A Harsh Environment: Factors Affecting the Distribution and Temporal Patterns of a Salt Marsh Endemic Mammal

Abstract

The salt marsh ecosystem, one of the world's most biologically productive natural communities, integrates characteristics of both terrestrial and aquatic environments. Despite its high productivity, few terrestrial mammals have adapted to this harsh environment with its fluctuating water levels and salinity. The Gulf salt marsh mink (Neogale vison halilimnetes) is endemic to the west coast of Florida, specifically restricted to salt marsh. However, little is known about the mink’s distribution, habitat use, activity patterns, and interactions with other mammals. From September 2014 to May 2016, we placed cameras on 513 floating platforms at 94 survey units. Using multi-species occupancy models, we studied the effects of environmental covariates and species interactions on the occupancy probability of Gulf salt marsh mink, raccoon (Procyon lotor), and marsh rice rat (Oryzomys palustris). We also used negative binomial regression to evaluate the effect of tide height and time of day on the activity of each species. Gulf salt marsh mink use of salt marsh was greater near oyster reefs, further from the forest edge, and closer to a major river. Raccoons were also detected near oyster reefs and in areas with a higher percentage of low marsh, while marsh rice rats were detected near the forest edge and farther from a major river. Time of day and tide height influenced activity patterns of raccoons and marsh rice rats but not the cathemeral Gulf salt marsh mink. Overall, the restricted range of the Gulf salt marsh mink suggests further investigation into their conservation status is warranted.