title: Genotypic trait variation modifies effects of climate warming and nitrogen deposition on litter mass loss and microbial respiration.
abstract: Intraspecific variation in genotypically determined traits can influence ecosystem processes. Therefore, the impact of climate change on ecosystems may depend, in part, on the distribution of plant genotypes. Here we experimentally assess effects of climate warming and excess nitrogen supply on litter decomposition using 12 genotypes of a cosmopolitan foundation species collected across a 2100 km latitudinal gradient and grown in a common garden. Genotypically determined litter-chemistry traits varied substantially within and among geographic regions, which strongly affected decomposition and the magnitude of warming effects, as warming accelerated litter mass loss of high-nutrient, but not low-nutrient, genotypes. Although increased nitrogen supply alone had no effect on decomposition, it strongly accelerated litter mass loss of all genotypes when combined with warming. Rates of microbial respiration associated with the leaf litter showed nearly identical responses as litter mass loss. These results highlight the importance of interactive effects of environmental factors and suggest that loss or gain of genetic variation associated with key phenotypic traits can buffer, or exacerbate, the impact of global change on ecosystem process rates in the future.
authors.affiliation: Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany; Smithsonian Environmental Research Center, Edgewater, MD, USA; German Center for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany.
authors.forename: Jes
authors.initials: J
authors.lastname: Hines
authors.forename: Marta
authors.initials: M
authors.lastname: Reyes
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Mozder
authors.forename: Mark O
authors.initials: MO
authors.lastname: Gessner
mesh_terms: D057231:Climate Change; D017753:Ecosystem; D014644:Genetic Variation; D005838:Genotype; D008954:Models, Biological; D009584:Nitrogen / Q000032:analysis*; D010101:Oxygen Consumption / Q000502:physiology; D018515:Plant Leaves / Q000378:metabolism; D006109:Poaceae / Q000235:genetics* / Q000254:growth & development; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D012987:Soil; D009584:Nitrogen
keywords: Phragmites australis; global change; interactive global-change effects; intraspecific genotypic diversity; litter decomposition