Location: Watershed Management Research2009 Annual Report
1a. Objectives (from AD-416)
The overall objective of this research project is to improve scientific understanding to transfer technology related to assessing and mitigating the impacts of ecological disturbances by invasion-weeds,fire and predation on rangeland water, vegetation and animal resources within sagebrush ecosystems of the Intermountain West. The aim is to provide sound science-base information and management tools in support of private and public land management activities. Specific research objectives inclued: 1) Develop strategic management tools and guidelines for use in fire impact assessment and rehabilitation planning of sagebrush ecosystems of the Intermountain West to aid land managers in determining the location, severity and persistence of fire impacts on post-fire runoff/erosion. 2) Improve guidelines and methods for monitoring and assessing impacts of juniper encroachment and management on plant, soil and water resources in sagebrush-steppe ecosystems to enhance efficiency and success in action agency planning and implementation of juniper-control treatments throughout the Intermountain West: 3) Develop methodology for classifying seedbed microclimate and identify microclimatic thresholds for successful germination and early establishment of seeded grass species in sagebrush-steppe ecosystems to improve success of rangeland restoration efforts across the Intermountain West: 4)Evaluate the effects of landscape-scale disturbance such as fire, invasive plants, and predation on livestock productivity and livestock use of stream systems and other critical resouces of sagebrush-steppe ecosystems throughout the Intermountain West so producers and land managers can employ adaptive management and better plan for changes in animal resources use and productivity.
1b. Approach (from AD-416)
A suite of hydrology, vegetation, remote sensing and animal behavior experiments will be conducted from point to landscape scales to improve scientific understanding and produce technology for managing impacts of ecological disturbances by fire,invasive-weed and predation within sagebrush ecosystems of the Intermountain West. This research project will deliver products to aid land managers in conducting fire impact risk assessments, inventory and assessing the impacts of juniper encroachment, planning and implementing juniper-control treatments, determining seedbed-microclimatic requirements for establishment of native and introduced rangeland-grass species appropriate plant species and optimal planting time for post-fire rangeland rehabilitation and restoration treatments, evaluating livestock behavioral response and resource use following disturbance and establish appropriate post-fire livestock grazing strategies. Outcomes of this project help to assesss and quantify environmental benefits of conservation practices and improve action agency land use planning and management activities. Resultant benefits include potential savings of millions of dollars in wildfire mitigation,improve water quality by reducing sediment delivery to streams, reduced loss of forage for livestock and wildlife from juniper and cheatgrass invaion, improved species diversity and wildlife habitat, and greater livestock productivity from rangeland systems.
3. Progress Report
The goal of this Northwest Watershed Research Center (NWRC) CRIS project is to deliver products to land managers related to fire and juniper management, rangeland restoration practices, and evaluating livestock behavior and resource use following disturbance. Long-term studies of the hydrologic effects of fire and juniper encroachment at five sites throughout the Great Basin continue to be sampled using simulated rainfall and overland flow techniques to quantify impacts on infiltration, runoff and erosion rates. These data are helping land managers assess the increased risk of runoff and erosion events and better understand site recovery rates following fire and mechanical juniper control practices. Data from these studies were combined with similar past studies and are being used to develop parameter estimation procedures for the concentrated flow component of the Rangeland Hydrology and Erosion (RHEM) model. The NWRC is investigating the use of Light Detection and Ranging (LiDAR) technology as a remote sensing tool to inventory and monitor juniper encroachment across vast landscapes. Detailed field plot data on juniper canopy characteristics has now been collected and will be used as ground-truth validation of the LiDAR. The NWRC expanded its research program on rangeland restoration practices by establishing field experiments in the Boise Front foothills to investigate prescribed fire, herbicide rate, seeding rate, and species effects on weed control and seeding success. The Boise Front field site is one of five being used to test restoration strategies under the Area-wide Ecologically Based Integrated Pest Management (EBIPM) project. First year results of this 4-year study have revealed large impacts of fall-applied herbicide and fire on weed composition and density during the spring establishment period. NWRC scientists also evaluated hydrothermal germination response of native sagebrush, four native perennial grasses and cheatgrass, and devised a numerical index for comparing potential germination response under field-variable temperature and moisture conditions. This index is currently being used in the NWRC modeling program to evaluate the potential utility of long-term weather forecasts for making revegetation and restoration decisions, and for selection of appropriate plant materials for dormant-fall seeding. In support of livestock use objectives, a seven year study on the long-term changes in livestock utilization patterns and animal activity budgets following prescribed fire was concluded and data are now being analyzed and interpreted. Data on animal use patterns following a second prescribed fire continue to be collected along with data on livestock utilization patterns in the presence of large predators. A third generation Clark GPS/Satellite-communication animal tracking collar was prototyped and is currently being lab tested in preparation for more extensive field tests.
1. EFFECTS OF PRESCRIBED FIRE ON RUNOFF AND EROSION FROM MOUNTAINOUS LANDSCAPES. Changing climate conditions and invasive weeds have increased the frequency and size of catastrophic wildfires on sagebrush rangelands. Millions of dollars are spent each year in the United States to mitigate the increased risk of severe runoff and erosion associated with these changing fire regimes. ARS scientists in the Watershed Research Unit in Boise, Idaho studied hydrologic impacts of using prescribed fire as a fuels reduction on sagebrush rangelands. Prescribed fire caused increased runoff and erosion due to reduced groundcover for two growing seasons until ground cover reached above 60%. Results from such studies provide the foundation for future hydrology and erosion modeling of burned rangelands and contribute insight to land manager assessments of increased risk of runoff and erosion following fire from steep sloping sagebrush landscapes.
2. A LOW COST METHOD FOR MEASURING AIR TEMPERATURE ACROSS RANGELANDS. Air temperature varies across a landscape and can influence where livestock spend time grazing. Mapping spatial changes in temperature can help to predict grazing animal distribution and use patterns. Measurement of air temperature requires equipment that must be shaded from the sun using shields that are fragile and expensive. Two styles of sun shields were constructed by ARS scientists in Boise, ID and tested as alternatives to commercially available shielding. Both instruments were able to measure air temperature to within approximately 3oC of actual air temperature and were approximately 10% cost of deploying commercial shields. These shields can significantly reduce the overall cost of measuring air temperature across extensive and remote landscapes.
Pierson Jr, F.B., Moffet, C.A., Williams, C.J., Hardegree, S.P., Clark, P. 2009. Prescribed-Fire Effects on Rill and Interrill Runoff and Erosion in a Mountainous Sagebrush Landscape. Earth Surface Processes and Landforms. 34:193-203.