Geographic analysis of species richness and community attributes of forestbirds from survey data in the mid-Atlantic integrated assessment region

Species richness of local communities is a state variable commonly used in community ecology and conservation biology. Investigation of spatial and te mporal variations in richness and identification of factors associated with these variations form a basis for specifying management plans, evaluating these plans, and for testing hypotheses of theoretical interest. However, e stimation of species richness is not trivial: species can be missed by inve stigators during sampling sessions. Sampling artifacts can lead to erroneou s conclusions on spatial and temporal variation in species richness. Here w e use data from the North American Breeding Bird Survey to estimate paramet ers describing the state of bird communities in the Mid-Atlantic Assessment (MAIA) region: species richness, extinction probability, turnover and rela tive species richness. We use a recently developed approach to estimation o f species richness and related parameters that does not require the assumpt ion that all the species are detected during sampling efforts. The informat ion presented here is intended to visualize the state of bird communities i n the MAIA region. We provide information on 1975 and 1990. We also quantif ied the changes between these years. We summarized and mapped the community attributes at a scale of management interest (watershed units).