Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, Australia.
Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, Australia; Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, Australia.
Mar Environ Res. 2021 Jun;168:105319. doi: 10.1016/j.marenvres.2021.105319. Epub 2021 Mar 27.
As habitat-forming species continue to decline globally, it is important to understand how associated communities respond to habitat loss and fragmentation. Changes in the density and spatial configuration of habitat have important consequences for associated communities. However, tests of these factors are often confounded by morphological variation of habitat-formers, which can be resolved by using standardised habitat-mimics. Furthermore, few studies have incorporated the role of predators in mediating the observed effects. To test whether predators mediate the abundance of invertebrates among algal habitats of varying configuration (isolated vs patches, and positions within patches), we placed macroalgal mimics into subtidal estuarine habitats for one month to sample epifaunal communities. At the same time, we conducted underwater video surveys of fish communities to quantify fish communities and their feeding behaviour among the artificial habitats. Isolated habitats did not differ from patch habitats, however, patch edges had the highest epifaunal abundance, where fish were least commonly observed. Observed fish feeding was highest in the middle of patches and increased fish observations and feeding in habitats with reduced epifaunal communities suggest that mesopredatory fish are mediating epifauna in patches, with predation pressure altered by the spatial configuration of the habitat. This contrasts to previous studies that focus on predators that congregate outside patches and suggest that fragmentation leads to reduced invertebrate abundance at habitat edges in contrast to centres. However, this study highlights that in habitat patches housing small mesopredators that also benefit from the increased structure, the centre of the patch experiences higher predation and therefore fewer epifauna in contrast to patch edges and individual algal mimics.
随着全球范围内形成栖息地的物种继续减少，了解相关群落如何对栖息地丧失和破碎化做出响应变得尤为重要。栖息地密度和空间配置的变化对相关群落有重要影响。然而，这些因素的测试往往受到栖息地形成者形态变异的干扰，可以通过使用标准化的栖息地模拟物来解决。此外，很少有研究纳入了捕食者在调节观察到的影响方面的作用。为了测试捕食者是否在调节不同配置（孤立与斑块，以及斑块内的位置）的藻类栖息地中无脊椎动物的丰度，我们将大型藻类模拟物放置在潮间带河口栖息地一个月，以采样附生群落。与此同时，我们对鱼类群落进行水下视频调查，以量化人工栖息地中的鱼类群落及其摄食行为。孤立的栖息地与斑块栖息地没有区别，然而，斑块边缘的附生动物丰度最高，鱼类观察到的次数最少。观察到的鱼类摄食在斑块的中部最高，而减少附生动物群落的栖息地中鱼类观察和摄食的增加表明，中型捕食者正在调节斑块中的附生动物，而捕食压力受到栖息地空间配置的改变。这与之前关注集中在斑块外的捕食者的研究形成对比，这些研究表明，与中心相比，破碎化导致栖息地边缘的无脊椎动物丰度减少。然而，本研究强调，在容纳小型中型捕食者的栖息地斑块中，由于增加的结构，斑块的中心经历更高的捕食压力，因此与斑块边缘和单个藻类模拟物相比，斑块中心的附生动物较少。
