Coupling of canopy and understory food webs by ground-dwelling predators
Coupling of canopy and understory food webs by ground-dwelling predators
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DOI：
10.1111/j.1461-0248.2008.01252.x
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发表时间：
2008-12-01
期刊：
影响因子：
8.8
通讯作者：
Fox-Dobbs, Kena
中科院分区：
文献类型：
--
作者：
Pringle, Robert M.;Fox-Dobbs, Kena
了解食物网动态需要知道物种组合是否被划分为不同的能量通道，如果是，这些通道在空间上是如何结构的。我们用同位素分析重建了肯尼亚森林草原的食物网。昆虫猎物是C-3（树木和灌木）或C-4（草）植物的相对专门的消费者。树栖捕食者（节肢动物和壁虎）也很特殊，90%的食物来自于以碳-3为食的猎物。相比之下，地面捕食者对C-3和c -4捕食的猎物都有很大的捕食。这种不对称表明，陆地捕食者群落受到重力驱动的补贴，因此，树上栖息的猎物掉落并被地面栖息的捕食者吃掉。因此，捕食者通常将这个食物网的C-3和C-4组成部分结合在一起，但地面捕食者比树栖捕食者更有效地发挥这一生态系统功能。尽管在垂直结构的陆地栖息地中，猎物补贴很少受到关注，但它们可能是常见的，对食物网组织很重要。
Understanding food-web dynamics requires knowing whether species assemblages are compartmentalized into distinct energy channels, and, if so, how these channels are structured in space. We used isotopic analyses to reconstruct the food web of a Kenyan wooded grassland. Insect prey were relatively specialized consumers of either C-3 (trees and shrubs) or C-4 (grasses) plants. Arboreal predators (arthropods and geckos) were also specialized, deriving c. 90% of their diet from C-3-feeding prey. In contrast, ground-dwelling predators preyed considerably upon both C-3- and C-4-feeding prey. This asymmetry suggests a gravity-driven subsidy of the terrestrial predator community, whereby tree-dwelling prey fall and are consumed by ground-dwelling predators. Thus, predators in general couple the C-3 and C-4 components of this food web, but ground-dwelling predators perform this ecosystem function more effectively than tree-dwelling ones. Although prey subsidies in vertically structured terrestrial habitats have received little attention, they are likely to be common and important to food-web organization.