Relict populations

Relict species were probably once more common in Minnesota when the climate was different than it is today. As the climate changed, most populations of these species were eliminated, but small, isolated populations survived in appropriate habitats.

The bluff vertigo is a rare landsnail found in a small number of sites in southeastern Minnesota. This species was more widespread during the Wisconsin glacial period (12,000 years ago), but it now survives only as small relict populations with very specific habitat requirements.

Bluff Vertigo (Vertigo meramecensis)

Relict populations

Ten reasons why species become rare

Habitat loss and degradation Invasive species and competition Pollution Habitat specificity Persecution and exploitation

Peripheral populations Vunerable characteristics Relict populations Disease Global climate change

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