Whisson Desley A, Dixon Victoria, Taylor Megan L, Melzer Alistair
Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia.
School of Medical and Applied Sciences, Central Queensland University, Rockhampton, Queensland, Australia.
PLoS One. 2016 Jan 6;11(1):e0144348. doi: 10.1371/journal.pone.0144348. eCollection 2016.
Understanding the ability of koalas to respond to changes in their environment is critical for conservation of the species and their habitat. We monitored the behavioural response of koalas to declining food resources in manna gum (Eucalyptus viminalis) woodland at Cape Otway, Victoria, Australia, from September 2011 to November 2013. Over this period, koala population density increased from 10.1 to 18.4 koalas.ha-1. As a result of the high browsing pressure of this population, manna gum canopy condition declined with 71.4% manna gum being completely or highly defoliated in September 2013. Despite declining food resources, radio collared koalas (N = 30) exhibited high fidelity to small ranges (0.4-1.2 ha). When trees became severely defoliated in September 2013, koalas moved relatively short distances from their former ranges (mean predicted change in range centroid = 144 m) and remained in areas of 0.9 to 1.0 ha. This was despite the high connectivity of most manna gum woodland, and close proximity of the study site (< 3 km) to the contiguous mixed forest of the Great Otway National Park. Limited movement had catastrophic consequences for koalas with 71% (15/21) of radio collared koalas dying from starvation or being euthanased due to their poor condition between September and November 2013.
了解考拉对环境变化的应对能力对于该物种及其栖息地的保护至关重要。2011年9月至2013年11月，我们在澳大利亚维多利亚州奥特韦角的甘露桉（Eucalyptus viminalis）林地监测了考拉对食物资源减少的行为反应。在此期间，考拉种群密度从每公顷10.1只增加到18.4只。由于该种群的高强度啃食压力，甘露桉的树冠状况下降，2013年9月有71.4%的甘露桉完全或严重落叶。尽管食物资源减少，但佩戴无线电项圈的考拉（N = 30）对小范围区域（0.4 - 1.2公顷）表现出高度的忠诚度。2013年9月树木严重落叶时，考拉从其先前的活动范围移动了相对较短的距离（范围质心的平均预测变化 = 144米），并留在了0.9至1.0公顷的区域内。尽管大多数甘露桉林地具有高度的连通性，且研究地点距离大奥特韦国家公园的相邻混交林很近（< 3公里）。有限的移动给考拉带来了灾难性后果，2013年9月至11月期间，71%（15/21）佩戴无线电项圈的考拉因饥饿死亡或因身体状况不佳而被安乐死。
