What is a major concern regarding invasive species in coastal areas?

The concern regarding invasive species in coastal areas primarily revolves around their ability to outcompete native species for resources. Invasive species often have traits that allow them to thrive in new environments, such as fast growth rates, reproductive advantages, or a lack of natural predators. This competitive advantage can lead to a decline in native species populations, which are often adapted to specific ecological niches.

When invasive species proliferate, they can disrupt existing food webs and nutrient cycles, alter habitats, and reduce biodiversity. In coastal ecosystems, this can have cascading effects not only on local flora and fauna but also on the overall health of the habitat, impacting fisheries, tourism, and other human-related activities.

The other options present misconceptions about the impacts of invasive species. They do not solely affect marine life, as they can also influence terrestrial and freshwater ecosystems. Additionally, invasive species have significant adverse effects on local ecosystems rather than having no impact at all. Moreover, while some might appear beneficial in specific contexts, overall, they tend to skew ecological balance and are not universally beneficial.