ECOSYSTEM SIZE, BUT NOT DISTURBANCE, DETERMINES FOOD-CHAIN LENGTH ON ISLANDS OF THE BAHAMAS.
ECOSYSTEM SIZE, BUT NOT DISTURBANCE, DETERMINES FOOD-CHAIN LENGTH ON ISLANDS OF THE BAHAMAS.
复制标题
DOI：
10.1890/07-1990.1
复制
发表时间：
2008-11
期刊：
影响因子：
4.8
通讯作者：
G. Takimoto;David A. Spiller;D. Post
中科院分区：
文献类型：
--
作者：
G. Takimoto;David A. Spiller;D. Post
长期以来，生态学家一直在努力解释自然生态系统中食物链长度的变化。在受到较大扰动的生态系统中，食物链长度预计会较短，因为较长的链理论上对扰动的适应能力较差。此外，在更大的生态系统中，食物链长度预计会更长，因为生态系统规模的增加会增加物种丰富度，稳定捕食者-猎物的相互作用，或增加总资源的可用性。在这里，我们测试了干扰和生态系统大小在决定巴哈马群岛陆地食物网食物链长度中的作用。我们发现干扰会影响顶级捕食者的身份，但不会改变食物链的长度，因为其他顶级捕食者占据了相似的营养位置。另一方面，生态系统规模增加106倍，食物链长度增加一个营养级。当交替顶端捕食者为营养杂食动物且营养地位相似时，干扰对食物链长度的影响较弱。这项研究和之前在湖泊中的研究表明，生态系统的大小可能是水生和陆地生态系统食物链长度的一个重要决定因素。
Ecologists have long struggled to explain variation in food-chain length among natural ecosystems. Food-chain length is predicted to be shorter in ecosystems subjected to greater disturbance because longer chains are theoretically less resilient to perturbation. Moreover, food-chain length is expected to be longer in larger ecosystems because increasing ecosystem size increases species richness and stabilizes predator-prey interactions, or increases total resource availability. Here we test the roles of disturbance and ecosystem size in determining the food-chain length of terrestrial food webs on Bahamian islands. We found that disturbance affected the identity of top predators, but did not change food-chain length because alternative top predators occupied similar trophic positions. On the other hand, a 106 -fold increase in ecosystem size elevated food-chain length by one trophic level. We suggest that the effect of disturbance on food-chain length is weak when alternate top predators are trophic omnivores and have similar trophic positions. This and previous work in lakes suggest that ecosystem size may be a strong determinant of food-chain length in both aquatic and terrestrial ecosystems.