Top-down and bottom-up diversity cascades in detrital vs. living food webs
Top-down and bottom-up diversity cascades in detrital vs. living food webs
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DOI：
10.1046/j.1461-0248.2003.00398.x
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发表时间：
2003-01-01
期刊：
影响因子：
8.8
通讯作者：
Letourneau, D
中科院分区：
文献类型：
--
作者：
Dyer, LA;Letourneau, D
顶端捕食者和植物资源都是维持生物群落多样性的关键，但在陆地系统中，自上而下和自下而上的力量对不同营养水平多样性的间接（“级联”）影响尚未得到很好的解决。对捕食者或资源的操纵可以直接引起某一营养水平的多样性变化，进而影响其他营养水平的多样性。资源和消费者变化的间接多样性效应在水生系统中最强，在陆地系统中中等，在分解者食物网中最弱。研究了上层捕食者和植物资源对林下灌木新枝胡椒内生动物多样性的影响。捕食者和资源可得性对内生动物群落的多样性有显著的直接和间接影响，但这种影响不是相互作用的，在活的和腐的食物网之间也不一致。第四营养级甲虫捕食者的加入增加了由活植物组织支持的消费者的多样性，而平衡的植物资源（光和营养）增加了碎屑资源食物网中初级到三级消费者的多样性。这些结果支持了陆地系统中自上而下和自下而上的多样性级联的假设，以及生物和碎屑食物网中不同因素对多样性的影响。
Apex predators and plant resources are both critical for maintaining diversity in biotic communities, but the indirect ('cascading') effects of top-down and bottom-up forces on diversity at different trophic levels are not well resolved in terrestrial systems. Manipulations of predators or resources can cause direct changes of diversity at one trophic level, which in turn can affect diversity at other trophic levels. The indirect diversity effects of resource and consumer variation should be strongest in aquatic systems, moderate in terrestrial systems, and weakest in decomposer food webs. We measured effects of top predators and plant resources on the diversity of endophytic animals in an understorey shrub Piper cenocladum (Piperaceae). Predators and resource availability had significant direct and indirect effects on the diversity of the endophytic animal community, but the effects were not interactive, nor were they consistent between living vs. detrital food webs. The addition of fourth trophic level beetle predators increased diversity of consumers supported by living plant tissue, whereas balanced plant resources (light and nutrients) increased the diversity of primary through tertiary consumers in the detrital resources food web. These results support the hypotheses that top-down and bottom-up diversity cascades occur in terrestrial systems, and that diversity is affected by different factors in living vs. detrital food webs.