COS 39-9 - The role of fire, simulated grazing, and flooding on wetland plant diversity and invasive plant biomass and growth

Tuesday, August 8, 2017: 10:50 AM
D135, Oregon Convention Center
Katherine Golden, Craig Davis and Samuel D. Fuhlendorf, Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK

Wetlands have a high propensity for invasion by dominant plants that form monotypic stands. Shoreline sedge (Carex hyalinolepis) is known to form these stands in nutrient rich wetlands and to produce substantive litter buildup, which causes light to be a limiting factor for the establishment of native forbs and overall plant diversity in the wetlands. Wetlands are also vulnerable to the undesired effects of herbicide application, limiting its use in sensitive ecosystems. Fire and grazing are historical and beneficial ecological processes, but little research has been conducted to determine the effects of these processes on wetland plant community composition and change. Our objectives were to assess the effects of fire and grazing on wetland plant communities and overall wetland plant diversity and to determine if varying intensities of historical disturbance mechanisms inhibit the growth pattern of a monoculture forming sedge species. We conducted both a field study and a greenhouse study to determine the effects of historical disturbance mechanisms on C. hyalinolepis. The field study utilized a nested plot design that examined pre and post fire plant community changes for both summer and winter burns. The greenhouse study examined the effects of burning, flooding, burning and flooding, and simulated grazing on the aboveground biomass of C. hyalinolepis.


Preliminary results indicate that historical disturbance methods likely will have little impact on reducing the biomass and growth of C. hyalinolepis. However, the combination of both burning and flooding offers potential for reducing the expansion of C. hyalinolepis in wetlands. The timing of burns may also impact the ability of fire to help increase wetland plant diversity. Summer burns may be more effective at increasing diversity than winter burns, but the results are likely short lived. We will continue to analyze the changes in plant community composition and response to time since fire, along with other variables that may influence the reduction of the monotypic stands of C. hyalinolepis. Results from this study will be informative in guiding management objectives and future research on the use of prescribed fire in wetlands.