A mountain lion is generally an apex predator (presuming for the moment that you're leaving humans out of the equation). Depending on its abilities as compared to the local apex predator, it may replace that predator by taking all its prey, it may come to live side-by-side with the indigneous species, or it may not be as well-suited to the existing environment as the local predator, so the introduced predator may live a comparatively short time. Without more information, it's impossible to say.
Loss of a large percentage of the wolf population (also generally an apex predator) would allow its prey to go unchecked. Chances are good that the food source of the prey animal would be rapidly depleted, and the prey species would therefore begin
Loss of a large percentage of the wolf population (also generally an apex predator) would allow its prey to go unchecked. Chances are good that the food source of the prey animal would be rapidly depleted, and the prey species would therefore begin