Indiana Bat Population Dynamics in the Midst of Climate Change and White-Nose Syndrome

Author

• Lexie Ann Schwartz, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2026

Degree Name

Master of Science

Department

Biological Sciences

First Advisor

Anderson, Frank

Abstract

Climate change and emerging diseases are altering species distributions and ecosystem dynamics worldwide. For temperate insectivorous bats in North America, food availability and winter climate influence hibernation energetics and survival. As climate warming alters insect phenology, these changes are likely to have an impact on hibernating bats. Many cavernicolous bats in North America are also threatened by white-nose syndrome (WNS), a newly emerged fungal disease devastating bat populations. This study examined the distribution of hibernating Indiana bats (Myotis sodalis) over time throughout their range. I used long-term weather data to simulate seasonal insect availability, the spring and autumn transitory periods, and then estimated hibernation length and winter foraging opportunities. I then evaluated how populations of hibernating bats varied with latitude before and after WNS, as latitude and winter severity are highly correlated variables. Before WNS was detected in the states (1930-2006), latitude was not a significant predictor of population growth, indicating that there was not a significant northerly shift in populations of hibernating Indiana bats. However, there did appear to be a northward shift occurring on a localized scale. Following the emergence of WNS, latitude significantly predicted population growth, indicating that WNS survival rates are influenced by a geographic gradient. Population increases were concentrated in specific regions that likely function as climatic refuges for WNS stressed bats. These results suggest that Indiana bats have adjusted their winter distributions in response to both climate change and disease. These results provide evidence of resilience to a changing environment, and emphasize the importance of long-term population monitoring, which is critical for detecting redistribution of individuals, and identifying how populations will respond under future warming and disease scenarios.