Bolt Your Door: Invasive Species Attacking Texas

Anna Armitage and Antonietta Quigg, marine biologists on the Galveston campus, have been studying how numerous plants and some animals not native to Texas have taken a very un-Texan like attitude about occupying as many wetlands and prairies as they can with the idea of a total takeover.

Both researchers are part of a group called TexRAT (Texas Rapid Assessment Team), a collection of state and federal agencies, universities and non-governmental groups that is studying invasive plants and animals that threaten the ecological and economic health of Texas. Its goal is similar to the fight in those horror flicks, but without the flamethrowers and army tanks — they are concentrating on whipping the pesky invaders through scientific means.

“The first thing we (TexRAT) are trying to do is measure the scope and size of the problem,” says Armitage. “We need to identify what we’re up against, locate these invasive habitats and then devise a plan to stop their continued growth. We already know it’s not going to be an easy problem to solve.”

Armitage says invasive species can cause extinction of native species through direct competition, disease or indirect changes to the local ecosystem. Some aquatic species include grass carp, tilapia, armored catfish, Australian jellyfish, pacu and zebra mussels, while invasive plants include Chinese tallow, water hyacinth, tamarix (also called salt cedar), Guinea grass and many others.

Anyone who thinks invasive species are no big deal should consider one word: kudzu.

The vine, native to Japan, has been Godzilla-like in its movements, literally blanketing much of the southern U.S. as it covers trees, shrubs, telephone poles and even buildings. Extremely difficult to control, kudzu has spread at an amazing rate the past 50 years, and it is estimated it advances an additional 150,000 acres every year. It is continuing to expand, and has already invaded east Texas and is moving westward as far west as Austin, Armitage notes.

But even kudzu has its soft side: it has promise as a medicinal drug to treat a variety of ailments, from heart disease to diabetes and even Alzheimer’s.

At TexRAT meetings, experts have estimated about $138 billion was lost to the U.S. economy since 2005 because of invasive species, and that figures rises to more than $1.4 trillion worldwide.

“Invasive plants tend to alter the ecosystem and almost never in a good way,” explains Armitage, an expert in wetlands and marshes. “Galveston Bay has not been impacted too much so far, but if you go just a few miles inland to freshwater creeks and ponds, the problem gets much, much worse.”

She notes that some invasive plants are actually very attractive and were originally introduced for ornamental or landscape purposes. But Armitage says introductions of invasive marine species frequently occur through shipping, when larval or juvenile animals are contained in ballast water from foreign ports is released in domestic harbors.

“Once invasive species get established, it can be very difficult to stop their growth, and some grow at an amazing rate,” she stresses. “Some fish, such as the grass carp, can consume huge amounts of natural plant life, reducing the ability of wetlands to improve water quality and provide nursery habitat for important fishery species.”

Finding ways to control invasive plants is difficult, Armitage says.

“If you use herbicides, they tend to kill the good plants along with the bad ones, so we need to look at other methods,” she adds.

Texas’ severe drought may have an upside, she says, because drier conditions tend to make many marshes and bays even saltier, which helps to control some types of invasive plants that are sensitive to high salinities.

“But we know this is going to be a long, difficult fight,” she adds. “It needs to start at local levels first, getting the public educated and increasing their awareness of the damage invasive species can cause. The Galveston Bay Foundation and the Texas Parks and Wildlife Department have started doing some ad spots about boaters rinsing off their boats when they pull them out of the water so some invasive plants won’t spread as much, and that’s a good start.

“People need to know that invasive plants and animals are huge problems that are not going away any time soon.”

Contact: Anna Armitage at (409) 740-4842 or armitaga@tamug.edu; or Keith Randall, News & Information Services, at (979) 845-4644 or keith-randall@tamu.edu

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