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Abstract
With rapid urbanization and extensive agriculture in the southeastern United States, natural and planted pine forests are increasingly embedded in a complex matrix of urban development and agricultural lands. For sound conservation management plans in the landscape, it is critical to understand how the matrix of urban development and/or agricultural lands influences biodiversity-habitat relationship and to identify important habitat characteristics. This requires a multiple-scale approach considering habitat characteristics at both local and landscape scale. Few studies have explored avian biodiversity-habitat relationship in pine forests, especially in urban/agricultural landscapes, at multiple-scales. Therefore, we investigated the relationship between site occupancy of avian species and spatial scales (1 local-scale and 2 landscape-scales), the effect of anthropogenic land uses on avian biodiversity (richness and RCS, Partners In Flight Regional Combined Score) along a gradient of urban-rural/agriculture-wildland, and the avian biodiversity-habitat structure-area relationship, in 3 ecoregions of Georgia. Occupancy by forest interior and forest edge species was more associated with landscape scale features, whereas occupancy of pine-grassland species more related to local scale features. Urban development and agricultural land uses positively influenced occupancy of species, avian richness and RCS. In particular, richness and RCS were higher at pine patches in a mixture of low level of urban development and agricultural land uses and in low level of agriculture matrix than other levels of human land-use including wildland. However, as human land-use increased, relative proportion of migrant and pine-grassland species in a community decreased. Richness and RCS were greater at moderate or low level of basal area (MS) which increased structural diversity within a patch. The effect of patch size varied with levels of basal area. While richness and RCS increased with size of MS patches, they did not change in patches of higher basal area (greater than MS). Our results suggest that both local and landscape scale habitat features need to be considered to improve avian biodiversity. The pine forests in the urban/agriculture matrix could play a potentially positive role in avian biodiversity conservation, and it is important to maintain moderate or level of basal area and preserve larger patches to enhance avian biodiversity.