Boundaries were refined by considering the
  (1) records for Conservation Targets from the Natural Heritage Program databases;
  (2) target occurrence data provided by experts (May 1998 Experts Workshop) and
      from primary and grey literature not currently in a digital database
      (e.g., wilderness study area reports);
  (3) spatial data sets for the Ecoregion's topography, hydrography, land use/land
      cover, GAP vegetation (and equivalent data for Mexico), land management status,
      and Thematic Mapper satellite imagery;
      
  and
  
  (4) indices of biophysical variation from biophysical modeling exercise