D3064: (2nd Place) Assessing the use of non-indigenous Vitaceae by native arthropods

The global spread of non-indigenous (NI) invasive species is considered one of the leading causes of biodiversity loss worldwide. Specifically, disturbances caused by NI plants displacing native vegetation may result in bottom-up trophic cascades affecting both primary and secondary consumers (insect herbivores and insectivores) that can lead to severe disruptions of food webs, subsequent species declines, and even regional extinctions at multiple trophic levels. The current dogma states that native herbivores are unable to successfully utilize NI plant species, and any exceptions that do so experience poorer growth and survival relative to those on native host plants. However, growing evidence suggests that some NI plant species are able to support diverse arthropod communities, though studies examining this are rare. To determine the extent to which established NI species have integrated into native trophic webs in their novel ranges in the Washington DC area, I conducted a field-based natural experiment in which I censused arthropod herbivore communities found on co-occurring, native and NI plant species pairs from the grape family (Vitaceae). I found that the NI species (Ampelopsis glandulosa; present in the region for nearly a century) supported the same richness and diversity of herbivores as its native counterparts (Vitis vulpina, Parthenocissus quinquefolia), but that the families that constituted these communities differed. Thus NI species can support arthropod diversities similar to those of their native counterparts. However, differing community compositions may mean that higher trophic levels are still poorly supported by the arthropods available on the NI species.