新疆阿尔泰红山嘴地区的表土孢粉与现代植被

Surface sporopollen and modern vegetation in Hongshanzui area,Altai,Xinjiang,China

在新疆阿尔泰山中段的红山嘴地区选取一条沿海拔745–2413m的不同植被带群落样方进行调查,对应采集37个表土样品进行孢粉统计和排序分析,初步探究了红山嘴地区的植被与表土孢粉之间的对应关系,并将之与新疆阿尔泰西部的喀纳斯西坡孢粉垂直带进行对比。结果表明,红山嘴地区表土孢粉谱依照海拔高度自上而下划分为4个孢粉组合类型,分别对应亚高山草甸、山地森林、灌丛草原和荒漠草原。乔木植物中云杉属(Picea)和松属(Pinus)花粉,灌木植物中麻黄属(Ephedra)及草本植物中的苋科和蒿属(Artemisia)因受到自然风力、水流及人为活动的影响,表现出明显的超代表性;乔木植物中的落叶松属(Larix)花粉,草本植物中的禾本科及莎草科花粉,却在其自身为优势种的群落中呈现低代表性;蒿属与苋科花粉百分含量的比值(Ar/Am)能较好地反映该区气候垂直带的干湿状况,灌丛草原带的Ar/Am低,在一定程度上反映了人类活动对草原灌丛化的影响。与新疆阿尔泰西部的喀纳斯西坡孢粉垂直带相比,红山嘴垂直带的孢粉类型偏少,同时相似的孢粉带在该区的分布高度比喀纳斯西坡高。此外,排序分析(RDA)结果表明,年降水量是影响该区表土孢粉组合的主要环境因子。

Aims Our aims are 1)to explore the relationship between vegetation and sporopollen in the surface soil in the Hongshanzui area,which is located in the middle slope of the Altai Mountains,2)to compare different sporopollen assemblages zones between the Hongshanzui area and the Kanas region,which is located in the western slope of the Altai Mountains of Xinjiang,and 3)to explore the relationships between surface sporopollen and environmental factors.Methods We collected 37 surface soil samples and carried out modern vegetation survey in the Hongshanzui area along an altitudinal gradient from 745 to 2413 m.Mathematical statistics and redundancy analysis(RDA)were applied to analyze the distribution pattern of sporopollen in surface soil and its relationships with modern vegetation.Important findings The results showed that the sporopollen spectrum of surface soil in Hongshanzui area was divided into four zones from top to bottom along the altitudinal gradient,corresponding to the major vegetation types in this region,including subalpine meadow,mountain coniferous forest,shrub steppe and desert steppe.The typical tree species,Picea and Pinus pollen,and shrub species Ephedra,herbs Amaranthaceae and Artemisia,were extra representation in the region,mainly because of the impact of wind and rivers in sporopollen dispersal.Larix,Poaceae,and Cyperaceae had low representations in communities where they were dominant species.Many previous sporopollen studies have shown that the ratio of the percentage of pollen content of Artemisia to Amaranthaceae(Ar/Am)was a good indicator of the degree of humidity in the semi-arid and arid areas.Our study confirms that Ar/Am roughly corresponded to the wet and dry conditions of the climate vertical zone in this area.To some extent,the low Ar/Am ratio for shrub steppe also reflected the influence of human activities on shrub steppe.Compared with the western slope of Kanas,the characteristics of sporopollen assemblage zones in the Hongshanzui region were incomplete,and the distribution height of similar sporopollen zones in this area was higher than that on the western slope of Kanas.In addition,the results of RDA on sporopollen assemblages and environmental factors(mean annual temperature(MAT),mean annual precipitation(MAP)and altitude(ALT))revealed that the MAP was the main environmental factor affecting sporopollen assemblages in the surface soil in the Hongshanzui region.