emergency Wetlands Reserve Program, grassland birds, Partners in Flight, presettlement, habitat restoration, restoration ecology, riparian, Wetlands Reserve Program
Conversion of Midwestern riparian areas for agricultural production has greatly altered their function and suitability for birds and other wildlife. Recently, however, restoration of riparian functions has been a major focus of land management agencies in the Midwest. We used historic land-use data to describe land-cover changes since European settlement and the subsequent effects of habitat restoration efforts on the landscape along a section of the Iowa River in east-central Iowa. We then used bird-density data collected in a subset of the study area in 2001 and 2002 to estimate changes in breeding bird populations of the entire study area resulting from these habitat restoration efforts.
Before settlement, the (>24,000 ha) Iowa River Corridor was dominated by herbaceous vegetation (72%), with wooded areas accounting for less than one-third of the area. Between the mid-1800s and 1992, agricultural conversion decreased the amount of herbaceous cover by >75%, and the cover of woody vegetation increased by >25%. After the 1993 flood, establishment of USDA conservation easements increased the amount of herbaceous cover in the corridor by >135% (>5,000 ha).
Populations of most grassland and wetland bird species in the corridor (13 of 17) increased with habitat restoration, although some species associated with open habitats, such as those that often breed in rowcrop fields, decreased. We estimated that these restored habitats provide habitat for >12,000 additional birds of grassland- or wetland-dependent species in the Iowa River Corridor, 5,000 of which are members of eight species that are of moderate or high conservation priority.
An understanding of presettlement land cover, the extent of land-cover alteration, and the effects of habitat restoration on the landscape and breeding bird populations provides a useful guide for both evaluating the efficacy of past restoration and for guiding future conservation and restoration efforts.
Journal of the Iowa Academy of Science
© Copyright 2007 by the Iowa Academy of Science, Inc.
Benson, Thomas J.; Dinsmore, James J.; and Hohman, William L.
"Changes in Land Cover and Breeding Bird Populations with Restoration of Riparian Habitats in East-central Iowa,"
Journal of the Iowa Academy of Science: JIAS: Vol. 113:
, Article 4.
Available at: http://scholarworks.uni.edu/jias/vol113/iss1/4