Assessing Forest Connectivity for Primates in Fragmented Landscapes

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I study habitat fragmentation and the ecological and demographic responses that animals have to this in forest ecosystems undergoing anthropogenic change. My work integrates field studies and computer modeling of threatened biodiversity impacted by habitat loss in agricultural landscapes to understand implications for species persistence. I focus on primates from Southern Bahia, Brazil, where the prevalence of shade-cocoa agroforestry and cattle ranching has created a heterogeneous landscape offering a natural experimental design to test human influence on populations, species, and communities. Arboreal primates that once resided in continuous forests now live in quite unnaturally fragmented landscapes with restricted dispersal. As a result, populations are going locally extinct and overall population sizes are declining. In addition to factors such as habitat quality and landscape availability that constrain movement, primates' sociality (e.g. defending territories, attracting mates and intergroup dispersal) also has implications on how animals move. In particular, our main focal species, golden-headed lion tamarins (Leontopithecus chrysomelas), are cooperative breeders that rely on helpers to successfully rear offspring. At small population sizes and in fragmented habitats, it can be difficult for individuals to achieve reproductive success. My research program for the next 5 years will emphasize the study of habitat connectivity (or lack of it) and animals' responses to this. My students and I will use a combination of spatial analyses, Geographic Information Science (GIS) and computer modeling to simulate populations under various scenarios of potential conservation action (such as building corridors or retaining forest in certain areas). Results from models with varying landscape design will be evaluated to determine the best outcomes for species persistence and maintenance of genetic diversity given both physical and social constraints. In the field, we will study social structure, mating and dispersal patterns and their resulting effects on population demographics (such as birth and mortality rates) in light of habitat and landscape variation, and incorporate this into our landscape models. Our aims are to 1) quantify functional connectivity in the existing landscape for species with differing abilities to use the matrix, 2) understand the roles of demographics, sociality, and animal movement in predicting how animals move around and interact with their landscape, 3) use models to assess varied corridor implementation strategies to increase long-term species survival, 4) use models to prioritize currently forested areas for retention given the continued forest loss and 5) validate primates' use of corridors by radio tracking group movement in newly afforested areas in Brazil. Though the work I will conduct in the next 5 years is species and region specific, its applicability and impact are far reaching. The spatiotemporal modeling we develop can be implemented to study other threatened species and will be useful to conservation practitioners seeking to understand processes and solutions to ameliorate biodiversity loss in fragmented ecosystems. For example, implications from the work are imperative for evaluating the benefits of forest restoration initiatives. Moreover, from a theoretical standpoint, we will gain a better understanding of the impact that matrix quality has on dispersing individuals and processes that affect a population's ability to rebound or further sink into extinction vortices. The training I will provide to students within this framework will undoubtedly contribute to expanding science-based conservation practice within Canada and elsewhere.