Eradication benefited both islands—but invertebrate recovery was uneven
WHAT THE EVIDENCE SAYS
A newly published analysis of historical surveys through 2018 found post-eradication gains in overall invertebrate abundance and taxonomic richness on both islands. Several groups eaten by mice increased clearly on Antipodes. Macquarie's overall abundance exceeded the immediately pre-eradication 2009 baseline, and flies increased significantly, but several other prey groups did not show clear significant gains. Simpson's diversity did not show significant pre–post increases on either island. Most comparisons identified invertebrates to order or class rather than species.
WHY IT MATTERS / OUR READ
The counter-signal is uneven recovery, not a failed eradication. Removing invasive mammals can deliver real benefits without restoring every part of a food web on the same timetable. Monitoring should track different invertebrate groups and habitat trajectories rather than treating either operational success or one null response as the whole ecological result.
CAVEATS / UNCERTAINTY
Two islands and imperfect historical surveys do not isolate the cause of their different responses. Sampling effort, season, pitfall-trap performance and uncertainty in baseline data constrain comparisons. Legacy rat and rabbit impacts are a plausible interpretation, not an experimentally separated cause. The paper analyzes older field records, not recovery measured in 2026.
SOURCE
Houghton et al. · Conservation Science and Practice · island invertebrate responses to rodent eradication
View original evidence ↗
Antipodes and Macquarie showed gains after invasive-mammal removal, but the response differed among invertebrate groups and measures of recovery.
Read the Wild Lands assessment →