Impacts of Roads, Hunting, and Habitat Alteration on Nocturnal Mammals in African Rainforests
Nocturnal mammals are poorly studied in Central Africa, a region experiencing dramatic increases in logging, roads, and hunting activity. In the rainforests of southern Gabon, we used spotlighting surveys to estimate abundances of nocturnal mammal species and guilds at varying distances from forest roads and between hunted and unhunted treatments (comparing a 130-km2 oil concession that was nearly free of hunting, with nearby areas outside the concession that had moderate hunting pressure). At each of 12 study sites that were evenly divided between hunted and unhunted areas, we established standardized 1-km transects along road verges and at 50, 300, and 600 m from the road. We then repeatedly surveyed mammals at each site during 2006. Hunting had few apparent effects on this assemblage. Nevertheless, the species richness and often the abundance of nocturnal primates, smaller ungulates, and carnivores were significantly depressed within approximately 30 m of roads. Scansorial rodents increased in abundance in hunted forests, possibly in response to habitat changes caused by logging or nearby swidden farming. In multiple-regression models many species and guilds were significantly influenced by forest-canopy and understory cover, both of which are altered by logging and by certain abiotic variables. In general, nocturnal species, many of which are arboreal or relatively small in size (<10 kg), were less strongly influenced by hunting and more strongly affected by human-induced changes in forest structure than were larger mammal species in our study area.
Keywords: African rainforest; Gabon; Gabón; bosque lluvioso Africano; bushmeat; cacería; carne de monte; desarrollo petrolero; efectos de carreteras; hunting; logging; mamíferos nocturnos; nocturnal mammals; oil development; road effects; tala
Document Type: Research Article
Affiliations: 1: Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama, Email: [email protected] 2: Monitoring and Assessment of Biodiversity Program, National Zoological Park, Smithsonian Institution, P.O. Box 37012, Washington, D.C. 20560-0705, U.S.A. 3: Institute of Environmental Sciences (CML), Leiden University, P.O. Box 9518, 2300 RA Leiden, The Netherlands
Publication date: June 1, 2008