Sunday, February 26, 2012

Obnoxious Weed - Water Lettuce

People are often surprised to find that I don’t like to swim. Considering I was born and raised in South Florida it shouldn’t be a surprise. When the ocean is warm enough to swim in it, the air is disgustingly hot and humid. In the winter when Florida is full of Canadians the water feels Polar Bear cold (anything below 68 for me). To add to it, just about every fresh water lake, pond or river is occupied by an alligator, which leaves swimming pools. I didn’t have one and the local community pool was full of something far more insidious than alligators, public pool peers.

Aquatic wildlife species have it tough when it comes to waterways choked with Water Lettuce (Pistia stratiotes). The floating plant, which is often found in Bald Cypress swamps, grows vegetatively as well as sexually and can blanket the surface of fresh waterways. It looks like a head of lettuce growing on the water and has the green vibrancy of a week-dead treefrog trapped between my sliding and screen door.

There is debate as to the origin of the plant’s native status in the United States with some saying it was introduced from the ballast of ships coming from Africa or South America. Native or otherwise, it is considered a noxious weed in many U.S. locations where it is found clogging up waterways.

Water Lettuce makes life tough for the Pied-billed Grebe (Podilymbus podiceps), a freshwater diver that seeks crayfish, fish and aquatic insects. Not only does the Water Lettuce block the light and limit visibility for diving birds, it also prevents the growth of other plants, leading to the reduction of nutrients and biological diversity.

For the carnivorous American Alligator (Alligator mississippiensis), there’s no chance in partaking of a salad but I have watched gator pups lounge about on several heads of water lettuce like they were tubing down a slow-flowing river. Sounds like fun, but still no chance of me going in that water. 

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