Invasive species can cause widespread ecological havoc and economic harm.

Unfortunately, several types of aquatic and riparian invasive species are in the Clark Fork watershed. Currently, Eurasian milfoil, curlyleaf pondweed, saltceder, purple loosestrife, flowering rush, and yellowflag iris are the most prevalent invaders in the basin. New Zealand mud snails and smallmouth bass have now also been found in the watershed. Although invasive mussels have not yet moved in, once they are established, they’re nearly impossible to eradicate. Preventing their spread is the best way to protect the Clark Fork watershed.