Australian Centre for Biodiversity, School of Biological Sciences, Monash University, Caulfield East, VIC, 3800, Australia.
Environ Manage. 2012 Jul;50(1):1-10. doi: 10.1007/s00267-012-9864-z. Epub 2012 Apr 28.
There have been significant diversions of water from rivers and streams around the world; natural flow regimes have been perturbed by dams, barriers and excessive extractions. Many aspects of the ecological 'health' of riverine systems have declined due to changes in water flows, which has stimulated the development of thinking about the maintenance and restoration of these systems, which we refer to as environmental flow methodologies (EFMs). Most existing EFMs cannot deliver information on the population viability of species because they: (1) use habitat suitability as a proxy for population status; (2) use historical time series (usually of short duration) to forecast future conditions and flow sequences; (3) cannot, or do not, handle extreme flow events associated with climate variability; and (4) assume process stationarity for flow sequences, which means the past sequences are treated as good indicators of the future. These assumptions undermine the capacity of EFMs to properly represent risks associated with different flow management options; assumption (4) is untenable given most climate-change predictions. We discuss these concerns and advocate the use of demographic modelling as a more appropriate tool for linking population dynamics to flow regime change. A 'meta-species' approach to demographic modelling is discussed as a useful step from habitat based models towards modelling strategies grounded in ecological theory when limited data are available on flow-demographic relationships. Data requirements of demographic models will undoubtedly expose gaps in existing knowledge, but, in so doing, will strengthen future efforts to link changes in river flows with their ecological consequences.
世界上许多河流和溪流的水资源都发生了重大转移；水坝、障碍物和过度抽取已经扰乱了自然水流模式。由于水流的变化，河流系统的许多生态“健康”方面都有所下降，这刺激了人们对这些系统的维护和恢复的思考，我们称之为环境水流方法（EFMs）。大多数现有的 EFMs 无法提供有关物种生存能力的信息，因为它们：(1) 将栖息地适宜性用作种群状况的代理；(2) 使用历史时间序列（通常持续时间较短）来预测未来的条件和水流序列；(3) 无法或不处理与气候变化相关的极端水流事件；以及 (4) 假设水流序列的过程平稳性，这意味着过去的序列被视为未来的良好指标。这些假设破坏了 EFMs 适当代表与不同水流管理选项相关的风险的能力；鉴于大多数气候变化预测，假设 (4) 是站不住脚的。我们讨论了这些关注点，并主张使用人口统计模型作为将人口动态与水流模式变化联系起来的更合适工具。讨论了一种“元物种”人口统计建模方法，作为从基于栖息地的模型向基于生态理论的建模策略的有用步骤，当关于水流与人口关系的有限数据可用时。人口统计模型的数据要求无疑会暴露现有知识的差距，但这样做将加强未来将河流流量变化与其生态后果联系起来的努力。
