【作者】 张彤；

【导师】 蔡永立；

【作者基本信息】 华东师范大学 ， 生态学， 2004， 硕士

【摘要】 崇明东滩是一个不断被圈围开发的河口潮滩湿地典型区域，本文对其现状景观格局和十几年来的变化进行了时间上和空间上的定量分析，主要内容包括以下4个方面： 1．崇明东滩景观的分类和提取。先建立了崇明东滩景观分类体系，在此基础上利用2002年和1998年两期SPOT遥感图像数据，采用ERDAS IMAGINE图像处理软件，对其进行监督分类(Supervised Classification)和人机交互目视解译，制出景观分类图。 2．崇明东滩景观格局定量分析。根据人类干扰强度和环境因子的梯度变化，将2002年景观分类图划分为3个景观带(经营景观带、半自然景观带、自然景观带)，采用FRAGSTATS景观格局分析软件，计算了各景观带的斑块密度和大小、形状、多样性、距离及蔓延和散布等方面的20个景观指标。分析结果表明区域内各景观地带分异强烈，具有各自独特的景观格局特征。文章还在此基础上分析了人类干扰对各景观带景观格局特征的改变趋势。 3．崇明东滩15年来景观变化分析。通过对东滩的动态发展、景观格局特征变化、土地利用变化进行的全面分析，得到东滩景观变化结果和推动因素： 1)八十年代后期的东滩景观异质性较高，较少受人类干扰，而在过去15年间，人类不断的围筑海塘和农业活动导致景观在总体上变得破碎化和不连通，逐步由自然景观向经营景观与自然景观并重的方向转变，并导致了景观的地带分异。 2)人类活动是东滩景观变化的主导因素，以两种方式改变了东滩景观，一方面是直接改造：92塘内原滩涂区域，团结沙上有大片连通性极高的芦苇带，东旺沙上盐沼、芦苇带、光滩、洼地、潮沟等要素交错分布，表现出很高的异质性，而人类大规模的围垦使该区域转变为集约农业的经营景观。另一方面，人类活动也间接影响了景观：98塘内原是海三棱藨草生长茂盛的地带，被围后虽未开垦，但因环境因子的改变而人为加速了景观演替，导致了景观要素的变化，并导致了严重的景观破碎化。甚至在98塘外的潮滩湿地区域，人类干扰也导致了景规格局特征的改变，因围塘潮滩上的潮沟面积缩小、数量减少、周长面积比减小、树枝形态退化，芦苇带和盐沼斑块的形状也随之变化；盐沼和芦苇带周围的斑块类型散布均匀性和多样性下降，斑块异质性降低等后果。 3)研究发现潮沟在崇明东滩景观变化中扮演着重要角色，作为河口潮滩湿地景观__仁的廊道，其格局特征的变化导致了其它景观要素相应变化。潮沟的退化与盐沼的散布与并列指数(IJI)的下降及连通性指数(COHESION)的上升密切相关，从而影响整个潮滩景观的异质性，并可能使景观连接性下降。4.崇明东滩景观变化的生态效应分析。通过格局分析得到的结果，解释了东滩_L发生的生态过程。认为生物多样性减少、底栖动物和鸟类群落结构与分布的改变等，与芦苇带面积减少、破碎化，盐沼散布与并列指数的下降，及景观斑块异质性的降低有关;并将东滩各景观带的特征与生物多样性建立了联系，解释了该地区发生的物种多样性损失的过程。还分析了各景观带变化对东滩湿地养分的去除效率、生物种的迁移和扩散的影响。最后提出了对东滩地区规划的建议。更多还原

【Abstract】 Chongming Dongtan is a typical case of estuarine tidal flat wetland which has been diked continually in the past. This paper quantificationally analysized the present landscape pattern and its change over the past more than 10 years. The main content concludes work in four aspects as follows:1. The landscape types classification and identification. We built up a landscape classification system for Chongming Dongtan, and then executed the landscape classification map by using two-period SPOT image of Chongming Dao as information resource and with support of remote sensing image classification technique.2. The quantificational analysis on the landscape pattern of Chongming Dongtan. According to the gradual change of the intensity of anthropogenic activities & environmental factors, the landscape classification mape of 2002 was divided into three landscape zones(managerial landscape zone, semi-artificial landscape zone and natural landscape zone). With the support of FRAGSTATS, a landscape indices computing software, twenty metrics referring to the density and size of patches, shape, diversity, distance and contagion&interspersion of pathes or landscape. The results showed that landscape of these zones distinguished by sea walls was differentiated, possessing their particular characteristics. On this basis, this paper analyzed the impact of human disturbance on all the three landscape zones, with the characteristics of each landscape zone as the indication.3. The landscape pattern change analysis over the past 15 years. Through analyzing the dynamic development of Dongtan, the change of landscape pattern characteristics and the change of landuse, we concluded the landscape and its driven factors as follows:1) The landscape of Chongming Dongtan in the later 80s was rarely disturbed by the people, owning a high degree of landscape heterogeneity as a result. The anthropogenic activities such as frequent diking and cultivation led to the landscape fragmentation, low connectivity and the landscape differentiation of the zones distinguished by sea walls.2) On the one hand, the anthropogenic activities altered the landscape derectly. As for the previous area inside 92-bank, there remained acres of reed marsh which owned high degree of connectivity in Dongwangsha, and the interlacting landscape patches such as salt marsh, reed marsh, bare flat, swamp and creek showed high degree of heterogeneity. One the other hand, the anthropogenic activities altered the landscape inderectly. Wihin the diked but not assarted area enclosed by 92-bank and 98-bank, the evironmental factors are changed, which led to the quickened landscape succession and serious landscape fragmentation. Even in the tidal flat wetland area outside the 98-bank, the human disturbance brought the result of the change of landscape pattern characteristics, such as the reduction and degradation of tidal creeks, the subsequent change of reed marsh and salt marsh’s shape, the decrease of patches’ richness and evenness around the salt marsh, and the decline of landscape heterogeneity, et al.3) We found the important role palyed by creek in the landscape change of Chongming Dongtan. As the corridor of estuarine tidal flat landscape, the pattern change of creek led to the subsequent change of other landscape elements. The degradation of creek is connected closely to the decline of Inspersion&Juxtapositon Index(IJI), and the elevation of connectivity index(COHESION) of salt marsh, which affected the whole heterogeneity and connectivity of tidal flat wetland landscape.4. The analysis of ecological effects of the landscape change of Chongming Dongtan. Through the result from the landscape pattern analysis, we interpreted some ecological process. We deemed that the decrease of biological diversity, the structural and distribution change of macrozoobenthic community were related to the area reduction and fragmentation of reed marsh, the decline of IJI of salt marsh, and the decline of patches’ heterogeneity更多还原