State and Transitions
State and transition models describe how rangeland communities change through time in response to natural disturbances and/or management actions. Where ecological systems are relatively well understood, these models can be used to predict the outcomes of such disturbances within the vegetative community. In the context of the information described here, such models can provide useful guides for understanding how big game habitat responds to various treatments.
An ecological state refers to a recognizable complex of soils and vegetation structure, which are connected through ecological processes and expressed as vegetative communities. Transitions refer to trajectories of change within the system brought about by natural disturbances and/or management actions. In the context of treating big game habitat, one ecological state is less desired, and a tool is used to bring about a transition to a new ecological state that is more preferred.
Since 2009, Ranch Advisory Partners has been working with Colorado’s White River Habitat Partnership Program (WRHPP) to examine response of various vegetative treatments intended to improve habitat for big game animals. WRHPP sought removal of mature mountain shrub communities in favor of plant communities that provided more foraging opportunities for wildlife. Through collection of much monitoring data on a variety of treated sites, Ranch Advisory has produced these state and transition models that predict how different vegetative communities respond to treatments.
State and transition models featured here are grouped according to the Natural Resources Conservation Service’s (NRCS) Ecological Sites, which provide a consistent framework for classifying and describing rangeland and forestland soils and vegetation; thereby delineating land units that share similar capabilities to respond to management activities or disturbance.
These models are presented through Prezi to make them 3-dimentional and more informative for the user. To view a model, click the “view presentation” link. It may take several minutes for the presentation to fully load. Once loaded, click the maximize screen button in the lower right corner of the presentation screen. Use the right arrow to click through the presentation.
Disclaimer: Data on vegetative composition before and after treatments is based upon permanently-established monitoring sites across a variety of ecological sites. These sites have only been actively monitored since 2009, which is a short window for treatments involving herbicides. Further, predicting longevity of treatment duration can be difficult in areas with rapidly-growing shrubs and/or varied levels of herbivory, so users should expect variation in longevity of treatments. Much work has gone into studying the vegetative response of these treatments in specific ecological sites, and these models are intended to provide guidance on the possibilities associated with various treatments. If you find these concepts unclear, ask for help.