Why are invasive species considered problematic in ecosystems?

Invasive species are considered problematic in ecosystems primarily because they can outcompete native species for resources such as food, habitat, and nutrients. When an invasive species is introduced to a new environment, it often thrives due to a lack of natural predators or competitors, allowing it to multiply rapidly. This can lead to a decline or extinction of native species, as they struggle to survive against the aggressive and dominant invasive species. Such disruptions can alter food webs and ecosystem dynamics, leading to a loss of biodiversity and changes in ecosystem function.

In contrast, the other options suggest scenarios that are not typical outcomes associated with invasive species. For instance, the idea that invasive species coexist peacefully with native species misrepresents the competitive nature of invasives, while the suggestion that they provide additional resources contradicts the pattern of resource competition. Lastly, the notion that they enhance biodiversity overlooks the fact that invasive species usually reduce it by displacing native organisms.