§ THE MAIN NEOTROPICAL FLYWAY IN THE WEST - TEN TIMES THAT OF ANY OTHER WESTERN CORRIDOR. § CRUCIAL POLLINATOR CORRIDOR FOR THE WESTERN HEMISPHERE. § THE LONGEST CONTINUOUS ARCHEAOLOGICAL RECORD IN THE CONTINENTAL U.S. § CONCLUSION: THE SAN PEDRO RIVER BASIN IS A “KEYSTONE” TRANSITION ZONE THAT SUSTAINS BIODIVERSITY IN OTHER ECO- REGIONS.