Relative influence of predators, competitors, and seascape heterogeneity on behaviour and abundance of coral reef mesopredators

Determining influences of predation and competition on community dynamics is particularly challenging in coral reef systems where interspecific interactions between many predator and prey species play out in patchy landscapes. We used ~1000 stereo-Baited Remote Underwater Video deployments (Stereo-BRUVs) to assess the relative abundance and analysed the behaviour of two size classes of mesopredatory teleosts (lutajnids, serranids, lethrinids) in the presence and absence of larger predators (mesopredatory and apex carcharhinids). For mesopredatory teleosts, the presence of sharks did not influence the abundance, time of arrival in vicinity of the stereo-BRUVs, the probability of feeding on bait, or the delay to feeding. Instead, the number of similar-sized competitors and surrounding habitat features were the strongest drivers of these behavioural metrics. We suggest that for most fishes, the predatory threat posed by highly mobile species such as sharks is likely to be sporadic and transitory, whereas competition is ubiquitous and ever present, particularly for schooling taxa. Ultimately, it is likely that both processes interact to determine behavioural phenotypes as individuals that are inferior competitors can be displaced from safe habitats or prohibited from access to resources and will be more susceptible to predation. Future studies should consider the relative effects of both processes and the degree to which each can be shaped by habitat when investigating trophic dynamics that regulate marine communities.,The data was collected using baited remote underwater stereo-video surveys in north west Australia.,This data has been collected by various organisations. Please contact GlobalArchive if you would like to use the data.,

解析捕食与竞争对群落动态的调控作用，在珊瑚礁生态系统中尤具挑战——此类生境破碎化的景观内，众多捕食者与猎物物种间的种间相互作用频繁发生。我们采用约1000次诱饵式水下立体视频布放（Stereo-BRUVs），评估了两种体型等级的中掠食性硬骨鱼（mesopredatory teleosts）——笛鲷科（Lutajnidae）、鮨科（Serranidae）、裸颊鲷科（Lethrinidae）——在存在与不存在大型捕食者（中掠食性类群及真鲨科（Carcharhinidae）顶级捕食者）环境下的相对丰度，并分析了其行为特征。对于中掠食性硬骨鱼而言，鲨鱼的存在并未对其丰度、抵达诱饵式水下立体视频设备附近的时间、摄食诱饵的概率以及摄食延迟时长产生影响。与之相反，同体型竞争者的数量与周边生境特征才是决定上述行为指标的最关键驱动因素。我们认为，对于多数鱼类而言，鲨鱼等高度移动性物种所构成的捕食威胁大概率是偶发且短暂的，而竞争则无处不在且持续存在，对于集群类群而言尤为如此。最终，这两种过程大概率会共同作用以塑造行为表型：竞争力较弱的个体可能会被逐出安全生境，或无法获取资源，进而更易遭受捕食。未来在探究调控海洋群落的营养动态时，应同时考量这两种过程的相对影响，以及生境对二者各自的塑造程度。
本数据集通过澳大利亚西北部的诱饵式远程水下立体视频调查采集所得。
本数据集由多家机构共同采集。若您希望使用该数据，请联系GlobalArchive。