Island invertebrate responses to single‐ and multi‐species invasive rodent eradications

Abstract Globally, islands have been invaded by invasive mammals with devastating impacts on biodiversity. In response, eradication programs have increased in number, scale, and success. However, the conservation benefits for small and cryptic invertebrates are rarely quantified. Monitoring invertebrate communities can provide insights into the ecosystem‐level response to eradications. House mice ( Mus musculus ) have invaded islands globally and are a major predator of invertebrates. Mice were declared eradicated from sub‐Antarctic Antipodes in 2018. House mice and ship rats ( Rattus rattus ) were declared eradicated from Macquarie in 2014. We analyzed pre‐ and post‐eradication macro‐invertebrate surveys on both islands to assess changes in invertebrate richness, diversity, and abundance. Overall abundance and richness of invertebrates increased post‐eradication on both islands, but not diversity. On Antipodes Island, where mice were the sole invasive mammal, abundance of invertebrate taxa preyed upon by mice increased significantly. On Macquarie Island, except for flies, the abundance of invertebrate taxa preyed upon by mice did not increase. The legacy impacts of invasive rabbits ( Oryctolagus cuniculus ) and ship rats persist in the island's ecosystem. Rodent eradications on islands benefit invertebrate communities. Restoration may take longer when a complex of invasive mammals has been eradicated.