贺兰山东、西侧典型植物群落物种多样性差异及其影响因子OA北大核心CSTPCD

Under the background of global climate change,understanding the species diversity characteristics of mountain plant communities and their environmental influencing factors in arid and semi-arid regions is the basis of regional biodiversity conservation.Helan Mountain was located in the transitional zone between temperate grassland and temperate desert in China.Its eastern and western parts are affected by different climates,making it an ideal area for species diversity study in mountain ecosystems.In this paper,five plant formations widely distributed in the eastern and western parts of Helan Mountain were selected,and their species diversity differences and main influencing factors were investigated by typical community structure and environmental factors analysis.The results showed that:1)the typical plant communities in eastern and western Helan Mountain were different in species number and water ecological type species compositions.The communities in western part were more arid than those in eastern part,leading to higher numbers of plant species in three formations,i.e.,Ulmus glaueescens,Populus davidiana,and Picea crassifolia.2)The species diversity in the eastern part showed a"hump"pattern along elevation gradients,while in the western region,it decreased as elevation increased.There were significant differences in species diversity between the eastern and western parts of some communities such as Ulmus glaueescens.3)Soil water content,soil available phosphorus contents,and soil bulk density were key factors affecting the total plant species diversity in the eastern and western Helan Mountains.Among them,soil bulk density and altitude were the main factors affecting the diversity of tree layers.Altitude and soil available phosphorus were the main factors for shrub layers,and soil available phosphorus and water content were the main factors for herbaceous layers.Species diversity of typical forest communities in the eastern and western parts of Helan Mountain,were correlated with altitude and soil physicochemical properties.The measurements which could improve soil physicochemical properties,can promote the growth and development of plants in the forest,thereby helping to increase community species diversity.These results are helpful for further understanding structure and function of mountain ecosystems in arid and semi-arid regions,and provide theoretical basis for conservation and restoration of these fragile mountain ecosystems.