| ALEUTIAN/BERING SEA ISLANDS |
| ALTOS DE CHIAPAS |
| APPALACHIAN MOUNTAINS |
| ARCHIPIELAGO DE REVILLAGIGEDO |
| ARCTIC PLAINS AND MOUNTAINS |
| ARRECIFE ALACRANES |
| ATLANTIC NORTHERN FOREST |
| BADLANDS AND PRAIRIES |
| BOREAL HARDWOOD TRANSITION |
| BOREAL SOFTWOOD SHIELD |
| BOREAL TAIGA PLAINS |
| CENTRAL HARDWOODS |
| CENTRAL MIXED GRASS PRAIRIE |
| CHIHUAHUAN DESERT |
| COASTAL CALIFORNIA |
| CUENCA DEL RIO BALSAS |
| DEPRESIONES INTERMONTANAS |
| DESIERTO DE BAJA CALIFORNIA |
| EASTERN TALLGRASS PRAIRIE |
| EDWARDS PLATEAU |
| EJE NEOVOLCANICO TRANSVERSAL |
| GREAT BASIN |
| GREAT LAKES |
| GULF COASTAL PRAIRIE |
| ISLA COZUMEL |
| ISLA GUADALUPE |
| ISLAS DEL GOLFO DE CALIFORNIA |
| ISLAS MARIAS |
| LOS TUXTLAS |
| LOWER GREAT LAKES/ ST. LAWRENCE PLAIN |
| MARISMAS NACIONALES |
| MISSISSIPPI ALLUVIAL VALLEY |
| NEW ENGLAND/MID-ATLANTIC COAST |
| NORTHERN PACIFIC RAINFOREST |
| NORTHERN ROCKIES |
| NORTHWESTERN INTERIOR FOREST |
| NOT RATED |
| OAKS AND PRAIRIES |
| PANTANOS DE CENTLA-LAGUNA DE TERMINOS |
| PENINSULAR FLORIDA |
| PIEDMONT |
| PLANICIE COSTERA DEL SOCONUSCO |
| PLANICIE COSTERA Y LOMERIOS DEL PACIFICO SUR |
| PLANICIE COSTERA Y LOMERIOS HUMEDOS DEL GOLFO DE MEXICO |
| PLANICIE COSTERA Y LOMERIOS SECOS DEL GOLFO DE MEXICO |
| PLANICIE COSTERA, LOMERIOS Y CANONES DE OCCIDENTE |
| PLANICIE DE LA PENINSULA DE YUCATAN |
| PLANICIE NOROCCIDENTAL DE YUCATAN |
| PRAIRIE HARDWOOD TRANSITION |
| PRAIRIE POTHOLES |
| SHORTGRASS PRAIRIE |
| SIERRA MADRE DE CHIAPAS |
| SIERRA MADRE DEL SUR |
| SIERRA MADRE OCCIDENTAL |
| SIERRA MADRE ORIENTAL |
| SIERRA NEVADA |
| SIERRA NORTE DE PUEBLA-OAXACA |
| SIERRAS DE BAJA CALIFORNIA |
| SIERRAS Y PLANICIES DEL CABO |
| SONORAN AND MOJAVE DESERTS |
| SOUTHEASTERN COASTAL PLAIN |
| SOUTHERN ROCKIES/COLORADO PLATEAU |
| SUR DEL ALTIPLANO MEXICANO |
| TAIGA SHIELD AND HUDSON PLAINS |
| TAMAULIPAN BRUSHLANDS |
| VALLE TEHUACAN-CUICATLAN |
| WEST GULF COASTAL PLAIN/OUACHITAS |
| WESTERN ALASKA |
| <all other values> |