Why Is It Important to use these Alternatives to Release? Every year, the introduction of harmful, non-native species into the U.S. has been increasing. Collectively, these invasive species make tremendous impacts to different things valued by many Americans. Ultimately, the cost of invasive species (terrestrial and aquatic) in the United States amounts to more than $100 billion each year. Go to the Unwanted Fish and Plants section to learn more about each species and their individual impacts. Click on the sections below for details on the negative impacts of harmful invaders.