中国北方几种主要森林群落表土花粉组合特征研究

中国北方68个不同森林群落表土花粉研究表明,东部森林区森林群落中乔木花粉百分比多数大于30%,草本花粉百分比小于50%;草原区河谷林和低山林带乔木花粉百分比低于30%,草本植物花粉高于50%。松、云冷杉林和桦木林花粉组合中的优势成分也是群落中的优势植物;落叶松林中蒿花粉含量最高,其次为松、落叶松;山杨林中松、桦是最主要花粉类型;栎、胡桃、鹅耳枥及青檀林中,除建群种外,松是最主要的乔木花粉类型,中华卷柏也较多;阔叶杂木林与油松阔叶混交林花粉组成相似,松、桦、中华卷柏是最主要的花粉类型。降趋对应分析、主坐标分析和聚类分析研究表明云冷杉、落叶松和桦林花粉组合及所代表的生境具有一定的相似性,为最耐寒喜湿类型;沙枣、榆树疏林和草原区人工杨树林花粉组合及所代表的生境为最喜干旱类型;山杨林较桦木林略喜暖干,栎林、鹅耳枥林和青檀林较山杨林更喜暖干,胡桃楸林为所有森林类型中最喜暖类型,但喜湿性低于桦木林高于栎林。森林区松蒿比(P/A)大于0.1,草原区松蒿比小于0.1。松林、油松阔叶混交林和阔叶杂木林以高松蒿比、高蕨类与草本比值(F/H)和低蒿藜比(A/C)为特征,云冷杉、落叶松和桦林以低松蒿比、低蕨类与草本比值和高蒿藜比为特征,栎、胡桃、鹅耳枥、杨、青檀等阔叶林以高松蒿比、高蒿藜比和低蕨类与草本比值,可与落叶阔叶杂木林、油松阔叶混交林、松林、桦林和针叶林区分开。但这些比值的可操作性,有待进一步研究。

SURFACE POLLEN ASSEMBLAGES OF SOME MAJOR FOREST TYPES IN NORTHERN CHINA

Studies on surface pollen of 68 different forest communities in Northern China show that arboreal pollen percentages are more than 30WTB3]%WTBZ] and herbs pollen percentages are less than 50% in the eastern broadleaves forest areas, while arboreal pollen percentages are less than 30WTB3]%WTBZ] and herbs pollen percentages are more than 50WTB3]%WTBZ] in the forest communities in the western steppe and desert areas. In Pinus, Picea and Betula forests, the pollen taxa with the highest percentages are dominated plants. In Larix forest, Artemisia has the highest percentages, then followed by Pinus and Larix. In Populus forest, Pinus and Betula are the two abundant components in the pollen assemblages. In Quercus, Juglans, Carpinus and Pteroceltis forests, except for their dominated plants, Pinus is the most important arboreal pollen type with certain fern spores. Pinus, Betula and Selaginella percentages are advantageous in mixed broadleaves forests and Pinus mixed broadleaves forests. The result of DCA, PCA and CLA analyses of samples show that the trees which mostly prefer to live in wet and cold areas are Picea, Larix and Betula, and the species which mostly prefer to live in arid areas are Elaeagnus, Ulmus and artificial Populus forest. Populus prefer to warmer and drier condition than Betula. Quercus, Carpinus and Pteroceltis prefer to warmer and drier condition than Populus. Juglans more prefer to warm conditions than all above the forest types. All those results are consistent with their ecological conditions. The pollen percentages ratios of Pinus/Artemisia (P/A) are more than 0.1 in the eastern broadleaves forests, and less than 0.1 in the western forest communities of steppe and desert. Pinus forests, Pinus mixed broadleaves forests and mixed broadleaves forests have high P/A ratios and F/H ratios (fern/herbs) with relative low A/C ratio (Artemisia/Chenopodiaceae). Picea, Abies, Larix and Betula forests have low P/A and F/H ratios with high A/C ratios. The high P/A and A/C ratios with low F/H ratios in Quercus, Juglans, Carpinus, Populus, Peroceltis forests distinguished from mixed broadleaves forests, Pinus mixed broadleaves forests, Pinus forests, Betula forests and needle forests. However, whether these results can be used widely still need further verification.