Includes bibliographical references (p. 441-463).

A conservation assessment of the terrestrial ecoregions of Mexico: a status report ; Habitat loss in North America fuels species extinctions / D.M. Olson -- Do freshwater ecoregion boundaries correlate with terrestrial? / R. Abell -- Defining marine ecoregions of the Pacific Continental United States / R.G. Ford -- Caribou migrations and calving grounds: globally outstanding ecological phenomena / A. Gunn -- Reconnecting grizzly bear populations in fragmented landscapes / S. Primm, E. Underwood -- Multiscale analysis of endemism of vascular plant species / J. Kartesz and A. Farstad -- Ecosystem and species diversity beneath our feet / D. Culver -- Keeping the cows off: conserving riparian areas in the American West / T.L. Fleischner -- Saving migratory songbirds ; The most threatened birds of continental North America / S. Robinson -- Fire exclusion in the eastern ecoregions of the United States and Canada / A. Weakley -- Exotic vascular plant species: where do they occur? / J. Kartesz -- Conservation threats moving northward into Canada / K. Kavanagh, A. Hackman -- Conservation assessments: a synthesis / R.F. Noss -- Globally outstanding biodiversity in our own backyard / E. Dinerstein, D.M. Olson -- Getting ahead of the cutting cycles: what happens when the trees grow back? / G. Orians -- Diverse forest ecoregions of North America: their protected status and importance in forest certification / D. DellaSala -- The conservation potential of military bases and related installations / S. Gatewood, R. Mondt.