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State and Transition Modeling Workshop

Updated 06/09/2006

Utah State University, Logan, Utah
January 25-26, 2000

Moderator - Joel Brown, USDA-NRCS, Cooperating Scientist

Agenda

Tuesday
8:30 AMWelcome.Fee Busby, Dean, College of Natural Resources, Utah State University, Logan, Utah
8:10 AMWorkshop Objectives Larry Butler, USDA-NRCS, Grazing Lands Technology Institute, Fort Worth, TX
8:20 AMOverview and Emerging Issues Fee Busby, Dean, College of Natural Resources, Logan, Utah
8:50 AMUtilizing State and Transition Models to Aid in the Decision Making ProcessGeorge Peacock, USDA-NRCS, Grazing Lands Technology Institute, Fort Worth, TX
9:15 AMBreak  
9:30 AMContinued Development of Non-Equilibrium Ecology for Rangeland Application Tamzen Stringham, Department of Rangeland Resources, Oregon State University and Pat Shaver, USDA-NRCS, Grazing Lands Technology Institute, Fort Worth, TX
10:20 AMChanges in Soil Properties: Relevance to State and Tranisiton ModelsArlene Tugel, USDA-NRCS, Soil Quality Institute, Las Cruces, NM
10:40 AMEcological Site Description Database Arnold Mendenhall, USDA-NRCS, National Soil Survey Center, Lincoln, NE
11:00 AMDevelopment of State and Transition ModelsChuck Ring, USDA-NRCS, Cheyenne, WY and Gary Brackley, USDA-NRCS, Reno, NV
11:45 AM Lunch  
12:45 PMGroup discussion on the development of state and transition models. Addressing the issues, questions, and concerns that have arisen in regards to developing models. Facilitated by Joel Brown, USDA-NRCS, Cooperating Scientist, Las Cruces, NM
Wednesday
8:00 AMContinued discussion on development of state and transition models. 
10:00 AMBreak  
10:20 AMWrap up and review of discussions  
11:00 AMStrategies for Development of Ecological Site Descriptions George Peacock, USDA-NRCS, Grazing Lands Technology Institute. Fort Worth, TX
11:45 AMWorkshop evaluation and adjourn  

Introduction

The NRCS system of range site descriptions has provided guidance for more than 50 years of solid, ecologically- based land management decisions. Describing the interactions among soils, vegetation and land management provided decision-makers with vital information to help set and achieve goals and objectives. However, over half a century of experience in observing ecosystem dynamics coupled with the emergence of a host of new land owners, land uses, management objectives and threats to sustainable management dictate that we redesign our system of land description if we are to continue to provide high quality assistance. In addition, the public interest in sustainable land management requires that we have a firm scientific basis for inventories and assessments of ecosystem health. The conceptual foundation for such a system of site descriptions has been laid in the recently released National Range and Pasture Handbook (Chapter 3, Section 1).

The core information of the Ecological Site Description is the vegetation dynamics model. This model describes how different disturbances (fire, grazing, flooding, mechanical) and stresses (drought, increased precipitation, climate change and variability, exotic species) affect the soil/vegetation interactions on a particular soil. The State and Transition Model (STM) as proposed by Westoby et al is currently regarded as the most accurate, robust and accessible method for describing soil/vegetation dynamics in a decision making context.

Although the concept of STMs has been around for over a decade now, acceptance and implementation at the field level has only recently become a priority. Inconsistencies and ambiguities in terminology and interpretation are currently limiting the efficiency. These inconsistencies need to be resolved to insure that the ecological site description effort is cost-effective and provides accurate information to all users.

Field experience and several recent workshops have identified several aspects of terminology and implementation that need to be resolved. Therefore, NRCS, with the assistance of USU hosted a workshop attended by a variety of agency, academic and research technicians and scientists to develop solutions to these problems.

Objectives of the Workshop:

  1. Resolve inconsistencies in definitions associated with the implementation of STM, particularly with regard to:
    1. what is a state and how to integrate plant communities with management significance
    2. what constitutes a transition and how do we define it
    3. what are, and how do we describe thresholds
    4. how do we cope with changes in soil properties

  2. Expand the knowledge base by including more academic and agency scientists


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