There are approximately 643 species of mammals in temperate North America, and according to one USGS report (Mac et al. 1998), the American Southwest region probably has the greatest diversity of mammal species in the country. Most of these species suffer from a scarcity of information. Many of the mammals in the southwest, such as shrews, pocket gophers, and pikas, are vulnerable to local extinction because populations may be restricted to a single mountain top or other island of habitat. There is increasing concern for several species of mammals adapted to arid habitats. Many species, such as jaguars and black bears, move seasonally or migrate across political boundaries where they are subject to different management policies and land use practices. Effective wildlife management requires strong partnerships with state, federal, and international agencies.