Effects of logging on gastrointestinal parasite infections and infection risk in African primates.
The impact of habitat disturbance on biodiversity conservation and animal health is poorly understood. Selective logging results in a suite of alterations that may increase infection risk and susceptibility to infection in resident populations. The aim of this study was to improve our understanding of this interplay by examining the effects of logging on infection risk and gastrointestinal parasite infections in three primate species whose populations have responded differently to selective logging in Kibale National Park, Uganda. Populations of redtail guenons Cercopithecus ascanius are declining in logged forest; red colobus Piliocolobus tephrosceles populations are in a state of slow recovery; and black-and-white colobus Colobus guereza populations are increasing in logged forest. We collected faecal samples from these three primate species over a period of 5 years in logged and undisturbed forest, to compare parasite infection prevalence and the magnitude of multiple infections. We also analysed canopy and ground vegetation plots to compare environmental contamination with primate parasites in logged and undisturbed forest. The prevalence and richness of gastrointestinal helminth and protozoan parasite infections, and the magnitude of multiple infections were greater for redtail guenons in logged than undisturbed forest, but these parameters did not differ between forest types for either colobine. Data from the canopy and ground vegetation plots revealed that infective stages of two representative generalist primate parasites occurred at higher densities in logged compared with undisturbed forest, signifying a greater infection risk for all primate species in logged forest. Synthesis and applications. This study demonstrates that selective logging can be associated with changes in an important ecological association between hosts and parasites. Our results indicate that anthropogenic habitat change could influence patterns of parasite infection in primates with associated effects on population performance.