Indiana bats from managed forests also had greater body mass. Post-treatment, adult male red bats exhibited higher cortisol levels than pre-treatment, regardless of forest type. For big brown bats, body mass and cortisol levels were similar across all sample years and forest types. These results suggest that small scale forest management could help reduce stress levels and increase body mass, particularly for smaller bat species such as Indiana bats and evening bats, by creating favorable foraging conditions and reducing competition. Overall, our study suggests that hair cortisol and body condition offer a non-invasive method to evaluate the impacts of habitat alterations on wildlife and provide valuable insights into how forest management practices impact bat health.
