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RESEARCH PRODUCT

Bird communities as indicators of stream quality

subject

description

Riparian communities of birds are characterized by a large number of species. Among these, some species depend closely on the running water, whereas other species depend on connected wet habitats or linear forests. For fifteen years, we have censused breeding birds on a 2500 km length of river course. The results underlined the importance of (i) the upstream-downstream gradient and (ii) the effects of the landscape characteristics of the valley on the structure of bird communities. In addition, our results showed that landscape structure may be described with a limited number of variables measured from field work or from analyses of satellite data. The bird census method used (IPA, spot abundance index) provided a robust description of the communities, and was presented as a suitable technique to study temporal or spatial bird community successions. We observed that bird censuses were accurate enough to detect environmental perturbations such as changes of land use within the valley or river channelizations. In addition our results showed that using birds as indicator species provided results that did not overlap those obtained using other taxa (fishes, invertebrates, algae), but instead brought complementary informations, particularly at the hydrosystem landscape level. Our initial attempts in the construction of a quality index based on bird communities indicated that separating bird communities for running waters, floodplains and land had more power than a global index.