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1.
受自然过程和人类活动的影响,海岛景观生态风险处于不断演变之中。以浙江舟山朱家尖岛为例,基于1988-2014年间3期Landsat TM/ETM+遥感数据,进行土地利用/景观分类,计算景观格局指数,并引入生态风险指数,分析景观生态风险及其演变。结果表明:(1)26年间朱家尖岛景观格局发生了显著变化,林地和农田景观类型面积呈下降趋势,而建设用地、养殖区及未利用地等景观类型面积呈上升趋势;(2)1988年朱家尖岛以低和较低生态风险等级为主,至2014年中等和较高生态风险区面积持续上升,沿海出现高生态风险区;(3)从景观生态风险的空间演化趋势和速率看,低和较低生态风险区不断向岛内退缩,而中等和较高生态风险区不断向岛内扩张,朱家尖海峡大桥建成通车后的13年间景观生态风险等级的演化速率较前13年快。并初步探讨了降低以人类活动为主要风险源的海岛景观生态风险的方法。 相似文献
2.
为了明确大辽河流域范围内主要的生态环境问题、生态环境脆弱区和对流域生态安全非常重要的区域,根据流域湿地景观格局的变化及驱动机制分析、流域生态环境敏感性评价和水生态系统服务功能重要性评价,运用定性分区与定量分区相结合的方法和自下而上的划分方法得到大辽河流域水生态系统功能分区图,将大辽河流域划分成5个一级区和13个生态亚区。按照"水体类型+干扰类型+功能类型"对每个生态功能区进行命名,明确了每一个生态功能区的特征,为大辽河流域产业布局、生态环境保护与规划建设提供了科学依据。 相似文献
3.
海岸带景观是沿海地区社会经济可持续发展的基础,研究人类活动影响下的海岸带景观生态风险演变对海岸带景观规划与景观资源的合理开发具有重要意义。本文基于1990—2010年间3期的Landsat TM/ETM+遥感数据源,结合野外实地调查,研究了象山港海岸带景观生态风险及其变化趋势。结果表明: (1)20 a间,象山港海岸带景观格局发生显著变化,耕地、海域和林地等景观类型面积呈下降趋势,而建设用地、未利用地和养殖用地不断增加;(2)1990年以来,象山港海岸带景观生态风险等级有不断增高趋势,部分低、较低等级生态风险区演变为中等级以及较高等级;(3)从不同等级生态风险区的空间分布上看,1990年以来海岸带景观低和较低等级生态风险区空间分布在沿海地区减少,而中等、较高和高生态风险区在沿海地区不断形成并向陆侧扩张。从演化速率上看,近10 a的较高和高生态风险区面积增加速率较前10 a显著加快。 相似文献
4.
基于定量技术以大连的滨海路作为实证对象探究海滨旅游景观廊道特征的分析方法,旨在从多个维度对景观廊道进行较全面的评价.结果表明:滨海旅游廊道形态美观、结构合理;景观要素构成特征表现为景点数量分布疏密相间,集中与分散有机结合;景观类型丰富多样,廊道各个部分存在明显差异.生态特征分析表明滨海景观廊道的不同部分生态承载力呈现空间分异;廊道各个部分存在显著的经济区位特征差异.各项指标相关分析表明大连滨海廊道开发建设具有合理性,但存在一些尚需克服的制约因素.如廊道的可达性和自然生态的保护等. 相似文献
5.
文章利用RS和GIS技术手段对辽宁省瓦房店市1990—2015年的变迁过程进行监测,得出各历史时期的土地利用变化信息。将各类土地利用信息与景观生态学相结合,利用景观格局破碎度、景观分离度、景观优势度作为指标构建景观损失指数,并利用景观组分的面积比重构建海岸带生态风险指数。基于ArcGIS和Fragstats软件平台,通过空间采样和插值方法得到区域生态风险的空间分布,据此重构了瓦房店市1990—2015年的生态风险值变化过程。监测表明,1990—2015年期间,耕地、林地和滩涂呈减少趋势,水域和建设用地逐年增加,其他类型变化幅度不大。虽然耕地所占总面积比例由45.37%减少至37.23%,但一直是瓦房店最主要的景观。25年间瓦房店生态安全总体呈下降态势,1990—2015年6时段的生态风险年平均值分别为0.211 9、0.200 3、0.203 2、0.194 9、0.209 7和0.209 1。在时间维度,1990—2005年和2010—2015年生态安全度下降明显;在空间维度,瓦房店市海岸带的李官镇-三台满族乡和谢屯镇-炮台镇的生态风险度高,西杨乡、东岗镇和驼山乡生态风险由极高降为高或中,生态安全度有所提高。研究表明,人口和社会经济发展是影响瓦房店市景观格局变化的主要因素,该区域未来海岸带要实现可持续开发必须要进行科学的规划。 相似文献
6.
分析评估海岸区域的生态景观和生态风险,对维持海岸带资源环境的可持续发展有重要意义。以1985、1995、2005及2014年4个时期的TM遥感影像为象山港流域景观格局分析的主要数据源,构建景观生态风险格局演变模型,对流域生态风险的时空特征进行分析。结果表明:(1)1985-2014年,研究区内景观结构发生了较大的变化,耕地、林地以及滩涂面积均呈减少态势,建设用地、未利用地和养殖用地及盐田面积呈增加态势;(2)近30年来,研究区内的景观生态风险在时间演变过程上发生了显著变化。1985年,象山港流域景观以低、较低等级生态风险区为主,分别占全区总面积的48.01%和34.35%,1995年低、较低等级生态风险区面积均有不同程度减少,中等生态风险区面积显著增加。至2014年,低生态风险区面积进一步减少,而高、较高生态风险区面积增加明显;(3)从风险格局演变来看,1985-2014年象山港流域景观低、较低等级生态风险区不断向流域上游迁移,面积呈减少趋势,中等、较高和高生态风险区在沿海地区不断扩展,侵占生态风险等级相对较低区域,以沿海平原的淤泥质海岸尤为典型。 相似文献
7.
长江口滨海湿地景观格局变化及其驱动力分析 总被引：3，自引：0，他引：3
长江口地区是我国经济比较发达的地区之一,滨海湿地为该区的发展提供了大量的后备土地资源和生态资源。通过对长江口地区的实地调查,将该区滨海湿地分为光滩沼泽、潮间沼泽、河口和浅海水域、河流湿地、湖泊湿地5种自然湿地景观,水塘、水田、水库3种人工湿地景观及居民地、建筑用地等非湿地景观类型。在景观分类的基础上,以1986年和1995年的TM影像、2005年的SPOT影像为主要材料,结合其他数据资料,利用相关软件生成了长江口滨海湿地的景观分布图。运用景观生态学原理,选择了景观斑块数(NP)、景观多样性指数(H)、优势度指数(D)、景观形状指数(LSI)等几个生态意义比较明确的景观格局指数来分析研究区景观格局的变化特征,并分析了该区景观格局变化的驱动因素。结果表明:1986~2005年,长江口滨海湿地的面积增加了5.81个百分点;景观斑块数(NP)由1986年的2 213块增加到2005年的2 667块,增加了20.51个百分点;景观多样性指数(H)由1986年的1.730 9上升为2005年的1.876 5;优势度指数(D)自1986年的1.122 7上升为2005年的1.293 4;景观形状指数(LSI)自1986年的44上升为2005年的48。其中面积的增加主要是长江所携带的泥沙在长江口不断淤积的结果,泥沙的淤积同时造成了长江口滨海湿地景观格局的变化,但是目前由于三峡大坝的截流和长江中上游植被面积的增加,长江携带的泥沙明显减少,使得长江口淤积速率有所减慢。上述几个景观指数的变化表示长江口滨海湿地的景观破碎化程度在加剧,景观格局在时间序列上也存在明显差异,调查研究表明,自然驱动力和人为驱动力同时作用于该区景观格局的变化。近20年来,随着经济的发展、人口数量的增加、围垦等活动的加剧,人类活动对研究区的改造导致了自然湿地的面积相对减少,滨海湿地的生态功能不断下降。 相似文献
8.
基于SPOT影像与Fragstats软件的区域景观指数提取与分析 总被引：4，自引：0，他引：4
景观指数是衡量区域景观质量的重要参数，也是进行区域生态规划、管理和恢复的重要信息依据。针对传统已有的矢量地图信息源及Excel、SPSS软件在景观指数计算中存在的不足和不便之处，研究了在ENVI4．2下，基于高分辨率SPOT-5遥感影像的自动景观分类及Fragstats3．3软件支持下的景观指数自动提取的计算方法，以屈原农场为例进行了实验研究，制作了景观现状图和计算部分景观指数。实验表明：该方法对景观质量的评价信息获取效率高、时效性强，通过快速分析与评价手段，可以大大地促进区域进行规划、管理和恢复的科学性和可操作性。 相似文献
9.
东山岛景观生态风险评价 总被引：11，自引：0，他引：11
以东山岛为例进行了景观生态风险评价理论和方法的探讨.针对东山岛主要生态风险源干旱、台风风沙、污染、水土流失可能对东山生态系统造成的损害,提出了度量生态损失与生态风险的指标与公式,并运用遥感资料、历史记录、调查数据和地理信息系统(GIS)技术,完成了区域景观生态风险综合评价,在此基础上提出东山的区域生态风险管理对策. 相似文献
10.
1989～2010年间厦门湾滨海湿地人为干扰影响评价及景观响应 总被引：2，自引：0，他引：2
选择厦门经济特区成立后的2个关键时段为监测期,利用1989～2010年的时间序列遥感影像,建立了3个时间节点的厦门湾湿地与非湿地景观类型数据库.基于景观生态学与地统计学理论与方法构建人为干扰度及其动态模型,评价了过去22a间滨海湿地人为干扰影响及其动态变化,并分析了景观格局的响应过程.结果表明：厦门湾滨海湿地退化程度不断加剧.自然湿地的面积从1989年的275.82 km2降至2010年的238.60 km2;非湿地从1989年的590.61 km2上升至2010年的637.09 km2.在城市化不同阶段,滨海湿地经历着从以向人工湿地转化为主,过渡到以向非湿地转化为主的过程.干扰度及其动态模型能较好地表征城市空间拓展模式与人为干扰影响的空间响应关系.人为干扰影响正逐渐扩大其规模和强度,并且呈现出由陆地向海洋扩展的趋势.在第一时段,环西海域海岸线成为厦门城市化空间发展的重要方向,滨海湿地资源空间成为城市化扩展、海水养殖业占用的重要目标.在第二时段,人为干扰度变化的高值区已经沿着海岸线向东部转移,形成了新的干扰带;中高值区在整个区域蔓延,滨海湿地资源空间被进一步挤压.干扰度动态变化高值区是滨海湿地退化最显著的区域,也是未来进行湿地保护与生态修复的重点区域.边缘密度、斑块密度与分离度综合起来能较好地反映出景观格局信息与人为干扰之间响应关系.研究区景观格局趋于复杂化,景观异质性程度升高,景观破碎度增大.非湿地景观类型逐渐居于主导地位,滨海湿地的优势景观控制力下降.人为干扰已成为厦门湾滨海湿地景观格局演变的主要驱动力. 相似文献
11.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
12.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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15.
《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
16.
The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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The behaviour of an axially pre-loaded cylindrical member of an offshore structure, hit by a supply ship, has been investigated. The effects of axial pre-loading on the dynamic properties of members, the extent of damage and propagation of dynamic instability in the tubular members have also been investigated. Numerical models have been validated using available experimental data from the literature although these are mostly static with no pre-loading. Axial pre-loading was found to change the dynamic characteristics of some cylindrical members quite dramatically while it had no significant effect on others. The study examined whether there was any change in the behaviour between local and global modes when the loading was dynamic rather than static. The effect of damping on the dynamic instability of axially pre-loaded tubes under lateral dynamic loads was also studied. It was observed that for some geometries the quasi-static response can be used to define the boundary between bounded and unbounded dynamic responses. The main contribution of this study, compared with previous investigations reported in the literature, is that both pre-loading and dynamic effects have been included. 相似文献
19.
Rahul Sharma 《Marine Georesources & Geotechnology》2000,18(3):237-250
Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in predisturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions. 相似文献
20.
Vance P. Vicente 《Marine Ecology》1989,10(2):179-191
Abstract. Long-term changes in the distributional patterns of commercial sponges ( Spongia spp. and Hippospongia spp.) within the West Indian Region indicates that: 1) commercial sponges had a widespread distribution throughout the whole West Indian Region and were ubiquitous in very shallow water until about the first half of the present century; 2) they were fished commercially not only in the traditional northern Caribbean sites (Florida, Gulf of Mexico, Bahamas) but also in the Greater ( e. g. , Hispaniola, Jamaica) and Lesser Antilles; and 3) they became extinct throughout most of the Lesser Antilles ( e. g. , Puerto Rico, Vieques, St. Thomas) sometime during the first half of this century. Mortalities of spongiids within the Antilles were found to differ from other marine mortalities in that: 1) species disappeared from a large region; 2) species vanished from different habitats and depths; and 3) natural populations never recovered. Species richness patterns suggest that commercial sponge genera ( Spongia and Hippospongia ) evolved under slightly cooler elimatic conditions than those found at present, and that these extinctions occurred as a direct or indirect effect of positive thermal anomalies in sea surface and atmospheric temperatures between 1900–1950. The concept that species diversity is stable on a regional scale is questioned. 相似文献