Linking ecological site characteristics to resilience and resistance

Primary components of an ecological site are climate, topography, and soils; all of which influence available moisture, temperature, and potential vegetation and productivity.  Ecological site characteristics determine soil temperature and moisture regimes, potential vegetation, and resilience to disturbance and resistance to invasive plants. The regimes are identified in soil maps as mesic (warm), frigid (cool), cryic (cold), aridic (dry), and xeric (moist). Potential vegetation + disturbance history + seed availability + time since disturbance or treatment determine current vegetation. If all of the ecological site characteristics are favorable for treatment and the site attributes and processes are all functioning within the natural range of variability, then levels of resilience to treatment application and resistance to invasive species are near potential for that site. However, if the site is not at potential because one or more components are below potential or missing, for example, perennial grasses are severely depleted or invasive annual grasses are abundant, resilience to disturbance and/or resistance to and invasive annual grasses will be lower than potential (Fig. 1 adapted from Miller and others 2013 and Chambers and others 2014).