Figure 3
Gray Squirrel distribution. (A) Occurrences in geographic space (yellow points) in invaded areas (red). (B) Display in environmental space of corresponding occurrences from invaded areas (yellow points). (C) Geographic occurrences (green points) in the native range, restricted to areas with environments analogous between native and invaded range (red). (D) Display in environmental space of models from occurrences in the native (green ellipsoid) and invaded ranges (yellow ellipsoid) falling in environments analogous between native and invaded range. Notice the occurrences from native areas (green ellipsoid) nested within the ellipsoid corresponding to occurrences from the invaded areas (yellow ellipsoid) in the environmental space (D). Background values are show as gray. Left figures done using ArcGIS 10.2 (ESRI, Redlands, CA, http://www.esri.com/) and right figures done using NicheA 3.0 [ref. 48].
