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.
Donella Meadows
Social services, not wealth per se, seem to be the key to lower birth rates. The Chinese, although among the poorest peoples of the world, have brought their fertility rate down to 2.4, partly by social coercion, but mostly by broadly available education, health care and family planning.
Donella Meadows