How does rodent removal affect insects?

Lord Howe Island: removing invasive rodents boosts invertebrates

Invasive rodents were eradicated from Lord Howe Island, and researchers documented a biological rebound: invertebrate life increased after the rodents were removed. Teams from the University of Sydney and collaborators carried out field observations and reporting to track changes in invertebrate populations following the eradication.

The result matters because it provides a clear example of how top-down ecological pressure can shape entire food webs. Rodents can reduce insects and other invertebrates either directly through predation or indirectly by altering habitat conditions. When the invasive mammals were removed, the invertebrates regained space, food availability, and breeding opportunities—allowing population growth.

This kind of outcome is especially important on islands, where ecosystems can be simplified and invasive species have outsized impacts. Lord Howe is a conservation-oriented setting, so the findings offer practical evidence that eradication can yield measurable benefits beyond the headline goal of removing one invasive animal.

The work also helps conservation planners anticipate secondary effects. A successful rodent removal doesn’t just “restore” the targeted species; it can trigger cascading changes that may affect birds, reptiles, and other native predators that rely on invertebrates. That means recovery can proceed in stages rather than all at once.

Overall, the study supports the idea that invasive species removal can be an effective lever for ecosystem recovery, but it also underscores the need for monitoring ecosystem responses—especially the often-overlooked invertebrate layer that supports much of island biodiversity.