Doctor of Philosophy, The Ohio State University, 2004, Evolution, Ecology, and Organismal Biology
In this study, we explore large-scale movements in ruffed grouse (Bonasa umbellus) in Ohio by characterizing juvenile and adult dispersal, investigating the effect of landscape characteristics on movement behavior and examining the relationship between movement and the risk of predation. Our first objective was to investigate the natal and adult dispersal characteristics of ruffed grouse throughout the entire annual breeding cycle, using a behavioral definition of dispersal. Once dispersal movements could be accurately identified, we explored whether landscape variables measured at coarse-grained scales could help explain general movement characteristics. We used Akaike Information Criterion (AIC) techniques for model selection to explore the relationship between metrics of both landscape composition and configuration and the decision to disperse by adults and juveniles, their net dispersal distances and rates of movement, and their home range sizes. Ecologists often assume that dispersing individuals experience an increase in predation risk due to increased exposure to predators while moving. We tested the hypothesis that predation risk is a function of rate of movement and site familiarity using a Cox's proportional hazards model. Overall, we documented a surprisingly high proportion of adults undertaking seasonal dispersal movements and juveniles undergoing dispersal in the spring, particularly compared to grouse studies conducted in the northern portion of its range (Chapter 1). We also found that coarse-grained landscape characteristics affect movement behavior, but effects varied considerably among specific behaviors and across spatial scales. While large-scale landscape composition (i.e. % forest) and edge density significantly affected dispersal behavior little evidence was found for landscape configuration per se affecting movements (Chapter 2). Finally, we found evidence indicating that increased movement rates may increase the risk of predation for adult (open full item for complete abstract)
Committee: Elizabeth Marschall (Advisor)
Subjects: Biology, Ecology