中国中亚热带北部灌丛群落植物空间周转及其驱动因素

Spatial turnover of shrubland communities and underlying factors in northern mid-subtropical China

环境因子是驱动物种空间周转的重要因素,灌丛作为亚热带地区重要的植被类型,探究其群落的物种空间周转格局及其驱动因素,能够为区域生物多样性保护提供科学依据。该研究以中国中亚热带北部灌丛群落为研究对象,采用广义相异性模型,以Bray-Curtis相异性指数为指标,分析了气候、土壤、地形、人为干扰等因素对灌丛群落物种周转的驱动效应。结果表明,气候因子对物种周转影响显著,且随着海拔、坡度、土壤总氮含量、国内生产总值的增加,物种周转速率显著增加,而年平均气温和距道路距离对物种周转无显著影响。在过酸过碱的土壤中,物种周转速率较低,在pH=5时,物种周转速率达到最大值。气候、土壤、地形、人为干扰等因素可以解释灌丛植物群落物种周转的33.55%。其中,土壤因素的解释率为26.54%,而气候和地形、人为干扰因素分别解释了13.39%和3.17%,土壤pH的相对贡献率(37.28%)最大。综上所述,环境因子对中国中亚热带北部灌丛群落的物种空间周转过程有重要作用,其中土壤因子为驱动物种周转的关键因素。

Aims Environmental factors are among the key factors governing the community species spatial turnover.As one of the widely distributed vegetation types in subtropical region of China,it is important to understand the species composition differences among shrubland communities,which will provide important information for protecting biodiversity and eco-security shield construction in the northern mid-subtropical region,China.However,little is known about which factors drive the species spatial turnover in subtropical region of China.The objectives of this study were to investigate the shrubland community spatial turnover pattern and to determine the key factors that shape the present distribution of species based on the field-based data in northern mid-subtropical China.Methods Based on the field-based data in mid-subtropical shrublands,we used the generalized dissimilarity modelling(GDM) by the Bray-Curtis dissimilarity index to explore the driving effects of climate,soil,topography,and human disturbance on species turnover of the shrubland communities in northern mid-subtropical China.Important findings The results showed that climatic factors had significant effects on plant species turnover of the shrubland communities in northern mid-subtropical China.With the increase of altitude,slope,soil total nitrogen content and gross domestic product(GDP),species turnover rate increased significantly.Mean annual air temperature and the distance to road had no significant effects on species turnover.The species turnover rate decreased when soil pH became too acidic or too alkaline,and the rate reached the maximum value when pH was 5.Climate,soil,topography,and human disturbance explained 33.55% of the species turnover deviances,of which,soil accounted for 26.54% of the GDM deviances,while climate and topography,human disturbance accounted for 13.39% and 3.17% of the GDM deviances,respectively.Soil p H contributed 37.28% of the deviances to the species turnover of shrubland community.In conclusion,environmental factors(especially soil p H) were the major drivers of the species spatial turnover in northern mid-subtropical shrubland communities.