Survey techniques for determining occupancy of isolated wetlands by round-tailed muskrats

Neofiber alleni (round-tailed muskrat) is a wetland-associated species of conservation concern restricted to the southeastern United States. This species is relatively unstudied and no standardized procedures exist for determining its distribution. We evaluated a survey technique for assessing presence-absence of round-tailed muskrats in small, isolated, freshwater marshes in central Florida. We conclude that ≥ 2 trained persons searching adjacent belt transects on foot for ≤ 30 min during fall-early winter can reliably determine occupancy for muskrats based on presence of their distinctive lodges. Resurveys of unoccupied wetlands did not reveal any false absences from our initial survey, and an investigation of lodge persistence indicated that false presences were unlikely. Broad-scale studies of distributional patterns and temporal trends in occupancy of the round-tailed muskrat are needed to assess its conservation status and threats.