Host density and human activities mediate increased parasite prevalence and richness in primates threatened by habitat loss and fragmentation

• Published in: The Journal of animal ecology Vol. 78; no. 1; pp. 210 - 218
• Main Authors: Mbora, David N. M., McPeek, Mark A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.01.2009; Blackwell Publishing; Blackwell Publishing Ltd; Blackwell
• Subjects: Africa; Animal and plant ecology; Animal ecology; Animal, plant and microbial ecology; Animals; Biodiversity; Biological and medical sciences; Cercocebus - parasitology; Cercocebus - physiology; Cercocebus galeritus; Colobus; Colobus - parasitology; Colobus - physiology; conservation; Conservation of Natural Resources; Ecology; Ecosystem; endangered species; Forest ecology; Forest habitats; Forests; Fundamental and applied biological sciences. Psychology; gallery forest; Gastrointestinal Diseases - epidemiology; Gastrointestinal Diseases - veterinary; General aspects; Habitat conservation; Habitats; Host-Parasite Interactions - physiology; Human influences; Humans; Kenya; Mammalia; Monkey Diseases - epidemiology; Monkeys; Nematodes; Parasite and Disease Ecology; Parasite hosts; Parasites; Parasitic Diseases, Animal - epidemiology; Parasitic Diseases, Animal - parasitology; Population Density; Prevalence; Primates; Procolobus; Risk Factors; structural equation modelling; Trees - physiology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Africa; Kenya; Europe, Tana R; Prevalence; Endangered species; structural equation modelling; Conservation; Loss; Africa; Parasite; Host; Density; Modeling; Fragmentation; Vertebrata; Mammalia; Human activity; Gallery forest; Primates; Habitat; Anthropogenic factor
• ISSN: 0021-8790; 1365-2656
• DOI: 10.1111/j.1365-2656.2008.01481.x

1. Habitat loss and fragmentation are the principal causes of the loss of biological diversity. In addition, parasitic diseases are an emerging threat to many animals. Nevertheless, relatively few studies have tested how habitat loss and fragmentation influence the prevalence and richness of parasites in animals. 2. Several studies of nonhuman primates have shown that measures of human activity and forest fragmentation correlate with parasitism in primates. However, these studies have not tested for the ecological mechanism(s) by which human activities or forest fragmentation influence the prevalence and richness of parasites. 3. We tested the hypothesis that increased host density due to forest fragmentation and loss mediates increases in the prevalence and richness of gastrointestinal parasites in two forest primates, the Tana River red colobus (Procolobus rufomitratus, Peters 1879) and mangabey (Cercocebus galeritus galeritus, Peters 1879). We focused on population density because epidemiological theory states that host density is a key determinant of the prevalence and richness of directly transmitted parasites in animals. 4. The Tana River red colobus and mangabey are endemic to a highly fragmented forest ecosystem in eastern Kenya where habitat changes are caused by a growing human population increasingly dependent on forest resources and on clearing forest for cultivation. 5. We found that the prevalence of parasites in the two monkeys was very high compared to primates elsewhere. Density of monkeys was positively associated with forest area and disturbance in forests. In turn, the prevalence and richness of parasites was significantly associated with monkey density, and attributes indicative of human disturbance in forests. 6. We also found significant differences in the patterns of parasitism between the colobus and the mangabey possibly attributable to differences in their behavioural ecology. Colobus are arboreal folivores while mangabeys are terrestrial habitat generalists.