塔里木河干流中游胡杨种群特征与动态分析

通过样地调查和数据统计,编制胡杨种群静态生命表,绘制存活曲线、生存率曲线、累计死亡率曲线、种群死亡密度曲线和危险率曲线,分析种群数量特征。同时,结合种群动态量化方法及时间序列预测,分析种群数量动态变化。结果表明:胡杨种群年龄结构呈金字塔型,幼龄级所占比例较大;存活曲线接近Deevey C(凹)型,且动态指数大于0,表明胡杨种群结构合理,为增长型种群。4个函数曲线表明,胡杨种群前期幅度变化较大,后期趋于稳定。时间序列分析表明,由于丰富的后续资源,种群能够稳定生长。     

梭梭与白梭梭气体交换特征对比分析

梭梭[WTBX](Haloxylon ammodendron)与白梭梭(H.persicum)[WTBZ]是古尔班通古特沙漠植物群落2个最主要的建群种。通过对梭梭与白梭梭光合特性及相关环境因子的同期观测,探讨其光合响应特征及其与环境因子关系的异同。结果表明：梭梭对弱光的利用能力大于白梭梭,而白梭梭利用强光的能力大于梭梭。梭梭和白梭梭净光合速率[WTBX](Pn)、气孔导度(Gs)、蒸腾速率(Tr)的日变化特征均为“单峰”型,但Pn、Gs峰值出现时间略有差异,Tr的峰值出现时间为16:00。根据梭梭和白梭梭Pn、胞间[WTBZ]CO2浓度[WTBX](Ci)及气孔限制值(Ls)的变化方向,推测梭梭光合“午休”主要由气孔因素引起。白梭梭日平均Pn、Tr和WUE（水分利用效率）均高于梭梭,说明白梭梭是一种高光合、高蒸腾、高水分利用效率的物种。相关分析表明,对梭梭、白梭梭的Pn影响最显著的环境因子是光量子通量密度(PPFD)。     

古尔班通古特沙漠梭梭和白梭梭树干茎流特征

通过对古尔班通古特沙漠2个主要建群种梭梭(Haloxylon ammodendron)和白梭梭(Haloxylon persicum)树干茎流的野外实验观测,分析植株冠层和降雨特征对树干茎流形成的影响,并明确了树干茎流量在降雨再分配中的比例。结果表明：当降雨量≥2.4 mm时,梭梭和白梭梭开始有树干茎流产生。梭梭、白梭梭的树干茎流量随树冠体积的增大而增加,但是,当梭梭树冠体积大于4 m³,白梭梭树冠体积大于1.5 m³时,树干茎流量随树冠体积的增加不再增大,甚至有下降趋势。梭梭和白梭梭的树干茎流量和降雨量之间存在显著正相关,累计树干茎流量分别占降雨总量的9.1%和6.4%。梭梭和白梭梭的集流率均随降雨量增加而增大,能够有效地将树干茎流汇聚到树干基部, 梭梭表现出更强的汇集树干茎流的潜力。     

孑遗植物新疆野苹果种群生命表与生存分析

应用”空间代替时间”及匀滑技术,编制新疆野苹果种群特定时间生命表,绘制其死亡曲线和存活曲线,分析其种群数量动态变化.结果表明:新疆野苹果种群处于生命力相对旺盛的中龄期(Ⅴ、Ⅵ龄级比例最高),但因幼龄个体数目稀少而存在衰退趋势;新疆野苹果的死亡率和消失率随着龄级的增加呈现先减小后增加的趋势,种群死亡率在Ⅰ龄级最高(83.2％),Ⅶ龄级最小(28.6％),种群动态表现为前期衰退、中期相对稳定、后期不稳定的特点.     

白梭梭开花及风媒传粉特点

对白梭梭的花期物候、开花式样、风媒传粉特点进行了观察,对柱头可授性、花粉一胚珠比(P／O)做了检测。白梭梭的花部特征有许多适应风媒传粉的特点：花小、无花冠、具光滑的花粉外壁、指状的柱头突起、较高的花粉一胚珠比。重力玻片法检测结果表明,白梭梭风媒传粉发生在晴朗、昼夜温差大、空气湿度高的4月中下旬;花期持续时间约14d,传粉盛期集中在前3d,花粉短距离传粉效率较低;对荒漠突发不良环境的适应,白梭梭具有爆发性的开花传粉机制。     

准噶尔盆地东南缘天然更新梭梭苗期动态生命表及生存分析

运用动态生命表方法,观察和分析了准噶尔盆地东南缘天然梭梭(Haloxylon ammodendron)幼苗生长动态。结果显示:梭梭当年生幼苗存在两个存活率下降快、死亡率和致死力高的阶段。第一阶段从4月1日至5月1日幼苗死亡率为69.9%。第二阶段为6月15日至7月15日,幼苗死亡率由79.1%增加到85.1%。早期生长阶段的高死亡率,是由于动物咬食和不利气候因素的影响;而后一阶段死亡率较高的原因,是由于浅层土壤水分下降所致。存活曲线属DeeveyⅢ型,表明幼苗早期个体死亡率较高,此阶段是幼苗天然更新的关键时期。幼苗期动态生命表的研究可以为梭梭天然更新及其管理措施的制定提供科学依据。     

遵义地区核桃云斑天牛自然种群生命表研究

为了探明贵州省遵义地区核桃云斑天牛自然种群变化因子,采用特定时间调查取样方法组建该地区云斑天牛的自然种群生命表。分析结果表明,遵义地区云斑天牛的自然种群数量正呈现增长的趋势。通过生命表和排除控制指数得知,影响云斑天牛自然种群最主要的致死因子是云斑天牛的卵孵化率低,其次是四斑露尾甲和阎甲的捕食作用,寄生性的跳小蜂和花绒寄甲也起到比较重要的寄生作用。因此,实际应用中可以着重研究导致卵不能成功孵化的原因对该虫进行有效防治。     

古尔班通古特沙漠白梭梭群落林下层物种多样性的空间分异

以野外样方调查数据为基础,采用重要值计算了多样性指数、均匀度指数、丰富度指数、优势度指数,对古尔班通古特沙漠南缘至腹地白梭梭群落林下植被的物种多样性进行了研究。结果表明:受降水梯度的影响,从南缘至腹地植被盖度变化范围在14%～36%,除南缘取样点(S1)受人类扰动较大,盖度有些波动外,总体呈现明显的下降趋势。但植株种群密度差异较小,初步推断,植被盖度的差异主要是由植株个体大小造成的,而不是植株种群密度。南缘至腹地,各样地的多样性指数、均匀度指数、丰富度指数均表现为先减后增的变化趋势,优势度指数变化趋势则与之相反。各指数的变化范围:物种数在5.9～11.4种/m2,多样性指数变化范围在1.0340～2.0971,各样地均匀度指数在0.6068～0.8760,优势度指数为0.2767～0.6643。距沙漠南缘6.57km处是物种多样性的一个重要转折点,是物种多样性较不丰富的地带。同时,对白梭梭群落林下植被在1m×1m,20m×20m,100m×100m三种尺度下,南缘到腹地植物物种数的变化分析得出,在100m2尺度以下,白梭梭群落林下植被的物种多样性随空间尺度的增大而增大。     

Spatial heterogeneity of soil chemical properties between Haloxylon persicum and Haloxylon ammodendron populations

Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soil resources distributed differently in different locations, and present significant spatial heterogeneity in desert ecosystems. In this study, conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations, Haloxylon persicum Bunge ex Boss., which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C. A. Mey.) Bunge, which inhabits interdunes in the Gurbantunggut Desert of Xinjiang, China. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (AN) and available phosphorus (AP) were significantly higher in H. ammodendron populations than that in H. persicum. The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10% < CV < 100%) except pH in both plots, (2) the variability of soil pH, EC and AP in H. ammodendron populations was higher than that in H. persicum populations, and (3) SOC and AN in H. ammodendron populations were lower than that in H. persicum populations. Geostatistical analysis revealed a strong spatial dependence (C0/(C0+C) < 25%) within the distance of ranges for all tested parameters in both plots. The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution, individual size of plants, and the topographic features, especially with the plants nearest to sampling points and the topographic features. In each plot, soil EC, SOC, AN and AP presented similar distributions, and fertile islands and salt islands occurred in both plots but did not affect every individual plant, since the sampling distance was larger than the size of such fertile islands. The results of topographic effects on soil heterogeneity suggested s     

Spatial heterogeneity of soil chemical properties between Haloxylon persicum and Haloxylon mmodendron populations

Spatial heterogeneity is a ubiquitous feature in natural ecosystems,especially in arid regions.Different species and their discontinuous distribution,accompanied by varied topographic characteristics,result in soil resources distributed differently in different locations,and present significant spatial heterogeneity in desert ecosystems.In this study,conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations,Haloxylon persicum Bunge ex Boss.,which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C.A.Mey.) Bunge,which inhabits interdunes in the Gurbantunggut Desert of Xinjiang,China.The results showed that soil pH,electrical conductivity (EC),soil organic carbon (SOC),available nitrogen (AN) and available phosphorus (AP) were significantly higher in H.ammodendron populations than that in H.persicum.The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10%＜CV＜100%) except pH in both plots,(2) the variability of soil pH,EC and AP in H.ammodendron populations was higher than that in H.persicum populations,and (3) SOC and AN in H.ammodendron populations were lower than that in H.persicurn populations.Geostatistical analysis revealed a strong spatial dependence (Co/(Co+C)＜25%) within the distance of ranges for all tested parameters in both plots.The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution,individual size of plants,and the topographic features,especially with the plants nearest to sampling points and the topographic features.In each plot,soil EC,SOC,AN and AP presented similar distributions,and fertile islands and salt islands occurred in both plots but did not affect every individual plant,since the sampling distance was larger than the size of such fertile islands.The results of topographic effects on soil heterogeneity suggested significant differences between the interdunes and dune-tops.Different topographic characteristics (physical factors) between plots result in the differences in SOC,AN and AP,while the heterogeneity of soil pH and EC arise from plant species and their distribution (biotic factor).Such biotic and physical factors did not occur in isolation,but worked together on soil heterogeneity,and played important parts in improving the soil properties.Hence these factors were ecologically valuable in the highly resource-stressed arid study area.     

艾比湖湿地盐生植物区系研究

对艾比湖湿地盐生植物区系和常见群落的土壤盐分特征进行了分析。结果表明:艾比湖湿地盐生植物物种多样性较为丰富,共有31科73属144种,分别占新疆盐生植物39科128属358种的79.5%、57.0%和40.2%,占中国盐生植物73科239属566种的42.5%、30.5%和25.4%;艾比湖湿地盐生植物地理成分在科的分布有4个类型4个变型;属的分布有9个类型7个变型,其中古地中海成分明显,没有区系特有成分。常见盐生植物群落冠下土壤盐分含量均显著低于裸地,能有效改良盐碱地。     

六盘山自然保护区两栖类种群动态与保护研究

两栖动物是评估其所在地生态系统水平的变化的重要指示性生物,其种群动态能够真实客观的反映环境变化。在2011-2016年,通过样线法和围栏陷阱法相结合的方法调查了六盘山自然保护区内的两栖类群落结构。结果显示,数量最多分布最广的两栖类为中国林蛙,占6年监测到两栖类总数的41.46%,为六盘山自然保护区两栖类的绝对优势种。六盘齿突蟾的种群数量最少,分布范围狭,受威胁程度最高。依据上述结果可为该地区两栖类的种群保护和生态恢复建设提供理论基础。     

胡杨、梭梭群落土壤理化性质及其相互关系

结合野外调查取样与实验室测定等手段,比较研究了新疆艾比湖湿地自然保护区裸地、梭梭与胡杨样地0～10 cm、10～30 cm、30～50 cm土层土壤氮素含量特征及土壤理化性质.结果表明:裸地、梭梭和胡杨样地内的土壤有机质、硝态氮、铵态氮、亚硝态氮与碱解氮均随着土层深度的增加而递减,具有表聚性特点.土壤中3种无机氮的含量为:硝态氮＞亚硝态氮＞铵态氮,硝态氮最高达到7.512 mg·kg-1,铵态氮最高仅为0.815 mg· kg-1,故硝态氮是土壤无机氮的主要赋存形式.同一土层胡杨氮素总含量高于裸地和梭梭,其有机质含量最高(均值为11.852 g·kg-1).相关分析表明,除铵态氮外,有机质与全磷和其他氮素间呈显著相关.pH与其他土壤理化性质及氮素含量间均呈不显著相关,碱解氮与土壤理化性质(除pH与电导率外)及其他氮素间均呈极显著相关(P＜0.01).     

艾比湖湿地自然保护区湿地植被研究

艾比湖湿地自然保护区湿地具有两个显著的特征,即分布海拔低,生态景观丰富。该湿地类型孕育了特殊的湿地植被和物种,并成为保护区主要的保护对象。根据考察结果,艾比湖湿地植被可划分为5个植被类型和17个群系。