【作者】 徐杰；

【导师】 白学良；

【作者基本信息】 内蒙古大学 ， 生态学， 2004， 博士

【摘要】 通过对31个样地的调查，鄂尔多斯地区苔藓植物有17科、41属、102种，其中2个中国新记录属，7个中国新记录种，8个内蒙古新记录种；沙坡头地区有苔藓植物3科、11属、24种，其中1个中国新记录属，2个中国新记录种。鄂尔多斯地区典型草原区有苔藓96种，占总种数的95％，荒漠草原区种类明显下降，仅12种，占11.9％；半荒漠区有10种，占9.9％。 苔藓物种景观上的分布规律主要表现为：1)种数由东向西随着降雨量的减少而减少，中旱生及旱生生态型逐渐成为的主要成分，由南向北随着纬度的增加而减少，符合生物多样性随纬度增加而递减的规律；2)生境多样性(空间异质性)的变化对物种分布影响巨大，不仅表现在大尺度上，在样地微生境上表现的更明显，多样的生境增加了物种的多样性。在生境尺度上主要表现为：1)环境湿度、土壤含水量与种类密切相关，阴湿和中湿环境物种数目明显多于干旱生境，坡底的种类明显高于坡顶；2)土壤的理化性质(PH值、土壤机械组成、盐分含量)直接影响苔藓的生长和分布；3)维管植物的种类和分布影响苔藓的生长和分布模式，其创造的微生境为苔藓的定居创造了避难所，但维管植物产生的地被物(枯枝、落叶)又抑制了苔藓在其下的分布。 苔藓α多样性的变化不仅与生境变化有关，而且还与构成生境的结构要素有关，这些结构要素包括群落的层片结构，维管植物的郁闭度、盖度、种类组成，地被物的盖度和分布格局，藻类盖度和分布格局。苔藓β多样性的变化与群落结构的关系更为密切，相似群落结构间的多样性相似系数明显高于结构存在差异的群落。盖度变化分析表明，随着坡地海拔高度的增加，藓类的盖度呈现下降的趋势，藻类的盖度则呈现小幅度上升趋势，结皮层藓类的盖度与藻类、维管植物的盖度存在不显著负相关。随着沙丘固定年限的增加，藓类和藻类植物的盖度都呈现上升的趋势，老固定沙丘鲜结皮盖度大于藻结皮盖度，而新固定沙丘藻结皮盖度则大于鲜结皮盖度。不同地带性植被区随着年均降雨量减少，鲜类和藻类盖度都明显降低;同一地区年季降雨量的波动也直接影响着鲜类和藻类盖度的波动。 不同鲜类单位生物量明显不同，同种鲜类随着海拔高度增高、干扰强度增人、地区降雨量的降低，单位生物量显著降低，主要是由于环境的变化影响了苔鲜植物的株高和密度，结皮厚度与株高存在明显的正相关(P<0.01)。随着沙rf..固定年代的增加，固沙量也显著增加:鲜类稳定沙丘表层土壤重量是自身重量的30一50倍，极大增强了结皮机械强度和抵御外界干扰和侵蚀的能力，同时鲜类吸水后能达到自身干重的6一10倍多，一方面为鲜类自身的生存和繁殖创造了条件，另方面对于提高土壤的保水能力，促进维管植物的萌发和定居有着垂要的才卜态作用。 真鲜和土生对齿鲜无性繁殖是其首要的繁殖策略，对种群的发展和维持及种群的扩散极为重要，营养繁殖的多样性增加了对多变的自然环境的适应性，抱子繁殖对稳定物种遗传多样性非常重要，也是植物体增强环境适应性的进一步表现。在土壤营养贫膺的半荒漠区很难看到优势鲜类的抱子体，表明其性表达的比例低，而伴生种和稀有种都存在有性繁殖和无性繁殖两种方式，在性表达的比例_}:明显高于优势种，可能的解释是由于生态位竞争的不平等，‘造成种群人而积发展的机会降低，物种消耗本身大量的资源产生抱子体，进而产生大量的饱子以扩人散布的空间距离和生境类型，其机理有待于进一步研究。鲜类多样的无性繁殖力一式为人工培养苔鲜植物技术及恢复鲜类结皮提供了多种选择。受损结皮层的自然恢复实验表明未受干扰的自然状态下受损鲜类结皮层样方在3一4年内达到70%的恢复率，主要依靠结皮层中优势种的茎、叶碎片、芽胞进行传播和克隆繁殖。人工恢复培养的醉类生长快，成活率高，但维持差，其原因可能与培养方法有关。野外及室内培养的真鲜形态和大小有显著差异，是真醉在不同环境条件的生态变异，但两种条件下真鲜繁殖特性完全相同，能够揭示生物结皮层形成过程中鲜类植物萌发和定居的繁殖生物学机理。 苔鲜形态解剖结构表明，旱生鲜类具有明显防止紫外线辐射和水分散失的适应性结构，在一定程度上减缓组织细胞内生理条件的剧烈变化，减弱细胞器受损伤的程度，加快其生理功能的恢复速度，使其更好的适应环境变化。 鲜类体内氨基酸分析表明氨基酸组成大部分与维管植物相同，其中天门冬氨酸、谷氨酸、丙氨酸、亮氨酸和精氨酸的含量最高，约占总氨基酸的50%。脯氨酸含量在所有氨基酸中处于较低水平，平均只占氨基酸总量的3.12%。半荒漠区分布的真鲜与草原区分布的真蓟有10种氨基酸(包括脯氨酸)含量有显著的均数差异(p<0.05)，而土生对齿鲜只有脯氨酸有显著的差异(p<0.05)，脯氨酸的含量在同一地区没有显著的差异，但在不同地区却有显著性差异(p<0.05)，真鲜平均总氨基酸含量大于土生对齿鲜。 生物结皮土壤Ca2+含量明显高于其他3种离子，Na+、r离子含量较少。苔鲜植物生物量与土壤P、土壤有机质明显正相关(P<0.05)，土壤PH值与土壤P含量和苔鲜植物生物量显著负相关(P分别<0.01和<0.05)，表明高的PH值显著影响土壤P含量和植物生物量。P含量还与N含量显著相关(P<0.05)，醉类结皮土壤中有机质、?更多还原

【Abstract】 Through several years of studying in 31 plots in fields, mosses of 17 families, 41 genera and 102 species were found in Erdos region. In the meanwhile, 2 genera and 7 species were newly recorded in china, and 8 species were newly recorded in Inner Mongolia. Mosses of 3 families, 11 genera and 24 species were found in Shapotou, Zhongwei County, Ningxia Hui Autonomous Region, 1 genus and 2 species were newly recorded in china. In Erdos region there were 96% species in steppe which counted for 95% of all the species, only 12 species in desert steppe counting for 11.5% and only 10 species in semi-desert counting for 9.9%.The distributive features of moss species on landscape were mainly as followed: (1) species number became smaller as the rainfall decreased from the east to the west; mesic xerophyre and xerophyre types ecologically came to be the major components, which would decreased in number as the latitude became high. And the biodiversity was consistent with the decreased law of the biodiversity respect to the latitude. (2) The change of habitat diversity (spatial heterogeneity) played a great role on the distribution of species, not only on the large scale but more noticeably on the microhabitat of plots as well. Diverse habitates would produce a higher diversity of species. On habitat scale, the main features were: (1) Environmental humidity, the content of water in soil and number of species were closely related to each other. Species in humid or semi-humid environment were much larger in number than in arid land and larger in bottom of a slope than on the top of a slope. (2) The physical and chemical characteristic of soil (pH value, soil mechanical component, salt content) would directly influence the ,rowth and distribution of moss. (3) The sorts and distribution of vascular plants affected in growth and distribution pattern. The microhabitat accordingly provide refuges for the establishment of mosses, but the ground layers (litter), Which were produced by vascular plants would prevent moss from the distributive below. The habitat difference (including temperature, moisture, and light etc.) was the main reason that leads to the richness difference of bryophyte species.The change of Alpha diversity of bryophytes not only had to do with the change of habitat; but also had much to do with the structural agents, which constituted the habitat. These structural agents contained the synusia structure of community, theIVcanopy density; cover degree and specific composition of vascular plants; the cover degree and distribution pattern of aphyllae. The change of beta diversity of bryophyte was more closely linked with the community structure, with the similarity index of the diversity of similar community structures being obviously higher than that of communities with different structures. Analysis of cover showed that with the increase of the altitude of the slope, the coverage of mosses decreased quickly and that of algae increased slowly. And the cover of moss crusts and that of algae and vascular plants are in insignificant negative relation. With the increase of the fixed-sand time, the cover of mosses and algae tends to enhance, the cover of old fixed dunes moss crusts is thicker than that of algae crusts and the cover of the new fixed dunes is thicker than that of moss crusts .in different zonal vegetation the cover of mosses and algae both decreases with the decrease of average annual precipitation. The fluctuation of annual precipitation in the same area directly affects the cover of mosses and algae.Unit biomass differs in different mosses; and unit biomass of the same specie of moss dramatically decreases with the increase of altitude and the disturbance intensity and the decrease of region precipitation. This was because the change of environment influenced the height and density of mosses, and there were remarkable correlated relationships between the thickness and the height of different species and types of mosses (P<0.01). Binding-sand quantity increased when the fixed sand time prolonged .更多还原