Responses of Lumholtz's tree-kangaroo ( Dendrolagus lumholtzi) to loss of habitat within a tropical rainforest fragment

Abstract

A key challenge for wildlife biologists is to predict how fauna will respond to habitat loss. During an ongoing study of habitat use by Lumholtz's tree-kangaroos ( Dendrolagus lumholtzi), an unexpected opportunity arose to study the responses of this rare arboreal marsupial to habitat disruption. The study took place on the Atherton Tableland in north Queensland, Australia, when half of a 20-ha rainforest fragment was unexpectedly clearfelled by the landowner. Prior to clearing, six animals had been fitted with radiocollars to monitor their locations and activity within the fragment. Most animals responded to clearing by remaining in trees until just before they were felled. Animals then fled for short distances (mean=33 m), but returned to their home ranges within 12–24 h. Nine additional resident animals were captured after forest clearing and radiocollared, and along with the original animals were tracked at ca. 12-h intervals for several months. Six females and five males directly affected by clearing continued to use their original home ranges, amongst the 1–2 m-tall tangles of woody debris. Contrary to expectations, animals did not relocate to nearby forest blocks, and only one animal established a completely new home range. Mortality rates of affected animals appeared to increase after clearfelling, with at least four perishing from attacks by domestic dogs or dingoes. Although some surviving tree-kangaroos lived within the debris for several months, their prospects for long-term survival were poor as the debris was eventually burnt to create cattle pasture, destroying the already modified habitat and leaving them vulnerable to predators. The remarkably strong site-tenacity of this species suggests that habitat availability will be critically limiting to their populations, and that displaced animals will have limited prospects for survival.