Distribution, Habitat, and Conservation Status of Muskrats (Ondatra zibethicus) Along the Canadian River Drainage of the Northern Texas Panhandle

Abstract

In the fall of 2002, muskrats were collected in newly constructed lakes and riparian areas along the Canadian River drainages in Roberts County, Texas. Evaluation of habitats and muskrat sign at several other sites confirmed the occurrence of these semi-aquatic rodents. These recent sightings combined with observation made by federal biologists in the early 1900s, counter recent speculation that muskrats have disappeared or are declining in the region. Rather, it appears that muskrats have always been present as metapopulations in the Texas panhandle, existing as sink/source populations in fragmented habitats, with relative numbers changing over time. An increase of rainfall and wetland restoration projects over the past 20 years have improved available surface water in riparian habitats that have positively impacted muskrat numbers. Analysis of nongeographic variation within muskrat populations revealed significant variation due to age for each measurement but no significant sexual dimorphism. Muskrats collected at the end of the beginning of the 20th century differ in external and cranial measurements from those collected at the beginning of the 21st century for reasons that are not readily apparent.