Karen A. Poiani

INFLUENCE OF WEATHER EXTREMES ON THE WATER LEVELS OF GLACIATED PRAIRIE WETLANDS

Orchid Meadows is a long-term wetland research and monitoring site on the Coteau des Prairie in extreme east-central South Dakota, USA. It is a 65-ha Waterfowl Production Area with numerous temporary, seasonal, and semi-permanent wetlands. Ground water and surface water have been monitored at the site from 1987 to 1989 and from 1993 to the present. Vegetation has been monitored since 1993. The monitoring record includes two nearly back-to-back weather extremes: a drought in the late 1980s and a deluge in the early- to mid-1990s. Wetlands differed sharply in water levels between 3-yr dry and wet periods. For example, the time of inundation ranged among semi-permanent wetlands from 13 to 71 percent during the dry years to 100 percent during the wet years, while for seasonal wetlands, it was 0–29 percent and 46–100 percent, respectively, during dry and wet periods. Temporary wetlands had no surface water during the dry period but had standing water 0–67 percent of the time during the deluge years. The highest ground-water levels during the dry period were lower than most levels during the wet period. The difference in the water-table elevations of temporary wetlands between the periods was as much as 4 m. Ground-water levels near semi-permanent wetlands were considerably more stable (annual range of 0.3–1.6 m) than those near temporary wetlands (1.3–2.5 m). The reslts support the concept that weather extremes drive the wetland cover cycle and other key ecological processes in prairie wetlands. The new data from Orchid Meadows, together with other long-term data sets from North Dakota and Saskatchewan, Canada, are useful for many research purposes, including the parameterization and testing of models that simulate the effects of climate variability and climate change on prairie wetland ecosystems.

A Spatial Simulation Model of Hydrology and Vegetation Dynamics in Semi-Permanent Prairie Wetlands

The objective of this study was to construct a spatial simulation model of the vegetation dynamics in semi-permanent prairie wetlands. A hydrologic submodel estimated water levels based on precipitation, runoff, and potential evapotranspiration. A vegetation submodel calculated the amount and distribution of emergent cover and open water using a geographic information system. The response of vegetation to water-level changes was based on seed bank composition, seedling recruitment and establishment, and plant survivorship. The model was developed and tested using data from the Cottonwood Lake study site in North Dakota. Data from semi-permanent wetland P1 were used to calibrate the model. Data from a second wetland, P4, were used to evaluate model performance. Simulation results were compared with actual water data from 1797 through 1989. Test results showed that differences between calculated and observed water levels were within 10 cm 75% of the time. Open water over the past decade ranged from 0 to 7% in wetland P4 and from 0 to 8% in submodel simulations. Several model parameters including evapotranspiration and timing of seedling germination could be improved with more complex techniques or relatively minor adjustments. Despite these differences the model adequately represented vegetation dynamics of prairie wetlands and can be used to examine wetland response to natural or human-induced climate change.

Global Warming and Prairie WetlandsPotential consequences for waterfowl habitat

In this article, the authors discuss current understanding and projections of global warming; review wetland vegetation dynamics to establish the strong relationship among climate, wetland hydrology, vegetation patterns and waterfowl habitat; discuss the potential effects of a greenhouse warming on these relationships; and illustrate the potential effects of climate change on wetland habitat by using a simulation model.

Redesigning biodiversity conservation projects for climate change: examples from the field

Few conservation projects consider climate impacts or have a process for developing adaptation strategies. To advance climate adaptation for biodiversity conservation, we tested a step-by-step approach to developing adaptation strategies with 20 projects from diverse geographies. Project teams assessed likely climate impacts using historical climate data, future climate predictions, expert input, and scientific literature. They then developed adaptation strategies that considered ecosystems and species of concern, project goals, climate impacts, and indicators of progress. Project teams identified 176 likely climate impacts and developed adaptation strategies to address 42 of these impacts. The most common impacts were to habitat quantity or quality, and to hydrologic regimes. Nearly half of expected impacts were temperature-mediated. Twelve projects indicated that the project focus, either focal ecosystems and species or project boundaries, need to change as a result of considering climate impacts. More than half of the adaptation strategies were resistance strategies aimed at preserving the status quo. The rest aimed to make ecosystems and species more resilient in the face of expected changes. All projects altered strategies in some way, either by adding new actions, or by adjusting existing actions. Habitat restoration and enactment of policies and regulations were the most frequently prescribed, though every adaptation strategy required a unique combination of actions. While the effectiveness of these adaptation strategies remains to be evaluated, the application of consistent guidance has yielded important early lessons about how, when, and how often conservation projects may need to be modified to adapt to climate change.

A scale-independent, site conservation planning framework in The Nature Conservancy

Abstract Site conservation planning in The Nature Conservancy is a scale-independent process that defines the landscape within which conservation targets (i.e., species and communities of concern) can persist. The process integrates more traditional preserve design and land acquisition activities with newer conservation biology and ecosystem management concepts into a single dynamic framework. Site conservation planning can be thought of as a series of questions, which if answered would constitute the major components of a plan. These questions are: (1) What are the significant conservation targets and long-term goals for those targets? (2) What biotic and abiotic attributes maintain those targets over the long term? (3) What are the basic characteristics of the human communities at the site? (4) What current and potential activities interfere with the survival of conservation targets and maintenance of ecological processes that sustain them? (5) Who are the organized groups and influential individuals at the site (i.e., stakeholders), what impacts will the goals have on them, and how might they help or hinder us in achieving those goals? (6) What can we do to prevent or mitigate threatening activities, and how can we influence important stakeholders? (7) What are the areas on the ground where we need to act? (8) What kinds of actions are necessary to accomplish our goals, who will do them, how long will they take, and how much will they cost? (9) Can we succeed in our goals, based on assessment of both ecological and human concerns and programmatic resources? (10) How will we know if we are making progress toward our goals and if our actions are bringing about desired results? Site conservation planning is best accomplished with an interdisciplinary team consisting of scientists, planners, and implementers. We recommend revisiting plans periodically to update and revise information, particularly threats to major ecological processes sustaining conservation targets and strategies that address those threats.

Global warming and prairie wetlands: potential consequences for waterfowl habitat

In this article, the authors discuss current understanding and projections of global warming; review wetland vegetation dynamics to establish the strong relationship among climate, wetland hydrology, vegetation patterns and waterfowl habitat; discuss the potential effects of a greenhouse warming on these relationships; and illustrate the potential effects of climate change on wetland habitat by using a simulation model.