Soil bacterial diversity in Liuxihe National Park

Abstract:

[Background] Forest soil bacterial diversity is one of important indexes to measure forest quality. The composition and change of soil bacterial community structure can reflect the structure and function of forest ecosystem. They play important roles in the circulation of nutrients in forest ecosystems. [Objective] The influence of different forestry density on soil bacterial community structure was analyzed and discussed in Liuxihe National Park, in order to provide a reference for the restoration of degraded ecosystems, rational utilization of forestry resources, conservation of soil fertility, improvement of ecosystem productivity and service functions of forests. [Methods] A manipulative field experiment was conducted to investigate the effects of three different forest types: high density forest type (HD), medium density forest type (MD), low density forest type (LD). The soil samples were collected by “S” sampling method and the total DNA of soil microbes was extracted. 16S rRNA gene sequences were sequenced by Illumina Miseq sequencing and analyzed using R language, SPSS 21.0 and other software. [Results] The soil fertility of high density forest was higher than those of medium and low-density forests. Soil bacterial diversity index and richness index differed among different density forests, and the highest was in middle-density forest. Proteobacteria and Acidobacteria are the major groups in Liuxihe National Park. [Conclusion] The soil bacterial diversity is abundant in Liuxihe National Park. Proteobacteria and Acidobacteria are the major groups. Soil bacterial diversity, richness and community structure were significantly affected by forest density. The medium density forest type (1 800?2 200 plants/ha) in Liuxihe National Park is suitable for bacterial growth. The fertility of soil was affected by the forest density and shrub weeds. Intragenomic heterogeneity of 16S rRNA genes causes overestimation of bacterial diversity.

Key words:Different density forest type, Soil bacterial diversity, Community structure