It is one of the most ecologically rich places on Earth. It harbors the highest diversity of mammals in the United States and the second highest in the world. In southern Arizona, the San Pedro River flows north from Mexico across the U.S. border. And with it flows a stunning variety of life. “The San Pedro riparian corridor is such a huge influence on migratory patterns for all kinds of animals but especially birds,” said Randy Serraglio of the Center for Biological Diversity. “For the entire continental United States it’s a very precious place.” But like many desert rivers the San Pedro has lost a good deal of its flow because the ground water pumping in the area has drawn down the water table. Expanding industry and development in nearby Sierra Vista and the Fort Huachuca army installation are the biggest users of water in the region. As more water is pumped from underground, less water makes it to the river itself. As a result the river is shrinking. Along with a diminishing water supply laws designed to protect the river’s many threatened and endangered species, and by extension the San Pedro itself were recently relaxed for the sake of local industry. The Renzi Rider as the legislation was called exempts Fort Huachuca and the surrounding community of Sierra Vista from the requirements of the endangered species act. Activist hope to reverse the exemption but for now, without laws that would ensure adequate water flow, community members are doing what they can to preserve this disappearing natural resource.