草原生态系统土壤多功能性及影响机制研究进展

草原是陆地生态系统的关键组成部分,为维持区域生态安全发挥着极为重要的作用。土壤多功能性（soil multifunctionality,SMF）是衡量土壤系统提供多种功能的综合指标,对评估草原生态系统功能和区域可持续发展具有重要指导意义。然而,目前SMF研究仍处于初步阶段,研究对象多为农田生态系统,对于草原等自然生态系统的研究较少。此外,对草原生态系统SMF与植物和土壤微生物的关系以及全球变化对草原生态系统SMF影响机制的认识十分有限。因此,本文从SMF的概念和内涵、量化指标及方法、植物和土壤微生物与SMF的关系、全球变化对SMF的影响以及SMF的空间变异性5个方面论述SMF的研究进展,梳理了草原生态系统SMF的变化特征及影响机制。根据当前研究中存在的问题提出了今后研究应重点关注的内容：（1）统一规整SMF量化体系;（2）SMF在不同空间尺度上的转换机制;（3）不同类型草原生态系统SMF驱动机制;（4）土地利用变化、降水增加、气候变暖和氮沉降等全球变化交互作用对SMF的影响;（5）地上植物功能与SMF的联系和互馈机制;（6）根系功能性状对SMF的影响和植物在不同组织水平对SMF的贡献;...     

Soil and vegetation seasonal changes in the grazing Andean Mountain grasslands

Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna（Vicugna vicugna） and alpaca（Lama pacos）. The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined： total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. Thegood soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.     

Higher species diversity occurs in more fertile habitats without fertilizer disturbance in an alpine natural grassland community

Are there some relationships among species diversity and soil chemical properties of high altitude natural grasslands？ Plant community composition and chemical properties of soil samples were compared to investigate the relationship between soil and species diversity, and the richness in Tibetan alpine grasslands. Results showed that species diversity was significantly positively related to soil organic matter （SOM）, total nitrogen （TN）, available nitrogen （AN）, total phosphorus （TP）, available phosphorus （AP）, and available potassium （AK） in the high alpine grasslands. Margalefs species richness index was also significantly positively related to SOM, TN, AN, and TP. Most soil chemical properties showed significantly positive correlation with species diversity and Margalef＇s richness index. Our results suggested that higher plant species richness index and diversity occurred in more fertile soil habitats in high altitude natural grassland community. In practice, fertilization management for the restoration of degraded grassland should be conducted with reference to the nutrient levels ofnatural grassland without the additional artificial fertilizer and with higher species-diversity and richness index.     

Radiative forcing over China due to albedo change caused by land cover change during 1990–2010

Land cover change affects surface radiation budget and energy balance by chang- ing surface albedo and further impacts the regional and global climate. In this article, high spatial and temporal resolution satellite products were used to analyze the driving mechanism for surface albedo change caused by land cover change during 1990-2010. In addition, the annual-scale radiative forcing caused by surface albedo changes in China＇s 50 ecological regions were calculated to reveal the biophysical mechanisms of land cover change affecting climate change at regional scale. Our results showed that the national land cover changes were mainly caused by land reclamation, grassland desertification and urbanization in past 20 years, which were almost induced by anthropogenic activities. Grassland and forest area decreased by 0.60% and 0.11%, respectively. The area of urban and farmland increased by 0.60% and 0.19%, respectively. The mean radiative forcing caused by land cover changes during 1990-2010 was 0.062 W/m2 in China, indicating a warming climate effect. However, spatial heterogeneity of radiative forcing was huge among different ecological regions. Farmland conversing to urban construction land, the main type of land cover change for the urban and suburban agricultural ecological region in Beijing-Tianjin-Tangshan region, caused an albedo reduction by 0.00456 and a maximum positive radiative forcing of 0.863 WIm2, which was presented as warming climate effects. Grassland and forest conversing to farmland, the main type of land cover change for the temperate humid agricultural and wetland ecological region in Sanjiang Plain, caused an albedo increase by 0.00152 and a maximum negative radiative forcing of 0.184 W/m2, implying cooling climate effects.     

匈奴消失之谜谁能解得开

公元前3世纪前后,中国北方草原上匈奴族兴起,到秦汉之际,第一代单于头曼单于建“头曼城”,以今内蒙古黄河河套及阴山为驻牧及统治中心,建立了强大的部落联盟国家,     

阿拉善草原 以沙漠绿洲荒原草原河流湖泊相间的美丽地方

“阿拉善”系蒙古语,意为“五彩斑谰之地”。阿拉善草原位于我国内蒙古自治区的最西端,隶属于阿拉善盟。阿拉善草原为内蒙古自治区第六大草原,     

在子科滩草原上捡拾阳光

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1981—2018年内蒙古典型草原季节性冻土对气候变化的响应

以1981—2018年内蒙古典型草原季节性冻土为研究对象,通过气候倾向率、Mann-Kendall法、多元线性回归等方法,分析最大冻土时空分布特征、年际、年代际变化,研究影响最大冻土深度变化的气象因子。结果表明：（1） 内蒙古典型草原季节性冻土冻结初日在9—11月,终日在4—6月,年内最大冻土深度出现在2—3月,深度在100~280 cm之间。（2） 最大冻土深度年际变化分为下开口抛物线型、上开口抛物线型、正弦曲线型,从最大冻土深度气候倾向率看呈现减小趋势的站点有68%。（3） 最大冻土深度年代际变化分为逐年代递减、减-增型和无明显变化规律,50%的站点在1989年以后最大冻土深度发生突变。（4） 多元线性回归表明气温冻结指数、年平均风速、年极端最低气温对最大冻土深度产生显著影响。该研究揭示了最大冻土深度存在退化的事实,为草原应对气候变化提供指导,为陆地土壤和大气碳循环交换的研究给出提示。     

黄河北岸兰州段荒漠-草原过渡带土壤粒径分形特征

研究土壤粒径分形特征,可为地区土壤质量评价提供科学依据.利用分形理论分析了黄河北岸兰州段荒漠-草原过渡带土壤粒径分形特征.(1)区域土壤颗粒主要为粉粒和极细砂粒,随荒漠化加重和土壤深度增加,土壤粗粒化,质地均匀性降低,粒径分布(PSD)频率曲线异质程度增大;(2)荒漠化加重和土壤深度增加降低了单重分形维数D_v和多重分形谱参数D₁、D₁/D₀、D₂、△α、△f;(3)D_v、D₁、D₂、D₁/D₀、△α和△f同黏粒、粉粒呈正相关,同砂粒呈负相关;黏粒、粉粒、D_v、D₁、D₂、D₁/D₀、△α和△f与荒漠化减弱程度呈正相关,砂粒与其呈负相关.土壤分形维数能反映区域土壤结构和变化,可为地区生态治理与巩固提升提供技术指导.