BIRD RELATIONSHIPS TO HABITAT CHARACTERISTICS CREATED BY TIMBER HARVESTING IN PENNSYLVANIA

• Published in: Journal of the Pennsylvania Academy of Science 2001-02, Vol.74 (2/3), p.71-84
• Main Authors: ROSS, BRAD D., MORRISON, MICHAEL L., HOFFMAN, WAYNE, FREDERICKSEN, TODD S., SAWICKI, RICHARD J., ROSS, ERIC, LESTER, MICHAEL B., BEYEA, JAN, JOHNSON, BRADLEY N.
• Format: Article
• Language: English
• Subjects: BIOLOGY; Birds; Coniferous forests; Forest habitats; Forest stands; Hardwood forests; Logging; Overstory; Trees; Understory; Warblers
• ISSN: 1044-6753; 2475-1898

Bird species richness, abundance, the abundance of individual species, and bird community composition were investigated to determine the impact of recent timber harvesting on 47 forest stands in northeastern Pennsylvania from 1996-98. Stands were located within northern hardwood and oak-hickory forest types and included mostly non-industrial private forestlands harvested within the past 10 years. Bird community richness and abundance both decreased with increasing retention of overstory cover, residual tree basal area, and litter cover, but both increased with increasing understory plant cover. We identified patterns between bird species richness and abundance, and measures of forest stand characteristics using correlation and correspondence analysis. Threshold levels were evident for tree basal area and understory plant cover above which bird species richness and abundance increased or declined. Bird species richness and abundance increased sharply when tree basal area for a stand dropped below 18m²/ha. Species richness and abundance of birds declined sharply for stands containing more than 26m²/ha tree basal area. Species richness of birds declined sharply when the understory plant cover in a stand dropped below 45%. Harvest intensity and forest type were the primary factors affecting bird community composition. Axis one of detrended correspondence analysis was characterized by increasing shrub, understory plant, and slash cover and volume of downed woody material, and decreasing conifer, snag, and live tree basal area and overstory, midstory, and litter cover. These vegetative characteristics correspond to heavily harvested versus lightly or nonharvested stands, respectively. Axis two separated northern hardwood and oak-hickory stands. Patterns and threshold levels of species richness and abundance of birds along gradients of forest stand characteristics, as well as the identification of forest stand characteristics preferred by species of management concern, provide natural resource professionals with guidelines for managing bird communities on stands harvested for timber in this region.