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中国沙漠 ›› 2008, Vol. 28 ›› Issue (5): 868-873.

• 生物土壤与生态 • 上一篇    下一篇

干旱区生物土壤结皮对种子植物多样性的影响

陈荣毅1; 魏文寿1; 张元明2; 吴 楠2,3; 张 静2,3   

  1. 1.中国气象局乌鲁木齐沙漠气象研究所, 新疆 乌鲁木齐 830002; 2.中国科学院新疆生态与地理研究所, 新疆 乌鲁木齐 830011; 3.中国科学院研究生院, 北京 100039
  • 收稿日期:2007-10-09 修回日期:2007-11-12 出版日期:2008-09-20 发布日期:2008-09-20

Effect of Biological Soil Crust on Plant Diversity in Arid Area

CHEN Rong-yi1; WEI Wen-shou1; ZHANG Yuan-ming2; WU Nan2,3; ZHANG Jing2,3

  

  1. 1.Institute of Desert Meteorology, China Meteorological Administration, Urumqi 830002, China; 2.Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 3.Graduate School of Chinese Academy of Sciences, Beijing 100039, China
  • Received:2007-10-09 Revised:2007-11-12 Online:2008-09-20 Published:2008-09-20

摘要:

通过调查古尔班通古特沙漠筑路形成的严重干扰样方与自然状态下轻微干扰样方种子植物多样性的差异,结合人为干扰生物土壤结皮样方的结果,综合生物土壤结皮土壤种子库、结皮上种子萌发、生长以及土壤养分与水分的特征,研究生物土壤结皮对种子植物多样性的影响。结果表明:完整结皮与适度干扰后结皮样方内植物多样性指数D分别为0.3296和0.5291,多样性指数H分别为0.8400和1.2957,差异均达到显著水平;严重干扰样方的多样性指数D和多样性指数H均显著低于轻度干扰样方的对应指标。说明对生物土壤结皮 “适度”干扰使其保持在早期发育阶段有利于增加种子植物多样性,而“严重”干扰使结皮变为流沙阶段会降低种子植物多样性。结皮影响种子植物多样性的机理主要在于发育后期的生物土壤结皮会降低土壤种子库,也会抑制多数种类种子萌发,夏秋季结皮深层土壤水分的减少也不利于深根植物的生存,但结皮土壤拥有相对较高的养分条件却能保证一年生短命植物生长和生存。相对于流沙,生物土壤结皮的存在有益于保持相对较高的植物多样性,这可能归功于生物土壤结皮有利于地表稳定性、以及其在防风蚀和土壤形成等方面重要的生态功能,因而,在采取 “适度”干扰措施以提高植物多样性之前需要慎重考虑可能带来的不利影响。

关键词: 古尔班通古特沙漠, 生物土壤结皮, 植物多样性, 干扰

Abstract:

The plant diversity in severe disturbing plots caused by building road and that in mild disturbing natural plots as well as in human-induced disturbance plots were investigated in the Gurbantonggut Desert. There is an abundant biological soil crust (BSC) on the sand surface of the desert. In the paper, the effect of BSC on vascular plant seed bank, seed germination, plant growth, and soil nutrient and water distribution was firstly discussed, and then the effect of biological crust on plant diversity was studied. The Simpsons diversity index in the control (without disturbance) is 0.3296 and that in the human-induced moderate disturbance plots is 0.5291; the Shannon-Winner diversity index in the control (without disturbance) and that in the human-induced disturbance plots are 0.8400 and 1.2957, respectively. The Simpsons diversity index and the Shannon-Winner diversity index in moderate disturbance plots of 200 meters away are significantly higher than the two severe disturbance plots near road. The near-road represent serve human-induced disturbance plots, and the plot of 200 meters away from the road represents natural mild disturbance. The results show that \!Moderate\" disturbance can maintain the BSC at early succession stage, which is beneficial to improve the plant diversity. However, \!heavy\" disturbance changed soil into shifting sand, which will decrease the plant diversity. The seed density and diversity decrease with the crust evolving from algal crust to lichen and moss crust, and BSC have a negative effect on the seed germination. Well developed BSC decreased soil water condition of deep soil, and has a negative impact on the survival of deep-rooted grass and shrubs. However, the BSC has a significant role in contributing to the soil formation and soil nutrient fixation and holding, further to the plant diversity. The BSC also has a profound impact on sand fixation, soil formation and soil fertility development, thus affect the establishment and survival of vascular plants. So all the negative effects should be carefully considered before making artificial disturbance to improve plant diversity in this region.

Key words: Gurbantonggut Desert, biological soil crust, plant diversity, disturbance

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