Human intervention through damming, diversion and extraction of water resources has created regulated dryland river systems. As a result, connectivity between river channels and floodplain wetlands has diminished. Wetland function is fundamentally linked to water availability: flooding exchanges water, nutrients, sediments and biota with the floodplain. Water allocation for environmental flows may mitigate wetland degradation following river regulation by improving hydrological connectivity between rivers and floodplain wetlands. We report the results (2014–15 to 2018–19) of a vegetation monitoring program in the Macquarie Marshes in north western New South Wales. As part of the long-term program, we monitored semi-permanent wetland (Water Couch (Paspalum distichum) grassland or sedgeland dominated) and River Red Gum (Eucalyptus camaldulensis) forest/woodland communities along with environmental and water resource availability predictors. During the five-year period, we found linear and nonlinear responses of functional group abundance and species richness to the water year and to time since last inundation. We also found differences in species assemblages in response to the flow and flooding regime, particularly water year and inundation duration. These results indicated that wetlands continued to express dry and wet phase responses. We also observed a depressed response to the large 2016–17 flood event by a subset of semi-permanent wetland sites that had not been inundated in 3 years, compared with sites that were more recently inundated. This result indicated that environmental water management, along with protection of natural inundation events, may improve the resilience of floodplain wetlands: increased hydrological connectivity may promote a stronger wetland response when floods occur. Our results indicate that inundation, in part comprised of managed environmental flows, is a primary driver of species assemblage and functional group representation in semi-arid floodplain wetlands.

中文翻译：

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监测生命体征：澳大利亚新南威尔士州麦格理沼泽湿地植被对水文资源的反应

通过筑坝、分流和开采水资源的人为干预创造了受监管的旱地河流系统。结果，河道和洪泛区湿地之间的连通性减弱了。湿地功能从根本上与水的可用性相关：洪水与洪泛区交换水、养分、沉积物和生物群。通过改善河流和洪泛区湿地之间的水文连通性，环境流量的水分配可以减轻河流调节后的湿地退化。我们报告了新南威尔士州西北部麦格理沼泽植被监测计划的结果（2014-15 至 2018-19）。作为长期计划的一部分，我们监测了半永久性湿地 (Water Couch ( Paspalum distichum )) 草原或莎草地为主) 和河红胶 ( Eucalyptus camaldulensis )) 森林/林地社区以及环境和水资源可用性预测因子。在五年期间，我们发现功能组丰度和物种丰富度对水年和自上次洪水泛滥以来的时间的线性和非线性响应。我们还发现物种组合对流量和洪水状况的反应存在差异，特别是水年和洪水持续时间。这些结果表明，湿地继续表现出干湿相响应。我们还观察到，与最近被淹没的站点相比，3 年内没有被淹没的半永久性湿地站点子集对 2016-17 年的大型洪水事件的反应低迷。这一结果表明，环境水管理以及对自然淹没事件的保护，可能会提高洪泛区湿地的恢复力：增加水文连通性可能会在洪水发生时促进更强的湿地响应。我们的研究结果表明，洪水（部分由受管理的环境流量组成）是半干旱洪泛区湿地物种组合和功能组代表的主要驱动因素。