The spatial-temporal dynamic characteristics of the marsh in the Sanjiang Plain

Using the methods of combining landscape ecology with GIS spatial analysis, this paper analyses the dynamics of the marsh landscape structure of the Sanjiang Plain in the past 20 years, furthermore, taking Fujin County, located in the north of the plain, as an example, analyzes the conversion between marsh and other land use types. It is shown that the marsh in the Sanjiang Plain decreased greatly in the past 20 years, but the trend has begun to reverse. The marsh area decreased by 51.33% from 1980 to 1996, whereas it decreased by 4.19% from 1996 to 2000. The fragmentation of the marsh increased; the number of the patches increased by 326 from 1986 to 1996, whereas it only increased by 18 patches from 1996 to 2000. It is obvious that the speed of patches number diminished and the marsh fragmentation decreased, which shows that the reclamation of the marsh converted from the fragmentation to the brim in a large area of the marsh. The reclaimed marsh has mainly converted to paddy field and dry land. Large-scale reclamation in the Sanjiang Plain influences its natural environment directly: the climate of the region turns from cold and wet to warm and dry, which makes the marsh both in the low-temperature northern part and in the deeply stagnant eastern part suitable for further agricultural development.     

洪泛区湿地生态环境功能及管理对策

洪泛区湿地是一种重要的湿地类型,是水陆自然景观的重要组成部分,为流域中水陆相互作用的交错带,具有独特的生态环境功能。对洪泛区湿地的生态环境功能进行了科学表述,针对我国洪泛区湿地目前面临的主要生态环境问题提出了合理的管理对策。     

龙感湖小流域元素时空分布及湿地拦截功能探讨

众所周知,湖滨湿地是湖泊环境的屏障,它对流域入湖物质具有吸收与拦截作用。通过长江中游龙感湖湖滨湿地和湖泊沉积物中元素含量在时间序列上的对比研究,发现湖滨湿地对入湖主要重金属元素确有明显拦截作用;但对于化学性质活跃,易以溶液态迁移的元素如Fe、Mn等不具备明显的拦截功能。人类活动对湿地的破坏,减弱了湿地对流域入湖物质的拦截功能,加速了湖泊生态环境的恶化。     

局地相似性理论在林地及林木湿地下垫面塔层中的应用研究

对局地相似性理论在“粗糙副层”范围的林地及在塔层范围的林木湿地下垫面大气边界层的适用性进行了研究。结果表明，对于二阶或更高阶的统计参数，局地相似性理论在林地及林木湿地是有效的。无量纲速度、垂直速度三阶矩、温度、湿度仅是无量纲长度ζ=z-d/L1的函数。其中，在对σT/T*l的分析中发现，σT/T*l按感热通量分层明显，感热通量大的数据点能更好地符合相似性关系。类似地，潜热通量大的数据点σT/T*l相似性关系也很好。     

长白山苔原湿地资源及可持续利用研究

本文按照海拔、坡向、地貌特征及植被结构把长白山苔原湿地划分为5个类型，并分别概述了各类苔原湿地的分布特征。长白山独特的生境蓄育了独特的植被与植物资源、土壤资源、水资源和旅游资源；为使其开发与保护协调发展，就必须对苔原湿地资源进行可持续开发利用。     

Total N, total P and organic matters content in floodplain soils of Xianghai Nature Reserve

Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.     

若尔盖湿地近25年湿地变化及分形特征分析

文章利用若尔盖湿地国家级自然保护区1989、1995、2001、2007和2014年5期遥感影像,研究了近25年保护区湿地面积的变化趋势,探索了保护区湿地分形维数的变化规律、质心的空间变化特征以及气候与湿地变化的相关性。研究结果表明:近25年,保护区湿地面积总体呈下降趋势,总共减少了52.28 hm2;保护区受到人为因素的干扰较大;湿地分布的质心向东北方向偏移;湿地面积变化与区域年平均温度相关性最大,与日照时数相关性最小。     

辽宁盘锦湿地监测数据分析

利用2013、2008、2003年的高分辨率航空影像、地理国情普查数据以及其他专业资料,对盘锦湿地10年来的地表覆盖实施了监测,分析了湿地周边水田面积、人类活动区域和南部海水养殖区的变化情况以及保护区内部地表覆盖现状和10年来的变化。结果显示,随着盘锦市经济的发展,对保护区的人为干扰逐年增强,湿地保护力度亟需加强。     

基于多波段全极化SAR影像的湿地分类

作为湿地类型较多、分布广泛的国家,中国的城市发展进程在一定程度上对我国丰富的湿地资源形成了很大的威胁,部分湿地遭到破坏。合成孔径雷达(Synthetic Aperture Radar,SAR)作为一种主动式微波遥感,其全天时全天候的特性十分适合湿地的监测工作。然而现在利用SAR进行湿地分类的研究尚未成熟,未能充分使用多个波段的信息分析,本文提出一种利用星载C波段以及机载p波段湿地分类的方法,有效地改善了分类的效果,提高了分类的精度。     

From Wetland to Saltland: Natural Obstacles and Socioecological Consequences in the Production of Solar Salt in Venezuela

ABSTRACT

This article provides a critical analysis of the process involved in transforming small-scale artisanal production of solar salt into large-scale industrial production by Produsal in Los Olivitos Wildlife Refuge and Fishing Reserve in Lake Maracaibo, Venezuela. In doing so, it highlights the socioecological impacts resulting from this process in the wetland and the fishing community of Ancón de Iturre. Using political economy of nature as a theoretical framework, especially notions of the formal subsumption of nature, materiality of natural resources, and the commodification of nature, this article explores how the biophysical characteristic of salt and the ecosystem where it is contained present a specific set of natural obstacles for its production; the different strategies used by Produsal to overcome these obstacles; and the social and ecological contradictions embedded in the process.