Local and landscape correlates of primate distribution and persistence in the remnant lowland rainforests of the Upper Brahmaputra Valley, northeastern India.
Habitat fragmentation affects species distribution and abundance, and drives extinctions. Escalated tropical deforestation and fragmentation have confined many species populations to habitat remnants. How worthwhile is it to invest scarce resources in conserving habitat remnants within densely settled production landscapes? Are these fragments fated to lose species anyway? If not, do other ecological, anthropogenic, and species-related factors mitigate the effect of fragmentation and offer conservation opportunities? We evaluated, using generalized linear models in an information-theoretic framework, the effect of local- and landscape-scale factors on the richness, abundance, distribution, and local extinction of 6 primate species in 42 lowland tropical rainforest fragments of the Upper Brahmaputra Valley, northeastern India. On average, the forest fragments lost at least one species in the last 30 years but retained half their original species complement. Species richness declined as proportion of habitat lost increased but was not significantly affected by fragment size and isolation. The occurrence of western hoolock gibbon (Hoolock hoolock) and capped langur (Trachypithecus pileatus) in fragments was inversely related to their isolation and loss of habitat, respectively. Fragment area determined stump-tailed (Macaca arctoides) and northern pig-tailed macaque occurrence (Macaca leonina). Assamese macaque (Macaca assamensis) distribution was affected negatively by illegal tree felling, and rhesus macaque (Macaca mulatta) abundance increased as habitat heterogeneity increased. Primate extinction in a fragment was primarily governed by the extent of divergence in its food tree species richness from that in contiguous forests. We suggest the conservation value of these fragments is high because collectively they retained the entire original species pool and individually retained half of it, even a century after fragmentation. Given the extensive habitat and species loss, however, these fragments urgently require protection and active ecological restoration to sustain this rich primate assemblage.
Ecology, Behaviour and Conservation Programme and School of Natural Sciences and Engineering, National Institute of Advanced Studies, Indian Institute of Science Campus, Bangalore, 560012, India; Nature Conservation Foundation, 3076/5, 4th Cross, Gokulam Park, Mysore, 570002, India.
Narayan
N
Sharma
M D
MD
Madhusudan
Anindya
A
Sinha
D063147:Animal Distribution; D000818:Animals; D044822:Biodiversity; D003247:Conservation of Natural Resources; D004777:Environment; D053476:Extinction, Biological; D007194:India; D011156:Population Density; D011323:Primates / Q000502:physiology*; D012621:Seasons; D013045:Species Specificity
Assamese macaque; Hoolock hoolock; M. assamensis; M. leonina; Macaca arctoides; Trachypithecus pileatus; abundance; abundancia; capped langur; extinción local; fragmentación de hábitat; habitat fragmentation; hoolock gibbon; local extinction; pig-tailed macaque; riqueza de especies; species richness; stump-tailed macaque