浑善达克沙地种子植物属的地理成分分析

运用植物区系地理学的基本原理,通过对浑善达克沙地种子植物属的组成、地理成分统计、排序和分析,结果表明:浑善达克沙地物种的多样性较高,属的分布区类型以温带成分占绝对优势,其中北温带分布型所占的百分比数最高,占本区种子植物区系中非世界属数的37.2%,其次是旧大陆温带分布,反映出该区系的温带性质,体现了浑善达克沙地植物分布与本地区的气候带相适应的结果。本区系具有一定数量的古老成分,地理成分混杂且具有明显的过渡性,同时该区系又具有明显的脆弱性;特有程度较低。     

腾格里沙漠东南缘4种灌木的生物量预测模型

灌木生物量模型是预测灌木生物量最有效的方法。选择腾格里沙漠南缘荒漠生态系统中常见的4种灌木（驼绒藜(Ceratoides latens)、盐爪爪(Kalidium foliatum)、珍珠猪毛菜(Salsola passerina)、红砂(Reaumuria soongarica)）为研究对象,以株高（H）和冠幅（C）的复合因子灌木体积（V）为自变量,通过回归分析,分别构建了4种灌木和混合物种的叶、新生枝、老龄枝、地上部分、地下部分和整株生物量的预测模型。通过决定系数（R2）、估计值的标准误（SEE）和回归检验显著水平（p＜0.05）筛选出了最优的生物量估测模型。结果显示:4种灌木的生物量模型主要以幂函数W=aVb为最优模型,少数以三次函数W=a+bV+cV2+dV3为最优模型。灌木生物量与V之间呈极显著的相关关系（p＜0.001）,决定系数较高,分别为:叶片（0.775＜R2＜0.866）,新生枝（0.694＜R2＜0.840）,老龄枝（0.819＜R2＜0.916）,地上部（0.832＜R2＜0.917）,地下部分（0.74＜R2＜0.808）,全株（0.811＜R2＜0.912）,说明预测模型可以应用于此4种灌木的生物量估算。不同物种之间及不同器官之间的生物量模型存在差异,在实际使用中,要根据物种来选择相应的模型。生物量模型的建立有助于全面估算荒漠生态系统的生物量,并进一步评估生态系统不同碳库的碳存储量与碳循环。为有效提高荒漠草地碳储量、合理实施生态系统管理和人为干预提供科学依据。     

Millennial-scale evolution of Hunshandake Desert and climate change during the Holocene in Inner Mongolia,northern China

The Hunshandake Desert is located at the northern edge of the East Asian monsoon region,and its natural environment is sensitive to monsoonal changes.Geologic records suggest that desert evolution corresponding to climate change had experienced several cycles in the Holocene,and the evolutionary process can be distinguished by four dominant stages according to changing trends of the environment and climate.(1) Holocene Ameliorative Period(11.0-8.7 cal ka B.P.),when the desert area gradually shrank following an approaching warm-wet climate and strengthening summer monsoon.(2) Holocene Optimum(8.7-6.0 cal ka B.P.),when the majority of moving sand dunes were stabilized and vegetation coverage quickly expanded in a suitable warm-wet climate and a strong summer monsoon.(3) Holocene Multivariate Period(6.0-3.5 cal ka B.P.),during a low-amplitude desert transformed between moving and stabilized types under alternating functions of cold-dry with warm-wet climate,and winter monsoon with summer monsoon.(4) Holocene Decay Period(since 3.5 cal ka B.P.),when the desert area tended to expand along with a weakened summer monsoon and a dry climate.     

Growth, ionic and osmotic relations of an Allenrolfea occidentalis population in an inland salt playa of the Great Basin Desert

Variation in growth, physiology and ionic relations patterns of Allenrolfea occidentalis, a perennial halophyte of dry habitats, was studied under field conditions from May 1996 to November 1997. An A. occidentalis community has a characteristic soil pH of 7·3–8·3. During the two years, the population was exposed to great variations in soil salinity, from 29 to 146 dS m⁻¹, and soil moisture, ranging from drought (9·2%) to wet (19%). The salt concentrations were significantly higher in the surface soil layers than in the subsurface layers. Seasonal changes in dry weight are directly related to soil salinity stress. Allenrolfea occidentalis had greater growth and biomass production under saline conditions. Na⁺and Cl⁻ions were accumulated in plant tissues in much greater amounts than K⁺, Ca²⁺, and Mg²⁺. Soil salinities were significantly reduced at the end of the growing season. Water potentials of the shoots decreased significantly with increasing salinity. The plant (F_v/F_mratio) was more affected by salinity and irradiation levels during the summer period.     

荒漠草地植物多样性对肥料添加的响应

选择古尔班通古特沙漠南缘典型丘间低地荒漠草地,采用完全随机区组设计,通过设置8个肥料添加处理（CK、N、P、K、NP、NK、PK、NPK）,研究了荒漠草地植物多样性对不同肥料添加处理的响应,得出以下结论:（1）研究区植被丰富度指数在P、NP、PK肥添加的作用下显著增加,而其余处理对其影响不显著, NK处理使研究区植被丰富度指数下降;多度指数在不同肥料添加下表现出与丰富度指数相同的特征;（2）不同施肥处理对荒漠草地的生物多样性有不同程度的影响:P肥、NP肥的添加使Simpson指数、Shannon-Weiner指数和Pielou指数与对照（CK）相比显著增加（p＜0.05）,表明P肥添加、NP肥添加是增加新疆荒漠草地生物多样性的有效措施;（3）植被丰富度指数在年际间的变化表现为:2009年开始施肥,2010年丰富度指数下降,2012年丰富度指数上升,即随着施肥时间的推移,同一块样地丰富度指数呈先下降后增加的趋势,均匀度指数随时间呈上升趋势。     

塔克拉玛干沙漠腹地天然植被调查研究

调查研究表明:塔克拉玛干沙漠腹地非河流影响区域,天然植物隶属于9科、12属、12种。生长型以多年生草本为主,占50%。建群种植物区系以塔里木特有种为主。绝大多数植物为风媒植物,根蘖能力很强。植物群落分为4个群系、9个群丛。多年生草本群落常由纯种群构成单优群落,灌木群落结构松散。随着沙丘的移动与掩埋,植物群落周而复始的生存于丘间地。     

气候变化对中国木本植物物候的可能影响

本文根据我国的３０年的物候资料和气候资料的统计分析，论证了气温是影响中国木本植物物候的主要因子，在此基础上建立了物候与年平均气温的线性统计模式，又利用此模式分析计算了未来全球年平均气温升高０．５－２．０℃和未来大气中ＣＯ２浓度倍增而增暖情况下，我国主要木本植物物候期的大致变幅。     

五台山冰缘地貌植物群落的数量分类与排序

在野外样方调查的基础上,采用双向指示种分析法(TWINSPAN)和除趋势对应分析法(DCA)对五台山冰缘地貌植被进行了数量分类和排序研究,将五台山冰缘地貌植被分为13个群丛,13个群丛是不同冰缘地貌生态景观的重要组成要素,各群丛的群落学特征与冰缘地貌生境有密切的生态关系。DCA样方排序结果和种排序结果表明,五台山冰缘地貌植物群落分布格局是土壤、水分、热量等综合环境因子决定的。而不同冰缘地貌上植物群丛优势种的分布格局在很大程度上决定着植物群丛类型的分布格局,反映出植物群落类型和物种分布随冰缘地貌类型及环境梯度变化的趋势。     

塔克拉玛干沙漠腹地地表辐射与能量平衡

利用2013年塔克拉玛干沙漠塔中流动沙面地表辐射、土壤热通量、土壤温湿度和湍流通量观测资料,分析了沙漠腹地地表辐射和能量收支特征及闭合状况。结果表明：除潜热通量外,其余地表辐射各分量和能量平衡分量的月平均日变化结果整体均表现为标准的单峰型日循环形态,其中R_s↓与R_s↑变化同步,R_l↑、R_l↓滞后R_s↓0.5 ~ 1 h。各分量均表现出夏季高、春秋季次之、冬季低的季节波动性。干旱和极低的植被覆盖造成沙漠腹地全年潜热通量始终较为微弱,约占净辐射的2.8%,感热通量成为能量的主要消耗形式,约占净辐射的49%。偶尔的降水会刺激潜热通量突然增加。地表反照率相对较高且稳定,日变化呈早晚大、正午小的“U”型趋势,并具有明显的冬季高、夏季低的季节波动性,年均值0.28,月均值0.25~0.32。能量残差各月的日变化也均呈单峰曲线,日出后和日落前能量闭合程度最佳,并出现过闭合现象,全年夏季小,春秋季次之,冬季较大,月平均日峰值5.1~99.9 W·m^-2。土壤表层热储存是影响该地区能量平衡的重要因子之一,考虑表层土壤热存储后,地表能量闭合率达75.3%,能量闭合率夏季 > 春季 > 秋季 > 冬季,白天相比夜间有大幅提升。     

Mercury distribution and accumulation in typical wetland ecosystems of Sanjiang Plain, Northeast China

Total mercury in soil,water,plant,insects,fishes and bird feathers were determined to study mercury distribution and accumulation in typical wetland ecosystems in the Sanjiang Plain,Northeast China.Results show that total mercury concentrations in soils of Deyeuxia angustifolia wetland and Carex lascarpa wetland are 0.046 mg/kg and 0.063 mg/kg,respectively.Total mercury concentration in water bodies is 0.053 μg/L on average.Of four plants studied,total mercury in moss is the highest with the mean of 0.132 mg/kg.Of 10 terrestrial insect species studied,total mercury in centipede(Scolopendra spp.) is the highest with the mean of 0.515 mg/kg while total mercury in grasshopper(Oxya spp.) bodies is the lowest.Total mercury concentrations in the herbivorous,omnivorous and predatory insects are 10.18 ng/g,16.47 ng/g and 213.35 ng/g on average,respectively.Total mercury concentrations of the adult feather(549.88 ± 63.04 ng/g),nestling feather(55.15 ± 23.53 ng/g),and eggshell(22.05 ± 5.96 ng/g) of the Grey heron(Ardea cinerea) are higher than those of the Great egret(Egretta alba)(adult feather:446.57 ± 90.89 ng/g;nestling feather:32.99 ± 17.15 ng/g;eggshell:21.02 ± 3.17 ng/g) in the wetlands of the Sanjiang Plain.The bioconcentration factors decrease in the order of piscivorous fish muscle > omnivorous fish muscle > herbivorous fish > insect.