云南省玉龙雪山表土花粉垂直散布与植被关系研究

ALTITUDINAL DISTRIBUTION OF SURFACE POLLEN AND THEIR RELATIONS TO MODERN VEGETATION IN THE YULONG MOUNTAINS,YUNNAN PROVINCE

对云南省玉龙雪山地区8个垂直植被带下采集的49个表土样品进行表土孢粉的垂直散布研究，同时选择43个受人类活动干扰较少的样品和20个主要木本花粉类型进行了降维对应分析（DCA）。结果表明，玉龙雪山地区不同垂直植被带的孢粉组合具有不同的代表性成分与变化特征，能够较好地反映相应的植被带类型。在植物稀疏、花粉产量低的高山杜鹃灌丛植被带中，孢粉组合以外来的松属、冷杉属、落叶松属、云杉属和铁杉属等为主；冷杉林、落叶松林、云杉林和铁杉林等植被带孢粉组合的指示性成分分别是冷杉属、落叶松属、云杉属和铁杉属花粉，它们对应的峰值分别为13．6％，4．7％，39．4％和11．5％；针阔混交林、中山湿性常绿阔叶林的孢粉组合分别以高含量的常绿栎类、栲／石栎属为特征，并都含有多种落叶阔叶乔木和灌木的花粉，但后者比前者所包含的阔叶乔木与灌木成分更多，且蕨类孢子的峰值也出现在中山湿性常绿阔叶林中；云南松林的孢粉组合中除松属外很少有木本花粉出现。DCA排序结果较好地反映了现代植被与环境之间的相互关系，认为温度是决定不同植被带样点分布的最重要因素，这与垂直植被带随着海拔升高、温度逐渐降低而发生更替的规律是一致的。

Ahitudinal distribution study of surface pollen was carried out on 49 samples collected from 8 vertical vegetation zones being orderly alpine Rhododendron shrubland,Abies forest,Larix forest, Picea forest, Tsuga forest, conifer and broadleaved mixed forest, mid-mountainous humid evergreen broadleaved forest, and Pinus forest from high altitude regions to low altitude regions in the Yulong mountain regions of Yunnan Province. Detrended correspondence analysis（DCA）was also employed on pollen data of about 20 main tree pollen types of 43 samples disturbed hardly by human activities. The results show that pollen assemblages of different vertical vegetation zones in the Yulong mountain regions have different representative components and change characteristics,which reflecting vegetation zone types. The pollen assemblage of alpine Rhododendron shrubland at altitudes of 4100 - 3900m with sparse plants and low pollen production is dominated by an exterior Pinus pollen（82.1% -91.7%）,and pollen of Abies ,Larix,Pieea, and Tsuga etc. with their definite percentages of 1.5% - 4.8%, 1.5% - 3.0%, 1.1% - 2.7%, and 1.4% - 2.3%, respectively. The indicative elements of the pollen assemblages in Abies forest at altitudes of 3860 -3600m ,Larix forest at altitudes of 3540 -3380m ,Picea forest at altitudes of 3325 -3100m,and Tsuga forest at altitudes of 3180 -3050m that locate in higher altitude regions are respectively pollen of Abies,Larix,Picea,and Tsuga with their peak values of about 13.6% ,4.7% ,39.4% ,and 11.5% respectively in their pure forests. Pollen assemblages of conifer and broadleaved mixed forest at altitudes of 3200 - 2840m and mid-mountainous humid evergreen broadleaved forest at altitudes of 2480 -2331 m are characterized by high percentage evergreen oaks and Castanopsis/Lithocarpus respectively, and have muhifold deciduous and broadleaved arbors pollen and shrubs pollen,although types of broadleaved arbors pollen and shrubs pollen are more in mid-mountainous humid evergreen broadleaved forest than those in conifer and broadleaved mixed forest,and the peak value of fern also occurs in the mid-mountainous humid evergreen broadleaved forest. Pollen of trees except for Pinus seldom occurs in the pollen assemblage of Pinus forest in regions between 2300m a. s. 1. and 2195m a. s. 1. As Pinus pollen in the studied area has very strong dispersal ability, its percentage, no matter how high it would be, can not be used for judging the vegetation type. The result of DCA ordination reflects well the relationship between modern vegetation and environment, and shows that temperature is the most important factor for the distribution of different vegetation zone types, which is consistent with the general rule that vertical vegetation zones change gradually along with the altitude rising and the temperature decreasing.