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首页> 外文期刊>Marine ecology progress series >Modelling ecological change over half a century in a subtropical estuary: impacts of climate change, land-use, urbanization and freshwater extraction
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Modelling ecological change over half a century in a subtropical estuary: impacts of climate change, land-use, urbanization and freshwater extraction

机译：在一个亚热带河口中模拟半个多世纪以来的生态变化：气候变化，土地利用，城市化和淡水提取的影响

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The Clarence River Estuary is the largest estuary in southeast Australia, with an extensive floodplain encompassing multiple river channels and a large coastal lagoon. It is the focus of major commercial and recreational fisheries and there is pressure to divert its freshwater inputs for agricultural and domestic uses. We used a spatial biogeochemical model to simulate the variability and evolution of this system on timescales from days to decades over the past half century. Like most tropical and subtropical estuaries, the Clarence River Estuary is strongly influenced by river discharge, sediment and nutrient loads. Given the high nutrient loads arriving from the upper catchment, plankton biomasses in the model were typically limited by flushing through the estuary channels. However, the longer residence times of the lagoons produced a profoundly different regime where higher zooplankton concentrations were supported by recycling of nutrients and detritus. Using alternative model scenarios, it was found that the ecology of the lagoon was sensitive to changes in land-use and urbanization within the local sub-catchment, but was largely insensitive to changes in upstream river discharge (i.e. rainfall or freshwater extraction). The opposite was true in the estuary channels, where changes in land-use or urbanisation in the populated lower catchment had little effect on the estuarine ecology, while even modest reductions in river discharges dramatically increased the biomass of the smaller phytoplankton and zooplankton groups, and favoured benthic algae over seagrass and macroalgae. The contrasting responses of these 2 estuarine environments suggests the need for distinct management approaches, with stringent controls on nutrient loads into coastal lagoons and protection of environmental flows into estuary channels.
机译：克拉伦斯河河口是澳大利亚东南部最大的河口，泛滥的平原包括多条河道和一个大型沿海泻湖。它是主要商业和休闲渔业的重点，并且存在将其淡水输入用于农业和家庭用途的压力。我们使用空间生物地球化学模型来模拟该系统在过去半个世纪中从几天到几十年的时间变化和演化。像大多数热带和亚热带河口一样，克拉伦斯河河口受到河流流量，沉积物和养分含量的强烈影响。鉴于来自上游流域的高养分负荷，该模型中的浮游生物量通常受到冲刷河口通道的限制。但是，泻湖的停留时间更长，产生了截然不同的环境，其中养分和碎屑的循环支持了较高的浮游动物浓度。使用替代模型方案，发现泻湖的生态对当地子汇水区的土地利用和城市化变化敏感，但对上游河流流量的变化（即降雨或淡水提取）不敏感。在河口河道中，情况恰恰相反。在河口河道，人口稠密的下游流域的土地利用或城市化变化对河口生态几乎没有影响，而即使河水流量的适度减少也显着增加了较小的浮游植物和浮游动物群的生物量，并且底栖藻类比海藻和大型藻类更受青睐。这两种河口环境的响应截然不同，这表明需要采取不同的管理方法，同时要严格控制沿海泻湖中的养分含量并保护流入河口通道的环境。

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