title: Fungi exposed to chronic nitrogen enrichment are less able to decay leaf litter.
abstract: Saprotrophic fungi are the primary decomposers of plant litter in temperate forests, and their activity is critical for carbon (C) and nitrogen (N) cycling. Simulated atmospheric N deposition is associated with reduced fungal biomass, shifts in fungal community structure, slowed litter decay, and soil C accumulation. Although rarely studied, N deposition may also result in novel selective pressures on fungi, affecting evolutionary trajectories. To directly test if long-term N enrichment reshapes fungal responses to N, we isolated decomposer fungi from a long-term (28 yr) N-addition experiment and used a common garden approach to compare growth rates and decay abilities of isolates from control and N-amended plots. Both growth and decay were significantly altered by long-term exposure to N enrichment. Changes in growth rates were idiosyncratic, as different species grew either more quickly or more slowly after exposure to N, but litter decay by N isolates was consistent and generally lower compared to control isolates of the same species, a response not readily reversed when N isolates were grown in control (low N) environments. Changes in fungal responses accompany and perhaps drive previously observed N-induced shifts in fungal diversity, community composition, and litter decay dynamics.
authors.affiliation: Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, 03824, USA.
authors.forename: Linda T A
authors.initials: LT
authors.lastname: van Diepen
authors.affiliation: Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, 03824, USA.
authors.forename: Serita D
authors.initials: SD
authors.lastname: Frey
authors.affiliation: Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, 03824, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Landis
authors.affiliation: Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, 03824, USA.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Morrison
authors.affiliation: Departments of Botany and Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Pringle
mesh_terms: D017753:Ecosystem; D005658:Fungi / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D012987:Soil; D012988:Soil Microbiology
chemical_list: D012987:Soil; D009584:Nitrogen
keywords: Harvard Forest; adaptation; common garden; evolution; fungi; global change; growth rate; litter decay; nitrogen deposition; phenotypic plasticity