Tropical wildlife corridors: Use of linear rainforest remnants by arboreal mammals

Abstract

In fragmented landscapes, linear forest remnants have the potential to provide habitat and movement corridors for wildlife. We used systematic spotlighting surveys to sample arboreal mammals in 36 linear rainforest remnants in tropical Queensland, Australia. The effects of corridor width, height, isolation, elevation, and floristic composition on mammals were assessed with multiple regression models. Six species were recorded during 108 surveys. The most vulnerable species, the lemuroid ringtail possum (Hemibelideus lemuroides), was found only in remnants comprised of primary rainforest that were linked to large tracts of continuous forest. Two other species, the Herbert River ringtail possum (Pseudochirulus herbertensis) and striped possum (Dactylopsila trivirgata), also favored corridors that were linked to forest tracts or fragments, with the former favoring high-diversity forest (primary forest or mixed regrowth) over low-diversity (Acacia) regrowth. Three other species, the coppery brushtail possum (Trichosurus vulpecula), green ringtail possum (Pseudochirops archeri), and Lumholtz's tree-kangaroo (Dendrolagus lumholtzi), occurred in both isolated and non-isolated remnants and both primary forest and regrowth. Our findings suggest that linear forest remnants that are floristically diverse (not Acacia-dominated regrowth) and at least 30-40 in width can function as habitat and probably movement corridors for most arboreal mammals in this region. The lemuroid ringtail, however, apparently requires corridors of primary rainforest of at least 200 m in width. Because the lemuroid ringtail is highly vulnerable to forest fragmentation, faunal corridors in this region should be designed wherever possible to meet its ecological requirements.