title: Temperature and substrate chemistry as major drivers of interregional variability of leaf microbial decomposition and cellulolytic activity in headwater streams.
abstract: Abiotic factors, substrate chemistry and decomposers community composition are primary drivers of leaf litter decomposition. In soil, much of the variation in litter decomposition is explained by climate and substrate chemistry, but with a significant contribution of the specialisation of decomposer communities to degrade specific substrates (home-field advantage, HFA). In streams, however, HFA effects on litter decomposition have not been explicitly tested. We evaluated responses of microbial decomposition and β-glucosidase activity to abiotic factors, substrate and decomposer assemblages, using a reciprocal litter transplant experiment: 'ecosystem type' (mountain vs lowland streams) × 'litter chemistry' (alder vs reed). Temperature, pH and ionic concentration were higher in lowland streams. Decomposition for both species was faster in lowland streams. Decomposition of reed was more accelerated in lowland compared with mountain streams than that of alder, suggesting higher temperature sensitivity of decomposition in reed. Q10 (5°C-15°C) values of β-glucosidase activity were over 2. The alkaline pH and high ionic concentration of lowland streams depleted enzyme activity. We found similar relationships of decomposition or enzyme activity with abiotic factors for both species, suggesting limited support to the HFA hypothesis. Overall, our results suggest a prime role of temperature interacting with substrate chemistry on litter decomposition.
authors: Department of Biology and Geology, ceiMar, University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain.
authors: Encarnación
authors: E
authors: Fenoy
authors: Department of Biology and Geology, ceiMar, University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain Andalusian Centre for the Evaluation and Monitoring of Global Change, CAESCG, 04120 Almería, Spain jjcasas@ual.es.
authors: J Jesús
authors: JJ
authors: Casas
authors: Department of Biology and Geology, ceiMar, University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain.
authors: Manuel
authors: M
authors: Díaz-López
authors: Department of Biology and Geology, ceiMar, University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain.
authors: Juan
authors: J
authors: Rubio
authors: Department of Agronomy, University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain.
authors: J Luís
authors: JL
authors: Guil-Guerrero
authors: Department of Biology and Geology, ceiMar, University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain.
authors: Francisco J
authors: FJ
authors: Moyano-López
mesh_terms: D029661:Alnus / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D057486:Carbon Cycle / Q000502:physiology; D002480:Cellulase / Q000378:metabolism*; D002980:Climate; D017753:Ecosystem; D018515:Plant Leaves / Q000378:metabolism* / Q000382:microbiology; D045483:Rivers / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D013696:Temperature; D001617:beta-Glucosidase / Q000378:metabolism*
chemical_list: D012987:Soil; D001617:beta-Glucosidase; D002480:Cellulase
keywords: HFA hypothesis; aquatic hyphomycetes; ionic strength; pH; substrate recalcitrance; β-glucosidase activity