Clearly different habitats can support different numbers of wildlife species. We need only compare an asphalt-paved parking lot with an open meadow to appreciate this. Most of us have come to appreciate the need for conserving greenspace and I salute those local politicians who address this cause.
Some people accept a scenario of irreversible future decline.
Thankfully, others are more optimistic and are addressing these problems. A wonderful new book rehearses this solution in some detail. Seven of the regions are in Asia and the East Indies, five each in Africa and South America, three in Australia and New Zealand, one in the Mediterranean, one in Central America and one encompasses all of Polynesia. Only two regions overlap with the United States. They are also lands stressed by terrific pressures.