Irrigated agriculture and wildlife conservation: Conflict on a global scale

The demand for water to support irrigated agriculture has led to the demise of wetlands and their associated wildlife for decades. This thirst for wat er is so pervasive that many wetlands considered to be hemispheric reserves for waterbirds have been heavily affected; for example, the California and Nevada wetlands in North America, the Macquarie Marshes in Australia, and the Aral Sea in central Asia. These and other major wetlands have lost most of their historic supplies of water and some have also experienced serious impacts from contaminated subsurface irrigation drainage. Now mere shadows of what they once were in terms of biodiversity and wildlife production, m any of the so-called "wetlands of international importance" are no longer t he key conservation strongholds they were in the past. The conflict between irrigated agriculture and wildlife conservation has reached a critical poi nt on a global scale. Not only has local wildlife suffered, including the e xtinction of highly insular species, but a ripple effect has impacted migra tory birds worldwide. Human societies reliant on wetlands for their livelih oods are also bearing the cost. Ironically, most of the degradation of thes e key wetlands occurred during a period of time when public environmental a wareness and scientific assertion of the need for wildlife conservation was at an all-time high. However, designation of certain wetlands as "reserves for wildlife" by international review boards has not slowed their continue d degradation. To reverse this trend, land and water managers and policy ma kers must assess the true economic costs of wetland loss and, depending on the outcome of the assessment. use the information as a basis for establish ing legally enforceable water rights that protect wetlands from agricultura l development.