This is a great article
that covers in-depth the importance of top predators, like wolves, to biodiversity in ecosystems. Where wolves are found you will also find an ecosystem that is healthy and strong and teaming with biodiversity - and make no mistake about it, in the greater Yellowstone area the wolves are the reason for this re-emergence of this native species biodiversity. It's all connected. Ecosystems need balance and when they don't have top predators, as the article points out, the whole ecosystem and balance shifts. It has been documented over and over again from the sea otters in California and their relationship to sea urchins and the underwater kelp forests to the deer of the east coast that have eaten the native plants and biodiversity out of the Appalachians, if you are missing a key piece of these puzzles you will change and weaken the entire ecosystem.