Print PageDeclining species richness, increasing homogenization, and variation in abundance and nestling survival across different land use regimes are well-documented consequences of urbanization. Annual survival of birds in different land use regimes may drive differences in species composition and abundance. However, questions regarding variation in survival across differing land use regimes are rarely addressed because they require multi-year data across geographic expanse large enough to capture differences. The Monitoring Avian Survival and Productivity (MAPS) long-term mist-netting program collects data useful to address such questions. We obtained MAPS data from 98 sites across the northeastern United States, and land cover information from Multi-resolution Land Characteristics National Land Cover Data (NLCD). We estimated percent cover of 10 land cover types within a 1-km radius around each 20-hectare site and used NMDS ordination to calculate composite indices of land cover. We used regression to evaluate the relationship between survival (estimated via MARK) and land cover metrics for 18 species. We predicted species responses based on species’ life-history characteristics and sensitivity to urbanization as reported in the literature.
Results/Conclusions
Three species showed significant or nearly significant relationships between annual survival and the first land cover index (up to 46% of variance explained). Five species showed significant or nearly significant relationships with the second index (up to 22% of variance explained). Three relationships were quadratic, suggesting there may be optimal levels of forest cover or disturbance associated with survival. Five species had significant relationships with one or a combination of land cover types (up to 43% of variance explained), and eight species exhibited nearly significant relationships (up to 30% of variance explained). Seven species showed no relationship with our metrics. Observed relationships were not always consistent with our predictions, possibly due to multiple other factors influencing annual survival. However, given the multitude of other factors expected to influence survival, that nearly half of our species show a relationship with a single variable of land cover may be meaningful. Predictors including human population density and climatic variables were also not always consistent with our predictions. These results may inform conservation priorities, as differential sensitivity of species to land cover and urbanization should be considered when evaluating conservation initiatives.
