本文選題：濱海濕地　切入點：潮間帶　出處：《華東師范大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：濱海濕地生態(tài)系統(tǒng)作為海陸過渡帶,具有凈化環(huán)境、提供生物棲息地、穩(wěn)定海岸、調(diào)節(jié)氣候等生態(tài)服務(wù)功能。當(dāng)前,在全球變化和人類活動的影響日益加劇的背景下,濱海濕地生態(tài)系統(tǒng)正面臨著愈來愈大的壓力。多穩(wěn)態(tài)現(xiàn)象普遍存在于多種生態(tài)系統(tǒng)中,它與生態(tài)系統(tǒng)的健康和可持續(xù)發(fā)展密切相關(guān)。因此,濱海濕地生態(tài)系統(tǒng)多穩(wěn)態(tài)研究具有重要的理論和實踐意義。本研究選取崇明東灘濱海濕地生態(tài)系統(tǒng)作為研究區(qū)域,力圖識別長江口濱海濕地生態(tài)系統(tǒng)中的多穩(wěn)態(tài)類型,從生物地貌正反饋作用方面分析多穩(wěn)態(tài)的形成機制,并在景觀尺度上對該機制進行驗證。主要研究結(jié)果如下:1.長江口濱海濕地生態(tài)系統(tǒng)多穩(wěn)態(tài)類型的識別遙感影像的歸一化植被指數(shù)(NDVI)分布結(jié)果顯示潮間帶鹽沼前沿NDVI指數(shù)分布存在"雙峰"特征,野外移栽實驗結(jié)果表明潮間帶鹽沼前沿存在生物量閾值現(xiàn)象,均證實了長江口濱海濕地生態(tài)系統(tǒng)植被前沿中存在多穩(wěn)態(tài),"鹽沼"和"光灘"是兩種結(jié)構(gòu)和功能截然不同的穩(wěn)態(tài)類型。2.長江口濱海濕地生態(tài)系統(tǒng)中多穩(wěn)態(tài)形成機制的分析長江口濱海濕地生態(tài)系統(tǒng)中,生物地貌正反饋作用是潮間帶前沿多穩(wěn)態(tài)形成的主要機制。與高程相關(guān)的淹水條件影響鹽沼植物的存活、生長和繁殖狀況,高強度的淹水對鹽沼植物各個生活史階段均有很強的脅迫作用,極大地限制了"鹽沼"穩(wěn)態(tài)的形成。密集的鹽沼植被具有消浪減流作用,有利于泥沙淤積,推動了"鹽沼"穩(wěn)態(tài)的發(fā)展。同時,泥沙淤積與植物生物量之間存在正相關(guān)關(guān)系,泥沙淤積造成的高程抬升減少了淹水脅迫對鹽沼植物的影響,進而又促進了"光灘"穩(wěn)態(tài)向"鹽沼"穩(wěn)態(tài)的轉(zhuǎn)換。這種生物地貌過程在斑塊尺度上發(fā)揮作用,導(dǎo)致了長江口濱海濕地生態(tài)系統(tǒng)中多穩(wěn)態(tài)現(xiàn)象的形成。3.景觀尺度上長江口濱海濕地生態(tài)系統(tǒng)穩(wěn)態(tài)轉(zhuǎn)換的探討景觀尺度上,崇明東灘三個斷面動力條件和沉積地貌呈現(xiàn)出明顯的空間異質(zhì)性。北斷面潮間帶鹽沼前沿以潮流作用為主,水動力最弱,流向垂直于植被帶,波浪強度和流速最小,水體濁度最高,水沙過程呈漲潮優(yōu)勢,高濁度水體高速度上灘,低濁度水體低速度下灘,這種水文動力條件極有利于細顆粒泥沙在灘面快速淤積;中斷面與北斷面的動力條件相似,淤積速率稍低于北斷面;南斷面潮間帶鹽沼前沿受到徑流和潮流的雙重作用,水動力最強,沿岸流特征較明顯,波浪強度和流速最大,水體濁度極低,水沙過程漲潮優(yōu)勢不明顯,這種水文動力條件不利于細顆粒泥沙淤積,以致于形成低淤積率的粉砂質(zhì)潮灘。在景觀尺度上,盡管三個斷面地貌特征不同,但是在潮間帶前沿均發(fā)生了"鹽沼"和"光灘"之間的穩(wěn)態(tài)轉(zhuǎn)換。長時間尺度上的穩(wěn)態(tài)轉(zhuǎn)換分析表明,崇明東灘一直都存在"鹽沼"和"光灘"兩種穩(wěn)態(tài),但2009-2015年間"光灘"穩(wěn)態(tài)向"鹽沼"穩(wěn)態(tài)的轉(zhuǎn)換量(12.25 km2)顯著高于2003-2009年(10.16 km2),"鹽沼"穩(wěn)態(tài)向"光灘"穩(wěn)態(tài)的轉(zhuǎn)換量(0.75 km2)明顯低于2003-2009年(2.22 kin2)這種穩(wěn)態(tài)轉(zhuǎn)換現(xiàn)象與2003年以后河口輸沙量迅速下降,2009年以后河口輸沙量又趨于穩(wěn)定的泥沙輸入量變化息息相關(guān)。本文中生物地貌正反饋機制以及"閾值效應(yīng)"等研究結(jié)果不僅可以從理論和方法上豐富濱海濕地生態(tài)系統(tǒng)多穩(wěn)態(tài)的機理研究,也可為我國河口型濱海濕地生態(tài)系統(tǒng)的植被修復(fù)及綜合管理提供數(shù)據(jù)支持和科學(xué)依據(jù)。
[Abstract]:The coastal wetland ecosystem as a transitional zone, with cleaning up the environment, provide habitat, stable coast, climate regulation and other ecosystem services. At present, impact on the global change and human activities in the background of growing coastal wetland ecosystem is facing more and more pressure. Multiple steady state exists in various ecosystems in the system, and it is closely related to the health of the ecosystem and sustainable development. Therefore, it has important theoretical and practical significance to study multi stable coastal wetland ecosystem. This study selected Chongming Dongtan coastal wetland ecosystem as the study area, trying to steady state type identification of Yangtze Estuary coastal wetland ecological system, the formation mechanism of the many state from the biogeomorphic positive feedback function, and verify the mechanism at the landscape scale. The main results are as follows: 1. the Yangtze River Estuary coastal Recognition of remote sensing image normalized vegetation of wetland ecosystem types in the steady state index (NDVI) results showed that the distribution of the intertidal salt marshes in front of the existence of the Shuangfeng NDVI index distribution characteristics, field transplanting experiment results show that the intertidal salt marshes are the frontier biomass threshold phenomenon, confirmed the existence of multiple steady state vegetation in the Changjiang Estuary Wetland Ecosystem frontier in the "salt" and "light tan" is a coastal wetland ecosystem in the Changjiang Estuary forming mechanism of the steady state of type.2. two structurally and functionally distinct Yangtze Estuary coastal wetland ecosystem in the steady state, biogeomorphologic positive feedback effect is the main mechanism with multi stable formation frontier intertidal. Flooding conditions correlated with elevation the influence of salt marsh plant survival, growth and reproduction of stress of high strength strong flooding on salt marsh plant has various life history stages, greatly limiting" Salt marsh "steady state. The formation of dense salt marsh vegetation has wave flow reducing effect, conducive to the sedimentation, promote the steady development of" salt ". At the same time, there is a positive correlation between plant biomass and deposition of sediment, sedimentation elevation uplift resulted in reduced water stress effects on salt marsh plants, and to promote the" light tan "to" steady state "conversion of salt marsh homeostasis. Play a role in the process of biological landscape patch scale, caused the coastal wetland ecosystem in the Changjiang Estuary multistability of.3. formation on landscape scale of Yangtze Estuary on landscape steady-state conversion of the wetland ecosystem scale, Chongming Dongtan three section dynamic conditions and sedimentary geomorphology shows obvious spatial heterogeneity. The tide dominated salt marsh intertidal frontier north section, the hydrodynamic flow perpendicular to the weakest, vegetation belt, wave intensity and minimum flow rate, water The highest body turbidity, water and sediment in the flood of high turbidity water, high speed and low turbidity water beach, low speed under the hydrodynamic condition of the beach, very beneficial for fine sediment deposition in the fast flat; similar dynamic conditions and the northern section of the interrupt, deposition rate is slightly lower than that of the north section of the dual role of the southern section; intertidal salt marsh front by runoff and tide, water power was the strongest, the coastal current characteristics is obvious, the wave intensity and the maximum flow rate, water turbidity is low, water and sediment the advantage is not obvious, the hydrodynamic condition is not conducive to the sedimentation of fine particles, resulting in the formation of low sedimentation rate in silty tidal flat. On the landscape scale, while the three section features are different, but with the steady state of frontier in the intertidal were "salt" and "light tan" conversion. The steady state on a long time scale transformation analysis shows that, Chongming Dongtan has always been there "Salt" and "light tan" two steady, but 2009-2015 years of "light Beach" to "steady state conversion of salt marsh" volume (12.25 km2) was significantly higher than that in 2003-2009 years (10.16 km2), the "steady state" to convert the light salt "beach" steady volume (0.75 km2) was significantly lower than that in 2003-2009 years (2.22 kin2) the steady-state conversion phenomenon and estuarine sediment after 2003 decreased rapidly after 2009, estuarine sediment and sediment input change tends to stable. This study is closely related to research on the mechanism of biogeomorphologic positive feedback mechanism and "threshold effect" results can not only enrich the multi stable coastal wetland ecological system from theory and method. Also, it can provide data support and scientific basis for coastal wetland ecosystem in China estuarine vegetation restoration and comprehensive management.

【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X171.1

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相關(guān)期刊論文 前10條

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