Tuesday, August 5, 2008: 2:10 PM
102 B, Midwest Airlines Center
Background/Question/Methods: Tussock sedge (Carex stricta) potentially enhances topographic heterogeneity, supports plant diversity, sequesters carbon, slows surface water flows, and increases nutrient removal, making it a useful target for wetland restoration. Earlier, we found that tussocks average ~19 cm tall in Great Lakes coastal wetlands, where it dominates as a “matrix” species that allows other plant species to coexist. Also, we found that tussocks average 15-25 cm tall in Wisconsin tussock meadows, where it increases species richness by 60% (compared to flat areas between tussocks). Recent research explains these capabilities.
Results/Conclusions: In the field, tussocks increase surface area by 40% and create at least three microsites (tops, sides and bases, with hydroperiods that can range from continual inundation to continual exposure). Their phenological differences indicate temporal resource segregation: C. stricta leaves grow exponentially (to ~130 cm long) in early spring, the plants fruit early, and the canopy achieves maximum height (70 cm above the tussock) by the summer solstice; in contrast, associated forb species (e.g., Aster, Solidago) grow under the C. stricta canopy until they emerge above the sedge in July and achieve maximum height (>90 cm above tussocks) and fruit in September. In mesocosms with continuous high water, tussock formation accelerates. In water that is ~10-20 cm deep, leaf bases and adventitious roots form dense structures that reach 12 cm tall within two years. Thus, there is potential for rapid carbon storage, high surface area for microbial communities, slowed water flow and enhanced nitrogen removal. C. stricta offers the potential to restore multiple ecosystem services in short time frames.
Results/Conclusions: In the field, tussocks increase surface area by 40% and create at least three microsites (tops, sides and bases, with hydroperiods that can range from continual inundation to continual exposure). Their phenological differences indicate temporal resource segregation: C. stricta leaves grow exponentially (to ~130 cm long) in early spring, the plants fruit early, and the canopy achieves maximum height (70 cm above the tussock) by the summer solstice; in contrast, associated forb species (e.g., Aster, Solidago) grow under the C. stricta canopy until they emerge above the sedge in July and achieve maximum height (>90 cm above tussocks) and fruit in September. In mesocosms with continuous high water, tussock formation accelerates. In water that is ~10-20 cm deep, leaf bases and adventitious roots form dense structures that reach 12 cm tall within two years. Thus, there is potential for rapid carbon storage, high surface area for microbial communities, slowed water flow and enhanced nitrogen removal. C. stricta offers the potential to restore multiple ecosystem services in short time frames.
