This doctoral research project combines stable isotope analysis with behavioral and environmental data to investigate how peatland fires and land clearance impact the health and energetics of a wild great ape species. The project advances understanding about how a keystone species adapts to climatic and human-induced fires and habitat loss, while also providing a model of potential energetic plasticity in our hominin ancestors during times of resource scarcity and in variable and unpredictable environments (like fire prone regions). The project supports conservation efforts, international research collaborations, and community engagement at the research site and provides training opportunities for undergraduate students, including those from underrepresented groups in STEM, at Rutgers University. <br/><br/>The project examines whether ecological disturbances such as peatland fire burns and road construction influence the local ecology and energetic status of wild orangutans. Carbon (δ13C) and nitrogen (δ15N) stable isotopes from urine and hair are used to identify changes in energy balance in orangutans that experience these ecological disturbances to varying degrees. Plant materials (which include a combination of orangutan plant foods and commonly encountered plants) are also isotopically analyzed to establish an environmental baseline and assess variation in plant physiology and nutrient availability at various distances from disturbances across the site. The project also analyzes urine samples previously collected from before, during, and after past peatland fires to assess the same impacts on health and energetics in orangutans. The researchers use Geographic Information System (GIS) data for spatial analysis and Generalized Additive Mixed Models (GAMMs) to identify shifts in isotopic signatures at different distances from the disturbances while incorporating variables such as age, sex, and environmental factors, to provide a comprehensive analysis of how disturbances influence orangutan health.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.