草业学报2016，Vol.25Issue(4)：26-35,10.DOI:10.11686/cyxb2015481
坡向对青藏高原东北缘高寒草甸植被构成和养分特征的影响
Variations in vegetation composition and nutrient characteristics related to aspect in an alpine meadow in the northeast margin of the Qinghai-Tibet Plateau
摘要
Abstract
Aspect is an important topographical factor that affects illumination,temperature,and soil nutri-ents,all of which affect the composition and distribution of plant species.In this study,we evaluated the effect of aspect on the soil nutrient characteristics and on the composition and spatial distribution of plant communi-ties in an alpine meadow in the northeast margin of the Qinghai-Tibet Plateau.The dominant and subdomi-nant species in grassland communities were Leymus secalinus ,Stipa krylovii ,and Koeloria cristata (Gra-mineae)on sunny slopes and Kobresia humilis and Kobresia capillifolia (Cyperaceae)and Melilotoids rutheni-ca var.inschanica (Leguminosae)on shady slopes.The herbage height,α-diversity index,and number of plant species in grasslands were greater on shady slopes than on sunny slopes,while theβ-diversity indexes of grasslands were similar between shady and sunny slopes.The plant life-form spectrum both on sunny and shad-y slopes mainly consisted of hemicryptophytes and geophytes,accounting for 89% and 71% of the total number of species,respectively.There were more annual and biennial plants and hemicryptophytes on sunny slopes than on shady slopes,but more hemicryptophytes on shady slopes than on sunny slopes.There were similar numbers of geophytes on sunny and shady slopes.The plant families contributing to total biomass in grassland communities on sunny slopes were Gramineae (78.3%)>Cyperaceae (8.3%)>Asteraceae (6.4%)>others (7%);and to grassland communities on shady slopes were Cyperaceae (54.3%)>Leguminosae (16.4%), Gramineae (14.8%)>Polygonaceae (5.3%),Asteraceae (4.6%),and others (4%).For all of the plant fami-lies except for the Asteraceae,the contribution to total biomass differed significantly between sunny and shady slopes,but the contribution to total aboveground biomass was similar between sunny and shady slopes.The ni-trogen content in the 0 -20 cm soil layer was higher on the shady slope than on the sunny slope,while the phosphorus,potassium,copper,and zinc contents in the 10-20 cm soil layer were higher on the sunny slope than on the shady slope.The soil temperature in the 0-30 cm layer was higher on the sunny slope than on the shady slope,whereas the water content in the 0-40 cm soil layer was higher on the shady slope than on the sunny slope.Together,these results show that aspect plays an important role in the composition of vegetation communities and in the physical and chemical properties of soil in alpine meadows.关键词
高寒草甸/坡向/群落构成/物种数/生活型/生物量/养分Key words
alpine meadow/slope/community composition/species number/life-form/biomass/nutrients引用本文复制引用
徐长林..坡向对青藏高原东北缘高寒草甸植被构成和养分特征的影响[J].草业学报,2016,25(4):26-35,10.基金项目
国家自然基金项目（31460566）和甘肃省农业科技创新项目《草业生态系统教育部重点实验室开放课题（GNCX-2014-27）资助。 （）
