Ward Colette L, McCann Kevin S, Rooney Neil
Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1.
National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, 735 State Street, Suite 300, Santa Barbara, CA, 93101-5504, USA.
Ecol Lett. 2015 Nov;18(11):1190-1197. doi: 10.1111/ele.12498. Epub 2015 Aug 27.
Classical food web theory holds that energy channels are regulated by top-down control with increasing productivity, arising from within-channel processes. However, these hypotheses do not consider the existence of parallel energy channels linked by shared resource pools and which can fuel generalist predators, imposing trophic control arising from multi-channel processes. Using 23 large marine food webs, we show that food web responses to increasing productivity are consistent with the apparent trophic cascade hypothesis (ATCH) - with rising productivity predators derive an increasing fraction of their diet from increasingly productive bottom-up controlled detritus channels, thereby subsidising predator biomass, and in turn strengthening top-down control in parallel grazing channels. These results testify to a fundamental role of detritus channels specifically and multi-channel processes in general in mediating food web response to productivity and demonstrate that the ATCH provides an alternative explanation for classical predictions of top-down control.
经典食物网理论认为，能量通道受自上而下的控制调节，生产力增加源于通道内的过程。然而，这些假设没有考虑到由共享资源库连接的平行能量通道的存在，这些通道可以为广食性捕食者提供食物，从而产生多通道过程导致的营养控制。通过对23个大型海洋食物网的研究，我们发现食物网对生产力增加的反应与表观营养级联假说（ATCH）一致——随着生产力的提高，捕食者从生产力不断提高的自下而上控制的碎屑通道中获取的食物比例越来越大，从而补贴捕食者生物量，进而加强平行放牧通道中的自上而下控制。这些结果证明了碎屑通道特别是多通道过程在介导食物网对生产力的反应中的基本作用，并表明ATCH为自上而下控制的经典预测提供了另一种解释。
