Patterns of resource partitioning by nesting herons and ibis: How are odonata exploited?

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• 作者：Farrah Samraoui^a ; ^{bsamraoui@yahoo.fr} ; Riad Nedjah^a ; Abdennour Boucheker^a ; Ahmed H. Alfarhan^b ; Boudjé ; ma Samraoui^a ; ^b
• 关键词：Ardeidae ; Dragonflies ; Wetlands ; Competition ; Predation ; Ecological niche
• 刊名：Comptes Rendus Biologies
• 出版年：2012
• 出版时间：April, 2012
• 年：2012
• 卷：335
• 期：4
• 页码：310-317
• 全文大小：475 K

文摘

Herons and ibis are colonially nesting waders which, owing to their number, mobility and trophic role as top predators, play a key role in aquatic ecosystems. They are also good biological models to investigate interspecific competition between sympatric species and predation; two processes which structure ecological communities. Odonata are also numerous, diverse, mobile and can play an important role in aquatic ecosystems by serving as prey for herons and ibis. A relationship between prey size and bird predator has been observed in Numidia wetlands (NE Algeria) after analyzing food boluses regurgitated by six species of birds (Purple Heron, Black-crowned Night Heron, Glossy Ibis, Little Egret, Squacco Heron and Cattle Egret) during the breeding period, which also shows a temporal gradient for the six species. Both the Levins index and preliminary multivariate analysis of the Odonata as prey fed to nestling herons and ibis, indicated a high degree of resource overlap. However, a distinction of prey based on taxonomy (suborder and family) and developmental stage (larvae or adults) reveals a clear size dichotomy with large-sized predators (Purple Heron, Black-crowned Night Heron and Glossy Ibis) preying on large preys like Aeshnids and Libellulids and small-sized predators feeding mainly on small prey like Zygoptera. Overall, the resource utilization suggests a pattern of resource segregation by coexisting nesting herons and ibis based on the timing of reproduction, prey types, prey size and foraging microhabitats.