Callan Michael N, Krix Dan, McLean Christopher M, Murray Brad R, Webb Jonathan K
Habitat Innovation and Management, 30 Lorimer Street, Llanarth, NSW 2795, Australia.
School of Life Sciences, University of Technology Sydney, Broadway, NSW 2007, Australia.
Biology (Basel). 2023 Feb 24;12(3):361. doi: 10.3390/biology12030361.
Loss of hollow-bearing trees threatens many hollow-dependent wildlife. To mitigate this process, artificial chainsaw-carved hollows (CHs) are often created in dead trees, yet little is known about their thermal profiles. We measured temperatures inside 13 natural hollows (8 live and 5 dead trees) and 45 CHs (5 live and 40 dead trees) in the central west of NSW, Australia, over the course of 2 summers. Maximum temperatures and daily temperature ranges within natural hollows and artificial hollows were similar in 2017-2018. Hollow temperatures were lower in thicker-walled hollows than in thinner-walled hollows. During the January 2019 heatwave, temperatures inside CHs in dead trees exceeded 4-35 °C higher than the upper limit of the thermal neutral zone of sugar gliders-for 6.2 consecutive days (range 0-9 days). CHs in dead trees provided little buffering from thermal extremes; when air temperatures peaked at 44.6 °C, CHs in dead trees were on average 2.4 °C cooler than ambient (range: 5.5 °C cooler to 1.0 °C hotter than ambient). These results show that CHs created in dead trees may not provide suitable thermal conditions for hollow-dependent marsupials during summer heatwaves. Retention of large live trees, coupled with revegetation, is crucial for conserving hollow-dependent fauna in agricultural landscapes.
中空树木的减少威胁到许多依赖中空环境生存的野生动物。为减缓这一过程，人们常常在枯树上人工锯刻出中空结构（CHs），但对其热特性却知之甚少。我们在澳大利亚新南威尔士州中西部，历时两个夏天，测量了13个天然中空（8棵活树和5棵死树）以及45个CHs（5棵活树和40棵死树）内部的温度。在2017 - 2018年，天然中空和人工中空内部的最高温度及日温度范围相似。壁厚的中空内部温度低于壁薄的中空。在2019年1月的热浪期间，死树中CHs内部的温度比蜜袋鼯热中性区上限高出4 - 35°C，且持续了6.2天（范围为0 - 9天）。死树中的CHs几乎无法缓冲极端温度；当气温峰值达到44.6°C时，死树中的CHs平均比环境温度低2.4°C（范围：比环境温度低5.5°C到高1.0°C）。这些结果表明，在夏季热浪期间，死树上人工锯刻出的CHs可能无法为依赖中空环境生存的有袋动物提供适宜的热条件。保留大型活树并结合植被恢复，对于在农业景观中保护依赖中空环境生存的动物至关重要。
