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United States Department of Agriculture

Agricultural Research Service

Research Project: Developing Ecological Site Description State and Transitions Models for Great Basin Rangeland Plant Communities

Location: Great Basin Rangelands Research

2013 Annual Report


1a.Objectives (from AD-416):
The USDA, Natural Resource Conservation Service is the agency tasked with the development and maintenance of ecological sites and for providing ecological site descriptions (ESDs) to stakeholders. The ecological dynamics associated with natural disturbances and / or management actions within an ecological site are described through a state-and-transition model. State-and-transition models describe the disturbances or combination of disturbances leading to the ecological degradation of an ecological site and the management or conservation practices necessary to rehabilitate a degraded site. In order to quantify the impact of prescribed conservation practices on degraded rangelands it is necessary to identify the ecological site and the current state and plant community phase associated with the location receiving a conservation practice. Identification of the current functional level of the ecological processes driving site degradation enhances management’s ability to determine the appropriate conservation practice and to predict the probability of success. Ecological sites descriptions are not complete without a state-and-transition model. Expediting the process of developing the state-and-transition models for describing the ecological dynamics associated with natural disturbances and / or management actions within an ecological site will enhance NRCS's ability to provide private land owners and land managers with the tools necessary to determine their land's current ecological condition and to make informed management decisions. In addition, quantification of the impact of the Conservation Effects Assessment Project (CEAP) requires an ecological site approach while simultaneously the data derived from the effort to quantify CEAP impacts allows improvement of the state-and-transition model for each ecological site.


1b.Approach (from AD-416):
In order to expedite the development of second generation ecological site descriptions and the CEAP quantification project the Ely District of the Bureau of Land Management has provided funding to ARS and NRCS, Nevada for the development of state-and-transition models for Major Land Resource Area (MLRA) 28 within Nevada. The Ely District encompasses approximately 12 million acres in eastern Nevada including White Pine County, Lincoln County and a small portion of Nye County with an estimated 200 ecological sites. Much of the District is representative of the Great Basin with large expanses of sagebrush, pinyon and juniper rangelands. ARS scientists will work with University of Nevada Reno, scientists and NRCS on the development of the State and Transition Models for MLRA 28 utilizing a process they have developed for expediting state-and-transition model development. The ARS Rangeland Hydrology and Erosion Model will be applied to new State and Transition models to provide first time estimates of changes in hydrologic processes as a state changes as a means of quantifying environmental benefits of conservation. This project is closely aligned with existing agreements with NRCS, BLM, University of Nevada-Reno and Society for Range Management to develop technology to define and monitor changes in Great Basin rangeland ecosystem processes.


3.Progress Report:

This is the final report for this project which terminated on September 30, 2013. This agreement is realated to objective 3 of the in-house project, "Develop and transfer innovative management approaches and technology for conserving and rehabilitating sagebrush, pinyon/juniper woodlands, and salt desert shrublands to meet natural resource and agricultural production goals". More specifically, to develop an integrated package of ground-based and remote sensing tools to quantify and assess the environmental impact of management decisions and conservation practices at hillslope and landscape scales in woodland, shrub-steppe, and desert ecosystems of the Great Basin.

This research directly supports ARS Pasture, Forage and Rangeland Systems National Program NP 215 Objective B.2. Develop decision support tools usable at multiple scales including landscape levels for inventorying and assessing rangelands; and, for selecting, implementing, and monitoring conservation and restoration practices.

This report documents the progress being made by the interagency team that was formed to develop new Ecological Site Descriptions for Nevada and provide training on use of this material for effective natural management decisions. The project was initiated in FY 2012 and is closely aligned with Projects 5370-136100-001-05S and 5370-11220-006-25S. Six meetings have been held with Bureau of Land Management (BLM), Natural Resources Conservation Service (NRCS), and University of Nevada, Reno (UNR), scientific partners to design the project. In addition, the team hosted a workshop for 60 federal employees with the Society for Range Management to train agency staff in the use and development of Ecological Site Descriptions. The Natural Resources Conservation Services, Bureau of Land Management, and University partners are currently developing new State and Transition models for sagebrush-dominated systems within Nevada using a Disturbance Response Group (DRG) approach. The DRG approach aggregates similar Ecological Sites that will respond to a disturbance, such as fire, into functional State and Transition models making post fire emergency management decisions more efficient than developing individual response plans by Ecological Sites. Field work has been initiated on 59 preliminary Ecological Site Descriptions for Major Land Resource Area (MLRA) 28A and 28B. Currently, MLRA 28 A and B have 40 DRGs, encompassing 198 ecological sites. A total of 59 different ecological sites were visited during 2012, with many receiving multiple visits. Of those 59 ecological sites, 21 were modal sites for different DRGs, and state and transition models have been initiated. Meetings this fall are scheduled to review current work and plans for 2014 field season.


Last Modified: 12/24/2014
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