Social Behavioural Changes and Stress Responses in Primates Under Habitat Disturbance and Forest Fragmentation

Abstract

Some of the most significant anthropogenic threats to primates include habitat disturbance and fragmentation. Primates are cognitively complex, highly social mammals that are often forest dependent and are very sensitive to changes in habitat size, habitat quality, habitat connectivity, food availability, predation risk, and human contact. This review focuses on the effects of habitat disturbance and fragmentation on primate social behavior and stress response, including effects on the social organization, mating behavior, aggression, competition, glucocorticoid activity, self-directed behaviors, and long-term health effects. The experience of primate ecology and conservation biology suggests that habitat loss can lead to a decrease in food availability, an increase in inter- and intra-group competition, alteration of ranging behavior and dispersal patterns, and raise the risk of human–wildlife conflict. Physiologically, disturbed environments are frequently linked to activation of the hypothalamic–pituitary–adrenal axis – the hormone cortisol or the hormone metabolites in feces are often used as markers for this. Exposure to disturbance for a prolonged period can lead to allostatic load, immune dysfunction, reproductive dysfunction, and population declines. Responses, however, are different among taxa, ecological flexibility, food resources, home range size, social system, and permeability of the matrix. While highly frugivorous species with large home ranges may be more likely to be vulnerable, some generalist species can sustain themselves in a fragmented landscape by altering their diet, activity budgets, and ranging. Such conservation efforts must, as a result, adopt a multi-dimensional approach that includes behavioral monitoring, physiological indicators, habitat restoration, ecological corridors, community involvement, and conflict reduction. Conservation planning for primates in a human-dominated environment can be enhanced by knowledge of the relationship between social behavior and stress physiology.