In experimental and modeling studies, researchers have attempted to determine the minimum amount of habitat required for all species to persist in a landscape (e.g., Parker & MacNally 2002). Nevertheless, our sample sizes are too small to determine the forest cover necessary to preserve all the forest avifauna. Other studies in Southeast Asia show that as much as 80% of the forest is needed to preserve all forest bird species (Posa & Sodhi 2006; Soh et al. 2006). It is possible that the original surveys missed some of Bintan’s rare species, which subsequently
became extinct without ever being recorded as residents (Pimm et al. 2006). In general, the species surviving on the islands were those that occur in a variety of habitats, including human-dominated areas (e.g., Oriental Magpie Robin [Copsychus saularis]; Asian Glossy Starling [Aplonis panayensis]; and Yellow-vented Bulbul [Pycnonotus goiavier]).
Species restricted to large tracts of old-growth forests (e.g., Scarlet rumped Trogon; Black-and-yellow Broadbill,Eurylaimus ochromalus; and Yellow-bellied Bulbul [Alophoixus phaeocephalus]) were lost from more than one island, indicating their general vulnerability. The
functional role (e.g., seed dispersal) of extirpated species may not be replaced in disturbed forests, which permanently affects certain ecosystem processes (Gardner et al.2009). Nevertheless, some species survived on one island but perished on another (e.g., Oriental Pied Hornbill and Common Flameback [Dinopium javanense]), indicating the randomness of extinctions. It is unclear why species vulnerability differs among islands, but it may depend on species-specific variables such as population sizes, availability of food and nesting or roosting sites, hunting pressure, and the amount of residual forest (Sodhi et al.2004b). Some species that use mangroves also vanished (e.g., Balambangan: Thick-billed Green-pigeon [Treron curvirostra]), probably due to the loss of this coastal forest habitat.
In experimental and modeling studies, researchers have attempted to determine the minimum amount of habitat required for all species to persist in a landscape (e.g., Parker & MacNally 2002). Nevertheless, our sample sizes are too small to determine the forest cover necessary to preserve all the forest avifauna. Other studies in Southeast Asia show that as much as 80% of the forest is needed to preserve all forest bird species (Posa & Sodhi 2006; Soh et al. 2006). It is possible that the original surveys missed some of Bintan’s rare species, which subsequentlybecame extinct without ever being recorded as residents (Pimm et al. 2006). In general, the species surviving on the islands were those that occur in a variety of habitats, including human-dominated areas (e.g., Oriental Magpie Robin [Copsychus saularis]; Asian Glossy Starling [Aplonis panayensis]; and Yellow-vented Bulbul [Pycnonotus goiavier]).Species restricted to large tracts of old-growth forests (e.g., Scarlet rumped Trogon; Black-and-yellow Broadbill,Eurylaimus ochromalus; and Yellow-bellied Bulbul [Alophoixus phaeocephalus]) were lost from more than one island, indicating their general vulnerability. Thefunctional role (e.g., seed dispersal) of extirpated species may not be replaced in disturbed forests, which permanently affects certain ecosystem processes (Gardner et al.2009). Nevertheless, some species survived on one island but perished on another (e.g., Oriental Pied Hornbill and Common Flameback [Dinopium javanense]), indicating the randomness of extinctions. It is unclear why species vulnerability differs among islands, but it may depend on species-specific variables such as population sizes, availability of food and nesting or roosting sites, hunting pressure, and the amount of residual forest (Sodhi et al.2004b). Some species that use mangroves also vanished (e.g., Balambangan: Thick-billed Green-pigeon [Treron curvirostra]), probably due to the loss of this coastal forest habitat.
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