1a. Objectives (from AD-416)
1) Evaluate the effects of fire, mechanical treatments, livestock grazing, introduced invasive weeds, western juniper expansion, and climate on the vegetation and watershed function of sagebrush steppe rangelands. 2) Improve our understanding of livestock behavior and livestock/environment interactions. Improve tools to manipulate livestock behavior and grazing patterns. 3) Understand mechanisms of weed invasion and develop management strategies that can be used to restore rangelands that have been degraded by weeds or other disturbances.
1b. Approach (from AD-416)
The mission of the Burns unit is to provide the science for sound land and livestock management. This five-year plan builds on a rich history of research at this location, in some cases reaching back to the 1940's. Rangelands of the Great Basin are spatially variable and land ownership patterns are a complex mix of public and private land. Annual weather variation is high, and can obscure vegetation responses to management treatments. Ranching forms the basis of the regional economy, underscoring the importance of forage production, and the large percentage of public land in the region translates into public scrutiny of management actions, and a focus on environmental impacts and biodiversity. Invasive species and expanding juniper populations represent major threats to existing land uses and values. Our research program has evolved with substantial public input and addresses questions raised by our customers. Land managers in this region are faced with information gaps in basic sagebrush steppe ecology, vegetation responses to management actions, plant community restoration, seedling establishment and livestock grazing management. Our research program will fill some of those gaps while expanding and enhancing current ecological theory and building on our long-term data sets. The unit also has a commitment to synthesizing research information and developing management tools. Formerly 5360-11630-005-00D (1/08).
3. Progress Report
Progress was made on all three objectives and their sub objectives during the past year. All the objectives covered in this report fall under National Program 215, Component 1, Problem A. Under Objective 1.A we continue to collect data on the hydrologic inputs and outflows from four small watersheds (< 100ha) near Jordan Valley, Oregon in far southeastern Oregon. This research is cooperative with the ARS unit in Boise, Idaho. The initial research conducted under Objective 1.B has been published and shows that deferment of grazing after prescribed fire had little impact on vegetation composition or productivity. Long-term measurements of both productivity and composition are being continued on the site. We continue to measure both climate and vegetation composition in and outside of our 13 grazing enclosures at the experimental range. This past year we also worked on summarizing and analyzing 70 years of climate data from the experimental range. The focus this past year under Objective 2 has been to summarize and analyze the large data sets associated with the livestock behavior GPS research. The data relates to grazing behavior of different classes of cows, and factors influencing grazing distribution in very large pastures (> 25,000 ha). Data collection has been completed for objective 3.A and we are currently analyzing the data, and several manuscripts have been submitted. Because of the number of zeroes associated with seedling establishment data, we have enlisted the assistance of the Area statistician to ensure the appropriate analysis techniques are applied. Results associated with objective 3.B show that leaf nitrogen productivity (leaf mass per unit of N) was the key trait contributing to variation in N capture among the invasive species tested. A portion of the data has been published and analysis of additional date was continued this past year. The initial results from objective 3.C have been published and additional publications are in progress. Objective 3.D is focused on long-term vegetation trends after juniper management and during the past year vegetation measurements were continued to quantify changes in plant community composition. Manuscript preparation is underway.
1. Reseeding is commonly used to improve forage production on rangelands. Each year millions of dollars are lost on rangeland reseeding failures. After years of research on this topic, success rates are still variable and relatively low. ARS scientists from Burns, Oregon identified the stage of seedling establishment which appears to limit success rates. Follow-up research is currently underway to incorporate this knowledge into management systems. Better reseeding techniques would improve forage production for both public land management agencies and private landowners.