Marine Spatial Ecology Lab and Australian Research Council Centre of Excellence for Coral Reef Studies, School of Biological Sciences, The University of Queensland, Goddard Building, Brisbane, Queensland, 4072, Australia.
Institute of Marine and Antarctic Studies and Centre for Marine Socioecology, University of Tasmania, 20 Castray Esplanade, Hobart, Tasmania, 7004, Australia.
Ecology. 2018 Feb;99(2):450-463. doi: 10.1002/ecy.2103. Epub 2018 Jan 12.
Refuge availability and fishing alter predator-prey interactions on coral reefs, but our understanding of how they interact to drive food web dynamics, community structure and vulnerability of different trophic groups is unclear. Here, we apply a size-based ecosystem model of coral reefs, parameterized with empirical measures of structural complexity, to predict fish biomass, productivity and community structure in reef ecosystems under a broad range of refuge availability and fishing regimes. In unfished ecosystems, the expected positive correlation between reef structural complexity and biomass emerges, but a non-linear effect of predation refuges is observed for the productivity of predatory fish. Reefs with intermediate complexity have the highest predator productivity, but when refuge availability is high and prey are less available, predator growth rates decrease, with significant implications for fisheries. Specifically, as fishing intensity increases, predators in habitats with high refuge availability exhibit vulnerability to over-exploitation, resulting in communities dominated by herbivores. Our study reveals mechanisms for threshold dynamics in predators living in complex habitats and elucidates how predators can be food-limited when most of their prey are able to hide. We also highlight the importance of nutrient recycling via the detrital pathway, to support high predator biomasses on coral reefs.
避难所的可获得性和捕捞活动改变了珊瑚礁中的捕食者-猎物相互作用，但我们对于它们如何相互作用以驱动食物网动态、群落结构以及不同营养级群体的脆弱性的理解还不清楚。在这里，我们应用了一种基于大小的珊瑚礁生态系统模型，该模型使用结构复杂性的经验测量进行了参数化，以预测在广泛的避难所可获得性和捕捞制度下，珊瑚礁生态系统中的鱼类生物量、生产力和群落结构。在未捕捞的生态系统中，出现了珊瑚礁结构复杂性与生物量之间的正相关预期，但对于捕食性鱼类的生产力，我们观察到捕食避难所的非线性效应。具有中等复杂性的珊瑚礁具有最高的捕食者生产力，但当避难所可用性高且猎物供应不足时，捕食者的生长速度会下降，这对渔业有重大影响。具体而言，随着捕捞强度的增加，在避难所可用性高的栖息地中生活的捕食者容易受到过度捕捞的影响，导致以草食动物为主的群落。我们的研究揭示了生活在复杂生境中的捕食者的阈动态机制，并阐明了当大多数猎物都能够躲藏时，捕食者如何可能受到食物限制。我们还强调了通过碎屑途径进行养分再循环的重要性，以支持珊瑚礁上的高捕食者生物量。
