An analysis of fringed myotis (Myotis thysanodes), with a focus on Colorado distribution, maternity roost selection, and preliminary modeling of population dynamics

The purpose of my research was to describe the distribution and roosting ecology of Myotis thysanodes in Colorado, and to initiate preliminary population dynamics modeling of the potential impacts of a changing climate on forest dwelling Myotis in the Southern Rocky Mountains. Seven hundred and twenty-nine Colorado capture and occurrence records of M. thysanodes were documented. I used 546 M. thysanodes records that included information about sex and reproductive status in an analysis of variance comparing elevational distribution among sex and reproductive classes. There were significant differences among reproductive classes, but not between sex classes. Sixteen actual or probable M. thysanodes maternity sites were identified in Colorado. In the maternity roost analysis using four landscape variables (elevation, grade, aspect, and proximity to permanent water), the model that incorporated grade and transformed aspect had most support using multi-model inference and Akaike's Information Criteria. In the maternity roost analysis using three roost-site variables (mean temperature, mean relative humidity, and estimated volume of the structure), the model that estimated volume of the roost structure had the most support. In preliminary Monte Carlo population simulations using three International Panel on Climate Change emissions scenarios, by year 2100 mean Myotis and M. thysanodes populations exhibited significant decreases from the original populations of 2,000 females in year 2000. All species specific M. thysanodes simulations exhibited at least 95 percent reduction by year 2100 from the original populations of 2,000 female bats in year 2000. An improved understanding of M. thysanodes distribution, roosting ecology, and the potential impacts of a changing climate can help inform conservation and resource management decisions in Colorado and elsewhere in the Rocky Mountain West.