The smallest subspecies of white-tailed deer, Key deer are found only the Florida Keys. Key deer can swim between islands of the archipelago and their current range extends from Big Pine Key to Sugarloaf Key, reduced from their historical range spanning most of the Keys. Habitat destruction and hunting decimated the Key deer population in the 1940s, with numbers falling to less than 50 individuals. The current population has recovered to approximately 800 individuals. Key deer are beloved and iconic in their native home. As land area is limited in the Florida Keys, the Key deer is well adapted to tolerate sharing space with human. In many areas, Key deer can be seen wandering in neighborhoods and other developed areas.
Key deer use all available habitats found within their range including areas populated by humans. Pine rockland communities, unique pine flatwoods found exclusively on limestone substrate in southern Florida and the Keys, provide particularly critical habitat as they contain essential permanent freshwater sources.
The Key deer is highly vulnerable to habitat loss stemming from sea level rise and land use change. Limited by open water barriers preventing migration off the Florida Keys, Key deer are expected to lose 32-75% of useable habitat to sea level rise. In addition to the direct threat of displacement, sea level rise will lead to increased salinity of freshwater drinking sources, a primary limiting resource for Key deer. Drought, shifting hydrological conditions brought on by changes in precipitation patterns, and strong storm surge events may further increase salinization of freshwater sources. Non-climate-related threats such as habitat fragmented by human development, highway mortality and the spread of disease and parasites linked to illegal feeding are also significant for this species.
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 Florida Key deer are sea level rise, the existence of natural barriers, the impact of potential changes in hydrology, and disturbance regimes on freshwater drinking sources. In addition, the species has relatively low genetic variation, which could impact the species' evolutionary adaptive capacity. Over 95% of the species' modeled potential habitat is expected to be impacted by a 1-meter sea level rise. This species is restricted to the Florida Keys, with water surrounding the islands serving as a natural barrier to the species. Key deer rely on freshwater for drinking - the primary sources for freshwater, freshwater holes and other freshwater wetlands, are threatened by saltwater incursion. Increased intensity of hurricanes and associated storm surges are likely to affect Key deer under climate change. Storm surges are a source of saline incursion and hurricanes are a source of direct mortality.
The primary factors contributing to vulnerability of the Florida Key deer are sea level rise, the presence of barriers, changes in precipitation, habitat fragmentation, changes in salinity, runoff and storm surge, and alterations to biotic interactions.