Dynamic influence of patch size on occupancy of woodland birds

Abstract

Throughout the long history of landscape ecology, scientists have devoted substantial efforts to understand potential forest patch size and isolation effects on the abundance and diversity of woodland species. Which bird species flourish or perish as a response to forest fragmentation may compose fundamental information for the reserve design and landscape management in a region. Here, we designed a bird survey of the urban forest areas in Dangjin city located on South Korea's west coast to test (1) if bird species richness follows the pattern predicted by species-area relationship and (2) if there is seasonal variation in the pattern. As expected, patch area was the most significant variable explaining patch occupancy of resident and summering woodland birds in every season. Our data about the number of dominant vegetation suggest that larger areas contain greater habitat heterogeneity and more diverse niches. About half of the resident species did not appear to be area-sensitive and were categorized as edge species. On the other hand, many summering species showed strong area-sensitivity, potentially avoiding small patches that are almost entirely edge habitats in urban landscape. Our results suggest that lots of contemporary forest edges, fragmented by agricultural or urban development, do not any more function for feeding or nesting places for those species.