title: Forest composition modifies litter dynamics and decomposition in regenerating tropical dry forest.
abstract: We investigated how forest composition, litter quality, and rainfall interact to affect leaf litter decomposition across three successional tropical dry forests in Costa Rica. We monitored litter stocks and bulk litter turnover in 18 plots that exhibit substantial variation in soil characteristics, tree community structure, fungal communities (including forests dominated by ecto- or arbuscular mycorrhizal host trees), and forest age. Simultaneously, we decomposed three standard litter substrates over a 6-month period spanning an unusually intense drought. Decay rates of standard substrates depended on the interaction between litter identity and forest type. Decomposition rates were correlated with tree and soil fungal community composition as well as soil fertility, but these relationships differed among litter types. In low fertility soils dominated by ectomycorrhizal oak trees, bulk litter turnover rates were low, regardless of soil moisture. By contrast, in higher fertility soils that supported mostly arbuscular mycorrhizal trees, bulk litter decay rates were strongly dependent on seasonal water availability. Both measures of decomposition increased with forest age, as did the frequency of termite-mediated wood decay. Taken together, our results demonstrate that soils and forest age exert strong control over decomposition dynamics in these tropical dry forests, either directly through effects on microclimate and nutrients, or indirectly by affecting tree and microbial community composition and traits, such as litter quality.
authors.affiliation: Department of Ecology, Evolution and Behavior, University of Minnesota, 140 Gortner Lab, 1479 Gortner Avenue, Saint Paul, MN, 55108, USA.
authors.forename: Erik M
authors.initials: EM
authors.lastname: Schilling
authors.affiliation: Department of Ecology, Evolution and Behavior, University of Minnesota, 140 Gortner Lab, 1479 Gortner Avenue, Saint Paul, MN, 55108, USA.
authors.forename: Bonnie G
authors.initials: BG
authors.lastname: Waring
authors.affiliation: Bioproducts and Biosystems Engineering, University of Minnesota, 2004 Folwell Avenue, Saint Paul, MN, 55108, USA.|Institute on the Environment, University of Minnesota, 1954 Buford Avenue, Saint Paul, MN, 55108, USA.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Schilling
authors.affiliation: Department of Ecology, Evolution and Behavior, University of Minnesota, 140 Gortner Lab, 1479 Gortner Avenue, Saint Paul, MN, 55108, USA. powers@umn.edu.|Department of Plant Biology, University of Minnesota, 140 Gortner Lab, 1479 Gortner Avenue, Saint Paul, MN, 55108, USA. powers@umn.edu.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Powers
mesh_terms: D065928:Forests; D018515:Plant Leaves; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D014197:Trees / Q000382:microbiology; D014329:Tropical Climate
chemical_list: D012987:Soil
keywords: Costa Rica; Drought; Edaphic gradients; Soil fungi; Succession