IMPACT OF CLIMATE AND LAND-USE CHANGE ON THE ACTIVITY PATTERNS OF A LARGE TROPICAL MAMMAL

Abstract

Large tropical mammals play a vital role in structuring ecosystems through their interactions with other species and their environments. Climate and land-use change are both causing population declines and behavioral changes in this important group. In this dissertation, I examine how the activity patterns of a keystone Neotropical species, the white-lipped peccary (Tayassu pecari), are impacted by these factors. Using agent-based modelling, I identify minimum thresholds of 40% forest cover to support landscape functional connectivity for this species, and 60% forest cover to preserve normal movement patterns. I also find that forest loss drives peccaries to increase their daily travel distance, which will require increasing the time they spend active. Analyzing empirical data from accelerometers, I show that rising temperatures drive peccaries to decrease their activity in four distinct biomes - the Amazon, the Atlantic Forest, the Cerrado, and the Pantanal. However, based on an analysis of camera trap data collected at a finer temporal scale in the Pantanal, they are able to compensate for decreased afternoon activity to an extent by increasing their nocturnal activity. Through a probabilistic analysis of energetics, I conclude that peccaries have very little scope for reducing their daily activity or daily travel distance while still maintaining a positive energy balance. Overall, these results suggest that in many areas, peccaries will be unable to maintain a positive energy balance in the future under opposing pressures from climate and land-use change. And I expect that other large tropical mammals will face similar challenges of shifting movement and activity patterns while navigating fragmented landscapes and trying to reduce heat stress.