共查询到18条相似文献,搜索用时 140 毫秒
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崇明东滩湿地位于长江入海口,是一处快速演替的潮滩湿地,动植物资源丰富、植被自然演替明显,是290多种鸟的重要栖息地,达到全球种群数量1%的鸟类有12种。东滩湿地互花米草的快速扩张、水上捕捞作业的影响、人工养殖鱼塘的大量萎缩使得鸟类栖息地不断丧失。崇明东滩湿地的保育从不同鸟类对栖息地的需求着手,通过对自然生境中互花米草的控制、植被分布的调整、水位的调控、土著作物和底栖动物的培育,增加生物种类和数量,使互花米草得到有效控制、生态环境更趋健康、人与自然更加和谐、鸟类有效栖息地显著增加、湿地景观异质可视、保护区管理更趋便利,实现了湿地在自然资源、环境教育、观光观鸟、生态保护宣传、科学考察和研究等方面的可持续利用。 相似文献
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亚太直达(APG)国际海底光缆(崇明S3段)施工将对海底泥沙产生扰动,扰动泥沙可能对崇明东滩鸟类保护区和长江口中华鲟自然保护区产生影响。采用MIKE软件建立长江口及杭州湾大范围二维潮流模型和近海段工程典型施工段的三维嵌套水动力和悬浮物扩散数学模型,重点研究了工程施工产生的悬浮物对崇明东滩鸟类自然保护区和长江口中华鲟自然保护区的水环境影响。研究结果表明:工程施工将对东滩鸟类国家级自然保护区核心区、缓冲区以及试验区造成不同程度的影响,不会对中华鲟自然保护区核心区造成影响,但对其保护区缓冲区和试验区有所影响。建议严格按照保护区管理部门的相关要求进行施工,避开鸟类迁徙高峰期、中华鲟洄游高峰期和幼鱼集中活动期,合理安排施工保护等措施。 相似文献
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海岸盐沼泥沙过程现场实验研究 总被引:20,自引:0,他引:20
在长江口南汇东滩进行了现场水文泥沙观测取样.以探讨海岸盐沼植物的存在对潮间带细顸粒泥沙运动的影响。分别对光滩、海三棱燕草和互花米草亚环境近底层流速、瞬时水位和悬沙浓度进行了测定。结果表明:盐沼及相邻光滩近底流速通常小于50cm/s;盐沼内。植被的摩擦使近底流速减少16%~71%;波浪传入盐沼后能量迅速降低;盐摺中悬抄浓度较相邻光滩低。 相似文献
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鄱阳湖湿地植物群落沿高程梯度变化特征研究 总被引:1,自引:0,他引:1
鄱阳湖湿地植物群落地理分布特征的研究对鄱阳湖的生态保护具有重要意义。基于野外植物群落的样方调查,结合数字高程模型,分析了鄱阳湖湿地植物在不同高程范围内的分布格局和变化特征。结果表明:鄱阳湖湿地植物以禾本科、莎草科、蓼科和菊科等植物最为常见,地上生物量随高程呈上升趋势;物种丰富度与高程呈非线性正相关关系,Shannon指数、Simpson指数在高程上均呈下降-上升-下降趋势;12.5~13.5 m高程范围内,生境差异较小,Jaccard指数较大,在12~12.5 m和14.5~15 m高程范围内,生境差异较大,属于湿生植物到中生、旱生(或沙生)植物的过渡地带,15 m高程以上植物生长环境趋于稳定。 相似文献
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对长江口南汇东滩工程促淤区的动态淤积特性进行系统分析,结果表明:工程促淤可将原不同地形地貌的滩涂调整为总体近岸高,离岸低,有一定坡度的连续性滩面。在充分促淤的条件下,工程区平均高潮位和纳潮口底高程可近似作为促淤后地形高程分布的范围指标。促淤区的空间分布表现为水深较深处比水深浅处的淤积强度大,水深越深,淤积量越多。各观测点的淤积强度随时间的延长呈递减趋势,一般经过2~3年的工程促淤,淤积厚度不再随促淤历时而有大幅度的增长。南汇东滩0 m等深线以上的促淤工程,在前2~3年的年均淤积强度约为0.2~0.3 m/a;-2 m等深线以上促淤工程,在前2~3的年均淤积强度约为0.5 m/a;-3~-4 m等深线以上促淤工程,前2~3年的年均淤积强度约为1.0 m/a。 相似文献
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《水科学与水工程》2020,13(1):24-33
The exotic species Spartina alterniflora(S.alterniflora) seriously threatens the stability and functioning of saltmarsh ecosystems in the Yangtze Estuary.Ambitious efforts have been undertaken to control this species,but subsequent re-invasion is frequent,presenting a significant barrier to restoration.The complexity and high cost of integrated physical control programs has necessitated a shift in focus,leading to considerable attention being paid to the potential of herbicides to control S.alterniflora.To find a strategy for emergency control of small and scattered patches of re-invading S.alterniflora,an in situ field experiment using Gallant(Haloxyfop-R-methyl) herbicide was conducted.The growth parameters of plant density and height were used to evaluate the control efficiency of different treatment dosages and times and sediment samples were taken for environmental toxicity analysis.The results show the following:(1) the control efficacy of the maximum proposed application dose(2.70 g/m2) was 92% for continuous swards and 100% for small patches,while those of other dosages(0.45 g/m2,0.90 g/m2,and 1.35 g/m2) were lower than 40%;(2) the appropriate implementation time was July to August with 100% mortality resulting from a single application,while S.alterniflora was shown to be capable of recovering rapidly after treatment in May;and(3) there were no significant differences in the community structure of meiofauna among the herbicide treatments and the control,and no herbicide residues were detected in sediment samples collected from treatment areas.This chemical control method was implemented in the Shanghai Chongming Dongtan National Bird Nature Reserve(CDNR).The results of this study indicate that Gallant is an environmentally friendly herbicide with high efficiency,which can be adopted for emergency control of re-invading S.alterniflora. 相似文献
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长江口湿地生态环境保护研究 总被引:3,自引:0,他引:3
湿地是地球上有着多种功能的、富有生物多样性的生态系统,是人类最重要的生存环境之一。长江口是中国第1大河流入海口,滩涂辽阔,食源丰富,拥有丰富的湿地资源,是长江流域生物多样性最丰富、生产力最高和最具生态价值的自然景观类型之一。长江口不仅是多种生物周年性溯河和降河洄游的必经通道,也是亚太候鸟迁徙的主要驿站。近几年出现了将大量滩涂湿地转为城市建设用地的现象,不利于长江口湿地生态系统的保护,如何有序开发长江口滩涂资源,合理保护长江口湿地,对于维持长江口地区生态环境和经济的协调发展有着重大的意义。通过对长江口水环境、水生态、湿地生态环境的演变进行分析,从维护长江口湿地生态平衡、保护湿地功能和湿地生物多样性、实现湿地资源的永续利用的角度出发,提出长江口湿地生态环境保护的建议。 相似文献
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崇明东滩水文泥沙过程分析 总被引:3,自引:0,他引:3
基于2005年9月在崇明东滩采集的现场观测数据,分析了水流和泥沙在潮滩上从光滩到植被区域的不同输运过程。研究结果表明,从光滩到植被带,涨潮和落潮流速逐渐变小,大潮时最大流速由113 cm/s(光滩)减小到8.1 cm/s(植被带);从光滩外侧(靠海)到内侧(靠岸),含沙量逐渐增加,至植被带再减小。潮周期内,流速和水体含沙量变化过程均呈现双峰,峰值出现在涨潮初期和落潮中期,最大含沙量高达7.7kg/m3。测点各潮周期内流速最大值、平均含沙量均与潮汐强弱显著相关。流速增大引起泥沙再悬浮,瞬时含沙量响应流速变化。表层沉积物由光滩外侧(靠海)到内侧逐渐变细,得出泥沙由光滩外侧区域再悬浮,经潮流输移至潮滩内部的泥沙输运模式。分析光滩和植被水沙数据差异表明,植被具有较强的缓流滞沙作用。 相似文献
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《水科学与水工程》2020,13(1):34-44
A saltmarsh has developed rapidly on the mudflat of Andong Shoal,in southern Hangzhou Bay,over the last decade since embankment.The saltmarsh vegetation changes are driven by both sediment dynamic conditions and the competition between the exotic species Spartina alterniflora(S.alterniflora) and the native species Scirpus mariqueter(S.mariqueter).This study attempted to investigate large-scale spatial variations in the exotic and native species,by analyzing and interpreting a time series(2016-2018) of high-resolution(less than 1 m) remote sensing images.The total area of the saltmarsh increased at a rate of 1.07 km~2/year,due to the accretion of the whole tidal flat.The spatial patterns revealed a new bimodal pattern for S.alterniflora invasion.S.alterniflora expanded over the upper to middle saltmarsh at a rate of1.68 km2/year.However,the S.alterniflora patches at the seaward edge expanded at a negative rate of-0.005 km~2/year,indicating a different pattern in competition:S.alterniflora had more advantages in the upper saltmarsh,while S.mariqueter had more advantages in the pioneer zone with low elevation.Consequently,S.alterniflora mainly established new habitats by invading S.mariqueter in the middle saltmarsh,but S.mariqueter occupied the bare mudflat for tradeoff.Our results aindicated that the interspecific competition result between S.alterniflora and S.mariqueter depended on elevation,and low elevation might create a favorable environment for S.mariqueter to win the competition with exotic species.This finding could be applied to future invasive species control and saltmarsh management. 相似文献
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Morphodynamic signatures derived from daily surface elevation dynamics can explain the morphodynamic development of tidal flats 下载免费PDF全文
Tim J. Grandjean Jaco C. de Smit Jim van Belzen Gregory S. Fivash Jeroen van Dalen Tom Ysebaert Tjeerd J. Bouma 《水科学与水工程》2023,16(1):14-25
Understanding the sensitivity of tidal flats to environmental changes is challenging. Currently, most studies rely on process-based models to systematically explain the morphodynamic evolution of tidal flats. In this study, we proposed an alternative empirical approach to explore tidal flat dynamics using statistical indices based on long-term time series of daily surface elevation development. Surface elevation dynamic (SED) indices focus on the magnitude and period of surface elevation changes, while morphodynamic signature (MDS) indices relate sediment dynamics to environmental drivers. The statistical analyses were applied to an intervention site in the Netherlands to determine the effect of recently constructed groynes on the tidal flat. Using these analyses, we were able to (1) detect a reduction in the daily SED and (2) determine that the changes in the daily SED were predominantly caused by the reduction in wave impact between the groynes rather than the reduction in tidal currents. Overall, the presented results showed that the combination of novel statistical indices provides new insights into the trajectories of tidal flats, ecosystem functioning, and sensitivity to physical drivers (wind and tides). Finally, we suggested how the SED and MDS indices may help to explore the future trajectories and climate resilience of intertidal habitats. 相似文献
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为了更好地研究河口区重金属的运动足迹,综合评估其对河口水源区的影响,进一步实现河口水污染精准防治,选择长江口为研究区域,根据2016年1—12月长江口6个断面的监测数据,分析了长江口枯水期典型月(1月份)、平水期典型月(5月份)、丰水期典型月(8月份)重金属的运动足迹规律,构建了二维非稳态水环境数学模型并进行了率定验证,探究了河口区重金属的时空分布。研究结果表明:①不同水文期,长江口重金属受到长江径流和潮汐作用的影响,粒子运动速度从大到小的时间排序是丰水期>平水期>枯水期;空间分布来看,徐六泾释放的粒子会进入长江口的3个水源区。②枯水期典型月(1月份),粒子运动足迹3处不一致,北港处重金属粒子运动速度最快,为4.98 km/d,最终汇入东海。③平水期典型月(5月份),徐六泾重金属粒子足迹运动不同于枯水期,沿北港方向流动,继而呈顺时针的螺旋型轨迹运动,最终流入东海,且运动速度最快,为7.03 km/d。④丰水期典型月(8月份),运动足迹与平水期类似,但徐六泾与北港处的粒子运动速度都大于平水期,北港处最大,为8.32 km/d。 相似文献
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利用遥感技术并通过多渠道信息对照分析得到盐城市规划阶段内的岸线变化,结合实地调研、专家咨询等对垦区的空间布局、用地功能定位、滩涂资源持续供应能力、生态环境保护以及综合试验区建设等方面进行评估。结果表明:盐城市滩涂开发匡围进展总体偏慢,应根据工程区域的自然条件变化、地方的经济发展需求等对下一阶段的开发进行局部调整;盐城市可开发的滩涂资源量仍有较大剩余,基础设施建设总体上与垦区的开发进展相协调,可持续开发能力较强;大规模滩涂开发利用将对水沙动力条件、海洋生态环境等多方面产生影响,应针对江苏沿海环境特征,建立围垦环境影响的综合评价体系,为今后滩涂的可持续开发利用提供依据。 相似文献
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回顾总结国内外沿海滩涂开发研究在利用模式、开发技术、对生态环境影响及管理方法等方面所取得的主要成果。指出当前学者主要研究的重点在于滩涂综合利用、关注水陆相互作用、重视与环境的影响以及加强综合管理方面。提出滩涂环境问题、水沙条件分析以及围垦技术及其行业标准的制定将是未来滩涂开发研究的重点。 相似文献