DESERT DENIZEN: A coyote patrols his territory in Cabeza Prieta. Human pressure is threatening to eliminate the areas wildlife. (Mark Boster / LAT)
DEBRIS: Water bottles left by migrants litter the desert in southern Arizona. Thirsty border-crossers are draining many scarce natural water sources and have damaged or destroyed tanks placed by biologists for bighorn sheep and pronghorn. (Mark Boster / LAT)
JUNKED: Roger DiRosa, who manages Cabeza Prieta National Wildlife Refuge, walks past a vehicle believed abandoned by smugglers. DiRosa says Cabeza Prieta is the most embattled refuge in the U.S. (Mark Boster / LAT)