Data from seasonal and environmental dynamics of avian assemblages at arid zone waterholes

In arid zone environments long-lasting waterholes can provide the only reliable sources of water during prolonged dry periods and hence play an important role in maintaining avian diversity in the longer term. We used camera traps and direct surveys to investigate avian assemblages at six long-lasting waterholes across three sampling seasons (two summers and one winter) within the MacDonnell Ranges Bioregion in central Australia. Compositional differences in avian assemblages over space and time were analysed using a combination of multivariate and non-parametric analyses. We found significant differences in the structure of avian assemblages, particularly between the two summers and the winter season. These were related to migratory and nomadic species and species not normally considered dependent of surface water appearing at waterholes during the summer seasons. There was significant variation in avian assemblages among waterholes, which appeared related to individual species responses to the environmental characteristics of different sites. Distance-based linear models indicated that ground-foraging species such as the Torresian Crow and Common Bronzewing were less frequent visitors at sites with higher canopy and shrub cover. Zebra Finches were observed less frequently at large waterholes (> 300 m2) and White-plumed Honeyeaters were observed more frequently at sites with taller canopies. Our findings, which benefitted from the application of two survey methods, suggest seasonal weather patterns and environmental characteristics are important factors that influence when and where species access long-lasting waterholes. This has potential management implications, for example if there is a loss of tree and shrub cover over time, this may deter visitation by canopy-foraging honeyeaters or increase visitation by opportunistic ground foragers (such as the Torresian Crow), which could negatively impact other species through increased antagonistic interactions such as egg and chick predation. The conservation of diverse waterhole habitats in upland arid zones will ensure they are accessible for a variety of species into the future.

在干旱地区的生态环境中，持久性的水塘在长期干旱期间能够成为唯一的可靠水源，因此对于长期维持鸟类多样性具有至关重要的作用。本研究通过相机陷阱和直接调查的方式，对澳大利亚中部MacDonnell山脉生物区域内六个持久性水塘的鸟类群落进行了调查，调查时间跨越三个采样季节（两个夏季和一个冬季）。运用多元和非参数分析方法，对鸟类群落随时间和空间的变化组成进行了分析。研究发现，鸟类群落的结构存在显著差异，尤其是在夏季和冬季之间。这些差异与迁徙性及游牧性物种以及通常不被认为是依赖地表水的物种在夏季季节出现在水塘有关。不同水塘之间鸟类群落的差异显著，这可能与个别物种对不同地点环境特征的个体反应有关。基于距离的线性模型表明，地面觅食物种如托雷斯岛乌鸦和普通青铜翅鸟在树冠和灌木覆盖度较高的地点出现频率较低。斑胸草雀在大水塘（> 300 m²）的出现频率较低，而白羽蜂鸟在树冠较高的地点出现频率较高。本研究得益于两种调查方法的应用，发现季节性天气模式和环境影响是影响物种何时何地访问持久性水塘的重要因素。这具有潜在的管理意义，例如，如果随着时间的推移树木和灌木覆盖度减少，这可能会阻止树冠觅食的蜂鸟访问，或增加机会主义地面觅食者（如托雷斯岛乌鸦）的访问，这可能会通过增加如卵和雏鸟捕食等对抗性交互而负面地影响其他物种。在干旱地区的高地保护多样化的水塘栖息地，将确保它们在未来对各种物种的可及性。