Final answer:
The red fox as an invader is detrimental to the invaded ecosystems, leading to declined native species, reduced biodiversity, and decreased ecosystem stability.
Step-by-step explanation:
The impacts of the red fox as an invader are primarily negative to the ecosystem it invades. These impacts can include a decline in native species due to increased predation and competition for resources. Introducing invasive species like the red fox often results in decreased biodiversity and ecosystem stability, contrary to enhancement in habitat quality.
In instances where an invasive species also changes the physical structure of the habitat, the ecosystem can be significantly and permanently modified. For example, invasive species can convert forested areas to meadows or prairies to monospecific forests, which can dramatically alter the original ecosystem functions and species compositions.