About Ecological Sites and Plant Community Types
In order to manage vegetation for range, timber, wildlife and recreation, the ecology of the plant communities in the presence and absence of disturbance must be understood. Community types are defined not only by their vegetation composition but also by the environmental conditions under which they occur.
The ecological classification of Alberta is a hierarchical classification structure starting at a broad scale of Natural Regions, subregions, and ecosections. The forested natural regions further subdivide by Ecological site, Ecological site phase. The grassland natural regions follow a similar hierarchical structure but subdivide by Range site, Ecological range site. Both systems end at the plant community, the lowest level of classification.
Ecological land cover spatial datasets outline Ecological site phase or Range site. These datasets include:
- Derived Ecosite Phase (DEP) – Available on landscapes with Alberta Vegetation Inventory
- Grassland Vegetation Inventory (GVI) – Fully Covers the Grassland natural region.
- Primary Land and Vegetation Inventory (PLVI) – in development for landscapes without AVI or GVI coverage.
Ecological Land Cover Datasets
To view and download ecological land cover datasets search for "Derived Ecosite Phase" and "Primary Land and Vegetation Inventory" on open data at:
Grassland Vegetation Inventory is available at:
Ecological site and Range Plant Community Guides
There are 6 Natural Regions and 21 Natural Subregions described for the province of Alberta. Ecological Site and Range Plant Community Guides are available for each subregion.
To view a guide for a particular subregion, search for "range plant community guides" or "ecological site guides" on open publications at:
Range Plant Community Guides
Below is a selection of Range Plant Community Guides that can be found on Open Government Publications.
Ecological Site Guides
Below is a selection of Ecological Site Guides that can be found on Open Government Publications.
What are stocking rates?
When range managers determine the number of head of cattle that can be supported by a given site for a given period of time, they are setting the stocking rate.
This stocking rate is the balance between the livestock's monthly forage utilization requirements, the plant production and the ecology of the site.
Ecologically Sustainable Stocking Rates (ESSR)
The ESSR reflects the maximum number of livestock [e.g. hectares (ha)/animal unit month (AUM)] that can be supported by the plant community given inherent biophysical constraints and the ecological goal of sustainable health and proper functioning of the plant community.
When the ESSR is expressed for the area [e.g. ha] of a plant community polygon, the result is termed carrying capacity [CC], and is written in AUMs.
Ecologically sustainable stocking rates are suggested for each plant community described within the Range Plant Community Type Guides.
Range Survey Manual
The various survey methods used by Rangeland managers to collect the information needed to calculate carrying and grazing capacities to manage public rangelands in Alberta is outlined in the documents below. See:
For more information, contact your local Rangeland Management Branch Office:
Updated: Oct 22, 2018