Comparisons of plant calcium fraction between two different vegetation zones in semi-arid region

To explore the characteristics of plant calcium(Ca) fraction, we analyzed 91 plant species in the Ningxia Habahu National Nature Reserve in Yanchi County of Ningxia and 84 plant species in Zhenglan Banner of Inner Mongolia. Results show that, for the two regions, there is no significant difference between Ca fraction for the same growth type, and between water soluble Ca content or between hydrochloric acid soluble Ca content for plants of the same ecosystem and between hydrochloric acid soluble Ca content for plants of the same family. In similar vegetation zones, there is a significant difference among hydrochloric acid soluble Ca content for different growth types in Yanchi County and Zhenglan Banner,which was the highest for annual herbs and the lowest for perennial herbs. There is a significant difference between acetic acid soluble Ca content and between hydrochloric acid soluble Ca content for sandy land and grassland ecosystems in Yanchi County. There is a significant difference among the same Ca fraction of different families in the same region. Thus, the characteristics of plant Ca fraction are results of long-term adaptation to the environment.     

内蒙古荒漠-草原过渡带灌木群落特征

荒漠-草原过渡带是草原逐渐被荒漠取代的区域.沿阿拉善左旗-乌拉特后旗调查灌木群落,分析植物群落的结构和物种多样性,以期为生物多样性保育提供理论依据.结果表明:该荒漠-草原过渡带有62种植物,隶属于18科、47属,禾本科、藜科、豆科和菊科的植物较多.植物主要由灌木和多年生草本构成,以旱生植物为主,主要包括红砂(Reaum...     

阿拉善高原荒漠植被组成分布特征及其环境解释 Ⅲ.植物功能群多样性对环境因素的响应

采用水分生态型(包括旱生植物、旱中生植物、中生植物和湿生植物)、生活型(灌木、半灌木、多年生草本和一二年生草本)和植物主要光合途径(C3和C4)等方法将研究区的植物种类进行了功能群(functional groups/types)划分,为进一步认知荒漠生态系统的结构、功能和过程提供了分析基础。植物功能类群相对集中是阿拉善荒漠植被组成的一个重要特点,这主要和植物趋于旱化、生态型相对简单密切相关。按优势功能群依次为:PFTs1(旱生C3一二年生草本)、PFTs2(旱生C3多年生草本)、PFTs3(旱生C3灌木)、PFTs4(旱生C3半灌木)、PFTs5(旱生C4一二年生草本)、PFTs7(旱生C4灌木)和PFTs8(旱生C4半灌木)。气候、土壤理化指标决定着植物功能类群的分布。其中年均降水量、湿润系数决定着植物的生态型、生活型在水平地带上的分布特征,同时,也影响C3和C4植物(海拔梯度上)的分布。土壤容重、砂粒、粉粒含量决定着植物生活型特征,而土壤pH值、Cl-、SO42-和Ca2+决定着植物水分生态类型的空间分布。这些结果揭示了极端干旱区植物对胁迫环境响应的多样性,是对极端环境条件下如何理解生物多样性维持机制和可持续发展的较好生态学解释。     

西鄂尔多斯荒漠灌丛生态系统碳密度

为了估算西鄂尔多斯天然荒漠灌丛生态系统碳密度并揭示碳储量在不同层片（灌丛植株、草本层、枯落物层及土壤层）、器官间的分配规律,以该区5种优势荒漠灌丛（沙冬青Ammopiptanthus mogolicus、霸王Zygophyllum xanthoxylum、四合木Tetraena mongolica、半日花Helianthemum songaricum和红砂Reaumuria songarica）群落为对象,测定了5种灌丛生态系统碳密度。结果表明：西鄂尔多斯5种荒漠灌丛生态系统碳密度40.28~55.51 t·hm^-2,其中土壤层碳密度占绝对优势（97.15%~98.51%）,为39.40~54.48 t·hm^-2,且在0~50 cm随着土层深度的增加而增加;植被层生物量密度垂直分布格局表现为灌丛层 > 草本层 > 枯落物层,灌丛层碳密度空间上表现为距离黄河越近碳密度越大（沙冬青和半日花灌丛生物量碳分别占各自植被层生物量密度的92.16%和62.42%）,而草本层碳密度表现出与之相反的规律;草本层根系生物量碳也是灌丛生态系统碳重要组成部分,碳密度8.41~38.29 g·m^-2,占植被层碳密度的5.36%~45.18%;除红砂灌丛外,灌丛草本层地下部分碳密度显著高于地上部分（P<0.05）;灌丛个体碳储量分布表现为枝条 > 根系 > 叶片,粗枝和粗根是单株灌丛碳储量的主要贡献者,且在灌丛种间差异显著（P<0.05）,根系生物量碳占植被层碳储量的20.00%~33.53%,叶片生物量碳占总植被层碳储量的2.02%~24.54%。     

C4 plant species and geographical distribution in relation to climate in the desert vegetation of China

Water use efficiency of C₄ plants is higher than that of C₃ plants, and CAM (Crassulaceae Acid Metabolism) plants have the highest water use efficiency. In the desert regions of China, CAM plants are scarce, and C₄ plants, especially C₄ woody plants, have an important position and role in the desert ecosystem. There are 45 species of C₄ woody plants in the desert regions of China, including semi-woody plants, accounting for 6% of the total desert plant species in China, and most of them are concentrated in the families of Chenopodiaceae and Polygonaceae, which are 19 species and 26 species, respectively. The number of C₄ herbaceous plants is 107 species, including 48 monocot species and 59 dicot species. C₄ woody plants mainly inhabit the northwestern arid desert regions of China west of the Helan Mountains. The drought-resistance and drought-tolerance of C₄ herbaceous plants are worse than C₄ woody plants, and C₄ herbaceous plants mainly inhabit areas with shallow groundwater depth and better water conditions in the desert regions, and are widely distributed along the margins of oases. The abundance of C₄ woody plants is closely correlated with drought, but the abundance of C₄ herbaceous plants increases with wet conditions.     

Impact of habitat heterogeneity on plant community pattern in Gurbantunggut Desert

1IntroductionStudy on the interrelationship between vegetation patterns and their habitat heterogeneity is important to recover and rehabilitate the desert vegetation, stabilize the desert ecosystem and prevent desert expansion. Domestic and foreign researchers have carried out many studies on this topic (Archer etal., 2002; Bolling etal., 2000; Chen etal., 2003; Dasti etal., 1994; Gu etal., 2002, Li etal., 2001; Li etal., 2001; Liang etal., 2003), which have used and refined statistic tech…     

Impact of habitat heterogeneity on plant community pattern in Gurbantunggut Desert

This paper reports a geomorphologic landscape investigation, vegetation survey and soil sampling at 14 sites across the Gurbantunggut Desert between 87o37'09'-88o24'04'E and 44o14'04'-45o41'52'N. The study encountered 8 species of low trees and shrubs, 5 of perennial herbs, 8 of annual plants and 48 of ephemeral and ephemeroid plants. These species of plants represent one-third of the species found in the Gurbantunggut Desert, and their communities make up a large proportion of desert vegetation with great landscape significance. In the investigation we found that the plant communities are accordingly succeeded with the spatial variation of macro-ecoenvironment. Using Principal Component Analysis (PCA) and Correlation Analysis (CA) we found that the micro-ecoenvironment heterogeneity of aeolian sandy soil's physical and chemical properties such as soil nutrient, soil moisture, soil salt, pH etc. only impacted the diversity of herb synusia (PIEherb) of the desert, with a negative correlation. Meanwhile, the impact of microhabitat on the plant community pattern with an antagonistic interaction made vegetation's eco-distribution in a temporary equilibrium.     

我国荒漠植被中的C4植物种类分布及其与气候的关系

C4植物水分利用效率高于C3植物,CAM植物具有最高的水分利用效率。在我国荒漠地区,CAM植物稀少,C4植物,特别是C4木本植物在荒漠生态系统中具有重要地位和作用。我国荒漠地区有C4木本植物45种,包括半木本植物,占我国荒漠植物总种数的6%,集中在藜科和蓼科,分别为19种和26种。C4草本植物共计107种,其中单子叶植物48种,双子叶植物59种。C4木本植物主要分布在贺兰山以西的西北干旱荒漠区。C4草本植物的耐旱性和抗旱能力不如C4木本植物,主要分布在荒漠地区潜水埋深较浅,水分条件较好的区域,在绿洲边缘广泛分布。C4木本植物丰度与干旱紧密相关,C4草本植物丰度随湿润条件而增加。     

古尔班通古特沙漠生境对植物群落格局的影响

This paper reports a geomorphologic landscape investigation, vegetation survey and soil sampling at 14 sites across the Gurbantunggut Desert between 87°37′09"-88°24′04"E and 44°14′04"-45°41′52′Nl. The study encountered 8 species of low trees and shrubs, 5 of perennial herbs, 8of annual plants and 48 of ephemeral and ephemeroid plants. These species of plants represent one-third of the species found in the Gurbantunggut Desert, and their communities make up a large proportion of desert vegetation with great landscape significance. In the investigation we found that the plant communities are accordingly succeeded with the spatial variation of macro-ecoenvironment.Using Principal Component Analysis (PCA) and Correlation Analysis (CA) we found that the micro-ecoenvironment heterogeneity of aeolian sandy soil′s physical and chemical properties such as soil nutrient, soil moisture, soil salt, pH etc. only impacted the diversity of herb synusia (PIEherb) of the desert, with a negative correlation. Meanwhile, the impact of microhabitat on the plant community pattern with an antagonistic interaction made vegetation′s eco-distribution in a temporary equilibrium.     

Desert grassland canopy arthropod species richness: temporal patterns and effects of intense, short-duration livestock grazing

Arthropods living in the canopies of two woody shrub species (a sub-shrub (Gutierrezia sarothrae) and a large shrub (Prosopis glandulosa)) and perennial grasses plus associated herbaceous species, were sampled on 18, 0.5 hectare plots in a Chihuahuan Desert grassland for five consecutive years. Mesquite shrubs were removed from nine plots, six plots were grazed by yearling cattle in August and six plots were grazed in February for the last 3 years of the 5 year study. Arthropod species richness ranged between 154 and 353 on grasses, from 120 to 266 on G. sarothrae, and from 69 to 116 on P. glandulosa. There was a significant relationship between the number of families of insects on grass and G. sarothrae and growing season rainfall but species richness was not a function of growing season rainfall on any of the plants. Several of the arthropod families that were the most species rich in this grassland were found on all of the plants sampled, i.e. Salticid spiders, Bruchid and Curculionid beetles, Cicadellid and Psyllid homopterans, and ants (Formicidae). There were more species rich families that were shared by grasses and the sub-shrub G. sarothrae than with mesquite. The absence of a relationship between growing season rainfall and species richness was attributed to variation in life history characteristics of arthropods and to the non-linear responses of annual and perennial desert grassland plants to rainfall.There were no significant differences in insect family or species richness on any of the plant types as a result of removal of mesquite (P. glandulosa) from selected plots. Intense, short duration (24 h) grazing by livestock during in late summer resulted in reduced species richness in the grass-herb vegetation layer but had no effect on insect species richness on snakeweed or mesquite shrubs. Livestock grazing in winter had no effect on insect species richness on any of the vegetation sampled.     

退化和恢复过程驱动的荒漠草地生态系统有机碳密度变化

荒漠草地是陆地生态系统的重要组成部分,研究退化和恢复荒漠草地生态系统碳密度的变化特征,是精确评估荒漠草地在全球气候变化中作用的关键,也能为中国碳达峰和碳中和提供数据支撑和理论依据.通过野外调查取样和室内分析,研究了腾格里沙漠南缘天然荒漠草地、重度退化荒漠草地和通过植被建设恢复良好的人工-天然荒漠草地的生态系统碳密度,主...     

Summer and winter drought in a cold desert ecosystem (Colorado Plateau) part I: effects on soil water and plant water uptake

We investigated the effects of winter and summer drought on plants of the Colorado Plateau in western North America. This winter-cold, summer-hot desert region receives both winter and summer precipitation. Droughts were imposed for two consecutive years using rainout shelters. Here, we examine drought effects on the hydrologic interactions between plants and soil. We chose three perennial species for this study, representing different rooting patterns and responsiveness to precipitation pulses: Oryzopsis hymenoides, a perennial bunch grass with shallow roots; Gutierrezia sarothrae, a subshrub with dimorphic roots; and Ceratoides lanata, a predominantly deep-rooted woody shrub. Drought effects on plant water status were qualitatively similar among species, despite morphological differences. Summer drought affected the water status of all species more negatively than winter drought. Isotopic analysis of stem water revealed that all three species took up deeper soil water under drought conditions and shallow soil water after a large rainfall event in summer. Thus all three species appeared to use the same water sources most of the time. However, after a particularly dry summer, only the deepest-rooted species continued to take up soil water, while the more shallow-rooted species were either dead or dormant. Our study suggests therefore that increased occurrence of summer drought could favor the most deep-rooted species in ecosystem.     

荒漠绿洲湿地水分来源及植物水分利用策略

水分是干旱区不同景观界面间的水分循环过程与水力联系的主体,维持着干旱区湿地生态系统的结构与功能。为量化水分来源及其对植物水分的贡献率,以河岸灌木湿地和草地盐沼湿地为研究对象,通过测定降水、径流、地下水、土壤水和植物水中δD、δ¹⁸O组成,利用多源线性混合模型分析水分来源对荒漠植物水分利用的贡献率。结果表明：（1） 黑河流域荒漠绿洲湿地年均降水量104.6 mm,约占蒸散量（604.47 mm）的17.03%,具有明显的季节性分布特征。地下水位与土壤含水量的波动取决于河流距离,离河道较近的河岸灌木湿地地下水深度及土壤含水量随季节波动较小,而离河道较远的草地盐沼湿地则变化很大。（2） 当地大气降水线δD=6.33δ¹⁸O+4.04 （R²=0.931）,斜率和截距均略小于全球大气降水线则符合黑河流域湿地整体降水少而蒸散量大的特点。黑河径流δD和δ¹⁸O均值分别为-43.80‰±12.09‰和-8.65‰±23.33‰,地下水为-50.98‰±13.18‰和-9.74‰±25.49‰,土壤水为 -42.07‰±6.89‰和-7.22‰±2.49‰,植物水为-51.84‰±14.46‰和-8.50‰±24.13‰。（3） 地表蒸发是荒漠绿洲湿地土壤氢、氧同位素富集的主要原因。地下水和河水分别是草地盐沼湿地与河岸灌木湿地的主要水分来源,贡献率分别约为61%和50%,表明湿地植物相比于干旱区脉冲式降水更依赖较为稳定的水源。（4） 植物根系深度和毛细根分布是决定荒漠绿洲湿地植物水分利用策略的重要因素。     

干旱半干旱区草原灌丛化的原因及影响-争议与进展

灌丛化作为全球干旱半干旱区草原普遍发生的现象,其定义为草原生态系统中灌木/木本的生物量、密度、盖度的增加以及草本的生物量、密度、盖度的减少。草原灌丛化是气候变化和人类活动多种因素综合作用的结果。过度放牧被认为是引发草原灌丛化的主要原因之一。最新的研究结果表明过度放牧并不能导致草原灌丛化,但过度放牧后实施休牧却改变了草本与灌木的种间作用,有可能导致灌木的扩张。灌木入侵草原长期以来被认为是草原的退化,结论来源于干旱区土壤沙化的情形,在沙化的灌木林中,土壤碳库被局限于灌木株丛及其周边,使草原的碳截留和储存降低。但最近的全球性集成研究表明草原中灌木覆盖率盖度增加对生态系统可以产生积极作用,灌木可以增加土壤水分的下渗,有利于生态系统的水分储存和和养分的转化(如加强氮的矿化过程)。草原灌丛化对生态系统结构和功能影响存在景观尺度和斑块尺度上的差异。进一步研究适应灌丛化过程的管理机制,综合不断变化的气候条件因素和地域因素,采取合理的草原管理策略,对于全球草原区生产具有极其重要的意义。     

中国温带荒漠植物蒸腾过程模拟的若干问题分析

荒漠植被蒸腾过程是研究干旱区生态水文过程的关键一环。当前对植物蒸腾过程模拟的发展方向是光合-气孔导度-蒸腾过程耦合模型,将植物叶片的水碳交换过程通过气孔导度模型耦合起来,从而反映植物生理生态对植物蒸腾的影响特征,也揭示水分胁迫是如何影响植物生长过程的。中国干旱区水分环境是特殊的,温带荒漠植物的生理生态对干旱环境下水分条件的响应过程也是独特的,这决定了荒漠植物蒸腾过程特征的独特性,也使得当前先进的水碳耦合蒸腾模拟方法针对中国荒漠植物需要进行有针对性的修改。这些修改的关键包括对干旱区荒漠植物SPAC水分运动过程、植物水分胁迫的生理生态响应规律和荒漠植物气孔导度变化规律等的理解和模拟。相关的国内研究近些年已经有了一些开展,部分领域也得出了许多有意义和可以借鉴的结论。但是围绕蒸腾模型建立所必需的一些水碳交换过程规律的深入认识和模拟等方面,目前的研究没有比较好的支撑,还需要进一步深入研究。     

沙埋对河西走廊荒漠绿洲过渡带一年生草本植物的影响

一年生草本植物是荒漠绿洲过渡带人工固沙植物群落草本层的优势植物类群,由于风沙活动剧烈,风蚀和沙埋成为一年生草本植物生存的关键选择动力因素。以河西走廊荒漠绿洲过渡带典型一年生草本植物狗尾草（Setaria viridis）、虎尾草（Chloris virgata）、白茎盐生草（Halogeton arachnoideus）和雾冰藜（Bassia dasyphylla）为研究对象,通过0（对照）、1、2、3、5、10、15 cm深度沙埋试验,探寻沙埋对一年生草本植物的影响。结果表明：（1）4种一年生草本植物在0—1 cm埋深出苗率最高,狗尾草最大出苗深度为10 cm,虎尾草和雾冰藜为5 cm,白茎盐生草为3 cm;（2）不同沙埋深度下,4种一年生草本植物的生长（株高和总生物量）和繁殖（种子数量和百粒重）高值区位于2—3 cm埋深,3 cm往下虎尾草和雾冰藜存活率显著下降,而狗尾草仍保持较高存活率;（3）不同沙埋深度下,4种一年生草本植物的渗透调节物质（可溶性糖、可溶性蛋白和游离脯氨酸）含量在2—3 cm埋深达到最高,丙二醛（MDA）含量高值主要位于3—5 cm埋深,叶绿素含量在1—2 cm埋深最高,2 cm往下开始降低;（4）一年生草本植物的生长存活与游离脯氨酸和叶绿素含量呈极显著相关关系,表明二者对保持植物叶片水分平衡和保证光合作用、维持植物正常生长起着更关键的作用。研究可为荒漠绿洲过渡带一年生草本植物恢复提供科学依据。     

黄土丘陵沟壑区乔灌草植物空间优化配置——以甘肃省定西地区为例

黄土丘陵沟壑区水土流失的影响因素有气候、植被、土壤、地形等,而乔灌草植物在空间上的不合理配置是造成该区水土流失严重的主要原因之一。本文选择研究区内限制植物生长与分布的4个关键环境因子 (高程、坡度、坡向和降雨量),利用多属性决策分析(MCDA)的方法,探讨乔灌草植物在空间上的优化配置,将整个研究区划分为5类乔灌草植物空间优化配置主模式和18类乔灌草植物空间优化配置子模式;同时,应用GIS聚类分析与统计分析方法,对所划分的乔灌草植物空间优化配置模式进行空间布局分析。结果显示:农民赖以生存的经济林/农林复合配置模式和农田/庭院经济配置模式是研究区的主要配置模式,占配置模式总面积的76.02％。     

氮素添加对黄土高原荒漠草原草本植物物种多样性和生产力的影响

为了解大气氮沉降对荒漠草原植物物种多样性和生产力的影响,在黄土高原荒漠草原区进行了氮素添加试验,研究了氮素添加量对草本植物物种多样性和植物生产力的短期影响.结果表明:随氮素添加量的增加,群落Margalef物种丰富度指数和Shannon-Wiener多样性指数显著减小,中,高水平氮素添加处理下,群落Margalef物种丰富度指数和Shannon-Wiener 多样性指数分别比对照下降了39.14%、47.07% 和25.57%、31.52%.随氮素添加量的增加,主要优势植物种相对重要值增大;处于弱势的伴生植物种在氮素添加后从群落中消失.氮素添加后,群落生产力显著提高,尤其是低水平氮添加时生产力增加量最大.氮素增加在短期内即可以提高黄土高原荒漠草原草本植物群落生产力,促进优势种群的生长,抑制不占主要地位的伴生种的生长,改变物种组成并降低物种多样性.     

荒漠草原植物群落光合速率对水氮添加的响应

氮沉降和降水格局改变对草原生态系统的结构、功能及关键过程具有重要影响。依托内蒙古乌拉特荒漠草原研究站的全球变化实验平台，研究了氮添加和增减雨（+50%、-50%）及其交互作用对荒漠草原植物群落光合速率和植被特征的影响，分析了荒漠草原植物群落光合速率与植被特征的关系。结果表明：（1）短期氮添加对荒漠草原植物群落光合速率和植被特征没有显著影响（P > 0.05）；（2）降水格局改变显著影响荒漠植物群落光合速率（P < 0.05），减雨50%显著降低了荒漠草原植物群落光合速率和优势种植物高度（P < 0.05），而降水增加50%没有改变群落光合速率和植被特征，降水改变下的土壤水分能很好地解释群落光合速率；（3）氮添加和增加降水的交互效应显著提高了群落的光合速率和优势种植物高度（P < 0.05），而减少降水与氮添加没有显著影响；（4）荒漠草原植物群落盖度、优势种盖度、优势种平均高度与群落的光合速率呈现出指数增加关系，解释率为40%~58%。干旱极大地抑制荒漠草原植物群落光合速率，而氮沉降则依赖于降水增加来提高群落的光合速率，荒漠草原植物群落光合速率与水肥处理下的植物生长特征具有密切的关系。     

多裂骆驼蓬乙醇提取物的杀菌抑菌试验研究

荒漠植物多裂骆驼蓬（Peganum multisectum (Maxim) Bobr）系蒺藜科的一种多年生草本植物,其种子的乙醇提取物对供试的4种常见细菌和9种植物病菌有较好的杀菌、抑菌活性。研究表明,随着提取液浓度的降低,杀菌、抑菌活性逐渐降低,但延长处理时间,其杀菌、抑菌活性升高,其中对金黄色葡萄球菌(Staphylococcus aureus)和普通变形杆菌 (Proteus vulgaris)的杀菌活性最强,杀菌活性可达90%以上。当用1∶10的种子提取液进行真菌孢子萌发抑制试验时,发现对病原真菌的作用中以对苹果白粉菌和黄瓜白粉菌抑菌活性最显著,其孢子的校正抑制率分别达79.52%和77.71%。实验结果表明,荒漠植物多裂骆驼蓬是潜力很大、有待开发的生物农药药用植物资源。