Regime shifts in shallow lake ecosystems along an urban -rural gradient in central China
Regime shifts in shallow lake ecosystems along an urban -rural gradient in central China
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中国中部城乡梯度浅湖生态系统的动态变化
DOI：
10.1016/j.scitotenv.2020.139309
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发表时间：
2020-09-01
影响因子：
9.8
通讯作者：
Zeng, Linghan
中科院分区：
文献类型：
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作者：
Cao, Yanmin;Langdon, Peter;Zeng, Linghan
由于不同的开发压力，城市-乡村梯度上的生态系统沿着往往表现出不同的生态结构和功能状态。考虑到开发的相对强度、规模和速度，这对湖泊恢复可能具有挑战性。本文以沿着城乡梯度分布的三个浅水湖泊（沙湖、沿溪湖和浮头湖）为研究对象，通过对近世纪生态变迁的研究，揭示了长江流域近百年来的生态变迁过程。研究结果表明，不同湖泊在演化轨迹、临界过渡时间和生态现状等方面存在差异。富营养摇蚊类群的显着增加，并取代水生植物相关的类群在城市沙湖和郊区的延西湖，从一个稳定的，植被为主的状态转变为替代，藻类为主的状态分别在1963 CE和1975 CE。农村浮头湖的生态状况在1980年前后发生了转变，但由于人为的水文控制，它仍然处于相对清澈的水体状态，有丰富的水生植物。沙湖和燕西湖摇蚊组成变化的最大变化是由人为污染物捕获的，分析表明，当这些压力很高时，它们可能会被气候变暖进一步放大。沿着城乡梯度的响应表现为城市沙湖已经转变为抵抗力和恢复力较弱的脆弱状态，而农村浮头湖已经稳定在一个新的状态，生态恢复力有所改善。郊区燕西湖仍在向一个新的状态发展，因此是不稳定的，因为外部压力的类型和大小正在随着城市的城市化而发生变化。鉴于湖泊不同的发展轨迹、驱动力和现状，建议沿着城乡梯度制定积极而精确的湖泊管理战略。
Due to differential exploitation pressure, ecosystems along the urban to rural gradients often exhibit different status in ecological structure and function. This can be challenging for lake restoration, given the relative strengths, magnitudes and speed of the exploitation. In this paper, we reconstructed the ecological changes over the past century and identified the regime shifts based on subfossil aquatic biota (chironomid records) in three shallow lakes (Shahu, Yanxi and Futou Lake) along an urban-rural gradient in the Yangtze floodplain, China. Our results illustrated the differences among lakes in trajectories, timing of critical transition and current ecological status. Eutrophic chironomid taxa increased markedly and replaced macrophyte-related taxa in urban Shahu Lake and suburban Yanxi Lake, indicated by the shift from a stable, vegetation-dominated state to an alternative, algal-dominated state in 1963 CE and 1975 CE respectively. The ecological regime in rural Futou Lake transited around 1980 CE but it is still in a relatively clear water state with abundant macrophytes due to anthropogenic hydrological controls. The greatest variance of chironomid compositional changes in both Shahu and Yanxi Lake was captured by anthropogenic pollutants, and analyses show that when these pressures are high they may be further amplified by climate warming. Responses along the urban-rural gradient are exemplified by urban Shahu Lake having shifted to a fragile regime with weak resistance and resilience, while rural Futou Lake has stabilized in a new regime with improved ecological resilience. Suburban Yanxi Lake is still moving toward a new state, and as such is unstable, because the types and magnitudes of external stressors are changing with urbanization in the city. It is suggested that active and precise management strategies for lakes should be established along the urban-rural gradient given their distinct development trajectories, drivers and current status.