Positive correlation between soil bacterial metabolic and plant species diversity and bacterial and fungal diversity in a vegetation succession on Karst

Abstract

The hypothesis that positive links exist among plant taxonomic diversity, belowground microbial taxonomic and metabolic diversities was tested for four secondary vegetation successional stages (tussock (T), shrub (S), secondary forest (SF) and primary forest (PF)) in Huanjiang county, SW China. Soil bacterial communities were characterized by DNA fingerprinting and metabolic profiling. Along the succession, Shannon diversity indices followed the order SF>PF>S>T for plant taxonomic diversity, T>SF>PF>S for bacterial operational taxonomic diversity, SF>T>S>PF for fungal operational taxonomic diversity, and SF>PF>S>T for bacterial metabolic diversity. Significant positive correlations were found between bacterial and fungal taxonomic diversities. However, there was no significant correlation between soil microbial taxonomic diversity and bacterial metabolic diversity. Two-way ANOVA revealed that vegetation and season, as well as their interaction, had significant effects on soil microbial (fungal and bacterial) taxonomic diversities, but that there were no seasonal effects on metabolic diversity. However, PCA and MANOVA revealed highly significant differences among the bacterial community-level physiological profiles, reflecting the successional sequence. The findings from this survey support the notion that there are strong interactions between aboveground and belowground communities and suggest that bacterial metabolic and plant taxonomic diversities, but not microbial taxonomic and metabolic diversities, can be correlated.

Soil bacterial community composition and diversity respond to cultivation in Karst ecosystems

“…The area has a subtropical mountainous monsoon climate with a mean annual temperature of 18.5°C and an annual rainfall of 1,389 mm (He et al 2008).…”

“…During the conversion process from forest to cropland, soil nutrients (Table 1) and the diversity of flora and fauna were significantly decreased, which may influence microbial diversity (He et al 2008;Ren 2005;Torsvik and Øvreås 2002). Moreover, the disproportionate distribution of OTUs affected bacterial diversity because the OTUs represented by only one clone were lower in the soil bacterial communities of cropland (30.0% of OTUs) and revegetated land (21.2%) when compared to the primeval forest (45.0%) ( Table 3).…”

“…Karst ecosystems are very fragile. The soil is typically thin, coarse, highly erosive and degenerative (He et al 2008). Karst soil covering about 0.55 million km 2 in southwest China, has been subjected to intensive anthropogenic disturbances, such as cultivation, deforestation, grazing and burning (Xiao and Weng 2007;Yao et al 2001).…”

“…Furthermore, by measuring the characteristics of the soil microbial community, the structure, status and quality of soil as well as the potential for successful vegetation recovery after soil degradation can be assessed (Badiane et al 2001;Mummey et al 2002). For degraded Karst ecosystems, existing studies have mainly focused on the changes of soil quality (including physical and biochemical properties) (Zhang et al 2006a), plant diversity (He et al 2008) and hydrological characteristics (Li et al 2004). However, the effects of human disturbance on other ecological components, such as soil microbial communities, have not been well studied for Karst ecosystems.…”

Nitrogen-fixing bacteria communities occurring in soils under different uses in the Western Amazon Region as indicated by nodulation of siratro (Macroptilium atropurpureum)

“…Soil management practices can influence the occurrence, density and diversity of these strains Jesus et al 2005;Nóbrega 2006) and probably LNB functionality. He et al (2008) showed that there were strong interactions between aboveground and below-ground microbial communities; however, the bacterial metabolic and plant taxonomic diversity, but not microbial taxonomic and plant diversity, were correlated in different land use systems in China. We found no studies showing that changes in land use affect LNB community functionality and no studies of the relationship between LNB communities and soil chemical and physical attributes under natural conditions.…”