Publications

We investigated whether small predator exclosures might be a useful tool for increasing duck recruitment. During a period of increasing drought from 1987 to 1991, we monitored populations of dabbling ducks on 9 51-km2 study areas, 3 of which contained a centrally located 25-ha predator exclosure and 3 of which served as control areas. We did not detect an increase in duck pairs per...

Many wetlands in the prairie pothole region are embedded within an agricultural landscape where they are subject to varying degrees of siltation. Cultivation of wetland catchment areas has exacerbated soil erosion; wetlands in agricultural fields receive more sediment from upland areas than wetlands in grassland landscapes and hence are subject to premature filling (i.e., they have...

When the Wisconsin glacier retreated about 10,000 years ago, it left innumerable depressions scattered throughout the northern Great Plains. These depressional wetlands, called prairie potholes, contain water for various lengths of time in most years (Kantrud et al. 1989). Their size, permanence, hydrology, water chemistry, plant associations, and invertebrate communities vary widely...

Stable-isotope ratio signatures of primary producers in a coastal wetland and in adjacent offshore waters of western Lake Superior indicated that phytoplankton are the primary source of carbon for the grazing food web of this ecosystem. This study outlines the possible roles of other autotrophs in this regard. Isotopic signatures of macrophytes reflected their life-form-associated...

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated...

Abstract not submitted to date

We exposed larval tiger salamanders (Ambystoma tigrinum) reared in the laboratory from eggs collected from a prairie wetland in North Dakota to three concentrations of atrazine (0, 75, and 250 i??g/L) in a static renewal test to determine the pesticide's effect on (1) plasma corticosterone and thyroxine concentrations, (2) larval size, and (3) days-to-stage at stages 2 and 4 of...

The prairie pothole region of the northern Great Plains is one of the most important areas for duck reproduction in North America. The region produces, on average, 50% of the primary species of game ducks on the continent (Smith 1995), yet accounts for only 10% of the waterfowl breeding habitat in North America (Smith et al. 1964). Twelve of the 34 species of North American ducks are...

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 4,000 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated...

Identification of capture and handling procedures that influence survival of waterfowl has important research and management implications. We captured 347 female Northern Pintails (Anas acuta) using rocket nets, fitted them with harness (backpack-type) radio transmitters, and monitored their survival during the first 10 d following release. Females were 16 times more likely to die during...

Habitat fragmentation can influence the abundance and distribution of birds. Decreases in patch size increase the amount of edge habitat, which can allow greater invasion by exotic species, predators, and brood parasites (Hagan and Johnston 1992, Donovan et al., 1995). Fragmented habitats may act as population sinks and result in local extinctions unless immigration occurs from source...

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated...