Livelihood strategy change and land use change —Case of Danzam Village in upper Dadu River watershed, Tibetan Plateau of China

Land use change in rural China since the 1980s, induced by institution reforms, urbanization, industrialization and population increase, has received more attention. However, case studies on how institution reforms affect farmers’ livelihood strategies and drive land use change are scarce. By means of cropland plots investigations and interviews with farmers, this study examines livelihood strategy change and land use change in Danzam Village of Jinchuan County in the upper Dadu River watershed, eastern Tibetan Plateau, China. The results show that, during the collective system period, as surplus labor forces could not be transferred to the secondary and tertiary industries, they had to choose agricultural involution as their livelihood strategy, then the farmers had to produce more grains by land reclamation, increasing multiple cropping index, improving input of labor, fertilizer, pesticide and adopting advanced agricultural techniques. During the household responsibility system period, as labors being transferred to the secondary and tertiary industries, farmers chose livelihood diversification strategy. Therefore, labor input to grain planting was greatly reduced, which drove the transformation of grain to horticulture, vegetable or wasteland and decrease of multiple cropping index. This study provides a new insight into understanding linkages among institution reforms, livelihood strategy of smallholders and land use change in rural China. Foundation item: Under the auspices of National Natural Science Foundation of China (No. 40601006, 40471009), National Basic Research Program of China (No. 2005CB422006)     

A landscape pattern analysis method based on boundaries and nodes: A case study in upper Minjiang River, China

Traditionally,patch-based analysis at the landscape scale fragmentation has been used in the study of landscape ecology while the study of boundary and node has not been considered as much detail until recently.This study investigated the possibility of applying boundary-and node-based methods in landscape pattern analysis to the upper reaches of the Minjiang River in the southwestern China.Boundary-based and node-based landscape indices were selected to be used in analyzing changes in landscape patterns,and the results were compared with analysis using traditional pattern indices.We compared the responses of patch-area-based,boundary-length-based and node-number-based indices,and concluded that boundary-based and node-based indices are more sensitive to disturbance than patch-based indices with various patterns,and node-based indices are even more sensitive than boundary-based ones.Thus,the results suggest that boundary-based and node-based pattern analysis methods provide helpful supplementary information to traditional patch-based pattern analysis methods.The results about pattern dynamics of landscapes in the upper reaches of the Minjiang River based on boundaries and nodes showed that with human disturbance,the dominance of forest landscape was weakened by other landscape types; thus the landscape pattern of the study area became more homogeneous and the boundary network became more complex.These changes further augmented disturbance interfaces in the landscape and increased the possibilities of further landscape fragmentation.     

赣江上游河流水化学的影响因素及DIC来源

对赣江上游38 处水体采样点的水化学特征和溶解无机碳稳定同位素的分析, 发现其总溶解质浓度较低, 其中, 阳离子以Na⁺、Ca²⁺ 为主, 阴离子以Cl^- 和HCO₃ ^- 为主, Si 的浓度较高, 表征了典型硅酸盐地区河流的水化学组成特征。通过海盐校正分析得出, 研究区大气降水对河水溶解质的贡献率为11.5%, 扣除降水的贡献部分, 利用主成分分析的方法, 计算得出赣南流域受硅酸盐岩风化作用强烈, 同时由于受附近盐矿的影响, 蒸发盐岩的风化作用显著。另外, 根据δ¹³C 溶解无机碳DIC 的测量值约为-8.35‰~-13.74‰, 平均为-11.65‰, 利用质量平衡计算得出, 研究区DIC 的主要来源, 约68.5%来自于土壤CO₂, 31.5%来自于碳酸盐矿物的溶解, 进而得出流域岩石化学风化过程消耗的土壤CO₂ 为2.11×105 mol/yr·km², 来自碳酸盐本身的HCO₃ ^-含量为9.6×104 mol/yr·km²。由于地理位置和流域环境以及人为因素的差异, 各支流DIC 来源的比例亦有所差异。     

论水土保持与金沙江农业综合开发：以云南省为例

金沙江流域光、热、土地等自然资源丰富，已经引起各方面的关注，正在进行农业综合开发。由于特殊的地质构造和特定的自然地理环境，其开发必须搞好水土保持。水土保持是金沙江农业综合开发的基础和环境保护的重要内容，水土保持型生态农业是金沙江农业综合开发的道路。     

论黄河上游多民族经济开发区资源开发战略

本文在分析黄河上游多民族经济开发区资源特点的基础上，论证了经济区资源开发模式及开发战略，并就经济蛆内各区域非平衡开发及开发时序提出了一些见解。     

向家坝水电站水库流域土地生态类型研究

分析金沙江下游向家坝水电站水库流域的土地生态类型的形成条件与类型特征，以及水库建成后对库周土地生态条件的影响。     

黄河上游崩滑体成因与稳定性综述

黄河上游龙羊峡至刘家峡段 ,山峻河窄 ,水流湍急 ,水量充沛稳定 ,是我国西北水力资源开发和利用的主要地段。已经修建和正在规划修建的梯级电站大多座落于黄河的高山峡谷之中 ,而这些区段往往是崩滑灾害的多发区。显然 ,崩滑体的稳定性与水电站的安全运行密切相关 ,一旦失稳将会造成难以弥补的损失。因此深入分析研究它们形成的原因 ,掌握规律 ,评价其稳定性 ,是工程技术人员普遍关注的重要工程地质问题之一。黄河上游广泛发育的崩滑体有其发生、发展和衰亡 ,由静到动 ,由动到静的过程。只有掌握它们形成的内在规律 ,才能防患于未然。影响坡…     

黄河上游的阶地与水系变迁

黄河上游于贵德盆地和共和盆地中有７级阶地，再往上游方向存在阶地级数递减的趋势。共和盆地中还有３级古黄河阶地，黄河上游水系是通过一级级河流袭夺相继贯通的，共和盆地与贵德盆地间的黄河古道始于中更新世末期，龙羊峡河段始于６０ｋａ Ｂ．Ｐ．前后，玛多与唐乃亥 间的峡谷河段是２０ｋａ Ｂ．Ｐ．才贯通的。