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.
The Nature Conservancy, Peoria, IL 61602, USA. jherkert@tnc.org
James R
JR
Herkert
D000383:Agriculture; D000818:Animals; D044822:Biodiversity; D001717:Birds / Q000502:physiology*; D015146:Midwestern United States