What role do non-native species like the European starling play in local ecosystems?

Non-native species, such as the European starling, can significantly impact local ecosystems by outcompeting native species for resources. This competitive advantage can lead to declines in native populations as the non-native species often adapt more quickly to changes in their environment or utilize resources in ways that native species cannot. The presence of non-native species can disrupt the balance of local ecosystems, altering food webs, and reducing biodiversity.

In contrast, the remaining options do not accurately reflect the role of non-native species. Non-native species typically do not enhance biodiversity; rather, they often lead to a decrease in native diversity as they push native species out of their habitats. While they may provide certain ecological benefits, these are generally outweighed by the negative effects they can have on native populations and ecosystems. Lastly, to suggest they only affect human populations ignores their broader ecological impact, which includes significant consequences for wildlife and habitats.