Diversity, ecological structure, and conservation of the landbird community of Dadia reserve, Greece

Birds are integral to many environmental monitoring schemes. However, there has been little research on the ecological basis of utilizing bird species as indicators of their respective communities and habitats. We used point counts to survey 72 landbird species, 16 of conservation concern, in the Dadia Nature Reserve, Greece, in order to understand the ecology of bird diversity patterns, analyse community composition, identify species characteristic of major vegetation types, and improve long-term management and monitoring protocols. We sampled 36 sites representing 21 vegetation types. Highly heterogeneous sites were the most species rich and rural mosaics (small fields and pastures of low intensity land use, separated by thick hedgerows and tree lines) were twice as rich as intensified crop monocultures. Using multivariate analysis, we found that vegetation cover and height affected the composition of the avifauna. Twenty-one predefined vegetation categories clustered into eight distinct bird habitat types: field crops, rural mosaics, mosaic sites, poplar trees, broadleaved woods, pinewoods, shrubs, and heaths. Ten bird species were highly characteristic of the main bird habitat types in the study area. Our results emphasize the importance of conserving rural mosaics, hedgerows, and openings within forests for landbird conservation in the Mediterranean countryside. We also provide evidence in support of maintaining horizontal heterogeneity at a local scale. Finally, we suggest that monitoring populations of certain indicator bird species can be a cost-effective and efficient way to monitor the state and habitat quality of the entire landbird community, thereby integrating the knowledge of community structure into conservation decision-making.