The importance of long-term capture-mark-recapture archives for wildlife monitoring and research: Two examples from bat populations

Abstract

Long-term capture-mark-recapture (CMR) projects provide useful data to study and monitor wildlife. Specifically, CMR data can help identify how an animal interacts with its environment and how these interactions change throughout its life. In this thesis, I use data and sample archives from temperate hibernating bats captured and tagged as part of a long-term project in Newfoundland and Labrador, Canada. In Chapter 2, I use fur collected from adult female 𝑀𝑦𝑜𝑡𝑖𝑠 𝑙𝑢𝑐𝑖𝑓𝑢𝑔𝑢𝑠 captured multiple times from 2012-2017 to investigate age dependent changes in the concentration of the toxic compound, methylmercury (MeHg). Results suggest total mercury concentrations, which are highly correlated with MeHg, decrease with age in the fur of adult female bats. This pattern indicates that adult female bats can eliminate enough MeHg from their tissues to have steady or decreasing concentrations in their fur. In Chapter 3, I use forearm measurements taken by multiple observers from captured and tagged 𝑀. 𝑙𝑢𝑐𝑖𝑓𝑢𝑔𝑢𝑠 and 𝑀𝑦𝑜𝑡𝑖𝑠 𝑠𝑒𝑝𝑡𝑒𝑛𝑡𝑟𝑖𝑜𝑛𝑎𝑙𝑖𝑠 to quantify the measurement error and observer bias associated with this morphometric variable. Results suggest measurement error can add enough variation to mask relationships between forearm length and related variables. Further, observer bias can cause type I errors when comparing populations with small differences in forearm length that were measured by different observers. These two studies exemplify the use of long-term CMR projects as an invaluable tool to assess research techniques, study wildlife biology, and monitor ecological changes.