Effects of Urbanization on Survival Rates, Anti-Predator Behavior, and Movements of Woodchucks (Marmota Monax)

flight initiation distance;home range;space use;urbanization;vigilance;woodchucks

Watson, Elizabeth L. ; Schooley, Robert L. ; Schooley ; Robert L.

关键词: flight initiation distance;    home range;    space use;    urbanization;    vigilance;    woodchucks;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/14642/1_Watson_Elizabeth.pdf?sequence=3&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Urbanization is increasing at a rapid rate and creating novel environmental conditions for wildlife species, even in already human-altered landscapes. We need a better understanding of demographic and behavioral responses by mammals to urbanization including those species that could be urban adapters. Furthermore, past research has focused on carnivores, but herbivores could respond to additional factors across urbanization gradients such as variation in real and perceived risk from predators. I examined survival, cause-specific mortality, anti-predator behavior, and movements of adult woodchucks (Marmota monax) across an urbanization gradient within an agricultural landscape in central Illinois from 2007 to 2009. As predicted, survival rates were related positively to urbanization. Survival rates of woodchucks were higher, and effects of urbanization were stronger during the inactive season relative to the active season for this hibernating species. Woodchucks in rural areas mainly died from predation and probable starvation during hibernation, whereas major causes of mortality for urban woodchucks were vehicle collisions or unknown reasons. Three measures of anti-predator behavior—levels of vigilance, foraging distance from burrows, and flight initiation distance—did not vary with urbanization. Julian date was related to all components of anti-predator behavior in a consistent manner, which indicates woodchucks take on more risk later in the active season as hibernation approaches. Home-range size of woodchucks in urban areas was ~10% of those in rural areas and urbanization had stronger effects on home-range sizes of males compared to females. Woodchucks are multiple central-place foragers and their use of burrows within home ranges also was influenced by urbanization. Number of burrows per individual decreased with urbanization, but the number of burrows was not scaled proportionally to home-range size. Distances between burrows increased in rural areas, and thus risk during inter-burrow movements could be greater for rural woodchucks. Aggregation of use among burrows increased with urbanization and was related positively to spatial connectivity of burrows. Urbanization created spatial variation in real risk for woodchucks and woodchucks responded by demonstrating substantial plasticity in movement behavior. However, although natural predators are reduced in urban areas, perceived risk affecting anti-predator behavior remained high overall for woodchucks in urban areas due to increased levels of human disturbance and lack of strong habituation to humans. My research demonstrates how combining demographic and behavioral studies can provide insights into responses to urbanization, and constraints to those responses, by an urban-adapter species.