关键词: 砒砂岩, 草本植物, 物种组成, 物种多样性, 水分

Abstract:

In order to explore the species composition and diversity of herbaceous species in different types of arsenic sandstone areas and the impact of environmental factors on them， different types of arsenic sandstone areas were selected in the Inner Mongolia Ordos City， to investigate the species composition and diversity of herbaceous plant. The results showed that： The dominant herbaceous species was different in different types of arsenic sandstone areas. The soil-covered area was Stipa capillata， Salsola tragus， Lespedeza bicolor， Tribulus terrestris； the sand-covered area was S. capillata， Setaria viridis， Artemisia argyi； the bare area was Chenopodium aristatum. The similarity index of sand-covered area and bare area was 50.0%， those of sand-covered area and soil-covered area and soil-covered area and bare area were 63.6% and 39.1%.There was no significant difference in the diversity index of herbaceous species among different types of arsenic sandstone areas.The evenness index of different topographic sites was significantly different （P=0.027） ， which is significantly higher on the slope than on the middle and lower slopes. The results of principal component analysis showed that relative humidity， air temperature， precipitation and soil water content were the main environmental factors affecting species composition and diversity， relative humidity， air temperature and precipitation accounted for 42.4%， 44.5% and 33.4% of the first principal component respectively， and soil moisture accounted for 66.8% of the second principal component. Therefore， understanding the relationship between water conditions and species diversity is helpful for ecological restoration， construction of revegetation and control of soil erosion in arsenic sandstone areas. This study can provide a near-natural plant spatial allocation model for vegetation restoration in arsenic sandstone area， so as to promote the effect of ecological restoration.

Key words: arsenic sandstone, herbaceous plant, species composition, species diversity, water