高寒草甸植被退化过程中生物土壤结皮演变特征  

Evolution characteristics of biological soil crusts( BSCs) during alpine meadow degradation

作　　者：李以康[1,2] 欧阳经政[1,2] 林丽[1] 张法伟[1] 杜岩功[1] 曹广民[1] 韩发[1] 

机构地区：[1]中国科学院西北高原生物研究所,西宁810008 [2]中国科学院大学,北京100049

出　　处：《生态学杂志》2015年第8期2238-2244,共7页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(31270576);青海省科技厅项目(2013-N-540;2013-Z-915)资助

摘　　要：对生物土壤结皮(BSCs)在青藏高原的分布和作用还知之甚少,为了解其在高寒草甸退化过程中的演变特征,以高寒草甸为对象,研究其退化和人工重建对BSCs生长和分布影响。结果表明:随草甸退化,植被盖度不断降低,苔藓类结皮在禾草嵩草草甸和6年人工草地出现频度最高,随植被退化出现频度降低,"黑土滩"阶段最低(43.6%);黑斑、菌斑和地衣都是在矮嵩草阶段形成,在小嵩草草甸裂缝期或者剥蚀期出现频度最高,在禾草嵩草群落、6年人工草地及黑土滩均未出现;相关分析表明,苔藓类结皮出现频率与植被盖度呈极显著相关(P<0.01),而与黑斑和地衣出现频率呈负相关,菌斑与地衣出现频度呈显著相关(P<0.05)。BSCs在高寒草甸广泛分布,不同演替阶段,其分布和物种组成存在较大差别。植被生长和表土稳定性状况导致了BSCs的异质性分布格局。Biological soilcrusts （BSCs） are an important component of ecosystems, especially in arid and semi-arid ecosystems, but we know little about their distribution and function on the Ti- betan Plateau. In this study, we investigated the effects of alpine meadow degradation and artifi- cial grassland construction on the distribution and growth of BSCs. Results showed that community coverage decreased with the degradation of alpine meadow. The occurrence frequency of moss was the highest in Graminaceous＋Kobresia community and 6-year-old artificial grassland, and then decreased along alpine meadow degradation succession, being the lowest in black soil beach （43.6%）. Black patches, white patches and lichen formed in K. humilis community, and were most abundant at Mattic epipedon crack stage of K. pygmaea meadow or Mattic epipedon erosion stage as indicated by the highest occurrence frequency, but were not observed in Graminaceous＋ Kobresia community, 6-year-old artificial grassland and black soil beach. The correlation analysis showed that the occurrence frequency of moss was significantly positively correlated with vegeta- tion coverage, but negatively correlated with the occurrence frequencies of both black patches and white patches. A significant positive correlation was observed between the occurrence frequency of white patches and lichen （P〈0.05）. These findings demonstrate that BSCs distribute widely in al- pine meadows, and vary greatly in distribution and species composition, indicating strong heteroge- neity in distribution pattern due to the changes in vegetation growth and soil surface stability with meadow degradation.

关 键 词：青藏高原 演替 植被盖度 苔藓类结皮 

分 类 号：S812.2[农业科学—草业科学]