Biodiversity Science ›› 2007, Vol. 15 ›› Issue (3): 271-281.doi: 10.1360/biodiv.060214

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Dynamics of species diversity and characteristics of halophytic plant communities around saline lakes in arid and semi-arid regions of Inner Mongolia

Quanying Du1*, Zhi Li2, 3, Shurun Liu4, Hongyan Liu1   

  1. 1 Department of Ecology, College of Environmental Sciences, Peking University, Beijing 100871
    2 The Key Laboratory for Environmental and Urban Sciences, Shenzhen Graudate School, Peking University, Shenzhen, Guangdong 518055
    3 College of Environmental Sciences, Peking University, Beijing 100871
    4 Inner Mongolia Education College, Huhhot 010010
  • Online:2007-05-20

Soil salinization is one of the main types of land desertification, which occurred widely around saline lakes in arid and semi-arid regions. Studies on the impact of salinization on the distribution and diversity of plant communities are still scarce. To explore the changes of halophytic vegetation along saline soil gradients, we collected halophyte samples around the lakes of Jartai, Ulansuhai Nur, Qagan Nur, and Ejin Nur, from desert, steppe-desert, desert-steppe, to typical grassland, representing a gradient of climate condi-tions. These plots also demonstrated a perfect salinity gradient both at a smaller scale (lake level) as well as at a larger scale (regional level). Using methodology of space-for-time substitution of halophytic plant communities as well as the extent of soil salinization, we analyzed the structure and distribution pattern of all communities. Based on 10 salinity gradients, salinity tolerance values of communities were calculated by mul-tiplying importance values and salt-tolerance values of each species. We also considered the significance of halophytic community as indicators of saline environments. The results showed that the halophyte communities are distributed around the lakes, accompanied with enrichment of community types and species number, from dry to wet climate zone. In particular, the communities were distributed following the sequence of Comm. Ach-natherum splendens, Comm. Kalidium foliatum, Comm. Salicornia europaea, Comm. Suaeda glauca, from margins to edges of lake banks and with the increase of salinity. On the other hand, species richness of the community declined from dry to wet climate zone due to appearance of similar species, and community struc-ture became simplified. As community salinity tolerance value increased, the α-diversity of all the communities decreased but at different rates. As for β-diversity, a more complex pattern appeared. We also found that the re-gional climatic conditions could influence halophytic community characteristics. Under conditions of slight salinization, the effects were more pronounced and the vegetation was characterized by a zonal vegetation. With the greater extent of salinization, the azonality character of the vegetation became more significant. These re-sults indicate that the halophytic vegetation in the study area was in a transition from zonal to azonal vegeta-tion.

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