Effects of human footprint and biophysical factors on the body-size structure of fished marine species

Marine fisheries in coastal ecosystems in many areas of the world have historically removed large-bodied individuals, potentially impairing ecosystem functioning and the long-term sustainability of fish populations. Reporting on size-based indicators that link to food-web structure can contribute to ecosystem-based management, but the application of these indicators over large (cross-ecosystem) geographical scales has been limited to either fisheries-dependent catch data or diver-based methods restricted to shallow waters (<20 m) that can misrepresent the abundance of large-bodied fished species. We obtained data on the body-size structure of 82 recreationally or commercially targeted marine demersal teleosts from 2904 deployments of baited remote underwater stereo-video (stereo-BRUV). Sampling was at up to 50 m depth and covered approximately 10,000 km of the continental shelf of Australia. Seascape relief, water depth, and human gravity (i.e., a proxy of human impacts) were the strongest predictors of the probability of occurrence of large fishes and the abundance of fishes above the minimum legal size of capture. No-take marine reserves had a positive effect on the abundance of fishes above legal size, although the effect varied across species groups. In contrast, sublegal fishes were best predicted by gradients in sea surface temperature (mean and variance). In areas of low human impact, large fishes were about three times more likely to be encountered and fishes of legal size were approximately five times more abundant. For conspicuous species groups with contrasting habitat, environmental, and biogeographic affinities, abundance of legal-size fishes typically declined as human impact increased. Our large-scale quantitative analyses highlight the combined importance of seascape complexity, regions with low human footprint, and no-take marine reserves in protecting large-bodied fishes across a broad range of species and ecosystem configurations.     

最近10年鄱阳湖区土地利用格局的时空变化

利用1988和1998年4月份的TM遥感数据,采用最大似然法对翻阳湖区的土地利用进行机助分类。把研究区土地利用分成7种类型：林地、灌草坡、水体、湖滩洲地、耕地、城镇用地和裸地。采用空间叠加的方法得到研究区土地利用的转移短阵。结果显示,林地、水体、城镇的面积增加,灌草坡的面积减少。1998年耕地面积比1988年面积减少11．3％,湖滩洲地面积减少42．7％。对不同高程的土地利用变化分析表明,耕地、灌草坡的面积都有所减少;城镇的面积增加,林地的面积增加明显,尤其在丘陵山区。土地利用的变化受到自然和人文因子的双重影响。水体面积增加的主要因于是降水量的增大;林地、灌草坡的变化明显受到政策等因素的影响,湖滩洲地减少的主要原因是水位的升高。     

Changes in Vegetation Cover and Socio-Economic Transitions in a Coastal Lagoon (Kalametiya, Sri Lanka), As Observed by Teledetection and Ground Truthing, Can be Attributed to an Upstream Irrigation Scheme

According to some non-scholarly reports, Kalametiya lagoon (dry zone of southern Sri Lanka, formerly 8.9 km², now 7.5 km²) had been a moderately or high salinity water body and a very important centre of prawn fishery until the late 1960s. Most of the lagoon area had remained open water until then. An upstream irrigation project, the Udawalawa irrigation scheme, came into operation in 1967, increasing the freshwater inflow to the lagoon. The flora, fauna and water quality of the lagoon was reported to have changed since then.The lagoon now is a shallow coastal water body with low salinity water. More than 75% of the lagoon is covered by freshwater species or mangrove species characteristic for water with a low salinity: Eichhornia crassipes, Typha latifolia resp. Sonneratia caseolaris. There is actually no commercially important fishery in the lagoon.The present study was carried out to assess scientifically the said changes in the vegetation within a GIS, using aerial photographs taken in 1956 and 1994 and IRS IC, PAN+LISS III satellite images of 1997 in combination with ground surveys and information from a questionnaire-based survey.It appeared from this work that the aerial cover by Sonneratia caseolaris has increased by more than 30 times over the period from 1956 to the recent dates. Also, the lagoon area with open water has been drastically reduced during the same period as a result of spreading of freshwater and low salinity plant species. The results strongly suggest that the locally reported changes (fisheries decline, water salinity decrease) can be corroborated by the observed profound changes in plant cover and that upstream water works may have had strong impacts on this ecosystem, thus causing these changes.This study couples data obtained from retrospective aerial photograph series, from spaceborne imaging, from actual ground surveys and from questionnaires amongst elderly people to reconstruct decadal environmental change, thus attempting to fill the gap of lacking historical environmental data.     

基于GIS和RS的晋江市土地利用变化与可持续利用研究

采用GIS和遥感技术，在拟订土地分类系统的基础上，对1996和2001年晋汀市土地资源进行遥感解译，得到这两期1：10万土地利用现状图及数据库，分析了晋江市土地利用类型的构成与比例，以及土地利用面积动态变化状况。结果表明，晋汀市自1996年以来，城镇居民点与工矿用地扩展较大，面积增幅达5312．55hm^2，交通面积增加1507．02hm^2，林地而积增加了293．05hm^2，园地面积也增加了4．17hm^2；但耕地面积锐减，减少面积为6419．43hm^2，减幅为14．6％，其去向主要是建设用地、生态退耕、园地和池塘用地。在此基础上，认为土地利用变化存在的主要问题是：耕地面积锐减；土地利用结构小平衡；生态环境恶化等。应采取针对性的土地可持续发展措施，重视土地管理制度创新和土地利用的优化配置。     

Quantifying landscape-ecological succession in a coastal dune system using sequential aerial photography and GIS

Summary This contribution presents an attempt to measure the path of habitat and vegetation succession in a coastal dune system (Kenfig Burrows, South Wales) using remote sensing and GIS. The loss of slack habitats associated with the continuing stabilization of this dune system is a major cause for concern. These habitats support a range of plant species, including the rare fen orchid,Liparis loeselii, as well as other hydrophytes. A decrease in their areal extent implies a reduction in biodiversity. To quantify the overall rate and spatial dimension of these changes, a series of aerial photographs dating from 1962 to 1994 were digitized and analysed in an image processing system. The resultant maps. transferred to a vector-based GIS, were used to derive a transition matrix for the dune system over this period of time. The results indicate that there has been a marked reduction in the total area of bare sand (19.6% of the dune system in 1962, but only 1.5% in 1994) and a decline in both the areal extent and the number of dune slacks. Over the same period of time, there has been an increase inSalix repens dominated habitats, at the expense of pioneer species. Analysis of the habitat maps, together with hydrological data, within the GIS suggests that even the dry slacks have the potential for further greening and to support invasive species. In terms of habitat management however, there is still scope to restore many of the slacks to their original state. It is estimated that at least 24% of the area occupied by partially and moderately vegetated slacks could be rehabilitated.     

航空遥感地震灾害信息的快速提取

航空遥感地震灾害信息的快速提取是地震灾害损失快速评估的关键技术。遥感与地理信息系统的结合应用使得震害调查快速而又正确。本文重点论述了震害地类的特性与建立解译模型的原则、方法与不同种类信息源所采用的二套技术方案,并比较分析了二套技术方案各自的优势,探讨地震灾害信息快速提取的技术方法。     

河北省海洋灾害遥感动态监测系统简介

为及时获取海洋灾害发生及其影响的监测信息，并为当地政府和有关部门提供决策服务，根据渤海湾海洋灾害发生的特点，从风暴潮、赤潮、海冰、海域污染等海洋灾害的遥感监测技术方法研究入手，介绍了河北省海洋灾害遥感动态监测系统的功能。应用服务情况表明，该系统对渤海的风暴潮、赤潮、海冰、海域污染的遥感监测效果良好。重点对利用NOAA／AVHRR数据开展的1998—2006年春季渤海海域污染遥感监测情况进行了客观的分析，结果表明，渤海湾近海水域从1999年开始出现大范围污染，其中，2002年最为严重，2003年以后有所好转，但是近两年的污染状况又趋严重。     

航空遥感的震害快速评估与救灾决策

根据邢台、海城、唐山、澜沧－耿马等震例的震害航空遥感信息建立的震害损失快速评估模型与技术系统，具有良好的应用效果，但是影响震害损失状态的因素甚多，使用时应注意区域的适用性和修订相应的常数。另外，还将自然科学与管理学综合为一体，总结了九种震害状态、九种救灾类型的决策系统，以供救灾实践的参考。     

双光谱卫星云图的模糊推理云分类

基于观测事实和分类经验,在对卫星云图上云系形态特征定性分析的基础上,采用模糊推理方法,提取出云类识别的诊断判别因子和模糊推理规则。通过对判别因子的模糊化处理和隶属度函数的调制优化,建立了卫星云图定量化的模糊推理云分类模型。4种常见云系的模糊推理分类试验结果表明,模糊推理方法在定量性、客观性和自动化等方面优于传统卫星云图目视判读方法,在卫星遥感资料的分析处理和天气预报等领域有较好的实用意义。