title: Arbuscular mycorrhizal fungal community composition is altered by long-term litter removal but not litter addition in a lowland tropical forest.
abstract: Tropical forest productivity is sustained by the cycling of nutrients through decomposing organic matter. Arbuscular mycorrhizal (AM) fungi play a key role in the nutrition of tropical trees, yet there has been little experimental investigation into the role of AM fungi in nutrient cycling via decomposing organic material in tropical forests. We evaluated the responses of AM fungi in a long-term leaf litter addition and removal experiment in a tropical forest in Panama. We described AM fungal communities using 454-pyrosequencing, quantified the proportion of root length colonised by AM fungi using microscopy, and estimated AM fungal biomass using a lipid biomarker. AM fungal community composition was altered by litter removal but not litter addition. Root colonisation was substantially greater in the superficial organic layer compared with the mineral soil. Overall colonisation was lower in the litter removal treatment, which lacked an organic layer. There was no effect of litter manipulation on the concentration of the AM fungal lipid biomarker in the mineral soil. We hypothesise that reductions in organic matter brought about by litter removal may lead to AM fungi obtaining nutrients from recalcitrant organic or mineral sources in the soil, besides increasing fungal competition for progressively limited resources.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.|Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama.
authors.forename: Merlin
authors.identifier: http://orcid.org/0000-0003-4888-9972
authors.initials: M
authors.lastname: Sheldrake
authors.affiliation: Center for Environmental and Climate Research, Lund University, Lund, 22362, Sweden.|Department of Biology, Lund University, Lund, 22362, Sweden.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Rosenstock
authors.affiliation: Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama.|Department of Biological Sciences, Northern Arizona University, PO BOX 5640, Flagstaff, AZ, 86011, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Revillini
authors.affiliation: Department of Biology, Lund University, Lund, 22362, Sweden.
authors.forename: Pål Axel
authors.initials: PA
authors.lastname: Olsson
authors.affiliation: Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama.|Department of Biology, Washington University in St Louis, St Louis, MO, 63130, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Mangan
authors.affiliation: Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama.|Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Sayer
authors.affiliation: Department of Biology, Lund University, Lund, 22362, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Wallander
authors.affiliation: Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Turner
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
authors.forename: Edmund V J
authors.initials: EV
authors.lastname: Tanner
mesh_terms: D044822:Biodiversity; D065928:Forests; D038821:Mycorrhizae / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology*; D018517:Plant Roots / Q000033:anatomy & histology / Q000382:microbiology; D012987:Soil / Q000737:chemistry; D014329:Tropical Climate
chemical_list: D012987:Soil
keywords: 454-sequencing; arbuscular mycorrhizal (AM) fungi; litterfall; nutrient cycling; organic matter; tropical forest