汾河中上游湿地植被β多样性

Beta diversity of wetland vegetation in the middle and upper reaches of the Fenhe River watershed

探讨和揭示群落构建机制(生态位理论和中性理论)是生态学和生物地理学研究的热点和难点之一。研究β多样性格局及其与空间距离和环境异质性的关系为解释群落构建机制提供了一定的理论依据,以往群落β多样性的研究主要集中于物种组成的差异性,对种间在进化关系和功能属性方面的差异则关注较少。在野外调查的基础上,分析了汾河中上游湿地植被Tβ(taxonβ-diversity)、Pβ(phylogeneticβ-diversity)和Fβ(functionalβ-diversity)多样性格局及其与空间距离和生境异质性的关系。结果表明:(1)随着样地间距离的增加,Tβ、Pβ和Fβ整体上表现出逐渐增加的趋势,即表现出群落的距离衰减效应。(2)土壤因子中,TP是影响样地间Tβ、Pβ和Fβ的主要因子(P<0.05);p H、TOC和TN对Tβ、Pβ和Fβ的影响均未达到显著水平(P>0.05)。(3)由于受到空间扩散限制和生境异质性的影响,样地间β多样性表现出较大的差异,Tβ(0.66—1)、Pβ(0.42—0.85)和Fβ(0.51—0.94)。(4)尽管Tβ、Pβ和Fβ反映了多样性的不同方面,但三者之相关性极显著(P<0.01);(5)对Tβ、Pβ和Fβ多样性格局及其与空间距离和生境异质性的关系进行研究,表明环境因子和扩散限制共同决定着β多样性的格局,即群落的构建机制由生态位理论和中性理论共同主导。

Exploring and revealing the mechanisms of community construction（niche theory and neutral theory） is a hot topic and a difficulty in ecology and biogeography research.Studies on the relationship between beta diversity and spatial distance and natural distance provide some theoretical basis for the construction of the community.However,studies on beta diversity have mainly been focus on species differences and little on differences in the evolutionary relationships and functional properties between species.Based on field investigations,we evaluated the two-element attribute data of the total species,that is when the species was in the stands,it was denoted as 1 and when it was not in the stands,it was denoted as0.We developed a master plant list of seed species found in the middle and upper reaches of the Fenhe River.According to the Linnaean classification system,the species were divided into six levels：Phylum,Class,Order,Family,Genus,and Species,and the phylogenetic trees of all species were built.Considering the plant morphology,physiology,and breeding phenology,plant properties including growth form,life history of plants,types of nitrogen fixation,photosynthetic pathway,light tolerance,leaf shape,flower shape,pollination mode,fruit type,seed dispersal mode,flowering time,floweringphase,fruit time,and fruit phase,were recorded to measure functional diversity and to express differences between individual plants in terms of productivity,resource utilization,ecological resilience,and ecological countermeasures.The measurement indicator,beta diversity,was calculated using the Jaccard index.The Tβ,Pβ,and Fβ diversity patterns of 17 stands in the middle and upper reaches of the Fenhe River were calculated,respectively,and the correlations among diversity patterns,spatial distance,and habitat heterogeneity were analyzed.The results showed that（1） with increasing distance of the 17 stands,the Tβ,Pβ,and Fβ patterns showed an increasing trend,that is,the distance of the community showed an attenuation effect.（2） TP（total phosphorus） is the main soil factor that influences the Tβ,Pβ,and Fβ in the sample areas（P 〈 0.05）,while the influence of p H,TOC（total organic carbon）,and TN（total nitrogen） was not significant（P 〉 0.05）.（3） Because of the restrictions on spatial diffusion and the influence of habitat heterogeneity,the diversity of beta diversity among the samples was obviously different（Tβ 0.66—1,Pβ 0.42—0.85,and Fβ 0.51—0.94）.（4） Although the Tβ,Pβ,and Fβ reflected different aspects of diversity,the relationship with each other was highly significant（P 〈 0.01）.（5） Based on the Tβ,Pβ,and Fβ diversity patterns and their relationship with spatial distance and habitat heterogeneity,it is suggested that the environmental factors and diffusion limitation jointly dominated the pattern of beta diversity,namely,the construction mechanism of the community was jointly decided by the ecological niche theory and neutral theory.