Changes in above- and below-ground biodiversity mediate understory biomass response to prescribed burning in Northeast China

AimBiodiversity plays an important role in regulating understory biomass. Aboveground and belowground biodiversity changes in response to fire-induced changes in environmental factors. However, little is known about the relationship between biodiversity and understory biomass after prescribed burning.MethodsWe selected Pinus koraiensis plantation and Quercus mongolica plantation in Northeast China, which have different regeneration strategies in response to fire. We analyzed the effects of prescribed burning on understory plant diversity (species diversity, functional diversity, trait efficiency and trait quantity) and soil microbial diversity (fungi and bacteria), and assessed the relationship between biodiversity and understory biomass after prescribed burning.ResultsPrescribed burning significantly increased functional diversity, trait efficiency, trait quantity and soil fungal diversity in P. koraiensis plantation, but significantly decreased functional diversity, trait efficiency and trait quantity in Q. mongolica plantation. Prescribed burning had no direct effect on understory biomass in either forest type, but had indirect positive effects on understory biomass in P. koraiensis plantation through trait quantity (i.e. total leaf phosphorus per unit area) and functional diversity (i.e. functional dispersion diversity based on leaf dry matter content); and indirect negative and positive effects on the understory biomass in Q. mongolica plantation through trait quantity (i.e. total leaf nitrogen per unit area) and soil fungal diversity (i.e. Chao index), respectively.ConclusionsThe responses of understory plant diversity and soil microbial diversity to prescribed burning depended on post-fire regeneration strategies of forest dominant species. This study improves understanding of the ecological mechanisms that influence understory biomass after prescribed burning.