Giant reed (Arundo donax L.), a woody grass native to the Mediterranean, has become a cause of concern for national water security in its invaded range of the arid southwestern United States, Australia, New Zealand, and South Africa. The main objective of this study was to provide the first, landscape-level estimates of water use by giant reed. The study utilized the eddy covariance method to quantify evapotranspiration (ET) throughout the 2014 and 2015 growing seasons along the Rio Grande River in Eagle Pass, Texas. We monitored ET concurrently with the implementation of a biological control program targeting giant reed. Daily ET rates were strongly associated with the phenology of giant reed, as estimated by degree day accumulation. Monthly ET was higher in each month of the active growing season (May–October) of giant reed in 2014 than in 2015. Consequently, seasonal (DOY 121-304) ET was substantially higher in 2014 (842 mm) than in 2015 (625 mm) even though the 2015 growing season was wetter. Cumulative rainfall from May to October was 188 and 264 mm in 2014 and 2015, respectively. Our study indicated that the reduction in ET could be attributed to the presence of specialist insect biological control agent, the stem-galling arundo wasp (Tetramesa romana). In 2015, we observed a 28.6% (May), 53.5% (June), and 44% (July) increase in the number of arundo wasps captured in sticky traps from the previous year. Additional studies are needed to quantify conservation and economic benefits of the biological control program in the Rio Grande Basin.

大芦苇 ( Arundo donaxL.) 是一种原产于地中海的木本草，在其入侵的美国西南部、澳大利亚、新西兰和南非的干旱地区已成为国家水安全问题的关注点。这项研究的主要目的是提供第一个景观水平的巨型芦苇用水量估计值。该研究利用涡流协方差法来量化德克萨斯州伊格尔帕斯里奥格兰德河沿岸 2014 年和 2015 年生长季节的蒸散量 (ET)。我们在实施针对巨型芦苇的生物控制计划的同时监测 ET。根据度日累积估计，每日 ET 率与大芦苇的物候密切相关。2014 年大芦苇生长旺季（5-10 月）每个月的月 ET 均高于 2015 年。因此，季节性（DOY 121-304）ET 在 2014 年（842 毫米）显着高于 2015 年（625 毫米），尽管 2015 年的生长季节较为潮湿。2014 年和 2015 年 5 月至 10 月的累计降雨量分别为 188 和 264 毫米。我们的研究表明，ET 的减少可归因于特殊昆虫生物控制剂的存在，即咬茎的芦竹黄蜂。罗马四叶草）。2015 年，我们观察到在粘性陷阱中捕获的芦苇黄蜂数量比上一年增加了 28.6%（5 月）、53.5%（6 月）和 44%（7 月）。需要更多的研究来量化里奥格兰德盆地生物控制计划的保护和经济效益。