Vertebrate use of muskrat (Ondatra zibethicus) structures in wetlands of the Nebraska Sandhills.

Muskrats (Ondatra zibethicus) are semiaquatic rodents native to North American wetlands, including marshes, ponds, and slow-moving streams. In water, muskrats commonly build houses and feeding platforms with herbaceous vegetation and mud. These island structures benefit other species, but few studies have examined the roles these structures play for a community of wetland vertebrates. We studied the diversity, frequency of occurrence, and behaviors of vertebrates on muskrat structures in the Sandhill Region of Nebraska. From camera traps, we recorded over 37,700 observations of vertebrates, representing 57 species, including amphibians, mammals, raptors, reptiles, songbirds, and waterfowl. Vertebrate behaviors on structures included basking, copulating, displaying, foraging, grooming, perching, preening, raising young, resting, and vocalizing. In the Nebraska Sandhills, muskrats created island habitats beneficial to both migratory and local species, with structures appearing of particular importance to life history functions of many waterfowl and turtles. Muskrats represent ecosystem engineers, as their structures were the only natural islands in wetlands due to the general lack of trees and rocks in the region. We frequently observed the use of structures by multiple species simultaneously, further suggesting that island structures are limited in Sandhill wetlands. Our study highlights the great number of vertebrates that use muskrat structures for a host of life history and ecological functions. Throughout the distri - bution of muskrats, many other species likely use and rely on these island structures, as muskrats are an integral component of many wetland ecosystems in North America. Understanding the functionality and frequency of use for these structures by other wildlife is essential when managing populations of muskrats and the wetlands these mammals inhabit. [ABSTRACT FROM AUTHOR]