Monday, September 12, 2011

Reptiles Where They Don't Belong

The Northern Curly Tailed Lizard,  Leiocephalus carinatus armouri
is endemic to the the Little Bahama Bank. In the 1940's about 20 pairs
were intentionally introduced into Palm Beach. It now inhabits much of
Florida's Atlantic Coast.   Photo JCM
The most popular posting on Serpent ResearchAn Attempt to Reduce Invasive Predators in the Florida Keys, has had almost 2000 visitors, about 5% of the total traffic to this blog. Why this post should attract so much attention is somewhat of a mystery, the next most popular post is Amphibians Prey for Epomis Beetles  has received only 20% of the attention the Invasive Predator has seen. So here is another note on a similar topic.

By moving species around humans are homogenizing the flora and fauna. One place becomes more like every other place on the planet. Introduced species create a loss of local biodiversity and local natural history. Two recent articles in Current Zoology emphasize the problems invasive species create..

Witman and Fuller (2011) report 1,065 vertebrate species have been introduced into the United States and its territories (86 mammalian, 127 birds, 179 reptiles & amphibian, 673 fish species). They note that In the United States, there have been some successes in invasive species management and eradication both on the mainland and islands and note we are becoming more knowledgeable and pro-active in responding to invasive vertebrate species. But invasions continue.

Florida is overrun with introduced species and Engemen et al. (2011) consider Florida's reptile fauna to be dysfunctional. Florida's climate is favorable for many amphibians and reptiles species from around the world and exotic snakes, lizards, turtles, and crocodilians are all breeding in Florida. They write, "Waves of exotic lizards have swept across much of the state, only to be joined or supplanted by subsequent lizard species..." The largest snake in Florida is no longer the Eastern Diamondback Rattlesnake or the Eastern Indigo. The state is now inhabited by the world's largest constrictors. The general public is unaware of most of the invasive species; the large constrictors are the exception. Florida now has three times more non-native lizard species breeding in the state than the native species. Many of the invasive lizards feed on the native lizards and at the same time compete for food and space.

They discuss five examples in some detail: Argentine Black and White Tegus, Burmese Pythons, Green Iguanas, Spiny-tailed Iguanas, Nile Monitors, and Northern Curlytail Lizards.

Invasive exotic reptiles in Florida are severe problem for native species, and the authors suggest that diversity of invasives in the state merit eradication, or at least control; pointing out that prevention is the most efficient and economical means to deal with invasive species. But, it is too late for those already there. 

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