北京城市发展对土壤微生物群落功能多样性的影响

为研究城市发展对土壤微生物功能多样性的影响,以北京市建成区为例,采用Biolog-ECO微平板技术分析不同环路内3种类型绿地(居民区内绿地、街道边绿地、公园内绿地)土壤微生物群落功能多样性的变化.结果表明:二环内各绿地类型土壤微生物群落的AWCD(average well color development,平均颜色变化率)相对较高,分别为1.107、1.192、1.007,表明其土壤微生物群落代谢活性较高,利用碳源能力较强,其他环路土壤微生物群落利用碳源能力相对较弱；其中,各绿地类型土壤微生物群落对羧酸类碳源的利用能力最弱.城市环路梯度下居民区对土壤微生物群落多样性的影响相对较大；街道对土壤微生物群落功能多样性无显著影响(或者城市环路梯度下街道边绿地土壤微生物群落功能多样性趋同)；四环～五环公园内绿地土壤微生物群落功能多样性与其他环路之间存在显著差异.对土壤微生物群落碳源利用能力进行主成分分析的结果显示,居民区内绿地、街道边绿地、公园内绿地提取的与土壤微生物碳源利用相关的主成分累积贡献率分别为86.79%、87.09%、84.92%,对主成分分离起主要作用的碳源主要是氨基酸类、糖类、多聚物类和羧酸类物质.冗余分析(RDA)表明,pH、土壤含水量是影响土壤微生物群落代谢能力和功能多样性的主要因素.城市绿地类型和环路因子对土壤微生物利用碳源分异存在一定影响,但对碳源代谢能力变异的解释量(5.91%)低于土壤理化因子的解释量(16.26%).研究显示,城市环路对土壤微生物功能多样性产生一定影响,但各环路街道边绿地土壤微生物功能多样性无显著差异,并且二环内、二环～三环、三环～四环各绿地类型土壤微生物多样性也无显著差异,说明城市发展可能使土壤微生物群落功能多样性趋于同质化. 

Effects of Urban Development on Soil Microbial Functional Diversity in Beijing

Abstract:The functional diversity of microbial communities was studied to investigate the effects of urban development.The functional diversity of soil microbial communities in three green-land types(street,residential and park green-lands) in different ring roads in Beijing were analyzed using the Biolog-ECO plates.The results indicated that the soil microbial carbon utilization was higher within the second ring road than other sample sites,and the values of AWCD of the soil microbial were 1.107,1.192 and 1.007,respectively.The soil microbial carboxylic acids utilization was lower in every sample site.There were significant differences in functional diversity of soil microbial between residential green-land within the second ring road and outside the fifth ring road,indicating that residential areas have more effect on functional diversity of soil microbial under urban development.There was no significant difference in soil microbial functional diversity in street green-lands.This demonstrates that urban development has no effect on functional diversity of soil microbial community in street green-lands(or that functional diversity of soil microbial community in street green-lands was homogenized under the urban ring roads).There were significant differences in functional diversity of soil microbial between park green-lands within the fourth and fifth rings and others rings.Principal component analysis demonstrated that principal components extracted from 31 carbon sources were related to soil microbial carbon source utilization；the principal components of different green-land types accounted for 86.79%,87.09% and 84.92% of the total variables variance respectively,in particular concerning carbohydrate,amino acids,carboxylic acid and polymer.Redundancy analysis showed that pH and soil water content were the main factors most highly correlated with variance of soil microbial carbon utilization.Green-land types and urban ring roads did have an effect on soil microbial carbon utilization,but they contributed less to the total variance compared with soil properties,which explained 5.91% and 16.26% of the variance,respectively.Functional diversity of soil microbial community will be influenced by urban development.The effects of soil characteristics on soil microbial functional diversity were different among different green-land types.Although the functional diversity of soil microbial community can be influenced by urban ring-roads,there were no significant differences in street green-lands of the different ring roads,and there were also no significant differences in green-land types within the second ring road,between the second and third ring roads,and between the third and fourth ring roads.The functional diversity of soil microbial community will be homogenized with urban development.