One approach to meet the goals of SARA is to identify currently occupied habitat by species at risk (SAR) and to manage those areas accordingly.  However, due to a species’ rarity, not all suitable habitat is likely occupied.  In order to manage all SAR habitat appropriately, a second approach is needed.

Habitat models use a statistical approach to predict where a species might be found by associating geo/bio/physical characteristics to its habitat preference based on recent geo-referenced sightings.  One problem when working with rare species is that non-occupancy does not necessarily equate to poor habitat potential.

Several new geospatial computationally-intense desktop modeling tools have been developed recently.  One application, MaxEnt, uses the concept of maximum entropy (traditionally applied to the study of energy, but has been expanded to include information processing) to model habitat potential.  MaxEnt takes GIS environmental layers as input, does not require absence data, and produces both graphical and geospatial (i.e. maps) output. 

AAFC-PFRA Range & Biodiversity and GIS & Data Management Divisions collaborated in a pilot project to generate preliminary habitat potential maps for burrowing owl and ferruginous hawk using MaxEnt.  Species occurrence data for southern Saskatchewan, generalized landcover, detailed soils (texture & slope), surficial geology, climate and elevation were used as input layers. Model output included habitat potential maps, diagnostics (fit), and input variable comparisons & analysis.  The next step is to incorporate high resolution satellite imagery to model potential habitat at a pasture level.