Arbuscular mycorrhizal fungal communities associated with switchgrass(Panicum virgatum L.)in the acidic,oligotrophic pine barrens ecosystem

Arbuscular mycorrhizal(AM)fungi contribute globally to ecosystem services and play an important role in sustainable crop production.However,it is unclear which factors contribute most to their colonization and community structure at different sites,particularly in understudied ecosystems.This study investigated the AM fungal communities associated with switchgrass(Panicum virgatum L.)in the understudied acidic and oligotrophic pine barrens ecosystem using next-generation sequencing.Switchgrass was also sampled from agroecosystems,as well as,from a native prairie for comparison.The pine barrens switchgrass harbored a distinct AM fungal community−Acaulospora and Ambispora were almost exclusively found in the pine barrens sites,and some of these species may represent undescribed taxa.Glomus was the most ubiquitous AM fungal genus recovered from all sites.This study suggests differences in the AM fungal community structure under different soil properties and land uses.This is the first sequence-based report of the AM fungal communities in the pine barrens ecosystem.

Influence of southern pine beetle on fungal communities of wood and bark decomposition of coarse woody debris in the New Jersey pine barrens

Dead coarse woody debris(fungal food resources)on the forest floor is an ignition source for forest fires.The rate of decomposition of the debris is largely influenced by fungi,determining its residence time on the forest floor.We asked if southern pine bark beetle(Dendroctonus frontalis)attack of pitch pine(Pinus rigida)alters the decomposition and fungal community of dead woody resources.Wood and bark from beetle infested and non-beetle infested resources were decomposed in litter bags on the forest floor.Decomposition was measured as mass loss and the fungal community by next-generation(PCR and Illumina metabarcoding)sequencing.Bark decomposed slower than wood and resources colonized by beetles decomposed faster than resources with no beetles.The initial differences in fungal communities colonizing the resources continued throughout the 42 months of decomposition.Fungal diversity was higher in wood than bark in initial decay stages,but significantly lower in wood than bark at the end of the 42 month incubation.In contrast,there were no significant differences in fungal communities between beetle infested and uninfested resources.The rate of decomposition of woody resources on the forest floor has great implications for the longevity of fuel sources for forest fires,however,our results indicate that beetle attacked wood poses no greater fire risk than other dead coarse woody debris regarding the residence time.