Final Report: Non-Linear Response of Prairie Pothole Landscapes to Climate Change and Land Management

EPA Grant Number: R833016
Title: Non-Linear Response of Prairie Pothole Landscapes to Climate Change and Land Management
Investigators: Johnson, Carter , Olker, Jennifer H. , Guntenspergen, Glenn R. , Millett, Bruce V , Rashford, Ben , Werner, Brett , Tulbure, Mirela , Fay, Phil , Adams, Richard , Voldseth, Richard
Institution: South Dakota State University , United States Geological Survey [USGS] , Oregon State University
Current Institution: South Dakota State University , Oregon State University , United States Geological Survey [USGS]
EPA Project Officer: Packard, Benjamin H
Project Period: July 1, 2006 through July 31, 2010 (Extended to December 31, 2010)
Project Amount: $856,574
RFA: Nonlinear Responses to Global Change in Linked Aquatic and Terrestrial Ecosystems and Effects of Multiple Factors on Terrestrial Ecosystems: A Joint Research Solicitation- EPA, DOE (2005) RFA Text |  Recipients Lists
Research Category: Global Climate Change , Ecosystems , Climate Change

Objective:

Freshwater wetlands are among the world’s most valuable but vulnerable ecosystems. The Prairie Pothole Region (PPR) of North America, a 750,000 km2 area embedded with 5-8 million wetland basins of recent glacial origin occurring in a grassland climate, is one of 11 large wetland ecoregions identified worldwide as conservation priorities. PPR wetlands are best known as prime nesting and migratory habitat for waterfowl, but they provide other important ecosystem goods and services, including flood retention, groundwater recharge, water purification, recreation, agriculture, and regional biodiversity.

While aspects of this vulnerability have been examined in previous research, strongly suspected threshold responses of these wetlands to environmental drivers have been largely unstudied. The objective of our research project was to identify possible future climatic, land use, and economic conditions that could sharply reduce the function and biodiversity of wetlands across the PPR. 

Research to meet this objective was carried out in three steps. First, we completed parameterization and testing of WETLANDSCAPE (WLS), a new mathematical simulation model of the prairie wetland complex, to identify environmental thresholds that control key ecosystems processes upon which functional wetlands depend. Second, we examined the potential benefits of planting “mitigation crops” in currently farmed wetland watersheds by positively influencing upslope watershed processes (runoff, evapotranspiration, groundwater recharge) and wetland water budgets. Lastly, use of a land use decision model enabled us to assess the economic costs associated with alternative cropping to achieve ecosystem goals. 

Summary/Accomplishments (Outputs/Outcomes):

The major findings (and manuscript sources) of research conducted on this STAR Grant project are:

  • Prairie wetland complexes will lose resilience in a 2xCO2 climate; Maintaining ecosystem goods and services at current levels will be a major challenge for the conservation community (Johnson et al. 2010).
  • Wetlands in the drier, western PPR are most vulnerable to climate warming; hindcast model simulations provide evidence that late 20th century warming in the PPRs western Canadian prairies has already produced drier and less productive wetlands as forecasted (Johnson et al. 2010; Millett et al. 2009, Werner et al. with editor).
  • Members of prairie wetland complexes will respond differently to climate change, with longer hydroperiod wetlands (semi-permanents, seasonals) the most sensitive; shortened wetland hydroperiods will preferentially affect vertebrates (waterfowl, amphibians) because of their longer life-cycle requirements (Johnson et al. 2010).
  • In a 2xCO2 climate, more of the PPR will be without functional wetlands and nesting habitat to support historic levels of waterfowl breeding; Mitigation in the climatically wetter (but heavily drained) portion of the PPR is problematic because of the high cost of wetland and grassland restoration easements where land prices and crop production are the highest (Johnson et al. 2010; Rashford et al. manuscript).
  • The response of model wetlands to incremental increases in temperature varies markedly across the PPR; Optimum temperatures based on the cover cycle index (CCI) for most weather stations occur under the current or a slightly warmer climate. Temperature increases above 2oC shift most stations (PPR subregions) into declining productivity (Johnson et al. 2010; unpublished data).
  • Small shifts in climate in the PPRs extreme west (drier climate) or the extreme east (wetter climate) can cross thresholds in the wetland cover cycle that greatly reduce wetland productivity; In the west, wetlands get stuck in the dry marsh stage while in the east they get stuck in the lake marsh stage; both fail to cycle for very long periods (decades) (Johnson et al. 2010; Werner et al. with editor).
  • Incremental temperature increases in model wetlands also produce sharp reversals in the CCI at specific temperatures at which state changes occur in the dynamic behavior of wetands; a few sub-climates in the PPR show continual improvement or continual degradation in CCI with increasing temperature from 0-5oC; however, most weather stations produce peaks and reversals in CCI over the temperature range (unpublished data).
  • The negative climate change effects are exacerbated by changes in relative crop prices, which are expected to favor landscapes such as corn or wheat that are less conductive to wetland health than the historical crop mixes of the PPR that were based on pasture and grazing enterprises (Rashford et al. with editor; Rashford et al. manuscript).
  • The explicit inclusion of human dimensions in this project indicates that analyses based strictly on static assumptions concerning land use and other human-based points may provide misleading information concerning the true consequences of the stressor being analyzed (Rashford et al. with editor; Rashford et al. manuscript).
  • Long-term data on wetland hydrology and vegetation during weather extremes of drought and deluge are essential to build, parameterize, and test simulation models of wetland response to a changing climate; during this project, considerable field data were added to three such databases in eastern South Dakota to assist in current and future modeling work (Johnson et al. 2004; Johnson et al. 2010).

Conclusions:

Research completed during this study strengthened earlier published assessments that the natural resources of the Prairie Pothole Region (PPR) are highly vulnerable to climate change. Many new insights, however, into the nature, sensitivity, and complexity of these vulnerabilities were discovered during the course of this study. First, this first-time assessment of climate change on an entire wetland complex did not ease fears that some types of wetlands might escape serious impacts; all of the members of the model complex lost hydroperiod during the warming scenarios. Second, a number of temperature thresholds were identified, that if reached, could push wetland complexes into long-term unproductive states. Third, the response of prairie wetlands to climate warming will vary strongly across the varied sub-climates of the PPR. A few sub-regions may be slightly favored by a warmer climate while the large majority will not. Fourth, because most prairie wetlands occur in farmed watersheds, crop choices and tillage methods can partially mitigate for climate warming effects. However, planting “mitigation crops” to favor wetland function may have economic costs to producers. This issue is further complicated by the fact that a new future climate itself will favor some crops, even new ones, over others. In summary, from our research to date, it is hard to see how the production of ecosystem goods and services by prairie wetland complexes in the PPR can be maintained at current levels without implementation of a comprehensive, and probably expensive, mitigation program strongly directed toward agriculture in the northern Great Plains.   


Journal Articles on this Report : 6 Displayed | Download in RIS Format

Other project views: All 58 publications 7 publications in selected types All 6 journal articles
Type Citation Project Document Sources
Journal Article Johnson WC, Werner B, Guntenspergen GR, Voldseth RA, Millett B, Naugle DE, Tulbure M, Carroll RWH, Tracy J, Olawsky C. Prairie wetland complexes as landscape functional units in a changing climate. BioScience 2010;60(2):128-140. R833016 (2008)
R833016 (2009)
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R833016 (Final)
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  • Journal Article Millett B, Johnson WC, Guntenspergen G. Climate trends of the North American prairie pothole region 1906-2000. Climatic Change 2009;93(1-2):243-267. R833016 (2007)
    R833016 (2009)
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    R833016 (Final)
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  • Journal Article Rashford BS, Adams RM, Wu JJ, Voldseth RA, Guntenspergen GR, Werner B, Johnson WC. Impacts of climate change on land-use and wetland productivity in the Prairie Pothole Region of North America. Regional Environmental Change 2016;16(2):515-526. R833016 (Final)
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  • Journal Article Voldseth RA, Johnson WC, Gilmanov T, Guntenspergen GR, Millett BV. Model estimation of land-use effects on water levels of northern Prairie wetlands. Ecological Applications 2007;17(2):527-540. R833016 (2007)
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  • Journal Article Voldseth RA, Johnson WC, Guntenspergen GR, Gilmanov T, Millett BV. Adaptation of farming practices could buffer effects of climate change on Northern Prairie wetlands. Wetlands 2009;29(2):635-647. R833016 (2008)
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  • Journal Article Werner BA, Johnson WC, Guntenspergen GR. Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region. Ecology and Evolution 2013;3(10):3471-3482. R833016 (Final)
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  • Supplemental Keywords:

    Ecological effects, non-linear effects, ecosystem, scaling, modeling, climate models, biodiversity, threshold, North Dakota-ND, South Dakota-SD, Iowa-IO, Minnesota-MN, Canadian Prairies, RFA, Scientific Discipline, Air, climate change, Air Pollution Effects, Environmental Monitoring, Ecological Risk Assessment, Atmosphere, anthropogenic stress, biodiversity, environmental stressors, ecosystem impacts, landscape characterization, climate variability, Global Climate Change

    Progress and Final Reports:

    Original Abstract
  • 2007 Progress Report
  • 2008 Progress Report
  • 2009 Progress Report
  • 2010 Progress Report