Effects of Stream Channelization on Avian Diversity and Density in Piedmont Virginia

Species diversity and density for game and non-game birds were studied during winter and summer, 1975 on three streams in the Virginia Piedmont which were channelized 2,5, and 9 years prior to Held work. Three study sites, each 1 hectare in size, were located along streams in secondary succession bottom land hardwood communities. Indices were calculated for bird species diversity (BSD) and foliage height diversity (FHD) using the Shannon-Weaver information theory formula. To further assess any differences in either diversity or density among the three sites the following variables were also examined: the number of breeding birds per hectare, the mean number of birds observed per hour, and the average number of bird species seen per day. Results indicated that BSD and FHD increased from the 2-year-old to 9-year-old channelized streams. A significant increase was observed in avian diversity and density through progressive successional stages of the channelized streams. Breeding birds per hectare was positively correlated with percent shnlb cover. Stream channelization was found to be a disruptive process which sets back plant community succession, resulting in lower avian diversity and density.

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