【作者】 李婷；

【导师】 岳明；

【作者基本信息】 西北大学 ， 生态学， 2018， 硕士

【副题名】基于区系数据库

【摘要】 海拔梯度上物种多样性的变化模式及其潜在机制一直是生态学研究的重要课题。然而,大尺度上物种的丰富度格局以及各种假说的相对解释能力仍需进一步探讨。本文以广义秦岭为研究对象,基于地方植物志资料中3538个物种的分布数据,分析了种子植物物种丰富度和特有种丰富度的海拔格局,检验不同假说对此格局的解释能力,并用多种方法检验Rapoport法则在本地区的适用性。此外,许多易于观测和度量的植物特征,都能客观地表现出植物对外部环境的适应性,沿海拔的空间变化能通过多种因素的综合作用影响这些植物功能性状的变化。但是,针对某一区域大量物种植物性状沿海拔梯度变化的研究较少,而且因为影响因素的复杂性需要更多的数据检验和机制研究。所以,我们还探讨了主要功能性状在海拔梯度上的变化规律及其对环境变化的响应。结果显示:秦岭山脉物种丰富度的海拔格局呈单峰型(R2=0.67,P<0.001),在海拔1000~1500m之间物种数达到峰值。而不同海拔上三种分类水平科、属、种的丰富度呈现出相似的变化趋势。秦岭地区特有种所占的百分比和密度均随海拔高度单调递增。然后,我们比较了种面积关系(SAR)、中域效应(MDE)和生态代谢理论(MTE)对这种格局的解释力。结果发现三种假说的独立解释量均很小,但SAR与MDE的共同解释量很大(80.4%)。之后,我们采用Pagel上限法检验秦岭种子植物物种海拔格局符合Rapoport法则,而逐种法、Rhode中点法和Stevens法检验结果不支持该地区存在Rapoport效应,将所有的物种按照其分布幅度分组后,大部分结果支持Rapoport法则。秦岭山脉植物生活型丰富,高海拔地区地面芽和地下芽植物占优势。植物叶片长度、宽度和叶片长宽比均随海拔单调递减,叶型谱以小叶物种数量最多,且叶形状变化不大的高位芽植物的叶面积随海拔单调递减。秦岭各海拔段平均种子质量随着海拔升高而减小,但在低海拔波动较大。将种子质量分级后发现1g以下的种子明显在高海拔占优势适应性更强,也与风传播物种沿海拔单调递增的结果相符。不同生活型种子重量对比时,高位芽植物的种子质量最高,与种子质量随着植株高度的增加明显单调递增的结果一致。结果表明,秦岭种子植物物种丰富度沿海拔单峰格局是多种因素共同作用的结果,单一的假说并不能完全解释这一过程,面积和空间约束是主要影响因子,即更适合用空间假说解释。而Rapoport法则普适性的检验结果明显受所采用的分析方法的影响,将物种按照分布幅度分组可以部分消除中域效应的影响,对Rapoport效应的线性趋势反映更明显。植物叶面积随海拔升高减少,符合小型叶植物更适应寒冷地区的规律。种子质量与植株大小相关,而且小种子在高海拔占优势受资源因素的制约。更多还原

【Abstract】 Diversity patterns along altitudinal gradients and underlying mechanisms had been important topics in the field of ecology.However,the patterns of species richness at large scale and explanatory ability of various hypotheses still be worth revisiting.Basing on the distribution data of 3538 species along altitudinal gradient derived from local flora of entire Qinling Mountains,we analyzed the patterns of endemic species and species richness,tested the explanatory ability of different hypotheses,and the applicability of the Rapoport’s rule in this region.In addition,many plant traits,which were easy to observe and measure,could objectively reflect responses to changing temperature regimes and other factors along elevational gradients.There was little research on the relationship between altitudinal gradient and plant traits of a large number of species in a region,and more data testing and mechanism researching were need for the complexity of influencing factors.The results were as follow:Total species richness showed a unimodal pattern along the altitudinal gradient,and the richness of three taxonomic families,genera and species showed a similar trend,while endemic species richness had significant monotonic increasing with elevation.Then,we compared the explanatory ability of species-area relationship(SAR),metabolic theory of ecology(MTE)and mid-domain effect hypothesis(MDE).The independent interpretation of the three hypotheses was very small,but the joint interpretation of SAR and MDE was large(80.4%).The result of Pagel upper method supported the Rapoport’s rule,but the results of Cross-species method,Rohde’s mid-point method and Stevens method didn’t support the Rapoport’s rule,but after the tests by sectioning method,the linear trend was more obvious.There were abundant life forms in Qinling Mountains.In high altitude areas,the hemicryptophyte and geophyte were dominant.The leaf length,width andlength-width ratio decreased monotonously with altitude,and the number of microphyll was the largest.Whose shapes changed less than the others,the leaf area of Phanerophyte gradually decreased with altitude.The average seed quality decreased with altitude,but it fluctuated at low altitude.The results of seed quality grading showed that 1000-seed mass below 1 g had better adaptability at high altitude and were consistent with the wind-borne species increasing with altitude.Compared the seed weight of different life-form,the seed quality of Phanerophyte was the highest,which supported the seed quality was related to plant size.The results showed that the unimodal pattern of species richness was the result of the concerted action of manifold factors.Single hypothesis could not fully explain the pattern of species richness along altitude gradient in Qinling,but area and geometric constraint were the major factors.However,the test results of applicability of the Rapoport’s rule were obviously influenced by the analytical methods,and the influence of mid-domain effect could be partially eliminated by grouping species according to their distribution range,then the results were more support the Rapoport’s rule.The leaf areas decreased with the elevation,which accorded with the rule that small leaf plants were more suitable for cold regions.The seed quality was related to the plant size,and small seeds were restricted by resource factors at high altitude.更多还原