Using a rigorous ecoregion-based approach, rather than the more common state-by-state analysis, a team of scientists from World Wildlife Fund has produced a unique and comprehensive assessment of the current status of biodiversity in North America north of Mexico. This book presents the rationale for the ecoregion approach, describes the biological distinctiveness of each North American ecoregion in detail, assesses the level of threats facing each, presents a conservation agenda for the next decade, and sets the recommendations for preserving and restoring biodiversity. In addition, a series of full-color maps present essential information about the ecoregions and the biodiversity they contain.