Submitted to: The 7th International Conference on the Ecology and Management of Alien Plant Invasions
Publication Type: Abstract Only
Publication Acceptance Date: May 30, 2003
Publication Date: November 3, 2003
Citation: Hardegree, S.P., Flerchinger, G.N., and Van Vactor, S.S. 2003. Microclimate constraints and revegetation planning in a variable environment. (abstract) 7th Internation Conference on the Ecology and Management of Alien Plant Invasions. p. 35 Technical Abstract: Water availability is a primary determinant of successful plant establishment on western rangelands. Two major factors that determine water availability are seasonal and annual patterns of precipitation, and the presence of competitive annual weeds. We calibrated a seedbed-microclimatic model and simulated hourly temperature and moisture at seeding depth for a 38-year period in southwestern Idaho. A hydrothermal model was used to assess potential germination response of two native bunch-grasses and a dominant annual weed for every day of the microclimatic simulation. Probabilistic-germination indices were developed to compare relative germination response as a function of seedbed microclimate. Model simulations of this type can be used to evaluate alternative management treatments and plant materials; and to incorporate medium and long-term weather forecasts into real-time management planning. In order to take full advantage of these tools it is necessary to separate short-term soil-stabilization, and long-term biodiversity and restoration objectives. Emergency rehabilitation policies prioritize establishment of plants that will both stabilize the soil and compete successfully with invasive weeds. Under this relatively short planning horizon, weather-forecast information may only be useful in selection of species to seed; and decisions regarding weed control methods. Weather-forecast information and modeling may be more applicable to longer-term restoration objectives. Historical weather probabilities can predict the frequency of years in which native-plant establishment is optimal. Treatment sites can be identified well ahead of time and seed can be obtained and stored in anticipation of favorable planting conditions. Inclusion of forecasting tools in rangeland restoration planning would require significant modification to current seeding and funding logistics. Future research is needed to adapt current weather forecast models for use in microclimatic modeling applications; to test the utility of these models under field conditions; and to assess the economic feasibility of forecast-modeling applications.