Neotoma floridana floridana: Natural history, ecology, and movements in north-central Florida

Abstract

A behavioral ecology study on the eastern woodrat (Neotoma floridana foridana) was conducted between September 1988 and February 1990 on the Katharine Ordway Preserve-Swisher Memorial Sanctuary. The Preserve is located in north-central Florida, approximately 5 miles east of Melrose. The goal of the study was to investigate factors that may influence density and distribution of Neotoma on the Ordway Preserve. Distribution of the eastern woodrat is closely associated with mesic hardwood hammocks on the Preserve. Five study sites were therefore selected in three habitat types: mesic hammock with open understory, mesic hammock with saw-palmetto understory, and bottomland hardwood swamp. Trapping along strip-transects at these sites demonstrated that the bottomland hardwood swamp consistently had the highest density of woodrats (4.3/ha at initiation of study). Densities fluctuated in all 5 study sites, and at Goose and Ashley lakes populations crashed. Radio telemetry was used to evaluate woodrat movements, habitat utilization, and den use. Woodrats were nocturnal with peaks in nighttime activity between 2000-2200 and 0100-0330 hours. Mean homerange size was larger in the mesic hammock with saw-palmetto understory (1.05 ha), which was least dense in horizontal woody growth. Home ranges were smaller in the mesic hammock with open understory (0.25 ha) and bottomland hardwood swamp (0.69 ha) which were more complex in horizontal and vertical vegetation structure. Home range size was positively correlated to number of dens used, which ranged from 1 to 3 dens in use at one time. Dens of woodrats were the center of all activity. Nest fidelity was high, but some individuals changed dens. Social tolerance was low, radiotelemetry and trapping observations rarely documented animals in close proximity to each other. In summary, the bottomland hardwood swamp, which has the highest stem density and vegetation cover supports the highest density ofwoodrats. These habitat features may influence smaller home ranges. The density fluctuations in all study sites and subsequent population crashes in two mesic hammock habitats, suggest woodrats may be influenced by external factors such as predation and drought conditions. Forests with less horizontal and vertical structural complexity may be marginal to woodrats due to cover requirements and food resource distribution. Populations inhabiting these environments may therefore be more vulnerable when heightened stress levels occur, such as changes in climatic conditions.