Impacts of water development on aquatic macroinvertebrates, amphibians, and plants in wetlands of a semi-arid landscape

Abstract

We compared the macroinvertebrate and amphibian communities of 12 excavated and 12 natural wetlands in western North Dakota, USA, to assess the effects of artificially lengthened hydroperiods on the biotic communities ofwetlands in this semi-arid region. Excavatedwetlandswere much deeper and captured greater volumes ofwater than natural wetlands. Most excavated wetlands maintained water throughout the study period (May to October 1999), whereas most of the natural wetlands were dry by June. Excavated wetlands were largely unvegetated or contained submergent and deep-marsh plant species. The natural wetlands had two well-defined vegetative zones populated by plant species typical of wet meadows and shallow marshes. Excavated wetlands had a richer aquatic macroinvertebrate community that included several predatory taxa not found in natural wetlands. Taxa adapted to the short hydroperiods of seasonal wetlands were largely absent from excavated wetlands. The amphibian community of natural and excavated wetlands included the boreal chorus frog (Pseudacris maculata), northern leopard frog (Rana pipiens), plains spadefoot (Scaphiopus bombifrons), Woodhouse's toad (Bufowoodhousiiwoodhousii), and tiger salamander (Ambystoma tigrinum). The plains spadefoot occurred only in natural wetlands while tiger salamanders occurred in all 12 excavated wetlands and only one natural wetland. Boreal chorus frogs and northern leopard frogs were present in both wetland types; however, they successfully reproduced only in wetlands lacking tiger salamanders. Artificially extending the hydroperiod of wetlands by excavation has greatly influenced the composition of native biotic communities adapted to the naturally short hydroperiods of wetlands in this semi-arid region. The compositional change of the biotic communities can be related to hydrological changes and biotic interactions, especially predation related to excavation.

Keywords:

• dugouts
• excavation
• hydroperiod
• impoundments
• North Dakota
• salamanders

Acknowledgments

Financial support for this project came from the U.S. Department of Agriculture's Custer National Forest and the U.S. Geological Survey. We thank Gary Foli, Clinton McCarthy, and Cindy Ragland for their help identifying the need and for funding this study. We thank the staff of both the Dickinson and Watford City Forest Service Field Offices and the Dakota Prairie Grasslands Office in Bismarck for a wide variety of assistance with this project. We thank Susan Rinehart for verifying plant identifications and Eric Routman for verifying our identification of the barred subspecies of the tiger salamander (Ambystoma tigrinum mavortium). Lastly, we thank all the technicians who assisted with field and laboratory data collection, Deborah Buhl for performing our statistical analysis, and Jane Austin, Robert Gleason, Jay Hestbeck, Douglas Johnson, Wayne King, Murray Laubhan, Mike McEnroe, Jim Ringleman, Dan Svingen, Ralph Tramontano, and Kevin Willis for providing comments on the final report from this project and/or earlier drafts of this manuscript. Any use of trade, product, or firm names in this report is for descriptive purposes only and does not imply endorsement by the U.S. Government.