Introduced mammal impacts on seabirds in the Îles Éparses, western indian ocean

Invasive mammals have devastated endemic island communities throughout the world, and seabirds have proven particularly vulnerable, with many species extinctions. Introduced predators have had the greatest effect through direct predation, but this effect can now be mitigated by modern eradication techniques. However, the removal of a species from a community can generate different indirect effects depending on the trophic levels that are interacting. Conservation managers eradicating introduced mammals must consider ecosystemwide effects and view island management within a “whole ecosystem” context. It is important to consider unexpected indirect effects from eradications. However, eradication of introduced mammals should not be delayed, especially when direct effects such as predation are a known cause of terminal decline for a threatened species. We use the French Îles Éparses of the Western Indian Ocean, with their various combinations of six introduced mammals, to demonstrate the direct and indirect effects that introduced mammals may have, and how those effects might affect the regionally important seabirds with breeding colonies on the islands. We conclude by making recommendations for the future management of the islands.