Globally, Invasive Non Native Species (INNS) pose the second biggest threat to biodiversity. The Tees catchment plays host to a number of problematic INNS that are spreading inexorably through the system. These include the poisonous Giant Hogweed, Himalayan Balsam, Japanese Knotweed and American Signal Crayfish. Work will be carried out to prevent the spread of INNS, which will improve the overall health of the River Tees.