New publication explaining the approach used in our ST-Sim software for forecasting landscape change

A description of the state-and-transition simulation model (STSM) methodology used in ST-Sim has just been published in the journal Methods in Ecology and Evolution.  The article entitled “State-and-transition simulation models: A framework for forecasting landscape change” describes the general approach used in developing and simulating STSMs and provides an example case study that considers land use and land cover change in the state of Hawaii.

Check out the new website for the Land Use and Carbon Scenario Simulator

The USGS Land Use and Climate Change Team has recently created a new website that describes the Land Use and Carbon Scenario Simulator (LUCAS). ST-Sim is used as the core engine in LUCAS for modeling land use and land cover change and for tracking carbon pools and fluxes.  The LUCAS website highlights a number of diverse applications ranging from local scale scenario analyses of management options for the Great Dismal Swamp to national scale land use projections.

View the online tutorial video on getting started with ST-Sim

Accompanying the release of ST-Sim version 3.0, we have just released a getting started tutorial video. The tutorial guides you through creating, running and viewing results for a simple state-and-transition simulation model using ST-Sim.


ST-Sim Version 3.0 now available for free download

Version 3.0 of ST-Sim, a spatially-explicit State-and-Transition Simulation Model framework, is now available for free download. This version adds a number of important features including: support for user defined probability distributions; enhancements to multiprocessing of model iterations and scenarios; the ability to display stock/flow model pathways; command line utilities for setting model inputs, running the model and exporting model outputs; and enhancements to link external models to ST-Sim.

New publication using ST-Sim considers the impacts of land use on future water demand in California

Authors from the USGS and The Nature Conservancy have recently published an article in Environmental Research Letters that considers the impact of projected land use change on future water demand in California. Using ST-Sim the authors projected potential future land use change and associated water demand.  The research suggests that if recent land use trends and water use efficiency rates continue unchanged to the year 2062, total water use is projected to increase by 1.8 billion cubic meters(+4.1%). Only a 25% reduction in municipal water use would result in no net change in water demand between the years 2012 and 2062.

Book Chapter on Applying State-and-Transition Simulation Models to Exotic Brome-Grasses in the Western US

A recently published book by Gerimino and others includes an informative chapter by Louis Provencher, Leonardo Frid, Christina Czembor and Jeffrey Morisette on applying state-and-transition simulation models to exotic brome-grasses in arid and semiarid ecosystems of the Western US. This chapter gives an overview of state-and-transition simulation models (STSMs) from a range management perspective and demonstrates STSM applications for determining efficient management resource allocation strategies; evaluating sources of uncertainty in models informed by expert opinion; and considering the potential consequences of climate change  on land management outcomes.

Webinar: Using State-and-Transition Simulation Models to Guide Sustainable Management of Ecosystems

The USGS National Climate Change and Wildlife Science Center has published a webinar of three case study applications of State-and-Transition Simulation Models to guide sustainable management of ecosystems. Sustainable management of natural resources under competing demands is challenging, particularly when facing novel and uncertain future climatic conditions. Meeting this challenge requires considering information about the effects of management, disturbance, land use and climate change on ecosystems. State-and-transition simulation models (STSMs) provide a flexible framework for integrating landscape processes and comparing alternative management scenarios, but incorporating climate change is an active area of research. In this presentation, three researchers present work funded by Climate Science Centers across the country to incorporate climate projections into STSMs.

ST-Sim Version 2.4 is now available for download

ST-Sim version 2.4 is now available for download at This version adds several important features incliuding:


  1. The ability to specify age classes and aggregate/dissagregate output by age
  2. The ability to specify transition multiplier values by state class
  3. A new feature to estimate transition probabilities from inventory data
  4. A User Interface for compacting a library
  5. Enhancements to the Ecological Departure report
  6. The ability to call an R script that generates transition multipliers dynamically at runtime

ST-Sim Version 2.3 is now available for download

ST-Sim version 2.3 is now available for download at This version adds several important features incliuding parallel processing capabilities for iterations and strata, percentile graphing, modeling of stocks and flows and control over where spatial outputs are stored.

Upcoming state-and-transition simulation model online conference presentation at the Society for Range Management

Leonardo Frid will be delivering an online conference presentation on using state-and-transition simulation models to evaluate alternative land managment scenarios at the 2014, Society for Range Management conference on February 12th as part of the Ecological Site Description workshop entitled "Emerging Technologies for ESD Development". The presentation will be webcast from 11:30 to 11:50 am EST. To register go to and select the third session (registration is free).


The presentation can also be viewed after the conference by clicking on this link.