Plant community characteristics and its coupling relationships with soil in depressions between karst hills, North Guangxi, China

Abstract

Aims Our objective was to study plant community characteristics and coupling relationships between plant and soil properties in different ecosystems in depressions between karst hills. Methods We established 24 sample plots of 20 m × 20 m dimensions in four ecosystems (grassland, scrub, secondary forest and primary forest) in depressions between karst hills. We investigated the species composition and diversity characteristics of these ecosystems. We chose 35 indexes covering plant community and soil properties to study the relationships between plant factors and soil nutrients, soil mineral chemical components and soil microbes using analysis by principal component analysis (PCA) and canonical correlation analysis (CCA). Important findings Along succession from grassland to scrub to secondary forest to primary forest, the maximum number of species, genera and families with importance values (IV) 10.00 and maximum species diversity were in secondary forest, and the optimal community structure was in primary forest. The depressions between karst hills had high landscape heterogeneity, and different ecosystems were influenced by different factors. Soil microbes were the dominant influence in karst fragile ecosystems, followed by scrub. CCA elucidated a close relationship between species diversity and soil nitrogen, Al2O3 , Fe2O3 , microbial biomass carbon (C mic ), fungi and bacteria. Vegetation improvement and management practices should focus on such characteristics of different ecosystems when undertaking restoration and reconstruction of karst fragile ecosystems.