Agricultural Intensification: Will Land Spared from Farming be Land Spared for Nature?

globally. If there is some decrement in per-hectare agri- cultural yield from wildlife-friendly compared with inten- sive agriculture and if the relationship between land-use intensity and measures of diversity is concave (upward) for a substantial number of species (both reasonable as- sumptions), then more bird diversity (in their analyses) could be sustained by partitioning land between inten- sive agriculture and reserves than by practicing wildlife- friendly farming. They demonstrate that with sustained rapid growth in per-hectare yields (something that is not assured), most of the increased food demand in de- veloping regions can be met from the current area of agricultural land, although some new land will be re- quired. (Given similar assumptions—and reasonable lev- els of trade—developed countries may require a little less agricultural land than at present.) They conclude that con- servationists should pay as much attention to increasing per-hectare yields of food crops as we do to human pop- ulation growth and rates of consumption.