Landscapes of change: the ecology of white-faced capuchins over space and time


As global change accelerates, there is a growing imperative to understand how wild animals respond to changing environments. I investigated how environmental variability, both in the short term (seasonality and habitat differences) and the long term (changing climate and habitats), shapes the behavioral ecology of white-faced capuchins (Cebus capucinus) in a highly seasonal dry forest mosaic in Costa Rica. I used a multi-scale approach with the ultimate goal of gaining a more complete understanding of how individual-level selective pressures scale up over space and time to affect group and population dynamics.

Perceived predation risk, based on alarm-call responses to distinct predator classes, varied among habitat types and was greatest in mature forest. The capuchins adjusted their anti-predator vigilance behavior to changing levels of perceived risk. Feeding efficiency varied over both space and time and was greatest during the wet season and in mature forest habitats, which were both associated with higher energy intake rates and lower energy expenditure rates. The hot dry season also favored smaller home ranges, with high-use zones concentrated around patches of mature evergreen forest. These findings demonstrate that environmental variability plays a key role in driving the spatial ecology of capuchin individuals and groups. Because the dry season is associated with greater energetic deficits, the capuchins’ increased preference for mature forest and more compact use of space during the dry season may be a behavioral adjustment aimed at maximizing use of the most productive foraging areas and reducing travel, perhaps at the expense of safety.

Finally, I examined spatial and demographic patterns in the growing capuchin population over multiple decades in relation to quantitative information on how the environment changed over the same period. The availability of evergreen habitats varied with the strength of the previous wet season, which in turn was strongly coupled with global climatic and oceanic cycles. Following extreme drought periods, population growth slowed, mean group size decreased, and reproductive rate declined. Future work will aim to develop a deeper understanding of how climate change will affect primate populations and to expand the scope and generality of this research to a global scale.

PhD Thesis, University of Calgary