Ecological Sites

An ecological site has been defined as:

"a distinctive kind of land with specific physical characteristics that differs from other kinds of land in its ability to produce a distinctive kind and amount of vegetation, and in its ability to respond to management actions and natural disturbances"

Ecological sites are a level in the Land Resource Hierarchy used by the NRCS, U.S. Forest Service, and BLM to divide the landscape into units for study, evaluation, and management. The divisions are based on differences in soil and climatic conditions that produce vegetation communties with varying potential.

Ecological Sites differ in:
  • Plant production, species composition and dynamic soil properties at reference conditions
  • Ecosystem services provided
  • Responses to management
  • Processes of degradation and restoration

These differences create distinct expectations regarding land health and potential uses. For example, it should not be expected that every location will produce suitable wildlife habitat, and thus should not be managed for it. Understanding site potential allows us to anticipate changes in reponse to management and disturbance, and well as provide a reference for the interpretation of monitoring and assessment data. Click here to view a powerpoint show on ecological sites.

st_model Ecological sites in California, an illustration of how differences in soil properties can create vegetation composition differences. (Moseley et al. 2010)

Monitoring and Assessment Based on Ecological Sites

Paraphrased from: Karl, J.W. and J.E. Herrick. 2010. Monitoring and Assessment Based on Ecological Sites. Rangelands 32:60-64.

  • When looking for monitoring or assessment methods, look at previous research or management that has been done in the same or similar ecological site.
  • Ecological Sites can be used to stratify sampling because samples within a stratum should have the potential to produce similar vegetation and have similar responses to disturbances and management.
  • Ecological Sites can help identify where monitoring should occur and determine sampling intensity.
  • Ecological Site Descriptions can help you interpret and understand monitoring and assessment data. For example, the qualitative assessment method "Interpreting Indicators of Rangeland Health" (IIRH), is built on the idea that soil stability, hydrologic function and biotic integrity vary by ecological site.
  • Ecological Sites can be used in the development and implementation of standardized monitoring protocols. Some example are the BLM's Assessment, Inventory, and Monitoring Strategy (AIM) and the NRCS's Natural Resource Inventory (NRI).
  • Ecological Sites can provide a context to support the use of remote-sensing techniques.
  • Ecological Sites can be used to create a dynamic framework for managing land use in the context of climate change. Ecological Site Descriptions and state & transition models can be appended to incorporate potential changes in temperature and precipitation and likely outcomes to vegetation communities.