Fungal diversity and community composition responses to the reintroduction of fire in a non-managed Mediterranean shrubland ecosystem

Background:More than a decade of fire suppression has changed the structure of fire-adapted shrubland ecosystems in Spain’s National Parks,which are now at extreme risk of uncontrolled wildfires.Prescribed burning can mitigate the risk of wildfires by reducing the fuel load but prescribed burning may also alter the soil properties and reduce microbial and fungal activity,causing changes in the availability of nutrients deep in the soil layer.Although fungal communities are a vital part of post-fire restoration,some fire effects remain unclear.To examine the short-term effects of prescribed burning on soil fungal communities in Doñana Biological Reserve(SW Spain),we collected soil samples pre-burn and 1 day,6 and 12 months post-burn from burned plots to perform physicochemical and metabarcode DNA analyses.Results:Prescribed burning had no significant effect on the total fungal operational taxonomic unit richness and abundance.However,changes in soil pH,nitrogen and potassium content post-burn affected fungal community composition.Small non-significant changes in pH and phosphorous affected the composition of ectomycorrhizal fungi.Conclusions:The ectomycorrhizal fungal community appears to be resilient to the effects of low-to moderate-intensity fires and saprotrophic taxa may benefit from this kind of fire.This finding revealed that prescribed burning is a potentially valuable management tool for reducing fire hazards in shrublands that has little effect on the total richness and abundance of fungal communities.

Soil fungal community is more sensitive to nitrogen deposition than increased rainfall in a mixed deciduous forest of China

Nitrogen(N)deposition and intensified rainfall can strongly affect soil microbial community,but compared with available studies on bacteria,those on soil fungi are quite limited.Here we carried out a field experiment in a mixed deciduous forest of China to study the influences of increased N deposition and rainfall on soil fungi by using quantitative PCR and high-throughput sequencing method.The results demonstrated that(1)N addition significantly increased fungal abundance and alpha diversity(richness,Shannon index and Invsimpson index),changed fungal community composition at OTU level,and marginally increased the relative abundance of Ascomycota and Zygomycota,while water addition showed no remarkable effects on fungal abundance,biodiversity and community composition.(2)N addition significantly increased the richness of saprotrophic fungi and pathogenic fungi,and the relative abundance of saprotrophic fungi,but water addition only slightly increased the abundance of pathogenic fungi.(3)Fungal composition dissimilarity closely correlated with the disparity of soil parameters as a whole.Soil NH_(4)^(+)-N exhibited strong positive correlation with the richness of pathogenic fungi and mycorrhizal fungi,while both soil moisture and NH_(4)^(+)-N tightly correlated with soil fungal abundance and alpha diversity indices.We concluded that in this N-limited but non-water-limited forest ecosystem,N deposition posed stronger effects on soil fungi than increased rainfall,partially mediated by changes in soil properties.