ABSTRACT:
A study of two watersheds in Central Pennsylvania, an undisturbed, forested (reference) one and a partially disturbed (agricultural and residential) one, was used to analyze how agriculture and residential development of the riparian corridor affected species richness, abundance, and the structure of guilds of the bird community. Bird species richness and abundance generally decreased with distance from the stream in the disturbed ivatershed, but remained relatively constant through the reference watershed. At disturbed sites most neotropical migrant birds with specific habitat requirements were recorded only during migration. Although an impoverished bird community can exist in the vicinity of the riparian bank immediately adjacent to the water with <10 m (30 ft) of natural vegetation, sensitive species will not occur unless an undisturbed corridor > 25 m (82 ft) in width on each bank is present. Presence of narrow 2 m (7 ft) bands of woody vegetation along the stream channel and fence rows seemed to be important in maintaining portions of the bird community in disturbed areas. Land owners and resource managers should be aware of responses by the avian community to small, incremental changes in land use, and try to protect existing stream corridors or restore native vegetation in riparian areas.
Footnotes
Mary Jo Croonquist was a research technologist and is now the habitat program manager for Region III of the Arizona Game and Fish Department, 5325 North Stockton Hill Road, Kingman, AZ 86401-1037. Robert-Brooks is an associate professor of wildlife ecology with the School of Forest Resources, The Pennsylvania State University, University Park, PA 16802, Funding was provided by the School of Forest Resources of The Pennsylvania State University, Pennsylvania Wild Resource Conservation Fund, Pennsylvania Game Commission, and U.S. Army Corps of Engineers. We appreciate the cooperation of landowners along both streams and the staff of Bald Eagle State Forest.
- Copyright 1993 by the Soil and Water Conservation Society
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