Conservation reserve enhancement program fields: Benefits for grassland and shrub-scrub species

Abstract

Almost 30,000 ha (74,100 ac) of grassland were created in south-central Pennsylvania through the USDA Conservation Reserve Enhancement Program (CREP) from 2000 to 2004. To assess the use of these fields by grassland and other birds and to develop region-specific management guidelines, we conducted transect counts of singing birds in 103 CREP fields during 2002 to 2004 and measured within-field vegetation and landscape characteristics. Thirty-two bird species were found on fields during the breeding season. Red-winged blackbirds (Agelaius phoeniceus) were most numerous, followed by three shrub-scrub species. Grassland obligate species were rare and were most abundant on larger fields with a lower density of vegetation and a predominance of cool-season grasses. Abundances of shrub-scrub species were highest on smaller fields with a higher density of vegetation and a higher proportion of warm-season grasses. Avian use of CREP fields in Pennsylvania differs from Midwestern Conservation Reserve Program fields in a number of important ways. Shrub-scrub species were more common, which may be due to the small mean field size and the more forested landscape. In addition, grassland obligates were found in greater densities on fields of cool-season grasses than in fields of warm-season or mixed grasses. Targeted enrollment and management of large fields or those adjoining other grasslands for grassland birds and small fields or those adjoining woodlands for shrub-scrub species may be the best approach to maximize the benefits of CREP for a range of bird species.