World fertility surveys indicate that anywhere from one third to one half of the babies born in the Third World would not be if their mothers had access to cheap, reliable family planning, had enough personal empowerment to stand up to their husbands and relatives, and could choose their own family size.
Biodiversity can't be maintained by protecting a few species in a zoo, or by preserving greenbelts or national parks. To function properly, nature needs more room than that. It can maintain itself, however, without human expense, without zookeepers, park rangers, foresters or gene banks. All it needs is to be left alone.