Response of bird populations to farmland set-aside programs.
The role of agricultural landscapes in biodiversity conservation has been largely ignored despite their potential role in conserving declining species. Within agricultural landscapes, set-aside programs may offer the most promising conservation opportunities due to the large area involved in these programs. I explored the relationship between set-aside effect size--on the basis of data from field studies of birds in cropland and set-aside fields--and population changes following establishment of these fields. Species whose abundance was most strongly influenced by the establishment of set-aside lands also tended to show positive changes in population trends following broad-scale implementation of the set-aside program. This relationship was strongest for grassland obligate birds, a group of birds experiencing broad-scale population declines throughout North America. There is now increasing evidence that set-aside lands within the United States are providing population-level benefits to grassland birds. Nevertheless, there are also increasing concerns about the stability of these set-aside lands in the face of increased demand for crops and rising commodity prices. If set-aside area within the United States is allowed to decline, additional declines of birds and perhaps other taxa within agricultural landscapes seem likely.
Herkert
James R
JR
The Nature Conservancy, Peoria, IL 61602, USA. jherkert@tnc.org
D000383:Agriculture; D000818:Animals; D044822:Biodiversity; D001717:Birds / Q000502:physiology*; D015146:Midwestern United States