Enemies of Americas Lakes

On my recent visit to Lake Sheldon I found some notices put up at the observation tower. The notices are meant to warn visitors about the threat these invasive species pose to the natural water bodies of this country and how they should be avoided or mitigated. The invasive species include some plants from India, Japan, and other parts of the world. I was thinking it is time all nations started this system of warning its people about invasive species. In India they need to put up signs about the all pervasive Parthenium plant which is from the United States that is the biggest menace for the entire country's open soil.