Introduced Species Threaten Galapagos Islands

July 07, 2014

Today, there are tremendous threats to the Galapagos Islands. Many of them are quite tangible and recognizable while others are more difficult to grasp and determine the impact of a particular alien species. Some of the recognized threats include poaching of natural resources (wildlife mainly) disturbances during critical nesting times of some birds species, the impacts of a very large tourism base and of course the introduction of non-native species. This last item, introduced species, has had an unbelievable affect on native flora and fauna and we still have much to learn about the long term affects of some of the more recent introductions to the islands.

Introductions in the past that have proven to be extremely problematic both in the devastation of habitat (flora and fauna) include goats, pigs, cats, dogs, donkeys and non-native rats. There have been many eradication programs that have been successful in removing these vertebrates from many of the islands. Once again, natural plant growth is prospering but now it seems that more tortoises are required to keep the native vegetation in check so that it can be used as nesting sites for ground nesting birds. The best example of this is on Espanola, where vegetation is becoming extremely thick and reducing the optimal area for nesting waved albatross. Today, a number of tortoises have been released so hopefully this problem will be remedied in the near future by grazing tortoises.

According to the Galapagos Conservancy, non-native introductions have included: 36 vertebrate species, one fish (tilapia), two amphibians (both are frogs), four reptiles (all are geckos), 10 birds and numerous insects and the most astounding, 543 species of plants. Insects and plants can have extremely devastating effects on ecosystems. Included in the insects introduced to the islands: scale insects that suck nutrients from their plant host, two wasps that predate upon native insect species, a parasitic fly that primarily predates on nestling birds, mosquitoes that potentially may spread West Nile Virus to both humans and birds, and fire ants. Fire ants can be devastating to ground nesting birds and reptiles as when the bird or reptile eggs hatch, the ants immediately sense this and descend upon the helpless young still in their eggs. Fire ants are the same creatures that are equally devastating to fauna in the Southern part of the U.S.

So, it is of extreme importance that cargo ships are checked for stow-aways and tourists are checked for “hitchhikers” (seeds) on their socks or shoes as they arrive from mainland Ecuador.

This will continue to be an on-going process and problem, as flora and fauna are accidentally and at times intentionally released on the islands. Nothing good comes from these introductions other than stress on an already fragile environment. Everyone can play a role in the prevention of non-native species. One easy step: Please be aware of what may be on your shoes, socks or in your luggage prior to boarding a Galapagos Islands cruise.

Learn how International Expeditions, through our partnership with IGTOA is funding the fight against introduced species.  

Naturalist Greg Greer is a favorite among IE travelers, and has gained a reputation for his friendliness and good humor, along with his incomparable knowledge of natural history. Greg's photos and articles have been widely published in books and magazines, including Georgia Outdoor News, Bird Watcher’s Digest, Alabama Outdoor News, Riversedge and Southern Wildlife.