„Cuatro Cienegas Natural Protected Area, Chihuahuan Desert, Mexico.“

INTRODUCTION: IN THE MIDDLE OF THE CHIHUAHUAN DESERT LIES AN UNUSUAL WETLAND C ALLED CUATRO CIENEGAS ("FOUR MARSHES") RECENTLY SET ASIDE BY MEXICO AS A BIOLOG ICAL RESERVE. DERIVING ITS MOISTURE FROM DEEP AQUIFERS, THE LAGUNAS (LAKES) AN D POZAS (POOLS) OF THIS 500-SQUARE-MILE REGION HAVE BEEN ISOLATED FROM ANY OTHER WATER SYSTEM FOR MILLIONS OF YEARS. WATER TEMPERATURES RANGE FROM 68 DEGREES AND COL DER TO BETWEEN 91 AND 93 DEGREES. HERE A RICH POPULATION OF PLANTS AND ANIMALS HAS DEVELOPED, SOME ENDEMIC, SOME UNIQUE TO THE REGION. NATURALIST/PHOTOGRAPHER GE ORGE GRALL HAS ILLUSTRATED THE VARIOUS STRATA THAT COMPRISE THIS ECOSYSTEM. -- LEGEND: Long-stemmed water lilies (Nymphaea ampla) reach for the hot Mexican s un while schools of pupfish, tetras, and cichlids feed in their shade. Because the wate r comes from deep underground, no sediments mar visibility, which is limited on ly by distance and light. Copyright: National Geographic / George Grall