INVASIVE PLANT ARUNDO DONAX REDUCES MAMMALIAN PREDATOR USE OF HABITAT IN A SOUTHERN CALIFORNIA RIPARIAN SYSTEM.
Molly Hardesty-Moore; UC Santa Barbara; Ecology, Evolution, and Marine Biology, UC Santa Barbara, SANTA BARBARA, CA, 93106-9620; (530) 913-7255; mhardestymoore@ucsb.edu; Devyn Orr, Douglas J. McCauley
The invasive plant Arundo donax is known to have significant impacts on riparian ecosystems in southern California, including by decreasing abundance and diversity of plants, birds, and arthropods, but little is known regarding its effects on mammalian predators. This study investigated the influence of Arundo on mammal assemblages in the Santa Clara River (SCR) Valley in Ventura County, in order to 1) determine if Arundo alters habitat quality for mammalian predators and propose potential mechanisms, and 2) examine effects of seasonality and fire on the impact of Arundo. We used remote cameras to compare mammalian predator use of habitat with differing abundance of Arundo along the SCR between Fall 2016 and Spring 2018. Small mammal abundance was estimated using mark-recapture. Overall, we found that Arundo decreases habitat quality for mammalian predators in this region. However, there was variation by species: coyotes were found to have lower probability of occupancy in Arundo, but bobcat occupancy did not differ by habitat type. Small mammals similarly did not differ overall by habitat type, indicating a prey source for predators in Arundo. There was no effect of seasonality or fire. This study suggests Arundo donax could be altering how mammals use riparian habitat.
The Anthropocene: Pathogens & Invasive Species   Student Paper