There are several key conditions that typically define a healthy ecosystem.

Lost is the variety that indicates a rich, healthy ecosystem.

A healthy ecosystem is the best chance we got.

By having all three elements, there are healthy ecosystem.

The Center aims to further human understanding of the key role that wolves plays a in a healthy ecosystem.

The hypothesis leads to the conclusion that only a few key species are necessary for a healthy ecosystem.

Stay out of the editorial space and let a healthy ecosystem develop.

This, in turn, helps maintain a healthy ecosystem for both people and wildlife.

But if this is to be a natural place, too, with healthy, self-sustaining ecosystems, then people need to approach it in a whole new way.

Good status means a healthy ecosystem and a low level of pollution.