Scale Differences in the Dependence of Seasonal Bird Diversity on Landscape Structure : A Case Study in Northeastern China

Wildlife interact with environmental variables at different spatial scales. We undertook point counts of birds in the Xianghai wetland reserve of northeastern China from 2000 to 2009, and used remote sensing and GIS technologies to map land cover types. We linked cover types to avian species richness, evenness, and Shannon's diversity using a stepwise linear regression model and regressions of proportions of cover types at different spatial scales. We recorded 109,026 sightings comprising 94 species, and found that avian diversity indices were positively influenced by the presence of open water, farmland, and alkaline marsh, and negatively by human settlement; and in addition, these relationships were only apparent when scale was considered. We detected the dependence of the avian assemblage on alkaline marshes and open water, which in turn might depend on incoming flows of water. We also found negative relationship between human settlements and bird diversity which extended to a distance of 3 km. Consequently, we provide evidence of significant scale dependence on landscape structure of wetland bird diversity. Therefore, scalar effects of different habitat variables need to be taken into account when managing wetland bird populations with the aim of conserving avian biodiversity.