Use of Soapweed Yucca (Yucca glauca) by rodents and other vertebrates in western Nebraska

Soapweed Yucca (Yucca glauca) is a conspicuous and common shrub in the Great Plains of North America, characterized by tall woody flower stalks, large flowers and seed pods, and dense masses of ground-level evergreen leaves. These plant structures can provide a variety of resources or functions to animals. In general, studies focus on single species associated with Y. glauca. We examined three groups of vertebrates that interacted with Y. glauca and the functions this plant provided for organisms in western Nebraska. We experimentally examined small mammals in areas with and without Y. glauca, and we descriptively noted birds and reptiles that used Y. glauca. We documented six mammalian, 13 avian, and four reptilian species using Y. glauca for cover, perches, basking sites, homes, and/or nests. We documented a greater species richness and relative abundance of rodents in areas with Y. glauca compared to areas without Y. glauca. Deer Mice (Peromyscus maniculatus) showed the greatest difference in relative abundance, with about six times as many individuals in areas with Y. glauca (83 individuals) compared to areas without Y. glauca (14 individuals). Upon release, a majority of Deer Mice (94%) ran from trap sites to Y. glauca, as did most other mammalian species. We observed birds mainly perching on flower stalks, as well as a few nesting activities. Soapweed Yuccas provided herpetofauna homes, sites for thermoregulation, perches to watch for predators or prey, and protective cover under leaves. Our findings demonstrated some of the ecological functions for Soapweed Yucca and a variety of vertebrate species using this shrub in grassland ecosystems. Soapweed Yucca is considered a weed in some regions of the Great Plains due to its high abundance in pastures with domestic livestock. On ranches where American Bison (Bos bison) have been reintroduced, individuals consume and actively remove yuccas, especially during winter grazing, and large, multi-headed, aboveground complexes of Y. glauca are less common across such ranches. Our study assisted in understanding the role of this native shrub in managed grassland systems.