Changes in native small mammal populations with removal of invasive ant

Abstract Efforts to remove invasive species may benefit native species, but the effects can be complex and unpredictable. Thus, studies of invasive-species removal provide important information for guiding management providing insight about variation in post-removal impacts within community. Using southern pine-grassland ecosystems as a model system, we hypothesized that long-established red-imported fire ant (Solenopsis invicta, hereafter RIFA) would positively influence altricial Peromyscus due increased survival young nest thus recruitment population, not impact semi-precocial hispid cotton rats (Sigmodon hispidus), which are mobile more quickly after birth at less risk depredation by RIFA. We compared small mammal populations on sites treated with granular insecticide (Extinguish Plus) RIFA southwestern Georgia, United States, from April 2018 December 2019. As expected, detected no difference rat recruitment. However, contrary our prediction, same was true mice (Peromyscus gossypinus) oldfield polionotus). found both mice, increasing average population rate change (λ) during study period. In contrast, observed lower similar λ estimates untreated sites, low sample sizes were problematic this species. Our results show have positive magnitude mammals mechanisms occur complex.