Your communities are under attack! It’s true: the backyards, gardens, sidewalks, and parks that your families and young children play in are undergoing an ecological invasion. The foreign lizard species Anolis sagrei, the brown anole, has been introduced to Houston area and is now locked in a vicious struggle for ecological dominance with our native lizard, Anolis carolinensis, the green anole- and it’s winning!
Anyone who has grown up in the Houston area will recall chasing the green anole around their porches and backyards, and being able to see the familiar creatures bobbing up and down atop fences and displaying their bright red neck frills, in elaborate mate-attracting escapades. I can certainly attribute countless childhood memories to the little green reptile. But within the last decade, the brown anole has become more and more prevalent in the Houston area, jeopardizing the balance of the Houston ecosystem and challenging the green anole for dominance.
While the brown anole originated in Cuba, it made its way into the Florida Keys in the 1970s and has gradually spread up into the mainland. By stowing away in shipments of potting soil, the brown anole was inadvertently introduced to the Houston area. Evidence for this is strongly supported by the fact that during the early days of the brown anole invasion, populations were only found around gardening centers such as Lowe’s and Home Depot. From these epicenters, the invasive species disseminated throughout the area.
One might ask why it matters that a new species of lizard is starting to take root in the area. Biodiversity is technically increased, isn’t it? And the brown anole, while not as colorful as its counterpart, does boast a unique diamond pattern along the ridge of its back. The problem arises in in the fact that the two lizard species each occupy the same niche. They live in the same habitats, eating the same food, and generally compete for the same limited pool of resources. However, in the words of John Lomax, “in their (brown anole) native Cuba, they’ve been competing with rival anole species for millions of years, and developed the bodies and skills best suited to occupying turf on the ground and low on tree trunks.”(Lomax 2015) The green anole has faced no such competition. Thus, the brown anole has rather easily started to outcompete the green anole, to the point where there is now a noticeable decline in the Houston green anole population. It was a subtle change that occurred over the span of several years and thus rarely stands out to people as a pressing issue, but if one compares the same neighborhoods from 15 years ago and now, the lovely green anole will be encountered far more sparsely, and will be entirely absent from some areas they used to occur in.
This is where a fascinating process of ecological adaptation can be observed: rather than continuing to fight a losing battle against the brown anole for limited resources, the green anole has started to occupy a new niche. They have moved from the ground to low hanging tree branches and bushes, and have even evolved larger toe pads in just 15-20 years to help them conquer this adjusted niche. To be sure, those who don’t think the invasive lizards are a pressing issue might argue that the green anole switching to occupy a new ecological role solves the issue and allows both to live in harmony, but population sizes of our native lizard are still far lower than they were before the invasion, and in areas without taller vegetation for the green anoles to retreat to, the native species is out of luck. At the rate green anole numbers are declining, they are on track for extinction. Some might ask why it matters if we lose our native species, since they pretty much fill the exact same role. Saving the green anole is important because of our inherent responsibility to preserve the world’s biodiversity. We were responsible for introducing the brown anole into the area, and now it’s our responsibility to reverse this mistake. If the green anole goes extinct, we lose any and all potential discoveries that could have sprung from the lizard. Plus, the green anole is much nicer to look at anyway.
I don’t think it’s too late to save the green anoles, and while the scale of the problem is quite large and the brown anoles are quite prevalent now, there are so many things we can do to fix this crisis. Breeding and release programs for the green anole can replenish numbers. Planting more trees can provide habitats for them as they move up off the ground. Releasing the natural predator of the brown anole to thin out numbers, or even something as simple as stomping out brown anoles whenever they’re encountered could make all the difference. For the more adventurous (or hungry) Houstonians looking to get involved, I’ve heard the brown anole is edible!
Barton, Amy, and Chris Garza. “A New Lizard in Town – the Cuban Brown Anole – Houston Arboretum & Nature Center.” Houston Arboretum Nature Center. Houston Arboretum and Nature Center, 03 Sept. 2015. Web. 05 Sept. 2016.
Kozdemba, Alice, Elizabeth Williams, and Maria Roque. “Brown Anole Lizards Migrate to Texas |.” Multimedia Newsroom. UT Austin School of Journalism, n.d. Web. 05 Sept. 2016.
Lomax, John. “The Green Anole, Your Resident Backyard Lizard, Is Being Pushed Out By Its Uglier Cousin.” Texas Monthly. TM, 03 Dec. 2015. Web. 05 Sept. 2016.