Give an example in which adding a new species to an ecosystem increases its biodiversity

Well to give a good example of "ecosystem increases its biodiversity" we must first define

biodiversity

"the variety of life in the world or in a particular habitat or ecosystem."

SO an example would be like bringing a frog from china to a pond in amercia,but this frog is new and there arent any frogs from the speicus

thinking it would be d not too sure but i think it's right