VDDT/TELSA Scenario Modeling
Level 1 Users are users with little GIS and remote sensing experience or access to specialized GIS or remote sensing software or hardware. Level 1 users will mostly interact with Toolbox-generated products and web applications and may work with level-2 or level-3 users to use other Toolbox tools for their management information needs.
Level 2 Users have an understanding of GIS and rangeland monitoring data and have experience with GIS software. Level 2 users can do some minor data creation (e.g., creating layers to define new management scenarios) or edit existing layers (e.g., correcting and updating polygons in the vegetation maps). They will use Toolbox tools and products to aid analyses for their management questions and may also run new scenarios based on existing state and transition models and vegetation maps. These users may provide outputs to level 1 users but may also require assistance from level 3 users to set up datasets for some tools.
Level 3 Users have a highly-developed skill set for manipulating and analyzing GIS, remote sensing, and assessment/monitoring data. They will have access to specialized software and hardware for creating new data layers (e.g., creating image objects from new imagery) and would set up the data layers that level 1 and 2 users would have access to. These users could also lead the process of creating new state and transition models or vegetation maps for new areas. Use of Landscape Toolbox tools in major planning efforts (e.g. RMP) would rely heavily on level 3 users.WHAT ARE THEY?
Quantitative state and transition (S/T) models and maps of current rangeland conditions can be used with simulation modeling tools to quantify and assess the potential effects of management activities, treatment options, and natural disturbances for managing landscapes toward a desired future condition. The results from scenario modeling inform planning efforts on the landscape-scale impacts of specific, site-scale management opportunities. This information can feed directly into planning documents or inform other processes like cost-benefit analyses.
The Vegetation Dynamics Development Tool (VDDT) developed by ESSA Technologies Ltd. (http://www.essa.com) is a dynamic modeling tool that uses S/T models to examine the potential effects of landscape-level management and disturbances. VDDT has been used successfully in projects like LANDFIRE (http://www.landfire.gov). TNC has been working with ESSA to improve the performance and efficiency of S/T modeling as part of the Landscape Toolbox. We developed the Cumulative Effects Analysis (CEA) Tool around the VDDT core as a robust user-friendly program for creating, running, and analyzing landscape scenarios for predicting how landscapes might change over time under different management and disturbance scenarios.
HOW DO YOU USE THEM?
The CEA Tool relies on S/T models where each state can be mapped on the landscape and each transition has been quantified by being assigned a probability of occurring. Once the current condition of the states has been mapped on the landscape, that information becomes the initial conditions for the scenario modeling.
Often more than one S/T model is needed to capture the ecological dynamics of a landscape. In these cases, the landscape is stratified based on biophysical and management attributes. Each stratum has a vegetation model associated with it that identifies the full suite of possible vegetation states and transitions between them. Transitions between states may be driven by natural processes such as succession and disturbance or by anthropogenic changes such as management actions. Within each stratum, the landscape is divided up into small polygons, and Monte Carlo simulation methods are used to determine if and when a transition happens to each polygon and if a transition occurs, then determines the new state. At the end of each time step, information on the states is collected and the simulation continues.
Outputs of the scenario models can be displayed to allow for comparison and ranking of management alternatives at the level required for decision making. The CEA Tool can be used to evaluate both predictions and uncertainty, or levels of confidence in model predictions. For example, results to be displayed could include map, tabular and graph summaries of: current and future vegetation; current and future wildlife habitat condition; and model inputs (location and proposed timing of management activities). Results in tabular form can be easily exportable to other applications such as MS Excel and statistical software.
Currently, the CEA Tool is a non-spatial form of landscape analysis. Non-spatial approaches treat each individual simulation polygon independently and track the only the frequency of vegetation states over time and not their configuration on the landscape. These models require fewer inputs than spatially explicit ones and are faster to simulate on a computer. Spatial models can provide additional information, such as the implications of alternative management strategies for the fragmentation of wildlife habitat or the comparison of alternative spatially explicit rules about where management actions may or may not occur. ESSA is currently working on implementing a spatially-explicit version of the CEA Tool.
WHERE DO YOU GET THEM?
The CEA Tool is still in active development. It runs as a stand-alone application on most Microsoft operating systems. Because it uses the VDDT core for it's simulations, VDDT must also be installed.
In order to use the CEA Tool, you will also need a set of S/T models that have been built and parameterized in VDDT. The VDDT models are imported into a CEA Tools project where management scenarios can be built and run. Complete CEA Tool project for each of our case studies as well as the original models that were developed in VDDT are available from our State and Transition Model Library. For other areas, you will need to either use existing VDDT models or create new models with the help of experts in rangeland ecology (not a trivial task!). You will also need information on the current status of your landscape in reference to the S/T models you are using (see the Landscape Toolbox Data Center to obtain data used in the case studies).
The Landscape Toolbox CLARP scenario-modeling tools can be downloaded below. In order to use these tools you will need to either obtain existing quantitative S/T models for your area of interest (see the State and Transition Model Library) or create new models with the help of experts in rangeland ecology (not a trivial task!). You will also need information on the current status of your landscape in reference to the S/T models you are using (see the Landscape Toolbox Data Center to obtain data used in the case studies).
These tools are intended for intermediate to advanced users who are comfortable with quantitative S/T models. Make sure you visit the Training and Documentation section of the Landscape Toolbox site for the most recent user guides and tutorials for how to use the CEA Tool.
- To obtain the CEA Tool, please contact Jason Karl (jkarl@nmsu.edu, 575-646-7086)
- The CEA Tool requires the most recent version of VDDT which can be downloaded free from ESSA's web site.
- Basic documentation on how to create, run, and analyze management scenarios with an existing CEA Tool project is availabe on the Training and Documentation page.