text: The species depends heavily on mesic habitats, and in areas on the periphery of its range, which contain distinctive and divergent subspecies, populations may be lost if the wetness of the habitats changes. A distinct Pleistocene relict subspecies, M. d. chihuahuensis, the Chihuahuan vole, was also found in Chihuahua, Mexico, but has not been recorded since 1988 after its habitat was degraded by recreational activities and especially overgrazing, and eventually the marsh was completely drained by the early 2000s. This subspecies displayed notable divergence from other populations and was highly isolated from any others, and would be considered a distinctive subspecies.  In addition, two other populations in New Mexico appear to have been extirpated in recent times, likely as a consequence of climate change-induced drying and overgrazing. Due to the heavy association between meadow voles and mesic habitats, they are especially at risk from drying trends in areas at the peripheries of their range, leaving many of these populations at heavy risk of extirpation.