The Effect of Re-Planting Trees on Soil Microbial Communities in a Wildfire-Induced Subalpine Grassland

Abstract

Abstract:Wildfire often causes tremendous changes in ecosystems, particularly in subalpine and alpine areas, which are vulnerable due to severe climate conditions such as cold temperature and strong wind. This study aimed to clarify the effect of tree re-planting on ecosystem services such as the soil microbial community after several decades. We compared the re-planted forest and grassland with the mature forest as a reference in terms of soil microbial biomass C and N (C mic and N mic ), enzyme activities, phospholipid fatty acids (PLFA) composition, and denaturing gradient gel electrophoresis (DGGE). The C mic and N mic did not differ among the grassland, re-planted forest and mature forest soil; however, ratios of C mic /C org and N mic /N tot decreased from the grassland to re-planted forest and mature forest soil. The total PLFAs and those attributed to bacteria and Gram-positive and Gram-negative bacteria did not differ between the re-planted forest and grassland soil. Principle component analysis of the PLFA content separated the grassland from re-planted forest and mature forest soil. Similarly, DGGE analysis revealed changes in both bacterial and fungal community structures with changes in vegetation. Our results suggest that the microbial community structure changes with the re-planting of trees after a fire event in this subalpine area. Recovery of the soil microbial community to the original state in a fire-damaged site in a subalpine area may require decades, even under a re-planted forest.

Microbial Taxa and Soil Organic Carbon Accumulation Driven by Tree Roots

“…Based on our data, and on previous studies, soil bacterial communities seem to recover faster than fungal communities [20]. After recovery, dominant species within soil microbial communities shift from fast-growing, pathogenic bacteria to beneficial, slow-growing fungal species, and pathogenic bacterial populations are eliminated [21,36]; thus, the bacterial community in NFS was similar to that in FPR (Figure 3). Furthermore, because the composition of the active functional fungal community changed from fast-growing and pathogenic fungal species to beneficial and slower-growing fungal species [21], the dominant fungal phylum in our groups shifted from Ascomycota to Basidiomycota (Figure 2).…”

Soil Fungal Community Structure and Function Shift during a Disease-Driven Forest Succession

“…We observed significant differences in fungal biomass among the three forests. The fungal biomass is a determinant of enzyme activities in forest soil ( 32 ) and contributes to total microbial biomass ( 33 ). Increased fungal biomass could indicate faster litter composition in the soil ( 34 ), affecting fungal biomass ( 35 ).…”

Microbial Community, Newly Sequestered Soil Organic Carbon, and δ15N Variations Driven by Tree Roots

“…The bacterial Shannon index of the FPR group was still lower than those of the TPR, MPR, TQR, MQR, and DPR groups (P < 0.05). After recovery of the soil microbial community, the dominant species had been shifted from fast-growing, pathogenic bacteria to beneficial, slower-growing fungal species, and the bacterial populations were eliminated (Chang et al, 2017;Hannula et al, 2017); thus, the bacterial diversity and UniFrac distances of the NFS group were similar to those of the FPR group. Compared with the bacterial community, the fungal community changed slower and more significantly (Hannula et al, 2017; FIGURE 7 | The δ 15 N values of soil and roots of control soil; middle portion of Pinus tabuliformis roots; tips of P. tabuliformis roots; middle portion of Quercus variabilis roots; tips of Q. variabilis roots; post-fire planted forest of P. tabuliformis; dead P. tabuliformis roots; and natural P. tabuliformis forest.…”