Data from: Conservation genetics of the eastern yellow-bellied racer (Coluber constrictor flaviventris) and bullsnake (Pituophis catenifer sayi): river valleys are critical features for snakes at northern range limits

On the North American Great Plains, several snake species reach their
northern range limit where they rely on sparsely distributed hibernacula
located in major river valleys. Independent colonization histories for the
river valleys and barriers to gene flow caused by the lack of suitable
habitat between them may have produced genetically differentiated snake
populations. To test this hypothesis, we used 10 microsatellite loci to
examine the population structure of two species of conservation concern in
Canada: the eastern yellow-bellied racer (Coluber constrictor
flaviventris) and bullsnake (Pituophis catenifer sayi) in 3 major river
valleys in southern Saskatchewan. Fixation indices (FST) showed that
populations in river valleys were significantly differentiated for both
species (racers, FST = 0.096, P = 0.001; bullsnakes FST = 0.045–0.157, P =
0.001). Bayesian assignment (STRUCTURE) and ordination (DAPC) strongly
supported genetically differentiated groups in the geographically distinct
river valleys. Finer-scale subdivision of populations within river valleys
was not apparent based on our data, but is a topic that should be
investigated further. Our findings highlight the importance of major river
valleys for snakes at the northern extent of their ranges, and raise the
possibility that populations in each river valley may warrant separate
management strategies.