title: Leaf litter mixtures alter microbial community development: mechanisms for non-additive effects in litter decomposition.
abstract: To what extent microbial community composition can explain variability in ecosystem processes remains an open question in ecology. Microbial decomposer communities can change during litter decomposition due to biotic interactions and shifting substrate availability. Though relative abundance of decomposers may change due to mixing leaf litter, linking these shifts to the non-additive patterns often recorded in mixed species litter decomposition rates has been elusive, and links community composition to ecosystem function. We extracted phospholipid fatty acids (PLFAs) from single species and mixed species leaf litterbags after 10 and 27 months of decomposition in a mixed conifer forest. Total PLFA concentrations were 70% higher on litter mixtures than single litter types after 10 months, but were only 20% higher after 27 months. Similarly, fungal-to-bacterial ratios differed between mixed and single litter types after 10 months of decomposition, but equalized over time. Microbial community composition, as indicated by principal components analyses, differed due to both litter mixing and stage of litter decomposition. PLFA biomarkers a15∶0 and cy17∶0, which indicate gram-positive and gram-negative bacteria respectively, in particular drove these shifts. Total PLFA correlated significantly with single litter mass loss early in decomposition but not at later stages. We conclude that litter mixing alters microbial community development, which can contribute to synergisms in litter decomposition. These findings advance our understanding of how changing forest biodiversity can alter microbial communities and the ecosystem processes they mediate.
authors: Department of Biology, Villanova University, Villanova, Pennsylvania, USA. samantha.chapman@villanova.edu
authors: Samantha K
authors: SK
authors: Chapman
authors: Gregory S
authors: GS
authors: Newman
authors: Stephen C
authors: SC
authors: Hart
authors: Jennifer A
authors: JA
authors: Schweitzer
authors: George W
authors: GW
authors: Koch
mesh_terms: D044822:Biodiversity; D015415:Biomarkers / Q000378:metabolism; D017753:Ecosystem; D005227:Fatty Acids / Q000378:metabolism*; D006090:Gram-Negative Bacteria / Q000378:metabolism*; D006094:Gram-Positive Bacteria / Q000378:metabolism*; D059013:Microbial Consortia / Q000502:physiology; D018515:Plant Leaves / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D013997:Time Factors; D014197:Trees
chemical_list: D015415:Biomarkers; D005227:Fatty Acids; D012987:Soil
references: Oecologia. 2010 Mar;162(3):763-9
references: 19921274
references: Can J Biochem Physiol. 1959 Aug;37(8):911-7
references: 13671378
references: J Microbiol Methods. 2004 Nov;59(2):223-31
references: 15369858
references: Ecology. 2011 Jan;92(1):160-9
references: 21560686
references: Microb Ecol. 2010 Jan;59(1):130-40
references: 19495854
references: Oecologia. 1979 Jan;40(1):51-62
references: 28309603
references: Science. 2011 Jun 10;332(6035):1273-7
references: 21659595
references: Proc Natl Acad Sci U S A. 2005 Feb 1;102(5):1519-24
references: 15671172
references: Ecology. 2008 Mar;89(3):773-81
references: 18459340
references: Microb Ecol. 2006 Jul;52(1):127-35
references: 16691328
references: Ecology. 2007 May;88(5):1167-76
references: 17536403
references: Ecology. 2009 Feb;90(2):441-51
references: 19323228
references: Oecologia. 2006 Aug;149(1):107-14
references: 16676206
references: Oecologia. 2007 Jan;150(4):590-601
references: 17033802
references: Proc Natl Acad Sci U S A. 2008 Dec 16;105(50):19780-5
references: 19064910