No Evidence for an Effect of Vegetation Productivity on the Structure and Diversity of a Reed-Bed Associated Passerine Assemblage during Autumn Migration

摘要: The structure of a species assemblage at given sites constitutes key ecological parameter to understand the dynamics bird assemblages. aim this paper is (1) quantify how variable passerine associated with an inter-tidal reedbed area main stopover site in Atlantic flyway northern Iberia and explore potential factors explaining variation, emphasis on vegetation productivity, (2) test whether inter-annual fluctuations reflect possible demographic trends. Migratory birds, especially those which show high flexibility stop over some places or others using opportunistic strategy, should be expected land larger numbers stay for longer periods years higher thus amount insect prey, since would permit achieving fuel deposition rates. We used ringing data collected Txingudi marshlands during autumn migration 2007–2016. had relatively simple structure, because few dominated number rest. Reed Warblers Acrocephalus scirpaceus nine out ten study years, supporting importance species. As compared other two most abundant passerines (the Sedge Willow Warblers, A. schoenobaenus Phylloscopus trochilus, respectively), ratio between these three warblers varied from year year, having much annual than This likely linked exploitation reed bed by species, but we did not find significant effect productivity (quantified Normalized Difference Vegetation Index, NDVI) diversity assemblage. Annual species' contribution vary linearly, except Bluethroat Luscinia svecica. Only Bluethroats proportion captures mean declined year. seem affected local conditions hence working spatial scales origin region migrants captured apparently may more relevant structural traits