Non-native species invasion, habitat fragmentation and climate change individually impose negative impacts on natural systems, but their synergistic effects may do more harm than the sum of their parts. We examined the combined effects of these global change drivers by studying the impacts of experimental warming on seed-dispersing forest ant nesting and foraging in the Southeastern U.S. to determine if warming and forest fragmentation facilitated non-native ant invasion effects on native ants. Spring ant phenology and activities were monitored for two years (2019-2020) at weekly bait stations and in artificial nest occupancy. We found that, when combined, forest edge habitat and experimental warming favored invasive non-native ant frequency, but the experimental warming alone did not appear to facilitate non-native ant incursion into forested habitat. We did find, however, that experimental warming exacerbated the negative effects of non-native ants on native ant foraging. Moreover, fragmented edge habitat strongly limited native forest ant foraging and experimental warming increased the negative effects of non-native ant invaders on native ants. Ultimately, the non-native ants displaced native seed-dispersing ants from artificial nests, and the displacement progressively increasing with greater experimental warming. Our results suggest that global change drivers such as warming, habitat fragmentation and species invasion imposed negative impacts individually, but their combined effects were worse than the sum of their parts. Moreover, our results indicate that predicting species reactions to global change poses great challenges given that the strongest impacts were the non-additive effects.
Brachyponera chinensis, Aphaenogaster rudis, climate change, habitat fragmentation, Solenopsis invicta, soil warming, species invasio
Department of Biology
Warren, Robert, "Global change drivers synergize with the negative impacts of non-native invasive ants on native seed-dispersing ants" (2022). Biology Faculty Datasets. 13.