EFFECT OF STAND WIDTH AND ADJACENT HABITAT ON BREEDING BIRD COMMUNITIES IN BOTTOMLAND HARDWOODS

Bottomland hardwood forests support an abundant and diverse avifauna, but area of this forest type)) has been reduced, and current projectio ns indicate continued declines. We compared breeding bird abundance in dices and species richness among bottomland hardwood stands ranging in width from <50 m to >1,000 m and enclosed by forested habitat. We als o compared avian abundance indices and richness among stands enclosed by pine (Pious spp.) forest and stands enclosed by field-scrub habitat s. Total species richness and species richness of Neotropical migrants were associated positively (P < 0.05) with stand width in all years. Total bird counts differed among width classes in all years, with coun ts generally greatest in width classes <50 m and >1,000 m. Counts of N eotropical migrants differed (P < 0.05) among width classes in 1993 an d 1995 and followed the same general trend as total bird count. Acadia n flycatcher (Empidonax virescens), blue-gray gnatcatcher (Polioptila caerulea), and red-eyed vireo (Vireo olivaceous) were more abundant in smaller width classes (P < 0.05), whereas the opposite was true for w hite-eyed vireo (Vireo griseus) and northern parula (Parula americana) . Probability of occurrence was associated positively (P < 0.05) with stand width for 12 species and negatively with stand width for 1 speci es. Total bird count and the counts of blue-gray gnatcatcher in 1995 a nd of northern cardinal (Cardinalis cardinalis) in both rears were hig her in field-enclosed stands (FES) than in pine-enclosed stands (PES). No species analyzed was more abundant in PES than in FES. We conclude that even narrow riparian zones can support an abundant and diverse a vifauna, but that conservation of wide (greater than or equal to 500 m ) riparian zones is necessary to maintain the complete avian community characteristic of bottomland hardwood forests in South Carolina.