Minnesota Land Trust Final Report - Let the Birds Guide You

Abstract

Identifying environmental and habitat characteristics associated with specific bird communities can help guide conservation and habitat management efforts. The goal of this project was to quantify and characterize bird communities in the St. Louis River Estuary (SLRE) based on bird-habitat associations. Bird communities are commonly described with respect to their associated cover types (i.e., habitat). However, birds often respond to combinations of local cover types and larger-scale landscape features (e.g., forested wetlands in proximity to emergent wetlands), which are not adequately described by a single attribute such as dominant plant species or aquatic habitat type. Therefore, to understand bird species’ ecological needs and habitat preferences, we evaluated community assemblages without initially linking the locations sampled for birds with standard habitat categories. Bird assemblages were first identified using hierarchical cluster analysis, which revealed relationships among locations sampled within the SLRE based solely on bird species composition. This approach identified assemblages of species that tend to co-occur irrespective of traditionally defined habitat types. We used percent perfect indication (PPI) models to identify which species or groups of species were most strongly associated with specific landscape features. We also assessed habitat availability at the landscape-scale (i.e., within a 400m buffer from the shoreline) to identify specific features that are under-represented in the SLRE but likely important to a species or group of species. We also quantified species relative abundance, richness, and diversity throughout the SLRE to identify locations of high use and diversity. Once those locations were identified, we summarized local-scale habitat data define vegetation characteristics at locations with the highest and lowest species richness. Together, these analyses will provide a holistic assessment of the environmental and habitat requirements of migratory and breeding birds at multiple spatial scales. We quantitatively assessed which landscape and habitat characteristics are most likely to be beneficial for birds that use the SLRE and, ultimately, to assist in informing habitat management objectives for current and future projects in the area.