Very little is known about the life history of the St. Andrew beach mouse, a subspecies of the small old-field mouse, endemic to a small range from the dunes of St. Joseph Peninsula in Gulf County, Florida to near St. Andrew Bay in Bay County, Florida. The beach mouse can reach a length of 5 inches. The St. Andrew beach mouse is dependent on dune habitat for food and shelter, burrowing under dune vegetation and eating a diet of insects, seeds and fruit. The species is monogamous and has the fast-reproductive cycle common of small mammals. Breeding season typically occurs during the early winter months but can continue year-round in optimal food and climate conditions.
The St. Andrew beach mouse relies exclusively on sand dune habitat on the Gulf coast of the Florida panhandle.
As a coastal endemic subspecies, the St. Andrew beach mouse faces substantial threats related to climate change. First, sea level rise is a grave impending threat to the beach mouse’s island habitat. Additionally, this species faces many of the same existing threats common to coastal or island species: habitat loss and degradation from coastal development, barriers to migration, habitat disturbance from recreational use and high mortality from non-native predators. These existing threats are likely to be magnified by the increasingly severe storm events and shifting conditions of a changing climate.
More information about general climate impacts to species in Florida.
The overall vulnerability level was based on the following assessment(s):
The primary factors contributing to vulnerability of the St. Andrew beach mouse are sea level rise, habitat fragmentation, changes in salinity, runoff and storm surge, and alterations to disturbance regimes. This species is already extirpated on non-protected lands.