基于岩溶生态系统特性的水土流失敏感性评价   总被引：7，自引：0，他引：7  

李阳兵  邵景安  王世杰  李荣彪 《山地学报》2007,25(6):671-677

在岩溶地区大范围内进行土壤侵蚀风险评价需要寻求新的简单有效的方法,建立适合岩溶地区特点的评估模型,才能避免水土流失治理规划的失误。考虑岩溶地区碳酸盐岩成土速率低、存在石漠化等特点,选取土壤允许流失量和退化岩溶生态系统的基岩裸露率,结合年平均降水、坡度、植被指数,在生成各单因素评价图的基础上,在Arcview中完成单因素图的叠加分析,得到贵州省岩溶地区水土流失敏感性综合评价图,并将其划分为不敏感、轻度敏感、中度敏感和强度敏感四级。在此基础上,探讨了贵州省水土流失敏感性的空间分异规律,提出水土流失预防治理的优先区。  相似文献   

洛阳城市-区域生态系统分析与生态城市建设的关键问题   总被引：2，自引：0，他引：2  

王发曾  张文信 《地域研究与开发》2007,26(1):80-85

洛阳市是我国著名的古都之一,在我国乃至世界的城市中具有鲜明特色和典型意义.在科学分析洛阳市域城市-区域生态系统结构、功能的基础上,有针对性地研究并解决生态城市建设的关键问题,对洛阳市的城镇化进程和可持续发展有重要意义.这些关键问题包括:建设洛南新区,增加生态容量;发挥开放空间的生态功能,调整生态城市空间格局;以生态理念经营城市,优化资源配置.  相似文献   

洞庭湖流域水生态系统服务功能经济价值研究   总被引：9，自引：2，他引：9  

李景保  常疆  李杨  周亮  喻小红 《热带地理》2007,27(4):311-316

以洞庭湖流域水生态系统为例,在明确河湖库塘生态系统服务功能内涵的基础上,运用生态学与生态经济学方法对洞庭湖流域各类水生态系统服务功能经济价值进行了评估。结果表明,全流域河湖库塘水生态系统服务功能总价值量为1106.19亿元,约占湖南省2004年GDP(5612.26亿元)的19.7%,其中,城镇和农村生活供水、工农业生产供水、水力发电、内陆航运等直接利用价值为415.698亿元;调洪、输沙、水资源贮存等间接利用价值为690.492亿元。可以认为,流域水生态系统服务功能对湖南省工农业生产的持续发展,维系生态环境健康和人民生命财产安全起到了不可替代的支撑和保障作用。  相似文献   

Stochastic modelling of soil moisture dynamics in a grassland of Qilian Mountain at point scale   总被引：2，自引：0，他引：2  

Liu Hu  Zhao WenZhi  He ZhiBin  Zhang LiJie 《中国科学D辑(英文版)》2007,50(12):1844-1856

Stochastic modeling of soil moisture dynamics is crucial to the quantitative understanding of plant responses to water stresses,hydrological control of nutrient cycling processes,water competition among plants,and some other ecological dynamics,and thus has become a hotspot in ecohydrology at present.In this paper,we based on the continuously monitored data of soil moisture during 2002―2005 and daily precipitation date of 1992―2006,and tried to make a probabilistic analysis of soil moisture dynamics at point scale in a grassland of Qilian Mountain by integrating the stochastic model improved by Laio and the Monte Carlo method.The results show that the inter-annual variations for the soil moisture patterns at different depths are very significant,and that the coefficient of variance(CV) of surface soil moisture(20 cm) is almost continually kept at about 0.23 whether in the rich or poor rainy years.Interestingly,it has been found that the maximal CV of soil moisture has not always appeared at the surface layer.Comparison of the analytically derived soil moisture probability density function(PDF) with the statistical distribution of the observed soil moisture data suggests that the stochastic model can reasonably describe and predict the soil moisture dynamics of the grassland in Qilian Mountain at point scale.By extracting the statistical information of the historical precipitation data in 1994―2006,and inputting them into the stochastic model,we analytically derived the long-term soil moisture PDF without considering the inter-annual climate fluctuations,and then numerically derived the one when considering the inter-annual fluctuation effects in combination with a Monte-Carlo procedure.It was found that,though the peak position of the probability density distribution significantly moved towards drought when considering the disturbance forces,and its width was narrowed,accordingly its peak value was increased,no significant bimodality was observed in the soil moisture dynamics under the given intensity of random fluctuation disturbance.  相似文献   

Effects of surface characteristics on infiltration patterns in an arid shrub desert   总被引：3，自引：0，他引：3  

Xin‐Ping Wang  Xin‐Rong Li  Hong‐Lang Xiao  Ronny Berndtsson  Yan‐Xia Pan 《水文研究》2007,21(1):72-79

Precipitation is often the sole source of water replenishment in arid and semi‐arid areas and, thus, plays a pertinent role in sustaining desert ecosystems. Revegetation over 40 years using mainly Artemisia ordosica and Caragana korshinskii at Shapotou Desert Experimental Research Station near Lanzhou, China, has established a dwarf‐shrub and microbiotic soil crust cover on the stabilized sand dunes. The redistribution of infiltrated moisture through percolation, root extraction, and evapotranspiration pathways was investigated. Three sets of time‐domain reflectometry (TDR) probes were inserted horizontally at 5, 10, 15, 20, 30 and 40 cm depths below the ground surface in a soil pit. The three sets of TDR probes were installed in dwarf‐shrub sites of A. ordosica and C. korshinskii community with and without a microbiotic soil crust cover, and an additional set was placed in a bare sand dune area that had neither vegetation nor a microbiotic soil crust present. Volumetric soil moisture content was recorded at hourly intervals and used in the assessment of infiltration for the different surface covers. Infiltration varied greatly, from 7·5 cm to more than 45 cm, depending upon rainfall quantity and soil surface conditions. In the shrub community area without microbiotic soil crust cover, infiltration increased due to preferential flow associated with root tunnels. The microbiotic soil crust cover had a significant negative influence on the infiltration for small rainfall events (～10 mm), restricting the infiltration depth to less than 20 cm and increasing soil moisture content just beneath the soil profile of 10 cm, whereas it was not as strong or clear for larger rainfall events (～60 mm). For small rainfall events, the wetting front depth for the three kinds of surface cover was as follows: shrub community without microbiotic soil crust > bare area > shrub community with microbiotic soil crust. In contrast, for large rainfall events, infiltration was similar in shrub communities with and without microbiotic soil crust cover, but significantly higher than measured in the bare area. Soil water extraction by roots associated with evapotranspiration restricted the wetting front penetration after 1 to 3 h of rainfall. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Terrestrial vegetation carbon sinks in China, 1981―2000     

FANG JingYun  GUO ZhaoDi  PIAO ShiLong  CHEN AnPing 《中国科学D辑(英文版)》2007,50(9)

Using China's ground observations, e.g., forest inventory, grassland resource, agricultural statistics, climate, and satellite data, we estimate terrestrial vegetation carbon sinks for China's major biomes between 1981 and 2000. The main results are in the following: (1) Forest area and forest biomass carbon (C) stock increased from 116.5×106 ha and 4.3 Pg C (1 Pg C = 1015 g C) in the early 1980s to 142.8×106 ha and 5.9 Pg C in the early 2000s, respectively. Forest biomass carbon density increased form 36.9 Mg C/ha (1 Mg C = 106 g C) to 41.0 Mg C/ha, with an annual carbon sequestration rate of 0.075 Pg C/a. Grassland, shrub, and crop biomass sequestrate carbon at annual rates of 0.007 Pg C/a, 0.014―0.024 Pg C/a, and 0.0125―0.0143 Pg C/a, respectively. (2) The total terrestrial vegetation C sink in China is in a range of 0.096―0.106 Pg C/a between 1981 and 2000, accounting for 14.6%―16.1% of carbon dioxide (CO2) emitted by China's industry in the same period. In addition, soil carbon sink is estimated at 0.04―0.07 Pg C/a. Accordingly, carbon sequestration by China's terrestrial ecosystems (vegetation and soil) offsets 20.8%―26.8% of its industrial CO2 emission for the study period. (3) Considerable uncertainties exist in the present study, especially in the estimation of soil carbon sinks, and need further intensive investigation in the future.  相似文献   

中国陆地生态系统脆弱带遥感模型   总被引：4，自引：0，他引：4  

布和敖斯尔  马建文  韩秀珍  马超飞 《遥感学报》2002,6(3):212-222

本研究通过对我国陆地生态系统8个典型样地的植被指数取样实验和图像计算结果发现，这8个样地植被指数随着水、热因子的季节变化，在时间和空间上具有一定的“绿波推移”和“景观更替”规律。在中国东部湿润的季风区（样地1－3），随着纬度的增高，其月平均植被指数与月平均气温有较大的相关。发现降水相对丰沛的地带，热量和光照条件的变化成为植被生长和变化的自然限制因子；而在中国北方森林－森林草原－典型昌原－荒漠草原－荒漠地带上，随着从东部（湿润地区）到西部（干旱地区）干湿条件的更替，月平均植被指数与降水多寡有较大的正相关关系。在8个样地上都呈现出共同的规律，即定向风的分布与植被指数的分布在时间和空间上具有逆相分布的“套合关系”。尤其在时间上有相逆套合关系，这正是中国北方沙尘暴和沙漠化加剧的自然原因。本研究定量地给出了我国陆地不同经纬度带生态系统脆弱季节和累积时间的分布。  相似文献   

土地利用变化对流域生态需水的影响分析   总被引：15，自引：3，他引：15       下载免费PDF全文

丰华丽  王超  朱光灿 《水科学进展》2002,13(6):757-762

人类对流域生态系统的干预,导致季节性淹没区减少,天然湿地丧失,生态环境的恶化和生物多样性锐减,土地利用方式发生了剧烈变化。以流域整体性理论、物种多样性理论、物种耐性理论和景观生态学理论为基础,分析了土地利用方式对生态需水的影响。结果表明,河岸天然植被生态系统通过削减洪峰、增补枯水和截留污染物的作用,来影响流域的水量分配和水质改善,使流域受水分不足威胁的程度降低,即在更大的时间与空间尺度上,保证了流域对生态水的需求。因此,为了流域生态系统的可持续发展,应采取保护湿地、河溪森林植被、水陆交错带等合理的土地利用方式。  相似文献   

试论大地热流对地表环境与生态演变的影响   总被引：7，自引：2，他引：7       下载免费PDF全文

匡耀求黄宁生  朱照宇胡振宇 《中国地质》2002,29(1):86-95

从地表自然生态系统发育与环境演变的一些难解之迷追索到地球内部能量的影响，对比世界各地主要地理单元的大地热流特征与生态环境特征发现，各地生态环境的优劣与区域大地热流的高低有密切的关系。典型森林生态系统的大地热流比较高，而典型荒漠生态系统的大地热流均比较低。大地热流不仅可能影响区域气候的干湿程度，而且还可能决定一个地区地表生态系统能量供给的下限，是区域生态系统发育与演变过程中一个重要的物种限制因子。大地热流低可能是导致一些盆地生态体系发育不良，进而演变成为沙漠的重要原因。研究大地热流对生态环境退化的影响和机理，了解区域生态体系和现代环境格局形成背景，以及区分环境和生态演化中自然和人文因素的作用具有重要意义，同时将为区域环境和生态建设以及管理决策提供科学依据。  相似文献   

空基GPS遥感地球大气参数方法研究   总被引：6，自引：0，他引：6  

蒋虎 《测绘学报》2001,30(3):238-241

探讨了空基无线电掩星技术应用于遥感地球大气参数方法，并将该方法编制成资料处理软件。对实测资料进行处理和分析后，给出了地球大气参数反演结果。发现指数函数外推法引入数据处理后大大改进了大气温度的归算结果，而对气压归算的影响却很小。比对结果显示我们的遥感结果同国外有关结果基本相符。  相似文献