GIS mapping
To assess whether population genetic structure corresponded to landscape
or ecological factors, we used QGIS (QGIS Development Team 2019) to
overlay Canadian canola spatial density and soil zone data
(open.canada.ca) on maps depicting the survey locations and average
genetic clustering output by Structure for the CFM population dataset.
The canola overlay depicts crop inventory values reported by AAFC
(averaged between 2009-2018) as rasters that indicate the level of
expected canola spatial density at each geographic location; regions of
green indicate high canola density and regions of pale yellow represent
low density. Yearly canola inventory maps were not available, so we were
unable to consider any impact of temporal changes in regional canola
inventory on CFM population structure. The soil zone overlay depicts the
approximate agricultural extent of the Canadian Prairies, and was used
to define the northern boundary of the CFM survey (see survey methods
above).
RESULTS