摘要
古尔班通古特沙漠地衣结皮对放牧踩踏干扰及其所引起的生境异质性具有重要的指示作用。研究表明:①放牧踩踏干扰主要集中于结皮层(0～5 cm),随机调查的样方中,90%的样方干扰率均低于30%,生物土壤结皮(BSCs)破损尚处于较安全的范围;②放牧踩踏干扰降低了BSCs总盖度,不同类型的结皮对践踏干扰的反应具差异性,其中,真菌-藻类共生形成的地衣结皮与干扰率呈极显著负相关(P<0.01),干扰率>30%的样方中,抗风蚀能力较强的苔藓结皮、地衣结皮盖度均显著低于未受干扰样方,地衣共生体的破坏导致真菌数量显著增加(P<0.05);③有机质、土壤容重等土壤理化指标均与干扰率呈负相关,干扰率>30%的样方中各指标均低于未受干扰样方。其中,土壤容重是对放牧干扰比较敏感的指标,与地衣结皮盖度亦呈极显著正相关(P<0.01),与流沙盖度呈显著负相关(P<0.05)。
Biological soil crusts（BSCs） occur extensively in the southern part of the Gurbantunggut Desert,and serve as one of the important biological factors relating to sand surface fixation.As a winter rangeland,the desert is trampled by grazed livestock widely.Lichen crusts are the main type of BSCs in the southern part of the Gurbantonggut Desert and serve as one kind of the important nitrogen resources.They are also one of the sensitive biomonitors of desert ecosystem health,habitat heterogeneity and human-induced disturbances.This study investigated the effect of trampling on cover of BSCs.The results were as follows：（1） The local disturbance rate mainly ranged from 10% to 20%,which was a relatively safe range against wind erosion;（2） The total coverage of BSCs was decreased due to the grazed livestock disturbance.The response of BSCs to grazing disturbance was different.Holistically,trample of grazed livestock reduced the coverage of dominant crusts,especially the lichen crusts.When disturbance rate was exceeded 30%,the average coverage of lichen crusts was lower than 30%.Because of the destroyed structure of fungal-algae symbiont,the quantity of fungi was increased（P0.05）.Contrast to the reduction of lichen crusts,more bare sand appeared with the increasing disturbance rate;（3） Grazing disturbance reduced soil organic matter content,soil bulk density and ion contents.There was an extremely significant positive correlation between soil bulk density and lichen crust coverage（P0.01）.
出处
《干旱区研究》
CSCD
北大核心
2012年第6期1032-1038,共7页
Arid Zone Research
基金
新疆维吾尔自治区青年科学基金项目(2009211B31)
国家自然科学基金项目(40901123)
国家重点基础研究发展计划(2009CB825104)
中国科学院西部之光项目(XBBS200906)
关键词
生物土壤结皮
放牧
干扰强度
盖度
微生物活性
古尔班通古特沙漠
biological soil crust
grazing
disturbance intensity
coverage
microbial activity
Gurbantunggut Desert
