The role of a dominant predator in shaping biodiversity over space and time in a marine ecosystem

1. Exploitation of living marine resources has resulted in major changes to populations of targeted species and functional groups of large-bodied species in the ocean. However, the effects of overfishing and collapse of large top predators on the broad-scale biodiversity of oceanic ecosystems remain largely unexplored. 2. Populations of the Atlantic cod (Gadus morhua) were overfished and several collapsed in the early 1990s across Atlantic Canada, providing a unique opportunity to study potential ecosystem-level effects of the reduction of a dominant predator on fish biodiversity, and to identify how such effects might interact with other environmental factors, such as changes in climate, over time. 3. We combined causal modelling with model selection and multimodel inference to analyse 41 years of fishery-independent survey data (1970–2010) and quantify ecosystem-level effects of overfishing and climate variation on the biodiversity of fishes across a broad area (172 000 km2) of the Sc...1. 海洋生物资源开发已导致海洋中目标物种及大型生物类群功能群的种群发生显著改变。然而，过度捕捞与大型顶级捕食者种群崩溃对海洋生态系统大范围生物多样性的影响，迄今仍未得到充分探索。2. 加拿大大西洋海域的大西洋鳕鱼（Gadus morhua）种群在20世纪90年代初遭到过度捕捞，多个种群最终崩溃，这为研究优势捕食者种群缩减对鱼类生物多样性的潜在生态系统级效应，以及解析此类效应如何随时间与气候变迁等其他环境因子相互作用提供了独特契机。3. 我们将因果建模（causal modelling）与模型选择、多模型推断相结合，对1970年至2010年共计41年的渔业独立调查数据开展分析，以量化过度捕捞与气候变异对某广袤海域（172000平方公里）鱼类生物多样性的生态系统级效应...