Final answer:
Invasive species like the Nile perch in Lake Victoria and the North American crayfish in Europe can devastate ecosystems by outcompeting native species and spreading diseases. Changes to ecosystems have also been observed with the introduction of beavers in Tierra del Fuego and paperbark trees in the Everglades. The round goby demonstrates that invasive species can have complex interactions with the environment, including both harmful and beneficial impacts.
Step-by-step explanation:
An invasive species can indeed have a negative impact on the environment. Two examples that demonstrate this are the introduction of the Nile perch to Lake Victoria and the importation of North American crayfish to Europe. The Nile perch — after being introduced in 1954 — significantly disrupted local ecosystems by out-competing and preying on native species, leading to biodiversity loss. Similarly, diseases carried by the imported North American crayfish have decimated native European crayfish populations. These cases illustrate that invasive species can lead to drastic ecological damage by altering food webs, out-competing native species, and introducing diseases.
Moreover, the introduction of beavers in Tierra del Fuego transformed forests into meadows, while Australian paperbark trees in the Florida Everglades did the opposite, showcasing how invasive species can modify entire ecosystems. The round goby in the North American Great Lakes exemplifies how an invasive species can have multiple effects, both negative and occasionally positive, as it preys on harmful mussels yet competes with and preys on native species.