Habitat selection of the passerine community nesting at the Ebro delta reed-beds (NE Spain): some management implications

In this study, we explored the habitat associations of the five most abundant passerine species nesting in the Ebro Delta reedbeds (NE Spain). Habitat characteristics (water depth, vegetation height and density, and plant-species composition) and abundance of all passerine species were measured at each of the 68 sampling points. The sampled area included most of the reedbeds in the Ebro Delta. Sampling points were classified according to the habitat parameters measured using cluster analysis. The resulting four habitat types differed in the composition and attributes of their passerine communities. The abundance of the great reed warbler (Acrocephalus arundinaceus) and reed warbler (Acrocephalus scirpaceus) was greatest in tall, permanently inundated and almost monospecific Phragmites reedbeds. In contrast, the numbers of the reed bunting (Emberiza schoeniclus) and Savi's warbler (Locustella luscinioides) were greatest in areas of drier soils and a denser basal stratum. Finally, the fan-tailed warbler (Cisticola juncidis) showed no clear habitat association. In the Ebro Delta, reedbed management includes freshwater inputs and burning of standing reeds. These practices promote tall, permanently inundated reedbeds with minimal detrital accumulation. Bird species richness and diversity were greater in less intensely-managed habitats, but only diversity was significant (p < 0.001). We conclude that, since reedbeds are important habitats for several scarce bird species, and the abundance of these species seem to be influenced by vegetation structure, bird conservation considerations should be incorporated into future reedbed management practices. © 2002, The Society of Wetland Scientists.