基于RS和GIS的干旱河谷范围界定方法研究

以10月份前后的1～2个月内的植被变化为主要依据,以RS和GIS为平台,选取Landsat遥感影像数据,通过对植被和裸地进行分类,提取植被覆盖变化范围,结合平均谷坡坡度大于25°的谷坡高程图,界定出大渡河上游干旱河谷的分布范围,并将该方法应用于大渡河上游干旱河谷范围的界定.结果为:大渡河上游分布的干旱河谷长约355.4km(包括两河口足木足河段),总面积约585.8km2.通过遥感图像和数字高程模型(DEM)来界定干旱河谷范围的方法,对于基础数据资料相对缺乏的川西地区的生境综合治理以及区域可持续发展具有实际指导意义.     

论“四荒”种药的优势及意义

介绍了"四荒"种药提出的背景,分析了"四荒"种药的优势,探讨了"四荒"种药的措施与对策.     

中国历史水灾案例数据库的建立及相关问题探讨

结合利用历史洪水灾害文献建立全国七大江河历史洪水灾害案例数据库的实践,阐述了灾害案例数据库的基本特征。针对历史水灾文献资源的特点及灾害案例数据库的要求,讨论了影响灾害案例数据库质量的各种因素,对建库过程中的误差进行分类并给出相应的处理方法。     

千河流域秦岭细鳞鲑资源调查报告

秦岭细鳞鲑(Brachymystax lenok tsinlingensis)属典型的陆封性冷水鱼类,国家Ⅱ级重点保 护水生野生动物,是细鳞鲑属(Brachymystax)所有物种中分布最南端的1个亚种,秦岭山脉北麓的 千河流域内目前数量较多.通过实地调查表明,千河流域内分布的秦岭细鳞鲑种群发生了3个明显 的变化:(1)分布最低高度由原来海拔1 000 m上移至1 200 m,分布范围缩小;(2)个体小型化; (3)种群数量减少.文中还就秦岭细鳞鲑的保护对策提出了建议.     

Depositional architecture and developing settings of large-scale incised valley and submarine gravity flow systems in the Yinggehai and Qiongdongnan basins, South China Sea

In the Ying-Qiong basins in the South China Sea developed a set of giant inner shelf slope and submarine gravity flow deposits in the Ying-Huang formations since the Late Miocene. These deposits can be classified into 9 sequences in which slope slump-debris flow, slope fan and particularly, the large-scale axial basin-floor incised valley fills have been recognized. They were distributed in a distinctive pattern attributed to tectonic control. The development of shelf slopes and abyssal plains in the basins was related to the last episode of rapid subsidence and a large amount of sediment inputs. Large-scale basin-floor incised valleys, formed during the late Miocene and Pliocene, indicate several major sea level falls that occurred in the South China Sea.     

四川牡丹群落物种生态位及空间关联度分析

四川牡丹(Paeonia decomposita)分布于大渡河上游两岸干旱河谷地带,为中国特有的珍稀濒危物种;由于自身和人为干扰的原因,该物种受到灭绝威胁。本文以群落样方为一维综合资源生态位,分析了四川牡丹灌丛灌木物种的生态位特征,在此基础上对四川牡丹与其伴生灌木物种的空间关联度进行了研究。结果表明,灌丛内四川牡丹、蚝猪刺、野花椒、橿子栎、散生栒子、野蔷薇、金花小檗、平枝栒子和小马鞍羊蹄甲种群的标准化生态位宽度依次为0.745、0.979、0.950、0.748、0.947、0.924、0.792、0.863和0.610,四川牡丹与优势种群蚝猪刺、野花椒、野蔷薇等生态位重叠较高,潜在竞争作用强。四川牡丹与金花小檗、小马鞍叶羊蹄甲、橿子栎在小于15 m的空间尺度上呈显著负相关;与平枝栒子、蚝猪刺、野花椒在0～5 m的空间尺度上呈负相关或接近负相关。本研究认为在四川牡丹群落内,四川牡丹受到蚝猪刺、野花椒、散生栒子等群落内优势物种的竞争排斥,加之自身种子萌发的特性和人为干扰等因素,造成四川牡丹自身生态位狭窄,位于濒临灭绝的境地。     

Analysis of ecosystem degradation factors in Yuanmou arid-hot valleys based on interpretative structural model

For ecological restoration and reconstruction of the degraded area, it is an important premise to correctly understand the degradation factors of the ecosystem in the arid-hot valleys. The factors including vegetation degradation, land degradation, arid climate, policy failure, forest fire, rapid population growth, excessive deforestation, overgrazing, steep slope reclamation, economic poverty, engineering construction, lithology, slope, low cultural level, geological hazards, biological disaster, soil properties etc, were selected to study the Yuanmou arid-hot valleys. Based on the interpretative structural model （ISM）, it has found out that the degradation factors of the Yuanmou arid-hot valleys were not at the same level but in a multilevel hierarchical system with internal relations, which pointed out that the degradation mode of the arid-hot valleys was ＂straight （appearance）-penetrating-background＂. Such researches have important directive significance for the restoration and reconstruction of the arid-hot valleys ecosystem.