Temporal and Spatial Use of Even-Aged Reproduction Stands by Bird Communities in Central Pennsylvania
Abstract In 1992, the Pennsylvania Bureau of Forestry adopted a new forest management practice known as even-aged reproduction with reservation (EAR), which replaces clearcutting on state forestlands. The EAR guidelines mandate the retention of at least 12 trees/ha and 24–36 m2/ha of basal area, representing a diversity of overstory and understory species. During summer 1998, we compared the temporal (breeding season vs. mid-summer) and spatial (edge versus interior) use of EAR stands by birds. In addition, we compared observed vs. expected use of overstory trees in EAR stands. In each of ten representative EAR stands, we sampled birds twice per season along two-edge and two-interior transects. Total species richness and abundance (all species combined), species richness and abundance of ground-shrub foragers, and species richness of canopy-sallier foragers were significantly (P < 0.05) higher in the breeding season than in mid-summer. Eight of 20 common bird species analyzed also were significantly (P < 0.05) more abundant during the breeding season (e.g., black-and-white warbler and chestnut-sided warbler), and one species was significantly (P < 0.05) more abundant during mid-summer. Total species richness, total abundance, and abundance of ground-shrub foragers were significantly higher (P < 0.05) in interiors compared to edges of EAR stands. Five species also were significantly (P < 0.05) more abundant in interiors of EAR stands, whereas no species was more common in edges. All species combined and three foraging guilds showed differential use (P < 0.05) of overstory tree species; eight species also differed significantly in their use of abundant tree species. Based on our findings, we believe that EAR stands are excellent substitutes for clearcuts on state forestlands, although we caution that our findings were based only on one yr of data. We recommend the continued retention of a diversity of overstory trees, especially snags and rough-barked trees, in both edges and interiors of EAR stands for use by a variety of bird species during both the breeding season and mid-summer. North. J. Appl. For. 20(3):117–123.