Giant Salvinia is Native to Brazil and grows in fresh water like ponds and reservoir. They were introduced to the U.S around the 1990's and are known to be the most noxious aquatic weeds because they take over quiet lakes or ponds. It's known to be an aggressive competitors for the environment in the water. What they do is "Forms dense mats that block sunlight and reduce oxygen levels"-Invasive Species: Aquatic Species. This effects the other fresh water plants due to that fact that this noxious weed produces quickly and a lot, meaning that the plants won't get the needed light and oxygen that is needed because of all of the mats covering the water and other plants, stealing their food and air.
