The correct statements are:
- They often compete with the native species for resources.
- They have the ability to displace the native species.
The invasive species are a hot topic, and that is mainly due to their impact on the native species. Though not always the case, the invasive species mostly manage to out compete the native species for resources, reproduce quicker, take over their habitat, and contribute to their decline. This is not always the case, as some invasive species don't manage to adapt to the new environment, but that also depends on the native competition as well.
A perfect example is Australia, where multiple animals have been introduced, thus became invasive species, with the rabbits and the cats being the most harmful ones. The rabbits reproduce very quickly, are opportunistic in their diets, and easily out compete the native species for food, thus displacing them and moving them away from the prime food sources. The cats, on the other hand, are predators against whom the native species don't have defense mechanisms, thus the cats contribute to the extermination of the native fauna.
