Giant Galapagos tortoise on Santa Cruz Island

A giant tortoise crosses the road in the highlands of Santa Cruz. © estivillml

According to a study published by researchers from the University of Western Australia, nearly half the vegetation canopy in at least one part of the Galapagos Islands is comprised of non-native shrubs, trees and grasses. The study focused on the humid highlands of the island of Santa Cruz, the most populous of the Galapagos Islands.

Invasive species in the Galapagos often outcompete native species for resources, such as light and water, and can change the environment, which can affect other plants and animals.

The researchers produced a map and database that details the distribution of native and non-native species across the landscape, a tool which should help conservation managers combat the problem going forward. Efforts have already been underway for years to eliminate particularly harmful invasive plants, such as wild blackberry, and replace them with native species in certain areas.

If you plan to visit the Galapagos you can help out by carefully checking your clothes, luggage and shoes for seeds and other plant material before you arrive. A recent study conducted in Antarctica found that just 853 visitors inadvertently brought 2,686 seeds and 535 bryophyte and lichen fragments with them to the “White Continent.” Now imagine what sort of unintentional mayhem the 200,000 people who visit the Galapagos each year have the potential to unleash.