71 resultados para Agricultural ecology

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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以纸坊沟流域为例,构建了黄土丘陵区流域农业生态安全评价指标体系。依据该流域近70 a来的农业生态安全状况,将该流域生态经济系统演变过程划分为4个阶段。从这4个阶段入手分析影响农业生态安全的主要因子,得出了一系列评价指标。结合选取指标的科学性、动态性、实用性等基本原则,参考压力—状态—响应(PSR)模型和多位专家的建议,进一步筛选、分类和确定评价指标,从而建立了一套由生态环境、社会经济、综合功能3大类,20个具体指标构成的适宜于黄土丘陵区的农业生态安全评价指标体系。

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为黄土丘陵区生态安全预警及其建设提供科学依据。【方法】以纸坊沟流域近70年代表年份生态安全态势及影响因子的分析为基础,参考压力-状态-响应(PSR)模型建立农业生态安全预警指标体系。运用层次分析法(AHP)和德尔菲法(Delphi)确定指标权重,采用综合指数法计算生态安全质量值,用演化轴解释生态安全预警模式,定量评价该流域1938~2005年的农业生态安全状况,并预测2015年的发展趋势。【结果】纸坊沟流域1938年处于蓝灯区,无需预警;1958年为黑灯区,需作生态安全恶化速度预警;1975和1985年处于红灯区,需作生态安全较差状态预警;1995年处于黄灯区,2005和2015年继续向良好方向演化,均不需预警,但从发展趋势来看,预计人口密度于2020年左右进入警戒状态。【结论】研究结果与该流域的实际情况相符,该指标体系和生态安全预警模型可以应用于黄土丘陵区。

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目录

第一部分总论

环境流体力学――它的意义,内容与方法 李家春

用于大气环流模式的陆面物理过程参数化研究进展 戴永久,曾庆存,欧阳兵

植被-陆面过程耦合模式的动力框架 欧阳兵

第二部分均匀下垫面的陆面过程

干旱地区陆面过程的研究 李家春,姚德良,沈卫明

阿克苏地区陆面蒸发的数值研究 沈卫明,姚德良,李家春

塔里木盆地陆气水热交换数值模拟 姚德良,沈卫明,李家春

植物固沙区土壤水热运移耦合模型研究 姚德良,李家春,沈卫明

Numerical simulation of watercycling and heat balance in agricultural ecosystems D.L.Yao,W.M.Shen and J.C.Li

在植物耗水条件下土壤水分动态的数值模拟 姚德良,邱克俭,冀伟,孙菽芬

干旱地区陆面过程耦合模式及其应用 李家春,姚德良,沈卫明

Modelling of terrestrial ecosystem B.Ouyang

森林生态系统生物循环过程的耦合模型(BCM)及其数值模拟 欧阳兵

森林生态系统生物能流的瞬态分析 欧阳兵

第三部分非均匀下垫面的陆面过程

Turbulence in the atmosphere and ocean J.C.Li

非均匀下垫面上大气边界层的研究进展 徐大鹏

非均匀植被的群体蒸发 徐大鹏

第四部分 区域尺度以上的陆面过程与水文模型

Sensitivity of IAP two-level AGCM to surface albedo variations Z.H.Lin,Q.C.Zeng and B.Ouyang

估算区域蒸发的能量法研究 聂松媛,徐丰

用卫星数据估算区域水资源蒸发研究 聂松媛

负轮分析法在水环境规划与管理中的应用 聂松媛

第五部分 陆面过程观测的指标体系

Mathematical modelling and index system in ecology J.C.Li

陆面过程的观测指标体系研究 欧阳兵,李家春,姚德良

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1. The stripe-backed weasel Mustela strigidorsa is one of the rarest and least-known mustelids in the world. Its phylogenetic relationships with other Mustela species remain controversial, though several unique morphological features distinguish it from congeners. 2. It probably lives mainly in evergreen forests in hills and mountains, but has also been recorded from plains forest, dense scrub, secondary forest, grassland and farmland. Known sites range in altitude from 90 m to 2500 m. Data are insufficient to distinguish between habitat and altitudes which support populations, and those where only dispersing animals may occur. 3. It has been confirmed from many localities in north-east India, north and central Myanmar, south China, north Thailand, north and central Laos, and north and central Vietnam. Given the limited survey effort, the number of recent records shows that the species is not as rare as hitherto believed. Neither specific nor urgent conservation needs are apparent.

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The black-crested gibbon, Hylobates concolor, is one of the few species of gibbons that has not yet been the subject of a long term field study. Field observations in the Ai Lao and Wu Liang Mountains of Yunnan Province, China indicate that in this area the habitat and ecology of this species differ markedly from those of other gibbons that have been studied to date. These differences are correlated with some behavioral differences. In particular, these gibbons apparently have greater day ranges than other gibbons. It has also been suggested that this species lives in polygynous groups. To demonstrate this requires observation of groups with two or more females with young. Our own observations and those from other recent studies suggest that there are alternative explanations consistent with available data.

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The Yunnan snub-nosed monkey (Rhinopithecus bieti), an endangered species in China, has received more protection in theory than in practice. Therefore it is on the very verge of extinction. The population of the species was estimated less than 2,000 individuals spread in 19 distinct groups. It was confirmed that the monkey was confined to the Yunling Mountain System, the area between the Yangtze River (Changjiang, aka Jinshajiang) to the east and the Mekong River (Lancangjiang) to the west. We further concluded that a lowland belt to the east, about 100 km long and 20 - 30 km wide was not suitable habitat for the monkeys, and appeared to serve as the natural ecogeologic barrier for the species. Our results indicated that the southern limit of the distribution was at Longma (26-degrees 14'N), and that the northern limit of the distribution was at Xiaochangdu (29-degrees 20'N). The distribution area of the species was substantially smaller than previously estimated. There were substantial ecological differences between the southern and northern parts of the species range. The monkey was found only in fir-larch forest.