Parasites a key to the decline of red colobus monkeys in forest...( Forest fragmentation threatens biodi...),Health

Forest fragmentation threatens biodiversity, often causing declines or local extinctions in a majority of species while enhancing the prospects of a few. A new study from the University of Illinois shows that parasites can play a pivotal role in the decline of species in fragmented forests. This is the first study to look at how forest fragmentation increases the burden of infectious parasites on animals already stressed by disturbances to their habitat.

The study, of black-and-white colobus monkeys and red colobus monkeys in tropical forests in western Uganda, appears in the American Journal of Primatology.

Once dominated by vast forests, Uganda now has less than one-twentieth of its original forest cover. According to the World Resources Institute, its tropical forests are being logged and converted to agricultural land at a rate that outpaces sub-Saharan Africa as a whole. Small tracts remain, however, hemmed in by pastures and croplands. Many of the species that thrived in the original forests are struggling to survive in these parcels, which can be as small as one hectare in size.

In Uganda, just looking at the primates, its one of the most biodiverse places on the earth, said professor of pathobiology Thomas Gillespie, principal investigator on the study. Youve got 12 to 13 species of primates in a core undisturbed forest. But if you go into these forest fragments, youll find only three or four species of primates.

Populations of black-and-white colobus monkeys appear to be stable in the Ugandan forest remnants, while their cousins, the red colobus monkeys, are in decline.

Gillespie and his colleague, Colin Chapman, of McGill University in Montreal, surveyed 20 forest fragments near the western boundary of Kibale National Park, in western Uganda.

They compared the abundance, variety and density of potentially harmful parasites in these fragments to the undisturbed core forest of the park.
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