Jens M. Olesen
Getting rid of invasive species is a Sisyphean task, and some ecologists have questioned whether the effort is worth it. Plants and animals that are introduced by humans to new ecosystems are blamed for crowding out natives and disrupting vital interactions, like pollination. But scientists don’t have much data to help them judge whether removing invasive plants really makes a difference to the health of an ecosystem. New findings from the Seychelles, an archipelago in the Indian Ocean, suggest that the hard work (and money) invested can pay big dividends for pollinators—including insects, birds, and reptiles—and for the native plants they assist. Researchers removed nearly 40,000 invasive shrubs from four mountaintop patches on the island of Mahé. They then carefully monitored the remaining plants for visits from pollinators: bees, butterflies, beetles, birds, and lizards like this skink, which pollinate native Polyscias crassa bushes (pictured). After collecting 1500 hours of observations over 8 months, they found that both the number of pollinators and their interactions with plants and each other were more than 20% higher in the test areas than in control plots (in which the invasive shrubs had been left alone), the team reports this week in Nature. Those extra interactions bore fruit—literally. The native plants in the test plots produced more flowers and more fruit than those in control areas.