Effects of Geographical Isolation and Land Use on Soil Microbial Distribution of Coastal Area and Islands in Beibu Gulf
To investigate the impact of geographical isolation(islands)and human activities(land use)on the distribution pattern and evolution of soil microorganisms,this study takes Beihai,Guangxi Zhuang Autonomous Region as the research area,including the mainland coastal zone(Beihai Continent),Weizhou Island,and Xieyang Island.It analyses the spatial distribution characteristics and influencing fac-tors of soil microorganisms(including community structure composition,biomass and diversity),explores the soil microbial biogeographic pattern of the continental coast and islands in Beibu Gulf region and ex-amines the contribution rate of geographical isolation and different land use types.The results are as fol-lows:(1)There is an obvious spatial differentiation of soil microorganisms in the study areas,and the bi-omass of soil microorganisms and their constituent communities on Weizhou Island and Xieyang Island is significantly higher than that in continental coast,presenting a distribution trend of Xieyang Island＞Weizhou Island＞Beihai Continent.(2)Soil bacteria is the dominant community in all study areas,but the ratio of different microorganisms varies.(3)In terms of the spatial distribution characteristics of soil microbial diversity indicators,Weizhou Island has significant advantages of Shannon-Wiener diversity and Simpson index,while Xieyang Island has the lowest Pielou evenness index,but its richness index is higher than that in Weizhou Island and significantly higher than that in continental coast.(4)Geographical iso-lation,land use and soil properties are the driving factors of the distribution characteristics of soil microor-ganisms in the study areas.Geographical isolation has caused significant spatial differences of soil micro-bial community characteristics in the three study areas;the soil microbial diversity distribution driven by land use is consistent with the moderate interference theory;compared to the natural forests,tillage re-duces the soil microbial biomass and richness significantly,but improves the diversity index,dominance index and evenness;soil texture,nutrient and C/N have significant effects on soil microbial biomass,but soil pH has more obvious effects on soil microbial community structure and diversity.
soil microbial distributiongeographical isolationland use typessoil propertiesislands
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