Battle against salvinia in Bringle Lake begins soon
TEXARKANA, Texas — The Texas Parks and Wildlife Department will start spraying the giant salvinia in Bringle Lake with herbicide this week, the first step in a battle to prevent the invasive plant species from causing biological catastrophe.
Calling the free-floating fern “one of the major threats to aquatic ecosystems in Texas,” TPWD announced last week that giant salvinia had been found in Bringle Lake, the centerpiece among group of parks and trails in the northern part of the city. Control efforts will begin as soon as weather permits this week, probably Wednesday, said John Findeisen, leader of TPWD’s Aquatic Habitat Enhancement Team.
Under ideal conditions, giant salvinia can double in size in less than a week. It forms thick mats of foliage on the surfaces of bodies of water, preventing light and oxygen from reaching any animals or other plant life beneath.
“It creates an aquatic desert,” Findeisen said. “Nothing else can live there.”
Left unchecked, giant salvinia also prevents water recreation — making fishing, boating and swimming impossible.
Because Bringle Lake’s giant salvinia infestation has spread throughout much of the lake and is mixed with other aquatic plant species, its complete eradication “is likely impossible,” though gaining control of it this summer is an attainable goal, Findeisen said.
This week TPWD will use an airboat equipped with a 100-gallon tank of herbicide to spray an acre of giant salvinia mats on Bringle Lake. Experts will spray the poison on giant salvinia foliage as precisely as possible to prevent contamination of the lake. It will be a challenge.
“Controlling giant salvinia when mixed with other aquatic plants can be complicated, especially when those other species comprise the majority of the aquatic habitat. In order to protect non-target, aquatic plants, we will have to limit herbicide use in these areas and rely on other management techniques such as physical removal,” TPWD officials said earlier.
Another control method is to introduce a species of weevil from South America, where giant salvinia also originated, that eats only the plant. But because weevils are unlikely to survive winter weather in this part of Texas, their use here is not an option. Cold temperatures also provide an advantage in the battle, however, as winter freezes can kill much of the giant salvinia invading a body of water.
TPWD urges anglers and other boaters to thoroughly clean, drain and dry their boats and other equipment after use to prevent spreading giant salvinia — and other invasive species such as zebra mussels — from one body of water to another. Hunters, too, should follow clean, drain and dry protocols, as invasive species can be spread through gear such as duck decoys, Findeisen said.
Transporting prohibited invasive species in Texas is illegal and punishable with a fine of up to $500 per violation. Boaters are also required to drain all water from their boat and onboard receptacles, including bait buckets, before leaving or approaching a body of fresh water.
(For more information on how to properly clean, drain and dry boats and equipment, visit the TPWD YouTube channel for a short instructional video. To learn more about common and giant salvinia along with other invasive species in Texas, visit tpwd.texas.gov/landwater/stop-invasives/. The department recommends that Texans who have frequent contact with bodies of water should learn to identify invasive species, and if they spot any they should report the sighting to TPWD at 409-6989121, Ext. 235, or by emailing photos and location information to aquaticinvasives@tpwd.texas.gov.)