Fransisca Ariantiningsih
Mapping Tolerance in Human–Orangutan Interactions: A Social–Ecological Systems Approach to Coexistence Strategies in the Leuser Ecosystem
As forests are converted to agricultural land across Sumatra, people and orangutans are sharing the same landscapes more often. These encounters can result in crop damage, economic losses, and tension between local communities and wildlife. Yet communities living under similar conditions often respond very differently. Some tolerate orangutans despite repeated encounters, while others view them as a serious threat. These differences suggest that ecological factors alone cannot explain how people respond to wildlife. My research examines how social and ecological factors shape tolerance toward orangutans across the Leuser Ecosystem.
The Leuser Ecosystem, one of the last remaining strongholds for the Sumatran orangutan, provides the setting for this research. Drawing on the Social–Ecological Systems framework, I combine household surveys, interviews, and spatial analysis to examine how ecological conditions, livelihoods, governance, and cultural values interact to influence tolerance toward orangutans. By linking social data with geographic information, I map patterns of tolerance across villages to better understand why coexistence varies across the landscape.
Rather than focusing only on where conflict occurs, this research examines the social conditions that make coexistence possible. I hope the findings will contribute to a better understanding of human–wildlife relationships and help inform conservation strategies that reflect both ecological priorities and the experiences of the communities living alongside orangutans.
Miarisoa Ramilison
Sociality, Life History, and Viral Dynamics in Lemurs of Southeastern Madagascar
Infectious disease is a powerful selective pressure on primate life history and sociality, influencing traits as varied as grouping and ranging, interbirth intervals, and prolonged juvenile dependence. However, our ability to understand the relationships between primate social behavior, life history, and viral transmission is limited, as most comparative spillover frameworks are based on a narrow range of primate species. Lemurs show considerable variation in body size, pace of life history, diet, and social systems, which are the same factors that likely structure pathogen exposure and transmission across hominins and other primates. We currently lack a comparative, multi-host virome dataset needed to test whether trait-based spillover models can generalize across distantly related primate lineages.
I will use viral metagenomic sequencing of oral, blood, and fecal samples from six sympatric lemur species living in Ranomafana National Park in Madagascar [Milne-Edwards' sifaka (Propithecus edwardsi), Black-and-white ruffed lemurs (Varecia variegata), Red-fronted lemurs (Eulemur rufifrons), red-bellied lemurs (E. rubriventer), Peyrierasi’s woolly lemurs (Avahi peyrierasi) and Rufous mouse lemurs (Microcebus rufus)] spanning major differences in social organization, diet, and pace of life history to quantify viral diversity within each host species and determine the influence of host traits, to identify which viral traits are associated with broader host ranges, and to determine whether anthropogenic disturbance increases viral sharing consistent with theory. I will also sample eight rodent species including six native and two invasive species to test whether the invasive rodents may serve as bridge hosts that connect endemic lemurs to viruses common in human-disturbed habitats.
As 94% of lemur species are already threatened with extinction, understanding disease dynamics is crucial for their conservation. My dissertation represents not only a significant contribution to scientific knowledge but also an opportunity to develop evidence-based conservation strategies that can help protect the unique lemur diversity of Madagascar for generations to come, and build sustainable local capacity by training Malagasy students in field technical methods.
Natalie Robinson
Ecological drivers of orangutan (Pongo pygmaeus wurmbii) ovarian function and reproduction at the Tuanan Research Station, Central Kalimantan, Indonesia
Central to the persistence of endangered species is their ability to reproduce successfully, yet the ecological factors that regulate reproduction remain poorly understood for many long-lived mammals. Studies in humans and other mammals have demonstrated that energy availability strongly influences ovarian function by altering hormone production and reproductive cycling. Increasing evidence also suggests that exposure to wildfire smoke may disrupt reproductive physiology. However, little is known about how natural ecological variation and anthropogenic environmental stressors shape reproductive physiology among Critically Endangered Bornean orangutans (Pongo pygmaeus wurmbii). Orangutans are among the slowest-reproducing mammals on Earth, and their populations continue to decline due to habitat loss, climate change, and increasingly frequent peatland fires. My dissertation investigates how ecological variation influences ovarian function in wild female orangutans at the Tuanan Research Station in Central Kalimantan, Indonesia. Orangutans experience substantial fluctuations in fruit availability, creating periods of energetic abundance and scarcity, while peatland fires expose them to prolonged episodes of smoke. Together, these environmental challenges provide a unique opportunity to examine how ecological conditions shape reproductive physiology in a long-lived great ape.
I will collect longitudinal urine samples from individually recognized females and measure urinary estrogen and progesterone metabolites, markers of ovarian function and reproductive cycling. These hormonal data will be integrated with long-term records of fruit availability, feeding behavior, dietary intake, activity budgets, biomarkers of energetic status (cortisol, ketones, and C-peptide), and fine particulate matter measurements that quantify smoke exposure from peatland fires. By integrating endocrine, behavioral, ecological, and air quality data, my dissertation will identify how environmental and physiological conditions influence ovarian function in wild orangutans. This research will advance our understanding of reproductive regulation in long-lived primates while informing conservation efforts to protect orangutans amid ongoing climate change and habitat loss.