千葉市西部の住宅地における鳥類相を規定する要因

抄録

Though factors influencing species composition in urban patchy woodlands have been studied, the ecological meanings of surrounding residential areas are still unclear. In residential areas in the Chiba City we surveyed relationship between bird species composition and land attributes such as vegetation structure and land cover considering landscape conditions indicated by the distance from the nearest large woodland and vegetation index, to clarify the factors influencing bird species composition, from January to March (wintering season) and April to June (breeding season) in 2009. The results were as follows. 1) Sixteen "urban avoider" species were recorded through the survey, which suggested that residential areas can play a role of movement pass for such species. 2) RDA (Redundancy Analysis) extracted three major axes of species compositional change in each season. Vegetation coverage of trees, agricultural land cover, coverage of grassland and distance from the nearest large (>5ha) woodland were significantly correlated with the axes. 3) The results indicated that two "urbanization gradients" could be considered in the residential area: one is the compositional gradient of woodland species and the other is that of grassland species.