Tuesday, December 16, 2014

Hunting is a greater threat than logging for most wildlife in Borneo

Persistence is the key factor in the two most common human stressors on tropical wildlife. In Malaysian Borneo, hunting continually diminishes wildlife populations, whereas the negative impacts from selective logging are more transient, according to a recent study in Conservation Biology.

The study, led by Jedediah Brodie of the University of British Columbia, deployed a series of camera traps across a gradient of disturbed areas to investigate direct and indirect impacts on wildlife. Although both hunting and new logging reduced the number of species in a given area, there was evidence that some wildlife may eventually return to selectively logged areas.

Although clearcutting usually causes complete habitat destruction, the impacts of selective logging are more nuanced and less clearly understood. Still, collateral mortality of non-target trees and ecological disruption are common features of selective logging.

"Logging companies are taking out the high-value timber and leaving everything else," Brodie explained. "But in so doing, they knock over smaller trees, make skid trails, compact the soil, and cause lots of erosion—so it's not a benign process by any means."

The study's findings emphasize the immediate impact of such logging: selective logging reduced occurrence for all 30 species detected in the study area and caused an 11.3 percent decrease in the number of mammal species present.

However, after the ecosystem has a chance to regenerate, evidence suggests there is some hope for wildlife.

"Our study shows that the recovery of mammal diversity after logging is faster than we thought, although it's variable by species and some carnivores remain averse to logged areas for a long time," said Brodie.