What characterizes an invasive species?

An invasive species is characterized as a non-native species that causes environmental harm. These species often thrive in new environments where they have been introduced, and they can outcompete, displace, or even eliminate native species. This can lead to significant disruptions in ecosystem dynamics, as the invasive species may lack natural predators in their new habitat, allowing them to proliferate unchecked.

For instance, invasive plants might dominate a region, altering the soil composition and light availability, which can have cascading effects on the native plant community and the animals that rely on those plants for food and shelter. This contrasts with other options that describe species enhancing biodiversity or improving habitat quality, which are typically associated with native species that have co-evolved with their environment and play a role in maintaining ecosystem balance. Similarly, species that have become rare in their habitat do not fit the definition of invasive, as they are not non-native and are not causing harm to the ecosystem.