7 Times Invasive Species Actually Helped

TL;DR

Some invasive species provide unexpected ecological benefits, like reducing mosquito bites, sheltering endangered butterflies, and boosting crocodile populations.

Key Points

• 1.Brown anoles in Florida reduce mosquito bites on humans. Invasive from Cuba and the Bahamas, these lizards attract mosquitoes away from residents, though their replacement by the even-more-invasive Peter's rock agama may reverse this benefit and affect West Nile virus spread.
• 2.Invasive lovegrasses gave Arizona's near-extinct Botteri's sparrow a comeback habitat. Introduced as cattle feed in the late 1800s, the grasses spread rapidly; when sparrows returned in the 1960s they nested in them at the same reproductive rates as in native grasses.
• 3.Symbiodinium trenchii, an Indo-Pacific algae invading Caribbean corals, boosts coral heat tolerance. It photosynthezes better under thermal stress than local symbionts, helping coral colonies survive rising temperatures, though it may slow exoskeleton formation as a potential hidden cost.
• 4.Australia's 23 million feral pigs appear to have aided saltwater crocodile population recovery. Bone isotope analysis from 2022 showed modern crocs eat more terrestrial prey than pre-1970s crocs; abundant, easy-to-catch pigs near waterways likely supplemented croc diets after hunting protections were enacted.
• 5.Invasive eucalyptus trees are a critical winter roost for western monarch butterflies, whose population has crashed 95% since the 1980s. With native canopy trees removed by logging, monarchs now rely on eucalyptus for shelter and nectar, giving a species scientists estimate has a 99% extinction chance by 2080 a better survival shot.