Desert riparian ecosystems are among the most threatened biodiversity hotspots in the United States, and efforts to conserve them have been increasing. In 2010–2011 and 2014–2016, we examined shifts in the distribution, habitat characteristics, diet, nest success, and productivity of the gray hawk (Buteo plagiatus), 25 years after a Riparian National Conservation Area was established along the San Pedro River in Arizona, USA, to determine how the removal of grazing and agriculture may have affected the ecosystem. The gray hawk population increased and expanded from mesquite (Prosopis spp.)‐dominated areas that they historically occupied into areas that were dominated by grassland. In contrast with the 1990s, percent of mesquite cover in pairs' territories did not correlate with their productivity. Gray hawk diets also included more mammals in our study period, particularly in territories with more grassland. We propose that conservation measures created habitat for gray hawks in areas that were previously unsuitable by allowing grasslands to regenerate and become habitat for their prey, and that management strategies in the San Pedro Riparian National Conservation Area could serve as a model for conservation of other desert riparian ecosystems. © 2020 The Wildlife Society.

中文翻译：

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河岸保护促进了灰鹰的扩张

沙漠河岸带生态系统是美国受威胁最大的生物多样性热点之一，保护它们的努力正在不断增加。在沿圣佩德罗河建立河岸国家保护区25年之后，我们研究了2010-2011年和2014-2016年灰鹰（Buteo plagiatus）的分布，栖息地特征，饮食，巢成功和生产力的变化。在美国亚利桑那州，以确定放牧和农业的迁移可能如何影响生态系统。灰鹰种群从豆科灌木（Prosopisspp。）占主导地位的区域，这些区域在历史上一直占据以草原为主的区域。与1990年代形成对比的是，成对的领土上的豆科灌木覆盖率与其生产力没有关联。在我们的研究期间，灰鹰饮食还包括更多的哺乳动物，特别是在草原较多的地区。我们建议采取保护措施，在以前不适合的地区为灰鹰提供栖息地，方法是允许草地再生并成为其猎物的栖息地，圣佩德罗河沿岸国家保护区的管理策略可以作为其他沙漠保护的模型河岸生态系统。©2020野生动物协会。