EGI OpenIR
模拟积雪覆盖变化对准噶尔荒漠草本植物群落的影响
Alternative TitleEffects of simulated snow cover changes on the community of herbaceous species in the Gurbantunggut Desert, China
安里菲热·安尼瓦尔
Subtype博士
Thesis Advisor张元明
2020-09-30
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline理学博士
Keyword积雪覆盖变化 草本植物 物种多样性 物候 古尔班通古特沙漠 Snow cover Herbaceous plant Species diversity Phenology Gurbantunggut Desert
Abstract积雪作为对气候异常变化最敏感的地球表面覆盖物, 可对土壤温度、 湿度等诸多理化特性产生影响, 从而导致生态系统中土壤、 微生物、 植物等构成要素发生改变。 新疆是我国积雪覆盖的三大区域之一, 其新疆北部积雪在近年呈现出逐年增加的趋势。 新疆北部的准噶尔荒漠是全球典型的温带荒漠, 其生态系统结构与功能对积雪变化的响应可能会更为敏感、 快速, 但这方面的研究尚十分缺乏。目前, 古尔班通古特沙漠存在稳定积雪是其植被(特别是草本层) 发育良好的主要原因。 基于此, 本研究以准噶尔荒漠腹地古尔班通古特沙漠草本植物群落为研究对象, 开展野外控制条件下的积雪变化模拟实验, 共采取 4 种处理方法, 即去除积雪、 自然积雪、 增加一倍积雪和增加两倍积雪, 研究了冬季积雪变化对 35种荒漠植物种子萌发率的影响, 并从短命植物和一年生长营养期植物中选取不同物种进行光合特性、 物候方面的研究, 继而探讨草本植物群落中两种生活型植物的空间分布、 物种多样性和初级生产力对积雪变化的响应, 旨在为揭示全球气候变化背景下, 温带荒漠生态系统的响应特征提供一定的理论参考。 本研究的主要结果如下:(1) 对种子萌发特性的影响。 不同生活型植物种子室内萌发实验和野外埋藏种子萌发实验均表明, 积雪增加对种子萌发率的影响不显著, 增加一倍积雪和自然积雪对种子萌发率均表现出相似的影响。 但去除积雪处理对不同质量和形状的种子萌发率具有抑制作用。 去除积雪处理下, 质量较重的种子萌发率最高, 表明积雪变化可能通过改变质量较重的种子萌发来改变荒漠草本植物群落结构。(2) 对光合特性的影响。 在干旱年份和湿润年份的短命植物生长旺季, 自然积雪和增加一倍积雪处理的土壤含水量均高于去除积雪处理, 植物叶片相对含水量在整个生长季的变化随土壤含水量的变化而变化。 其中 4 种短命植物的叶干物质及最大净光合速率在湿润年和干旱年之间差异显著。(3) 对物候期的影响。 增加积雪使短命植物和一年生长营养期植物的展叶期、 开花期和结实期均提前, 而枯黄期均延迟; 同时, 群落水平植物物候开花始期、 开花末期、 结实始期、 结实末期和展叶期均提前, 枯黄期推后。 因此, 尽管不同物种物候期对积雪覆盖变化的敏感程度不同, 但温带荒漠草本植物个体、 生活型和群落水平的表现基本一致, 积雪增加均使荒漠草本植物的生长季延长了1-2 周。 自然积雪使荒漠草本植物展叶始期提前, 对枯黄期的影响较小; 增加一倍积雪使植物枯黄期延迟, 但对展叶期影响较小。(4) 对空间分布格局的影响。 湿润年增雪促使荒漠草本植物群体以聚集式分布为主, 通过小尺度的群体聚集增加种间的竞争强度, 从而可能改变不同物种对资源和空间的竞争能力, 有利于群体的更新。 而干旱年促使群体由聚集式分布向随机分布转变, 表明积雪足够多才有利于群体生存。 同一个物种或同一生活型的空间分布格局存在尺度依赖性, 即各种尺度下的空间分布特征并不完全相同。(5) 对物种多样性和生物量的影响。 积雪增加或减少均能导致物种和物种多样性发生变化。 不同处理下, 3 种物种多样性指数整体表现为湿润年高于干旱年, 均匀度指数并没有发生显著变化。 去除积雪处理显著降低物种多样性。 积雪量增减也能够导致生物量的响应。 积雪处理下, 湿润年地上生物量(18.4 g·m−2)高于干旱年(3.2 g·m−2)。 随积雪增加, 地上生物量逐渐升高, 增加两倍积雪时达最大。 表明未来积雪增加不仅会改变荒漠草本植物群落的物种组成, 而且会改变地上生物量, 从而促进荒漠草本植物的生长。
Other AbstractAs the surface covering most sensitive to abnormal climate changes, the snowcover exerts influences on many physical and chemical properties of the soil(temperature, moisture, etc.), leading to changes in components of the ecosystem (soil,microorganisms, plants, etc.). The Xinjiang region is China's three majorsnow-covered regions, and the snow cover in Northern Xinjiang has reported anincreasing trend in recent years. As a typical temperate desert in the world, theJunggar Desert in Northern Xinjiang may be more sensitive and have a rapid responseto changes in snow cover, such as ecosystem structure and function. However, littleresearch was conducted in this field. At present, the stable snow cover in theGurbantunggut Desert in winter is considered to be the main reason for its favorablevegetation (especially the well-developed herbaceous layer). Based on this,herbaceous plant communities in the Gurbantunggut Desert in the hinterland of theJunggar Desert were taken as the research objects of the snow change simulationexperiment under field control conditions. Four snow manipulation treatments (Snowremoval, Ambient snow, Double snow and Triple snow) were used in this research.The research covers the following: influences of changes in snow cover in winter onthe germination percentage of 35 desert seeds; different species of ephemeral plantsand long-lived annual plants were sampled and studied for photosyntheticcharacteristics, phenology, etc., and then the responses of spatial distribution, speciesdiversity and primary productivity of two life-forms in the herbaceous plantcommunity to changes in snow cover were discussed. The research aims to providetheoretical references for revealing the response characteristics of temperate desertecosystems in global climate changes. The following main results were obtained inthis research:(i) Influences of snow cover changes on the germination characteristics of seeds.Both the indoor seed germination experiment and field buried seed germination experiment of plants with different life-forms showed that the increase in snow coverhad no significant influence on the germination percentage of seeds, and the resultswas similar for double snow and ambient snow. But in the case of snow removal, thegermination rate of seeds with different dry weights and shapes was suppressed.Under the snow treatment, the heavier seeds had relatively higher germinationpercentage. It indicated that the change of snow cover may result in structural changesin herbaceous plant communities by changes the germination of the heavier seeds inthe Junggar Desert.(ii) Influences of snow cover changes on the photosynthetic characteristics.During the peak growth season of ephemeral plants in dry and humid years, the soilmoisture content of ambient snow and double snow is higher than that of snowremoval. The relative water content of plant leaves changes with the soil moisturecontent during the entire growth season. Four ephemeral plants showed significantdifferences in leaf dry matter and maximum net photosynthetic rate during dry andhumid years.(iii) Influences of snow cover changes on the phenological period. If the snowcover increases, the leafing period, blooming period, and fruiting period of ephemeralplants and long-lived annual plants are advanced, while the withering yellow period isdelayed; in the meanwhile, the phenological beginning of blooming, the end ofblooming, the beginning of fruiting, the end of fruiting, and the leafing period ofcommunity-level plants are advanced, while the withering yellow period is delayed.Therefore, regardless of the different sensitivity of phenological periods of differentspecies to changes in snow cover, the phenological periods of ephemeral plants andplants in one-year vegetative period, as well as at the population and communitylevels, are basically the same. If the snow cover increases, the growth season of desertherbaceous plants is extended by 1 to 2 weeks. The ambient snow helps to advancethe beginning of leafing of desert herbaceous plants, but has little effect on thewithering yellow period; double snow will delay the withering yellow period of plants,but has little effect on the leafing period.(iv) Influences of snow cover changes on the spatial distribution pattern. Snowincreased in humid year, desert herbaceous plant population mainly distributes in anaggregated manner. A small-scale population aggregation increases the intensity ofinter-species competition, which may change the ability of different species tocompete for resources and space, and is conducive to population regeneration.However, with the snow increase in dry year, the population changed from aggregateddistribution to random distribution, indicating that only sufficient snow cover can helpthe population survive. Scale dependence exists in the spatial distribution pattern ofthe same species or life-forms, that is to say, the spatial distribution characteristics atdifferent scales are not exactly the same.(v) Influences of snow cover changes on the diversity of species and biomass. Itcan be found the plant species and species diversity changed with snow variation.Under different snow treatments, the three kind of species diversity index in a humidyear were higher than that in a dry year, the Pielou index of the species had nosignificant changes. Snow removal can significantly decrease the species diversity.The increase in snow cover remarkably increased the aboveground net primaryproductivity (ANPP). The aboveground biomass under snow cover was 18.4 g·m−2and 3.2 g·m−2 in humid and dry years, respectively. Aboveground biomass increasedwith snow cover increases, and till the highest when snow cover increased to triple. Itindicates that the future increase in snow cover not only change the speciescomposition of community in desert herbaceous, but also change the abovergroundbiomass, thereby can hasten the growth of desert herbaceous plants.
Subject Area植物学
Language中文
Document Type学位论文
Identifierhttp://ir.xjlas.org/handle/365004/15401
Collection中国科学院新疆生态与地理研究所
研究系统
Affiliation中国科学院新疆生态与地理研究所
First Author Affilication中国科学院新疆生态与地理研究所
Recommended Citation
GB/T 7714
安里菲热·安尼瓦尔. 模拟积雪覆盖变化对准噶尔荒漠草本植物群落的影响[D]. 北京. 中国科学院大学,2020.
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