LAUSR

Invasive plants can have significant negative interactions with native flora and fauna, often decreasing the abundance and diversity of native plants and invertebrate and vertebrate herbivores. Less is known, however, about how invasive plants influence higher-order consumers, such as carnivores. Arundo donax is a globally distributed invasive grass that forms dense monotypic stands in the habitats where it successfully establishes. This study investigated the influence of Arundo invasion on mammal assemblages in California’s Santa Clara River Valley. Specifically, we aimed to determine whether Arundo alters habitat use for carnivores, and if so, assess the possible mechanisms driving these differences. We used remote cameras to evaluate carnivore habitat use and model occupancy, and live traps and remote cameras to assay abundance of small mammals, common prey of these larger predators. We found that detections of all carnivores were significantly lower in Arundo-dominated habitat patches, suggesting decreased preference for Arundo habitat. This was reflected in the occupancy model, which found the highest probability of coyote and bobcat habitat use in native patches and lowest in Arundo; however, habitat did not seem to be as important of a predictor as in the pooled species results. Small mammal abundance was similar if not higher in Arundo, suggesting the possibility of Arundo acting as a refuge for prey species and altered predator–prey dynamics in Arundo-dominated patches. This study improves our knowledge of the often-complex ways that invasive plants, like Arundo, influence the ecology and behavior of faunal communities in invaded ecosystems.