Characteristic Of Species Composition And Soil Microbial Community In Major Forests In Jiangxi Province

The restriction mechanism of forest structure and function is the important foundation for community ecology, quantitative ecology and forest ecosystem management. It’s also the hotspot and difficulties in the above research field. Based on the the ecosystem service of biodiversity, we explored the relationship between species diversity and soil microbial diversity in different forest types. We also explored maintaining effect of the species diversity and functional diversity on ecosystem productivity and the effect of soil microbial diversity. Our research could provide theoretical support for the forest ecosystem management.The major results were as follow:(1)The inventory indicated that forest community types and flora were diverse. The family compositions were similar in middle and southern Jiangxi province, which were Lauraceae, Fagaceae, Theaceae and Rosaceae. But species in Lauraceae and Fagaceae were dominant in middle and southern Jiangxi Province, respectively. In addition, Myrsinaceae and Euphorbiaceae were only abundant in middle and southern Jiangxi Province, respectively.(2)In evergreen broad-leaved forests, shrub layer had higher species richness and diversity index but lower evenness index than tree layer and herb layer. Only tree layer had a significant difference in the diversity index and composition in different succession stages. In Chinese fir plantations and masson pine plantations, the diversity index, species richness and evenness in shrub layer were all higher than in tree layer and herb layer. The species composition of Chinese fir shrub layer was distinct in different ages. In addition, no significant difference was found in herb layer of Chinese fir and masson pine plantations. Generally, it suggested that age had limited effect on diversity of understory.(3)In evergreen broad-leaved forests, C/N and soil available potassium were the major factors to tree composition; the shrub composition were variable with altitude; herb composition were affected by slope, Cu and Ca. In Chinese fir plantations, slope aspect affected shrub composition, while soil potassium and altitude affected herb layer. In masson pine plantations, only altitude and soil available potassium affected shrub composition.(4)In evergreen broad-leaved forests, shrub and herb biomass had positive relations with its diversity index. Only shrub species richness was positive to biomass in masson pine plantations. Plant functional diversity (FRic) was negative to environmental factors (slope aspect) and FDiv was positive to altitude and Na content in soil.(5)Compared the soil microbial community structure of evergreen broad-leaved forests, Chinese fir plantations and masson pine plantations, Chinese fir plantations had larger microbial biomass (including bacteria, fungi, actinomycetes and AMF) than evergreen broad-leaved forests, while masson pine plantations had the lowest ones. G+was dominant in masson pine plantations and Chinese fir plantations, while G- was abundant in evergreen broad-leaved forests. Bacteria were the major microbial group in these forests, with the biomass evergreen broad-leaved forest> Chinese fir plantation> masson pine plantations. Additionally, masson pine plantation had the highest biomass in fungi.(6)The major vegetation factor which affected evergreen broad-leaved forests were tree richness, shrub biomass, and soil factors including soil Na content and total carbon. The richness of tree and shrub layers and herb biomass all affected soil microbial composition in masson pine plantations. Additionally, shrub coverage, shrub number and richness of shrub and herb all positively related with soil microbial biomass in masson pine plantations. It indicated that shrub richness may shed more influence on soil microbial community. In Chinese fir plantations, tree coverage, soil potassium content were closely related with soil microbial community composition.