Science. 1990 Nov 9;250(4982):811-4. doi: 10.1126/science.250.4982.811.
Experimental manipulations of fish in a Northern California river during summer base flow reveal that they have large effects on predators, herbivores, and plants in river food webs. California roach and juvenile steelhead consume predatory insects and fish fry, which feed on algivorous chironomid larvae. In the presence of fish, filamentous green algae are reduced to low, prostrate webs, infested with chironomids. When the absence of large fish releases smaller predators that suppress chironomids, algal biomass is higher, and tall upright algal turfs become covered with diatoms and cyanobacteria. These manipulations provide evidence that the Hairston, Smith, Slobodkin-Fretwell theory of trophic control, which predicts that plants will be alternately limited by resources or herbivores in food webs with odd and even numbers of trophic levels, has application to river communitics.
在加利福尼亚北部河流的夏季基流期间对鱼类进行的实验操作表明，它们对河流食物网中的捕食者、食草动物和植物有很大的影响。加利福尼亚蟑螂和幼体虹鳟鱼捕食食虫昆虫和鱼苗，而这些鱼苗又以食藻类摇蚊幼虫为食。在鱼类存在的情况下，丝状绿藻减少到低而匍匐的网中，被摇蚊幼虫寄生。当大型鱼类不存在时，会释放出较小的捕食者，从而抑制摇蚊幼虫，藻类生物量更高，高大直立的藻类草皮上覆盖着硅藻和蓝藻。这些操作提供了证据表明，Hairston、Smith 和 Slobodkin-Fretwell 的营养控制理论，该理论预测在具有奇数和偶数营养级的食物网中，植物将交替受到资源或食草动物的限制，适用于河流群落。
