Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania, 7001, Australia.
Antarctic Climate and Ecosystems CRC, University of Tasmania, Private Bag 80, Hobart Tasmania, 7001, Australia.
Ecol Appl. 2021 Jul;31(5):e02343. doi: 10.1002/eap.2343. Epub 2021 May 20.
Quantifying the links between the marine environment, prey occurrence, and predator distribution is the first step towards identifying areas of biological importance for marine spatial planning. Events such as marine heatwaves result in an anomalous change in the physical environment, which can lead to shifts in the structure, biomass, and distribution of lower trophic levels. As central-place foragers, seabirds are vulnerable to changes in their foraging grounds during the breeding season. We first quantified spatiotemporal variability in the occurrence and biomass of prey in response to an abrupt change in oceanography as a result of a marine heatwave event. Secondly, using multivariate techniques and machine learning, we investigated if differences in the foraging technique and prey of seabirds resulted in varying responses to changes in prey occurrence and the environment over a 2.5-yr period. We found that the main variables correlated with seabird distribution were also important in structuring the occurrence and biomass of prey; sea-surface temperature (SST), current speed, mixed-layer depth, and bathymetry. Both zooplankton biomass and the occurrence of fish schools exhibited negative relationships with temperature, and temperature was subsequently an important variable in determining seabird distribution. We were able to establish correlations between the distribution of prey and the spatiotemporal distribution of albatross, little penguins and common-diving petrels. We were unable to find a correlation between the distribution of prey and that of short-tailed shearwaters and fairy prions. For high-use coastal areas, the delineation of important foraging regions is essential to balance human use of an area with the needs of marine predators, particularly seabirds.
量化海洋环境、猎物出现和捕食者分布之间的联系是确定海洋空间规划中具有生物重要性的区域的第一步。海洋热浪等事件导致物理环境异常变化，从而导致低营养级别的结构、生物量和分布发生变化。作为中心觅食者，海鸟在繁殖季节很容易受到觅食地变化的影响。我们首先量化了由于海洋热浪事件导致的海洋学突然变化，猎物出现和生物量的时空变化。其次，我们使用多元技术和机器学习，研究了在 2.5 年的时间里，海鸟觅食技术和猎物的差异是否导致它们对猎物出现和环境变化的反应不同。我们发现，与海鸟分布相关的主要变量对于猎物的出现和生物量的结构也很重要；海面温度（SST）、海流速度、混合层深度和水深。浮游动物生物量和鱼群的出现与温度呈负相关，温度是决定海鸟分布的重要变量。我们能够确定猎物的分布与信天翁、小企鹅和普通潜鸟的时空分布之间的相关性。我们无法确定猎物的分布与短尾鹱和神仙企鹅的分布之间的相关性。对于高使用率的沿海地区，划定重要的觅食区域对于平衡人类对该区域的使用与海洋捕食者（特别是海鸟）的需求至关重要。
