Comparison of breeding -bird communities associated with young even -aged stands of differing size and shape in a northern hardwood forest

I compared breeding-bird communities among young even-aged stands of differing size and shape in a northern hardwood forest of McKean and Potter Counties, Pennsylvania, 1989--1991. I tested the hypotheses that composition and structure of breeding-bird communities do not differ (1) among four size and shape categories of young even-aged stands, (2) among interiors and edges of young even-aged stands, and forests adjacent to young even-aged stands, and (3) between uncut forests adjacent to young even-aged stands and forests distant from young even-aged stands. Interiors and edges of young even-aged stands had significantly (P < 0.05) greater mean species richness (9.4 species/visit, 8.6 species/visit, respectively) than adjacent forests and distant forests (4.1 species/visit. 4.6 species/visit, respectively). Mean richness in interiors of large (30--45 ha) young even-aged stands (10.0 species) was significantly (P < 0.05) greater than in interiors of small (6--16 ha) stands (8.7 species). Edges of circular young even-aged stands had significantly (P < 0.05) greater mean richness (9.5 species) than edges of linear stands (7.6 species), and mean richness in interiors of young even-aged small-circular stands (8.4 species) was significantly (P < 0.05) lower than in interiors of large-circular stands (11.0 species). Overall, in young stands, even-aged forest management strongly promoted a very diverse and abundant breeding-bird community dominated by Neotropical migrants that nest in early successional habitats. Shape of young even-aged stands was less important than size in structuring breeding-bird communities in young stand interiors and edges. Even-aged management, however, resulted in reduced richness and abundance of mature forest species in the harvested stand.;I also examined the effect of size of young even-aged stands on depredation rates of artificial avian nests in a northern hardwood forest of Pennsylvania. I tested the hypotheses that predation rates did not differ among artificial avian nests placed (1) in large versus small stands, (2) at the ground versus above ground (arboreal), (3) in interiors and edges of young stands, forests adjacent to young stands, and reference forests, and (4) with increasing distance away from young even-aged stands. Nest predation rates in large young even-aged stands (29.0%) were significantly ( P < 0.05) lower than those in small stands (70.5%). (Abstract shortened by UMI.).