Recovery of native ant assemblages following the landscape-scale removal of the Argentine ant

Species introductions are a costly and pervasive form of environmental change that cause impacts including degraded ecosystem services, agricultural disruptions, and species extinctions. Surprisingly little information exists, however, regarding the capacity of ecosystems to recover after introduced species removal. The experimental removal of introduced species can also provide unparalleled opportunities to examine community reassembly. Here we use 16-years of data to examine the reassembly of native ant assemblages following the landscape-scale removal of the Argentine ant from Santa Cruz Island, California. This species displaces other ant species, and its removal makes it possible to examine how native ants recover genetic diversity, species diversity, community structure, and ecological function. Following Argentine ant removal, we observed both structural (species diversity, species composition, abundance) and functional (assemblage-level predation and scavenging) recovery of native ant assemblages (relative to uninvaded control sites) within a decade-long time frame. Multifaceted approaches, such as those employed in this long-term study, can clarify the rate and extent to which ecosystems recover from different drivers of environmental change. Given the widespread ecological disruptions caused by ant invasions, our study illustrates how eradication efforts can be used to achieve ecosystem restoration.