School of Life and Environmental Sciences (Burwood Campus), Centre for Integrative Ecology, Deakin University, Geelong, Victoria, Australia.
Biodiversity Division, Department of Environment, Land, Water and Planning, East Melbourne, Victoria, Australia.
Glob Chang Biol. 2023 Jun;29(11):2953-2967. doi: 10.1111/gcb.16661. Epub 2023 Mar 14.
Ecosystem management in the face of global change requires understanding how co-occurring threats affect species and communities. Such an understanding allows for effective management strategies to be identified and implemented. An important component of this is differentiating between factors that are within (e.g. invasive predators) or outside (e.g. drought, large wildfires) of a local manager's control. In the global biodiversity hotspot of south-western Australia, small- and medium-sized mammal species are severely affected by anthropogenic threats and environmental disturbances, including invasive predators, fire, and declining rainfall. However, the relative importance of different drivers has not been quantified. We used data from a long-term monitoring program to fit Bayesian state-space models that estimated spatial and temporal changes in the relative abundance of four threatened mammal species: the woylie (Bettongia penicillata), chuditch (Dasyurus geoffroii), koomal (Trichosurus vulpecula) and quenda (Isoodon fusciventor). We then use Bayesian structural equation modelling to identify the direct and indirect drivers of population changes, and scenario analysis to forecast population responses to future environmental change. We found that habitat loss or conversion and reduced primary productivity (caused by rainfall declines) had greater effects on species' spatial and temporal population change than the range of fire and invasive predator (the red fox Vulpes vulpes) management actions observed in the study area. Scenario analysis revealed that a greater extent of severe fire and further rainfall declines predicted under climate change, operating in concert are likely to further reduce the abundance of these species, but may be mitigated partially by invasive predator control. Considering both historical and future drivers of population change is necessary to identify the factors that risk species recovery. Given that both anthropogenic pressures and environmental disturbances can undermine conservation efforts, managers must consider how the relative benefit of conservation actions will be shaped by ongoing global change.
面对全球变化,生态系统管理需要了解同时发生的威胁如何影响物种和群落。这种理解可以确定和实施有效的管理策略。这方面的一个重要组成部分是区分哪些因素在(例如,入侵性捕食者)或在(例如,干旱,大型野火)地方管理者的控制范围内。在澳大利亚西南部的全球生物多样性热点地区,中小型哺乳动物物种受到人为威胁和环境干扰的严重影响,包括入侵性捕食者、火灾和降雨量下降。然而,不同驱动因素的相对重要性尚未量化。我们使用长期监测计划的数据来拟合贝叶斯状态空间模型,该模型估计了四种受威胁哺乳动物物种(Bettongia penicillata、Dasyurus geoffroii、Trichosurus vulpecula 和 Isoodon fusciventor)的相对丰度的空间和时间变化。然后,我们使用贝叶斯结构方程模型来确定种群变化的直接和间接驱动因素,并进行情景分析以预测未来环境变化对种群的反应。我们发现,栖息地丧失或转换以及初级生产力降低(由降雨量下降引起)对物种的空间和时间种群变化的影响大于研究区域内观察到的火灾和入侵性捕食者(红狐 Vulpes vulpes)管理措施的范围。情景分析表明,气候变化预测的更严重的火灾和进一步的降雨量下降,共同作用可能会进一步降低这些物种的丰度,但入侵性捕食者的控制可能会部分缓解这种情况。考虑人口变化的历史和未来驱动因素对于确定可能危及物种恢复的因素是必要的。鉴于人为压力和环境干扰都可能破坏保护工作,管理者必须考虑正在进行的全球变化将如何影响保护行动的相对效益。