Alternative Futures for Landscapes in the Upper San Pedro River Basin of Arizona and Sonora

The Upper San Pedro River Basin in southeastern Arizona is well known for its avian diversity; however， water use by Sierra Vista， Fort Huachuca， and agriculture in the basin threatens to lower its water table. This， in turn， could alter vegetation in the basin in a way that would negatively impact habitat currently supporting nesting of the endangered Southwestern Willow Flycatcher (Empidonax trailii extimus) and foraging for a large number of resident and neotropical migratory birds during the breeding season and migration. We determined the range of potential Alternative Future growth patterns for the basin (Alternative Futures) and compared them for their relative impacts on a suite of environmental parameters including hydrology， biodiversity， and landscape vegetation pattern. The intent is to inform decision makers of which potential Alternative Future would have the greatest and least impacts on those parameters. This paper has been adapted from Alternative Futures for Changing Landscapes: The Upper San Pedro River Basin in Arizona and Sonora by Steinitz et al.， published by Island Press， 2003 (800-828-1302). (In: Ralph， C. John; Rich， Terrell D.， eds. Bird conservation implementation and integration in the Americas: proceedings of the third International Partners in Flight Conference， March 20-24， 2002， Asilomar， California. Gen. Tech. Rep. PSW-GTR-191. Albany， CA: U.S. Dept. of Agriculture， Forest Service， Pacific Southwest Research Station: p.93-100)

亚利桑那州东南部的上圣佩德罗河盆地以其丰富的鸟类多样性享誉学界；然而，锡拉维斯塔市、华楚卡堡及流域内农业活动的用水需求，正威胁着当地地下水位的下降。这一变化继而可能改变流域内的植被格局，进而对两处关键生境造成负面影响：一是为濒危物种西南柳鹟（Empidonax trailii extimus）提供筑巢栖息的生境，二是为繁殖季与迁徙季的大量居留鸟类及新热带迁徙鸟类提供觅食场所。本研究明确了该流域潜在替代未来发展模式（Alternative Futures）的范围，并对比了各模式对一系列环境参数的相对影响，涵盖水文、生物多样性及景观植被格局。本研究的核心目标是为决策者提供决策参考，以明确何种潜在替代未来模式对上述环境参数的影响最为显著，何种影响相对最小。本文改编自Steinitz等所著、Island Press于2003年出版的《变化中的景观：亚利桑那州与索诺拉州的上圣佩德罗河盆地》（联系电话：800-828-1302）。（收录于：拉尔夫·C·约翰、特里尔·D·里奇 主编. 《美洲鸟类保护的实施与整合：第三届国际飞行伙伴会议论文集》，2002年3月20日至24日，加利福尼亚州阿西洛马。《PSW-GTR-191号通用技术报告》。加利福尼亚州奥尔巴尼：美国农业部森林服务局太平洋西南研究站：第93-100页）