中国北方典型灌丛群落表土花粉组合特征

来自中国北方20个典型灌丛群落的54个表土样品的花粉组合特征研究表明除蒿及沙棘灌丛外,其它灌丛中的优势植物种类在表土花粉组合中的百分比多数低于20%。阔叶林区灌丛与荒漠区和草原区灌丛表土花粉组合差别较大。阔叶林区灌丛中常有一定量的中华卷柏,蒿属和藜科百分比之和低于40%,花粉类型多样性指数多高于2.0;而草原区及荒漠区中华卷柏很少出现,蒿藜百分比高于50%,花粉类型多样性指数多低于2.0。落叶阔叶林区灌丛花粉组合中,松蒿比(P/A)大于0.1,而草原及荒漠区灌丛则小于0.1,但草原区灌丛蒿藜比(A/C)大于1,荒漠区则小于1。将松蒿比(P/A)与蒿藜比(A/C)、花粉类型多样性指数联合起来可较好地将荒漠、草原及落叶阔叶林区灌丛分开。

Surface pollen assemblages from typical shrub communities in North China

This study collected pollen assemblages for 54 surface pollen samples from 20 typical shrub communities in North China.The study results show that the pollen percentages of most dominant shrub plants,except Artemisia and Hippophae,are usually less than 20%. The pollen assemblages of shrubs in different ecological areas differ greatly. As to most of the shrubs in forest zone,the spores of Selaginella sinensis are common or abundant,and the pollen percentages of Artemisia and Chenopodiaceae are less than 40%,their pollen type diversity index is usually higher than 2.0.As to the shrub communities in steppe or desert zones,the spores of Selaginella sinensis are rare,and the pollen percentages of Artemisia and Chenopodiaceae are more than 50%,the pollen type diversity index is usually lower than 2.0. The ratio of Pinus to Artemisia (P/A)is higher than 0.1 in forest zones,while lower than 0.1 in steppe and desert zones. However the ratio of Artemisia to Chenopodiaceae (A/C) is higher than 1 in steppe area and lower than 1 in desert area. So if the ratio of Pinus to Artemisia(P/A),that of Artemisia to Chenopodiaceae (A/C),and pollen type diversity index are considered together,the different ecological areas can be differentiated from one another easily.