Final answer:
Invasive species greatly impact ecosystems by modifying habitats and causing harm to native species. They can have multiple effects and vary in their impacts depending on the context. The threat they pose includes biodiversity loss and economic consequences.
Step-by-step explanation:
Invasive species have significant impacts on ecological communities. One major effect is the modification of entire ecosystems, such as altering the physical structure of habitats and converting forests to different vegetation types. For example, the introduction of North American beavers in Tierra del Fuego has led to the transformation of forests into meadows, while Australian paperbark trees in the Florida Everglades have converted prairies to paperbark forests.
Invasive species can also have multiple effects on native species, harming some and benefiting others. A well-known example is the round goby in the Great Lakes, which feeds on native invertebrates and competes with other fish species but also preys on zebra and quagga mussels.
The impacts of invasive species can vary depending on the context, and the same species may have different effects in different regions. Overall, invasive species pose a threat to biodiversity, ecosystem functioning, and can have economic consequences as agricultural pests or weeds.