As nations grow wealthy, their wildlife may pay a price. Ecologist Robin Naidoo and economist Wiktor Adamowicz, both at the University of Alberta in Canada, compared GNP and endangered species lists of 150 countries. The number of threatened species in five out of seven taxonomic groups—plants, amphibians, reptiles, fish, and invertebrates—consistently rose as per capita GNP increased. The findings contradict a widely held theory that economic growth hurts the environment during only early stages of development. Later, ecology should improve as citizens place a greater value on preservation. In reality only birds and sometimes mammals benefit from a healthy economy, perhaps because of what Adamowicz calls the cute-and-fuzzy factor. "We may be focusing on species based on human preferences, when the small and slimy things are the ones that need the effort," he says.