Galapagos tortoises thrive on invasive plant species

April 7, 2015

Brett Smith for redOrbit.com – @ParkstBrett

When we think of Asian carp invading the Mississippi River or pythons taking over parts of the Everglades, we think of how invasive species can decimate an ecosystem. However, invasive species can sometimes have a positive impact.

That’s what an international team of researchers found recently on the Galapagos Islands, where tortoises are thriving on non-native plants.

According to a new report in the journal Biophilia, the Galapagos tortoises actually prefer invasive plants to native foliage and in turn, the invasive plants are a good source of nutrition for the reptiles.

“Biodiversity conservation is a huge problem confronting managers on the Galapagos Islands,” said study author Stephen Blake, an honorary research scientist at Washington University in St. Louis. “Eradicating the more than 750 species of invasive plants is all but impossible, and even control is difficult. Fortunately, tortoise conservation seems to be compatible with the presence of some introduced species.”

Pretty odd

The team conducted their study on the island of Santa Cruz, a dormant volcano that is home to two species of giant tortoise, as well as the biggest human population in the Galapagos. Farmers have modified most of the highland moist zones to farming and at least 86 percent of the highlands and other moist zones are now deteriorated by either farming or invasive species.

Past research by some of the same scientists showed that tortoises migrate seasonally between the arid lowlands, which flourish with vegetation only in the wet season, to the lush meadows of the highlands, which remain productive year-round.

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