Taylor Brad W, Flecker Alexander S, Hall Robert O
Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA.
Science. 2006 Aug 11;313(5788):833-6. doi: 10.1126/science.1128223.
Harvesting threatens many vertebrate species, yet few whole-system manipulations have been conducted to predict the consequences of vertebrate losses on ecosystem function. Here, we show that a harvested migratory detrital-feeding fish (Prochilodontidae: Prochilodus mariae) modulates carbon flow and ecosystem metabolism. Natural declines in and experimental removal of Prochilodus decreased downstream transport of organic carbon and increased primary production and respiration. Thus, besides its economic value, Prochilodus is a critical ecological component of South American rivers. Lack of functional redundancy for this species highlights the importance of individual species and, contrary to theory, suggests that losing one species from lower trophic levels can affect ecosystem functioning even in species-rich ecosystems.
捕捞对许多脊椎动物物种构成威胁，但很少有人进行过全系统的操纵实验来预测脊椎动物数量减少对生态系统功能的影响。在此，我们表明，一种被捕捞的洄游碎屑食性鱼类（脂鲤科：玛丽亚锯脂鲤）会调节碳流和生态系统代谢。玛丽亚锯脂鲤数量的自然减少以及实验性移除都降低了有机碳的下游运输，并增加了初级生产和呼吸作用。因此，除了其经济价值外，玛丽亚锯脂鲤还是南美河流的关键生态组成部分。该物种缺乏功能冗余凸显了单个物种的重要性，并且与理论相反，这表明即使在物种丰富的生态系统中，较低营养级别的一个物种消失也会影响生态系统功能。
