Abstract Water resource development on rivers significantly affects life cycles of species reliant on wetlands. However, assessing ecological impacts is often difficult because they are realised over long-time periods and large spatial scales, particularly on highly variable dryland rivers. Thirty percent of all Ramsar wetlands are in drylands. We examined the effects of diversions of water upstream on colonial waterbird breeding at the Narran Lakes, supplied by a highly variable dryland river. Narran Lakes is an important Ramsar-listed wetland in Australia for its provision of habitat for wetland fauna during key life history stages, including colonially breeding waterbirds. We use historical ibis breeding data over five decades (1970–2016) to determine the flow requirements for colonial waterbird breeding and modelled the impacts of water resource management options (current and restoration) on breeding. We identified thresholds (>154,000 ML in 90 days with a secondary threshold of >20,000 ML in the first 10 days) of river flow volume necessary to stimulate breeding. Water resource development reduced the frequency of large flows resulting in ibis breeding by 170%, from 1 in 4.2 years to 1 in 11.4 years. Restoration efforts by government to recover water for the environment was predicted to improve colonial waterbird breeding frequency associated with large flow events to 1 in 6.71 years, representing a 59% reduction from pre-development periods. Our framework has global application as a method for identifying long-term impacts of water resource development on key Ramsar wetland areas. This is important, as few mechanisms exist for assessing impacts and identifying restoration options on the listed criteria for many Ramsar wetlands.

中文翻译：

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殖民地水鸟繁殖的减少凸显了拉姆萨尔湿地功能的丧失

摘要 河流水资源开发显着影响依赖湿地的物种的生命周期。然而，评估生态影响通常很困难，因为它们是在长期和大空间尺度上实现的，特别是在高度可变的旱地河流上。30% 的拉姆萨尔湿地位于旱地。我们研究了上游改水对纳兰湖（Narran Lakes）水鸟繁殖的影响，该湖由一条高度可变的旱地河流提供。纳兰湖是澳大利亚重要的拉姆萨尔湿地，为湿地动物在关键的生命历史阶段提供栖息地，包括殖民繁殖的水鸟。我们使用 50 年（1970-2016 年）的历史宜必思繁殖数据来确定群落水鸟繁殖的流量要求，并模拟水资源管理选项（当前和恢复）对繁殖的影响。我们确定了刺激繁殖所需的河流流量阈值（90 天内 >154,000 ML，前 10 天的次要阈值 >20,000 ML）。水资源开发将导致朱鹭繁殖的大流量频率减少了 170%，从 4.2 年一例减少到 11.4 年一例。政府为恢复环境用水而进行的恢复工作预计会将与大流量事件相关的群落水鸟繁殖频率提高到 6.71 年中的 1 次，比开发前时期减少 59%。我们的框架作为一种确定水资源开发对主要拉姆萨尔湿地地区的长期影响的方法在全球范围内得到应用。这很重要，因为很少有机制可以根据列出的许多拉姆萨尔湿地标准来评估影响和确定恢复方案。