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...

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Bibliographic Details
Published in:	Conservation biology Vol. 22; no. 3; pp. 721 - 732
Main Authors:	LAURANCE, WILLIAM F., CROES, BARBARA M., GUISSOUEGOU, NICAISE, BUIJ, RALPH, DETHIER, MARC, ALONSO, ALFONSO
Format:	Journal Article
Language:	English
Published:	Malden, USA Blackwell Publishing Inc 01-06-2008 Blackwell Publishing, Inc Blackwell Blackwell Publishing Ltd
Subjects:	African rainforest Animal, plant and microbial ecology Animals Applied ecology Biodiversity Biological and medical sciences bosque lluvioso Africano bushmeat cacería carne de monte Circadian Rhythm Conservation Conservation biology Conservation, protection and management of environment and wildlife desarrollo petrolero Ecosystem efectos de carreteras Forest conservation Forest habitats Forest roads Fundamental and applied biological sciences. Psychology Gabon Gabón Human Activities Human influences Hunting Logging Mammalia Mammals Mammals - physiology mamíferos nocturnos nocturnal mammals oil development Parks, reserves, wildlife conservation. Endangered species: population survey and restocking Primates Rain forests Rainforests road effects Roads & highways Rodents tala Transportation Trees Tropical Climate Tropical rain forests Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution Africa Gabon oil development Hunting bushmeat Rain forest Highway Alteration road effects Wild animal Meat nocturnal mammals African rainforest Gabon Vertebrata Game Mammalia logging Habitat Environmental protection
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Summary:	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. /// Los mamíferos nocturnos casi no han sido estudiados en África Central, una región que experimenta un incremento dramático de tala, carreteras y actividades cinegéticas. En los bosques lluviosos del sur de Gabón, utilizamos muestreos con lámparas para estimar las abundancias de especies y gremios de mamíferos nocturnos a distintas distancias de carreteras y entre tratamientos con y sin cacería (comparamos una concesión petrolera de 130 km² que prácticamente estaba libre de cacería con áreas afuera de la concesión que tenían presión cinegética moderada). Establecimos transectos de 1 km a lo largo de carreteras y a 50 m, 300 m y 600 m de la carretera en cada uno de los 12 sitios de estudio, que estaban divididos en áreas con y sin cacería. Posteriormente, muestreamos mamíferos en cada sitio durante 2006. La cacería tuvo pocos efectos aparentes sobre este ensamble. Sin embargo, la riqueza de especies y, a menudo, la abundancia de los primates nocturnos, de ungulados pequeños y de carnívoros disminuía significativamente a ∼30 m de las carreteras. La abundancia de roedores trepadores incrementó en los bosques con cacería, posiblemente como respuesta a los cambios de hábitat provocados por la tala o la agricultura de tumba-roza-quema. En los modelos de regresión múltiple, muchas especies y gremios fueron influidos significativamente por la cobertura del dosel y del sotobosque, que son alteradas por la tala y ciertas variables abióticas. En general, las especies nocturnas, muchas de las cuales son arborícolas o de tamaño relativamente pequeño (<10 kg), fueron menos afectadas por la cacería, pero más afectadas por los cambios en la estructura del bosque inducidos por humanos, que las especies de mamíferos mayores en nuestra área de estudio.
Bibliography:	ark:/67375/WNG-CC5VVT44-S istex:2A21E6274302177E5E2D112094E521AB39A7D6DA ArticleID:COBI917 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2
ISSN:	0888-8892 1523-1739
DOI:	10.1111/j.1523-1739.2008.00917.x