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971.
The Tibetan Plateau (TP) holds fundamental ecological and environmental significances to China and Asia. The TP also lies in the core zone of the belt and road initiative. To protect the TP environment, a comprehensive screening on current ecological research status is entailed. The teased out research gap can also be utilized as guidelines for the recently launched major research programs, i.e. the second TP scientific expedition and silk and belt road research plan. The findings showed that the TP has experienced significant temperature increase at a rate of 0.2°C per decade since 1960s. The most robust warming trend was found in the northern plateau. Precipitation also exhibited an increasing trend but with high spatial heterogeneity. Changing climates have caused a series of environmental consequences, including lake area changes, glacier shrinkage, permafrost degradation and exacerbated desertification. The rising temperature is the main reason behind the glaciers shrinkage, snow melting, permafrost degradation and lake area changes on the TP and neighboring regions. The projected loss of glacial area on the plateau is estimated to be around 43% by 2070 and 75% by the end of the century. Vegetation was responsive to the changed environments, varied climates and intensified human activities by changing phenology and productivity. Future global change study should be more oriented toward integrating various research methods and tools, and synthesizing diverse subjects of water, vegetation, atmosphere and soil.  相似文献   
972.
973.
子午岭地区草本药用植物种间联结性研究   总被引:1,自引:0,他引:1  
该研究以子午岭地区桥山林区最常见的几种药用植物为研究对象,通过种间联结系数(AC)、Ochai指数(OI)、Jaccard指数(JI),结合Pearson系数和以及χ2统计量对研究区内的药用草本植物两两之间及药用草本植物与本区常见优势木本植物间的种间联结性进行分析,以了解子午岭地区野生药用植物资源的分布。结果显示:(1)药用草本物种间白头翁与苦参、黄精与沙参显示出极显著的正联结关系,而穿龙薯蓣与刺儿菜、翻白草、祁州漏芦、茵陈蒿、远志,刺儿菜与玉竹,翻白草与黄精,黄精与茵陈蒿则表现出极显著的负联结关系。(2)木本植物与药用草本植物的关系因物种不同而异,其中刺槐与刺儿菜、辽东栎与穿龙薯蓣、辽东栎与玉竹、辽东栎与黄精、白桦与穿龙薯蓣均具有极显著的正联结关系;而刺槐与穿龙薯蓣、玉竹,辽东栎与刺儿菜、翻白草、茵陈蒿、苦参,槲栎与龙牙草、茵陈蒿,白桦与天南星、茵陈蒿,油松与益母草,野胡桃与黄精均具有极显著的负联结关系。(3)基于物种关联性的不同,将药用草本植物划分为3个生态种组。研究认为,种间联结性的研究结果可以反映物种的生理生态特性,对该区药用经济植物的资源开发与利用具有一定参考价值。  相似文献   
974.
Understanding the factors that affect the health of a semi-arid region's eco-economy is necessary for its sustainable development. The health evaluation, or diagnoses, of an eco-economy at the small watershed scale requires the integrated analysis of ecological, economic, and social factors, yet few studies have achieved this. The health of an eco-economy comprises three components: vigor, organization, and resilience. We use an analytic hierarchy process to develop a health evaluation index system that evaluates the health of an eco-economy system. We then use this diagnostic method to explore the factors affecting the health status of a semi-arid loess watershed in China in 2007 and 2009. The results show that between 2007 and 2009 the health status of the eco-economy improved from the “better” stage to the “benign circle” stage. The primary productivity of grassland, land productivity, rural per capita net income, number of livestock per household, input–output ratio, commodity rate of farm produce, and labor productivity were the main factors influencing the health of this eco-economy. Furthermore, this study shows that the eco-economy depends on material input from regions outside the watershed.  相似文献   
975.
Wei-Chun Li  Dong Liu 《ZooKeys》2015,(475):113-118
Metaeuchromius glacialis Li, sp. n. is described from the Tibetan glacier area of China. The new species is similar to Metaeuchromius circe Bleszynski by the distal projection of costa exceeding the apex of valva, and the phallus with strong spine-like cornuti in the male genitalia. Images of male adult, tympanal and scent organs as well as genitalia of the new species are provided.  相似文献   
976.
【目的】未来数十年的气候变化预计会是造成很多物种生境丧失的一个重要因素。对适应能力相对脆弱的地方性物种,预测气候变化对其生境的影响将对生物多样性保护具有重要意义。【方法】本文基于最大熵模型,对珍稀蝉科中国特有种枯蝉Subpsaltria yangi在当前和未来气候条件下的生境适宜度进行了评估。【结果】结果表明,枯蝉主要局限分布于黄土高原及邻近地区。预计至2050年,即使在温和的气候变化情景下,枯蝉的生境面积也会明显减少。影响枯蝉栖息地分布的关键因素为年平均气温、最冷月的最低气温、最冷季的平均气温和最潮湿月份的降水量。枯蝉现存种群栖息地应当受到保护,甘肃天水和陕西延安地区应作为枯蝉分布的核心区予以保护,以应对气候变化对其生境带来的影响。【结论】本研究获得的枯蝉适宜生境分布图可以为该稀有物种的新种群发现、现生种群分布地土地规划管理以及有效的自然保护区设立提供重要信息。  相似文献   
977.
杜维波  卢元 《生物多样性》2019,27(11):1260-773
物种编目是了解生物多样性的基础。本文收集已出版的专著和文献, 查阅标本馆的馆藏标本信息, 在此基础上, 对黄土高原的石松类和蕨类植物的多样性和地理分布数据进行统计和分析。科属排列采用Flora of China的分类系统, 科属界定依据分子系统学的最新研究成果。结果表明, 黄土高原共有石松类和蕨类植物18科42属165种2亚种5变种, 其中中国特有种35种, 占总种数的20.35%。种类数量最多的5个科依次为凤尾蕨科(29种, 含种下单位, 下同)、鳞毛蕨科(28种)、水龙骨科(19种)、蹄盖蕨科(16种)和铁角蕨科(16种); 种类数量最多的6个属依次为铁角蕨属(Asplenium, 16种)、鳞毛蕨属(Dryopteris, 15种)、耳蕨属(Polystichum, 12种)、岩蕨属(Woodsia, 11种)、卷柏属(Selaginella, 10种)和瓦韦属(Lepisorus, 10种)。黄土高原的石松类和蕨类植物中, 无珍稀濒危保护植物, 无中国特有属。依据生态类型可划分为4类, 即土生植物(112种)、石生植物(75种)、附生植物(18种)、水生植物(3种), 该区域石松类和蕨类植物土生或石生的种类占总种数的89.53%。在地理分布上, 黄土高原石松类和蕨类处于我国现生类群分布的边缘区域, 这与我国的石松类和蕨类分布规律基本一致。  相似文献   
978.
979.
黄土丘陵区不同植被根系数量特征及离散程度   总被引:1,自引:0,他引:1  
董宾芳  石辉  傅瓦利 《生态学杂志》2007,26(12):1947-1953
根系的空间分布与植物自身的生物学特性、土壤资源、土壤结构等因素有密切的关系。对黄土丘陵区3种植被类型根系的数量特征及离散程度进行了研究,结果表明:山杨、灌丛和油松林地的根系数量随着根系径级的增加而减少;山杨林地根系最丰富,油松林次之,灌丛地根系数量最少。3种植被根系离散程度随深度的增加有明显的差异,其中灌丛和山杨林根系的离散指数在15cm深处达到最大值,随后又降低,而油松林的变化没有明显规律。无论是表层或是深层,3种植被根系离散指数均小于1,说明植被根系在土壤中呈聚集分布。在土壤相对均质的黄土地区,根系的空间聚集分布可能是根系的固有特性。  相似文献   
980.
Question: Is there any generality in terms of leaf trait correlations and the multiple role of leaf traits (response to and/or effect on) during secondary succession? Location: A secondary successional sere was sampled at four different ages since abandonment from several years to nearly 150 years on the Loess Plateau of northwestern China. Method: Specific leaf area (SLA), leaf mass per area (LMA), leaf nitrogen (Nmass, Narea), leaf phosphorus (Pmass, Parea) and leaf dry matter content (LDMC) were measured for all species recorded in the successional sere. Above‐ground net primary productivity (ANPP) and specific rate of litter mass loss (SRLML) were measured as surrogates for ecosystem properties. Soil total carbon (C) and nitrogen (N) were measured in each stage. Leaf traits were related to ecosystem properties and soil nutrient gradients, respectively. Results: LMA is correlated with Narea and Parea' and negatively with Nmass. Correlation between Narea and Parea was higher than between Nmass and Pmass. At the community level, field age, community hierarchy and their interaction explain 64.4 ‐ 93.5% of the variation in leaf traits. At the species level, field age explains 22.4 ‐ 45.5% of the variation in leaf traits (excl. Parea) while plant functional group has a significant effect only for Nmass. LDMC is correlated with ANPP and negatively with SRLML; Pmass is correlated with SRLML. Conclusions: Mean values of LMA, Nmass and Narea are close to the worldwide means, suggesting that large‐scale climate has a profound effect on leaf mass and leaf nitrogen allocation, while environmental gradients represented by succession have little influence on leaf‐trait values. Correlations between leaf traits, such as LMA‐Narea, LMA‐Parea and LMA‐Nmass shown in previous studies, are confirmed here. Although none of the leaf traits is proved to be both a response trait and an effect trait independent of time scale and community hierarchy, mass‐based leaf N is likely a sensitive response trait to soil C and N gradients. In addition, LDMC can be a marker for ANPP and SRLML, while mass‐based leaf P can be a marker for SRLML.  相似文献   
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