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湿地脆弱性评价是近年来湿地科学及可持续性科学领域的热点和前沿.湿地脆弱性评价研究经历了从湿地脆弱性特征定性评价,到湿地脆弱性定量评价,再到气候变化下湿地脆弱性评价的发展历程.首先,在对湿地脆弱性概念归纳总结的基础上,提出湿地脆弱性是在自然环境和人为压力下湿地退化的程度和可能性.其次,定性介绍了水土流失、水热分配不均、湿地退化等主要脆弱性特征表现;并以脆弱性评价的基本步骤为主线论述了模型法、特征法、综合指数法、EFI评价法、空间分析法等主要研究方法;同时,从不同角度概述了气候变化背景下的湿地脆弱性,总结了湿地水文景观分类法、生物完整性指标法、模型法、空间分析等评价方法.最后,指出湿地脆弱性研究中存在的概念不统一、评价标准不一致、评价指标范围较狭窄、动态研究偏少、定量评价的不确定性等主要问题,提出了完善评价体系、加强动态研究和国内对气候变化下湿地脆弱性的定量研究以及不确定性分析、脆弱性评价与决策管理衔接等湿地脆弱性未来研究的重点. 相似文献
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青藏高原植被覆盖变化与降水关系 总被引：15，自引：6，他引：9
The temporal and spatial changes of NDVI on the Tibetan Plateau, as well as the relationship between NDVI and precipitation, were discussed in this paper, by using 8-km resolution multi-temporal NOAA AVHRR-NDVI data from 1982 to 1999. Monthly maximum NDVI and monthly rainfall were used to analyze the seasonal changes, and annual maximum NDVI, annual effective precipitation and growing season precipitation (from April to August) were used to discuss the interannual changes. The dynamic change of NDVI and the corre- lation coefficients between NDVI and rainfall were computed for each pixel. The results are as follows: (1) The NDVI reached the peak in growing season (from July to September) on the Tibetan Plateau. In the northern and western parts of the plateau, the growing season was very short (about two or three months); but in the southern, vegetation grew almost all the year round. The correlation of monthly maximum NDVI and monthly rainfall varied in different areas. It was weak in the western, northern and southern parts, but strong in the central and eastern parts. (2) The spatial distribution of NDVI interannual dynamic change was different too. The increase areas were mainly distributed in southern Tibet montane shrub-steppe zone, western part of western Sichuan-eastern Tibet montane coniferous forest zone, western part of northern slopes of Kunlun montane desert zone and southeastern part of southern slopes of Himalaya montane evergreen broad-leaved forest zone; the decrease areas were mainly distributed in the Qaidam montane desert zone, the western and northern parts of eastern Qinghai-Qilian montane steppe zone, southern Qinghai high cold meadow steppe zone and Ngari montane desert-steppe and desert zone. The spatial distribution of correlation coeffi- cient between annual effective rainfall and annual maximum NDVI was similar to the growing season rainfall and annual maximum NDVI, and there was good relationship between NDVI and rainfall in the meadow and grassland with medium vegetation cover, and the effect of rainfall on vegetation was small in the forest and desert area. 相似文献
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汞的污染已经引起地学和环境工作者的关注,尤其是作为全球两大汞-锑矿带之一的我国西南地区.近年来,我们系统研究了西南地区自然过程和人为活动向大气的排汞通量、土法炼锌和土法炼汞对生态环境的影响、大规模汞矿开采造成的环境汞污染、高汞背景和多汞污染来源地区水库汞的生物地球化学循环演化特征.研究表明,无论自然过程还是人为活动,西南地区尤其是贵州省是全球大气汞的重要释放源;矿业开采造成了严重的环境汞污染,对当地居民的身体健康构成了严重的危害;这一地区的新建水库是汞甲基化的重要场所,对生态环境有潜在的危害. 相似文献
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