Mammalian Diversity and Distribution in Human-Altered Tropical Landscapes

• Main Author: Smith, Joseph Alexander
• Published: Imperial College London 2009
• Subjects: 591.7
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506905

Habitat loss at the hands of human enterprise continues to drive the global decline inbiodiversity. While much attention has been placed on the use of protected areas as ameans of conservation, there is an increasing need to understand the capacity ofunprotected, human-altered landscapes to provide refugia and connectivity at largerspatial scales. This study evaluates the mammalian diversity that persists underalternative land management regimes and degrees of landscape change in south-centralSumatra, Indonesia. Species occurrence data compiled from extensive field surveysacross 1600km2 form the basis for analyses of community composition and speciesspecificresponses to the current landscape. Results indicate that species richnessdeclined with increased landscape alteration. The lowest observed species numberswere in areas of industrial scale oil palm production rather than scrub habitats ordegraded forest. Endangered mammals that persisted in the wider matrix were extirpatedfrom the oil palm dominated areas. Comparisons between the ecological traits shared bypersistent versus locally extirpated species revealed that in the initial stages of landscapechange there is the capacity to support large specialist species with slow life histories. Aslandscape degradation continues to an agricultural matrix only habitat and dietgeneralists persisted. Tests of species-specific responses to landscape alteration focussed on the occurrencepatterns of Sumatran tigers (Panthera tigris sumatrae) and four principal prey species. Measures of human prevalence derived from survey data and a novel application ofoccupancy estimation techniques, identified significant negative responses to higherlevels of landscape development. Satellite derived measures of habitat connectivity andlocalised landcover degradation found that connectivity to areas of least disturbed forestwas more important for reclusive species such as tapir (Tapirus indicus) and red muntjac(Muntiacus muntjak), while the occurrence of the wide-ranging tiger was more stronglyinfluenced by local landcover degradation. The capacity of human altered landscapes tocontribute to the conservation of mammalian communities is closely allied to theavailability of degraded forests rather than alternative human altered landcovers. Giventhat these areas of forest are increasingly subject to degradation and conversion, spatialplanning and proactive management are required to safeguard these resources.