【作者】 李洁；

【导师】 许清海；

【作者基本信息】 河北师范大学 ， 自然地理学， 2014， 硕士

【摘要】 过去全球变化研究中，陆地生态系统环境变化的证据，对理解和揭示全球气候、植被变化的机制和结果起着至关重要的作用。花粉作为植物繁殖的一部分，由于体积小、产量大、散布广、外壁坚固，在地层中易以化石的形式保存下来等优势，成为模拟古植被、古气候变化的一种重要代用指标之一。但由于花粉在传播以及沉积过程中的复杂性，导致花粉谱和植被间的关系表现的极其复杂和多变，使其成为孢粉学应用中最基本、最困难的研究内容之一。因此某一区域内花粉与植被、气候关系研究，对于这一地区进行古植被、古气候环境的重建、提高可信性具有重要意义。目前解释花粉与植被之间关系常用的模型为ERV(Extend RValue model)模型，而运用ERV模型重建古值被、古气候时，应估算研究区植物属种的相对花粉产量和相关花粉源范围。本文基于内蒙古东乌珠穆沁旗草甸草原区30个表土花粉样品，以及样点周围植被详细调查的基础上，计算了研究区11种常见花粉类型的沉降速率，并运用ERV模型，计算了11种主要植物种属的相对花粉产量(Relative pollenproductivity，RPP)和相关花粉源范围(relevant source area of pollen，RASP)。研究结果如下：研究区孢粉组合以草本植物花粉为主，主要为藜科、禾本科、蒿属、菊科、莎草科等，较好地反映了草原区的植被特征。受邻区植被影响，样点中松属、栎属、桦属等乔木植物花粉类型含量较高。花粉粒个体大小是影响花粉沉降速率的重要因素，研究区球形花粉中的蒲公英属花粉个体最大(平均27.32975μm)，其次为石竹科(平均26.754μm)、禾本科(平均23.84038μm)、唐松草属(平均20.86175μm)，藜科花粉粒最小(平均19.18538μm)。椭球形花粉中的菊科大蓟属(平均长轴×平均短轴：45.62822×32.65292μm)个体最大，其次为蓼科(32.40125×22.6282μm)、莎草科(28.21175×19.56325μm)、百里香属(27.44×19.4775μm)、紫菀属(24.74081×21.62820μm)、地榆属(23.09125×18.92625μm)、蒿属(18.80427×16.57415μm)，狼毒属花粉粒最小(17.18675×16.06111μm)。研究区主要花粉类型的沉降速率排序为：菊科花粉0.0374m/s(蒲公英属、紫菀属、大蓟属3个花粉类型的平均值)＞蓼科0.0358m/s＞莎草科0.02719m/s＞百里香属0.02553m/s＞石竹科0.02165m/s＞地榆属0.01723m/s＞禾本科0.01719m/s＞唐松草属0.01316m/s＞蒿属0.01115m/s＞藜科0.01113m/s＞狼毒属0.00893m/s。应用ERV模型估算的内蒙古东乌珠穆沁旗草甸草原区11种常见花粉类型以禾本科为参照种的相对花粉产量显示：蓼科(42.51±2.49和33.59±2.03)、藜科(33.81±5.41和30.35±4.96)的相对花粉产量最高，莎草科(22.08±0.26和19.77±0.22)、石竹科(19.83±2.61和26.98±2.95)、狼毒属(14.46±0.73和13.17±0.67)和菊科(12.78±0.63和11.62±0.58)的相对花粉产量居中，蒿属(7.64±0.57和5.66±0.51)、地榆属(4.81±0.57和5.16±0.59)和唐松草属(3.52±0.68和4.22±0.67)的相对花粉产量次之，百里香属(1.60±0.17和1.79±0.18)与禾本科(1)接近，相对花粉产量较低。研究区相关花粉源区为1000m左右，受风速、花粉类型、花粉沉降速率影响较小。相对花粉产量检验表明，草甸草原区利用禾本科、蒿属、藜科、蓼科、菊科相对花粉产量重建的植被丰度与实际植被具有较高一致性，而利用石竹科、莎草科、唐松草属、地榆属、狼毒属、百里香属花粉产量重建后的植被略低于实际植被，相对花粉产量被高估。因此，利用相对花粉产量恢复古植被的时需慎重选择花粉类型。与其它研究区的研究结果对比显示：不同地区由于实际植被组成、植被斑块大小、禾本科不同种属花粉产量的差异以及人类活动等，可能导致研究区花粉产量与其它地区存在较大差异的原因。更多还原

【Abstract】 The evidences of terrestrial ecosystem changes play an important role tounderstand the mechanism and the process of climatic changes and vegetationalsuccessions in the studies of past global changes. As a part of plant propagules, sporesand pollen become one of important index in simulating paleovegetation andpaleoclimate changes because their small size, huge pollen production, wide spread,hard ectotheca and easy preservation in sediments. However the complexity of pollenspread and pollen deposition makes the relationships between pollen and vegetationmore complex and changeable, which results the relationship becoming one of themost basic and difficult researche issues on palynology. So, studies on therelationships between pollen and vegetation, pollen and climate are very important toreconstruct the paleovegetation and paleoclimate.Nowdays the common used model in explaining the relationship between pollenand vegetation is ERV model (Extend R Value model), but when we use the ERVmodel we need calculating the relative pollen productivities (RPPs) and Relevantsource area of pollen (RASP) of major pollen species in study area.We calculated the pollen fall speed and then estimated the RPPs for commonpollen types of meadow steppe area using ERV models based on pollen analysis,pollen fall speed and vegetation survey from30sampling sites in East UjimqinBanner, Inner Mongolia. The results are presented as follow:In meadow steppe area, herbaceous pollen types are dominant in pollenassemblages including Chenopodiaceae, Poaceae, Artemisia, Compositae andCyperaceae etc, reflecting the steppe community appropriately. Duo to the influenceof surrounding vegetation, arbor pollen of Pinus, Quercus, Betula and so on also takea certain proportions in pollen assemblages.Pollen grain size plays a very important role in pollen fall speeds, in ellipsoidalpollen of Taraxacum has relative larger pollen grain size (average27.32975μm), andthen the Caryophyllaceae (average26.754μm), Poaceae (average23.84038μm), andThalictrum (average20.86175μm), while Chenopodiaceae pollen (average19.18538μm) has the smallest pollen grain size. In spherical pollen of Cirsium (averagelength×width:45.62822×32.65292μm) of Compositae family has relative largerpollen grain size, and then the Polygonum (average32.40125×22.6282μm), Cyperaceae (average28.21175×19.56325μm), Thymus (average27.44×19.4775μm),Aster (average24.74081×21.62820μm), Sanguisorba (average23.09125×18.92625μm) and Artemisia (average18.80427×16.57415μm), while Stellera (average17.18675×16.06111μm) has the smallest pollen grain size. So the alphabet of pollenfall speed is Compositae0.0374m/s (average of Taraxacum, Aster and Cirsium pollenfall speed)＞Polygonum0.0358m/s＞Cyperaceae0.02719m/s＞Thymus0.02553m/s＞Caryophyllaceae0.02165m/s＞Sanguisorba0.01723m/s＞Poaceae0.01719m/s＞Thalictrum0.01316m/s＞Artemisia0.01115m/s＞Chenopodiaceae0.01113m/s＞Stellera0.00893m/s。The RPPs of11common pollen types of meadow steppe estimated by ERVmodel using Poaceae as reference taxon in East Ujimqin Banner, Inner Mongoliashows that: Polygonum (42.51±2.49and33.59±2.03), Chenopodiaceae (33.81±5.41and30.35±4.96) have relative high RPPEs，Cyperaceae (22.08±0.26and19.77±0.22),Caryophyllaceae (19.83±2.61and26.98±2.95), Stellera (14.46±0.73and13.17±0.67)and Compositae (12.78±0.63and11.62±0.58) have moderate RPPEs, and then areArtemisia (7.64±0.57and5.66±0.51), Sanguisorba (4.81±0.57and5.16±0.59) andThalictrum (3.52±0.68and4.22±0.67)，while Thymus (1.60±0.17and1.79±0.18) hasthe lowest RPPEs which is similar to Poaceae (1). The estimated RSAP is about1000m which has little effect by wind speed, different estimated numbers of species andpollen fall speeds. The test of RPPs indicates that there are high consistency betweenthe estimated and actual vegetation abundance of Poaceae, Artemisia,Chenopodiaceae, Polygonum and Compositae, while Caryophyllaceae, Cyperaceae,Thalictrum, Sanguisorba, Stellera and Thymus estimated vegetation abundance arelower than actual ones, which means the RPPs was overestimated. The results suggestthat the pollen types should be considered with caution when we using RPPs inreconstructing the past vegetation.Comparing the RPPs result of meadow steppe in East Ujimqin Banner, InnerMongolia with other regions shows that the variations in vegetation structure andspecies composition, differences RPPs in Poaceae species and human activities indifferent areas may produce obvious changeable RPPs in different regions.更多还原