The spatial structure and sustainability of subsistence wildlife harvesting in Kabo, Congo

The harvest and sustainable use of wildlife in Central Africa is an important conservation and development issue. Rural people have few other sources of protein so that healthy wildlife populations are required for human livelihoods as well as biodiversity conservation and forest ecosystem functioning.Although there has been growing concern about the sustainability of wildlife hunting in tropical forests, researchers propose that the spatial distribution of hunting pressure may play a key role in sustaining hunting offtake. Much of this research has focused on duikers, small antelopes in the genus Cephalophus proposed to exhibit source-sink dynamics in response to hunting.Using data from one year of hunter surveys and market surveys from two different time periods in Kabo, a logging town in northern Congo-Brazzaville, I found that hunting offtake has increased substantially from 1999 to 2006. However, hunting has not depleted ungulate populations, the preferred prey species.This continued hunting offtake may result in part from the unusual spatial distribution of hunters in this area. I found that hunters concentrate offtake in small areas of a rare forest type, monodominant Gilbertiodendron dewevrei forest, suggesting that hunters create and exploit source-sink dynamics between the most widespread forest type in the region (mixed forest) and monodominant forest.Modeling exercises show that for blue duikers (C. monticola), high levels of subadult dispersal would allow these high harvests to be sustained. However, one year of blue duiker radiotelemetry research revealed only moderate levels of dispersal among subadults. It is unclear if this dispersal will be sufficient to maintain hunting through source-sink dynamics. The extent and scale of hunting pressure and wildlife dispersal must be considered in order to evaluate the impact of hunting and enact hunting management, including spatial management.Spatial management, a technique that relies upon creating sources, or no-take zones, has been widely promoted for use in tropical forests. Through a review of the literature I find it does offer advantages over conventional harvesting, but is not a simple or fail-proof management strategy, requiring more research prior to implementation.