Institute of Land Water and Society, Charles Sturt University, PO Box 789, Albury, 2640, Australia.
CSIRO Land and Water and the Murray-Darling Freshwater Research Centre, La Trobe University, Wodonga, VIC, 3689, Australia.
Environ Manage. 2018 Mar;61(3):481-496. doi: 10.1007/s00267-017-0861-0. Epub 2017 May 4.
For many floodplain rivers, reinstating wetland connectivity is necessary for ecosystems to recover from decades of regulation. Environmental return flows (the managed delivery of wetland water to an adjacent river) can be used strategically to facilitate natural ecosystem connectivity, enabling the transfer of nutrients, energy, and biota from wetland habitats to the river. Using an informal adaptive management framework, we delivered return flows from a forested wetland complex into a large lowland river in south-eastern Australia. We hypothesized that return flows would (a) increase river nutrient concentrations; (b) reduce wetland nutrient concentrations; (c) increase rates of ecosystem metabolism through the addition of potentially limiting nutrients, causing related increases in the concentration of water column chlorophyll-a; and (d) increase the density and species richness of microinvertebrates in riverine benthic habitats. Our monitoring results demonstrated a small increase in the concentrations of several key nutrients but no evidence for significant ecological responses was found. Although return flows can be delivered from forested floodplain areas without risking hypoxic blackwater events, returning nutrient and carbon-rich water to increase riverine productivity is limited by the achievable scale of return flows. Nevertheless, using return flows to flush carbon from floodplains may be a useful management tool to reduce carbon loads, preparing floodplains for subsequent releases (e.g., mitigating the risk of hypoxic blackwater events). In this example, adaptive management benefited from a semi-formal collaboration between science and management that allowed for prompt decision-making.
对于许多洪泛平原河流而言，恢复湿地连通性对于生态系统从几十年的管理中恢复至关重要。环境回流（有管理地将湿地水输送到相邻河流）可被战略性地用于促进自然生态系统连通性，使营养物质、能量和生物从湿地生境转移到河流。我们使用非正式的适应性管理框架，将回流从一个森林湿地综合体输送到澳大利亚东南部的一条大型低地河流。我们假设回流将：(a) 增加河流营养物浓度；(b) 降低湿地营养物浓度；(c) 通过添加潜在限制营养物来增加生态系统代谢率，从而导致水柱叶绿素-a 浓度的相关增加；(d) 增加河流底栖生境中微型无脊椎动物的密度和物种丰富度。我们的监测结果表明，一些关键营养物的浓度略有增加，但没有发现明显的生态响应证据。尽管可以从森林泛滥平原地区输送回流而不会有缺氧黑水事件的风险，但为了增加河流生产力而返回营养丰富和富含碳的水受到可实现的回流规模的限制。尽管如此，使用回流将碳从泛滥平原中冲洗出来可能是减少碳负荷的有用管理工具，为随后的释放（例如，减轻缺氧黑水事件的风险）做好准备。在这个例子中，适应性管理得益于科学和管理之间的半正式合作，从而可以进行及时的决策。
