Global Human Footprint on the Linkage between Biodiversity and Ecosystem Functioning in Reef Fishes

Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas.难以将理论与实验研究结果推广至更大尺度的实际生态系统中，这一问题引发了学界围绕生物多样性丧失对自然生态系统功能的影响的争议。本研究依托全球珊瑚礁鱼类群落（reef fish assemblages）调查数据，结果显示：与此前的理论及实验研究结论相悖，该生态系统的功能（以现存量生物量（standing biomass）为衡量指标）随生物多样性（以物种丰富度和功能丰富度为衡量指标）呈非饱和变化模式。本野外调查同时发现，人类人口密度与生物多样性对生态系统功能存在显著的负交互效应：即当人类活动密度相同时，物种更丰富的珊瑚礁的现存量生物量下降幅度更为显著。研究表明，此类人类影响与捕捞、沿海开发及土地利用胁迫因子密切相关，目前全球超过75%的珊瑚礁均受到此类干扰。本研究结果证实，基于现有学术认知，珊瑚礁生态系统生物多样性丧失的影响已被大幅低估；同时，珊瑚礁鱼类群落，尤其是物种多样性最高的群落，极易受沿海地区人为胁迫因子的扩张与强度提升的威胁。