title: Competing pressures on populations: long-term dynamics of food availability, food quality, disease, stress and animal abundance.
abstract: Despite strong links between sociality and fitness that ultimately affect the size of animal populations, the particular social and ecological factors that lead to endangerment are not well understood. Here, we synthesize approximately 25 years of data and present new analyses that highlight dynamics in forest composition, food availability, the nutritional quality of food, disease, physiological stress and population size of endangered folivorous red colobus monkeys (Procolobus rufomitratus). There is a decline in the quality of leaves 15 and 30 years following two previous studies in an undisturbed area of forest. The consumption of a low-quality diet in one month was associated with higher glucocorticoid levels in the subsequent month and stress levels in groups living in degraded forest fragments where diet was poor was more than twice those in forest groups. In contrast, forest composition has changed and when red colobus food availability was weighted by the protein-to-fibre ratio, which we have shown positively predicts folivore biomass, there was an increase in the availability of high-quality trees. Despite these changing social and ecological factors, the abundance of red colobus has remained stable, possibly through a combination of increasing group size and behavioural flexibility.
authors: McGill School of Environment, McGill University, Montreal, Quebec, Canada H3A 2T7 Department of Anthropology, McGill University, Montreal, Quebec, Canada H3A 2T7 Wildlife Conservation Society, Bronx, NY 10460, USA colin.chapman@mcgill.ca.
authors: Colin A
authors: CA
authors: Chapman
authors: Department of Anthropology, McGill University, Montreal, Quebec, Canada H3A 2T7.
authors: Valérie A M
authors: VA
authors: Schoof
authors: Department of Psychology, University Hall, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4.
authors: Tyler R
authors: TR
authors: Bonnell
authors: Department of Biology, McGill University, Montreal, Quebec, Canada H3A 1B1 Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany Research group Epidemiology of Highly Pathogenic Microorganisms, Robert Koch Institute, 13353 Berlin, Germany.
authors: Jan F
authors: JF
authors: Gogarten
authors: Département de Biologie, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1K 2R1 Departamento de Conservacion de la Biodiversidad, El Colegio de la Frontera Sur, Chetumal, Mexico.
authors: Sophie
authors: S
authors: Calmé
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D003104:Colobus / Q000502:physiology* / Q000523:psychology; D004032:Diet; D017753:Ecosystem; D056727:Endangered Species; D005502:Food; D063427:Food Quality; D065928:Forests; D016014:Linear Models; D008992:Monkey Diseases / Q000469:parasitology; D010273:Parasitic Diseases, Animal / Q000469:parasitology; D011156:Population Density; D013312:Stress, Physiological; D014197:Trees; D014454:Uganda
keywords: endangered populations; endocrinology; glucocorticoids; non-equilibrium dynamics; nutritional ecology