11 December 2009

Invasive Plant Harming Texas Lake

In the image, that is green mat of vegetation on top of the lake. >>>

Houston Chronicle: NO ROOM TO GROW
Going green isn't always for the best at Caddo Lake
Caddo is a mystical wonderland. The shallow half-lake/half-swamp on the Texas/Louisiana border, created by natural forces at least 200 years ago, is unlike anything most folks imagine exists in this state.

“It certainly is unique in Texas,” Tim Bister, district supervisor of Texas Parks and Wildlife Department's inland fisheries division, said of the 25,000-acre waterway.

“It's one of those places that is so different that it makes an impression on everyone who sees it.”

Disturbingly, Caddo Lake also is one of the most threatened ecosystems in the state. The lake, the life in it and the one-of-a-kind culture it has spawned faces being smothered by a blanket of invasive aquatic plants.

Because of its shallow depth (most of the lake is less than 10 feet deep), high nutrient content of its water, stable water level and swampy character, Caddo is the perfect place for invasive aquatic vegetation to thrive. And it has, beyond anyone's wildest nightmares.

Giant salvinia, a floating plant that grows and multiplies so quickly it can double the area it covers in as little as a week and creates mats so thick that it blocks the sun from the water, can kill a body of water. Beneficial aquatic vegetation is smothered. Dissolved oxygen levels under the salvinia mats fall too low to support fish or other aquatic life. Water under solid mats of giant salvinia are, quite literally, a dead sea.

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