Background:In contrast with the negligible contribution of the forest understorey to the total aboveground phytobiomass of a forest,its share in annual litter production and nutrient cycling may be more important.Whet...Background:In contrast with the negligible contribution of the forest understorey to the total aboveground phytobiomass of a forest,its share in annual litter production and nutrient cycling may be more important.Whether and how this functional role of the understorey differs across forest types and depends upon overstorey characteristics remains to be investigated.Methods:We sampled 209 plots of the FunDivEUROPE Exploratory Platform,a network of study plots covering local gradients of tree diversity spread over six contrasting forest types in Europe.To estimate the relative contribution of the understorey to carbon and nutrient cycling,we sampled non-lignified aboveground understorey biomass and overstorey leaf litterfall in all plots.Understorey samples were analysed for C,N and P concentrations,overstorey leaf litterfall for C and N concentrations.We additionally quantified a set of overstorey attributes,including species richness,proportion of evergreen species,light availability(representing crown density)and litter quality,and investigated whether they drive the understorey’s contribution to carbon and nutrient cycling.Results and conclusions:Overstorey litter production and nutrient stocks in litterfall clearly exceeded the contribution of the understorey for all forest types,and the share of the understorey was higher in forests at the extremes of the climatic gradient.In most of the investigated forest types,it was mainly light availability that determined the contribution of the understorey to yearly carbon and nutrient cycling.Overstorey species richness did not affect the contribution of the understorey to carbon and nutrient cycling in any of the investigated forest types.展开更多
Microorganism plays an irreplaceable role in litter decomposition,and the dynamics of microbial activity in litter is of ecological significance in understanding the mechanism of litter decomposition. Therefore,the dy...Microorganism plays an irreplaceable role in litter decomposition,and the dynamics of microbial activity in litter is of ecological significance in understanding the mechanism of litter decomposition. Therefore,the dynamic characteristics of microorganism in rubber litter decomposition were studied during 300 and 240 days by mesh bag method under different control measures in plantations. And the results were as following:(1) Microbial populations were closely related to litter residues and decomposition environments. The microbial population has been rising firstly and then falling on the ground but directly dropping under the ground by time.(2) Microbial populations under different environments as follows:0.07 mm aperture of mesh bag > 1 mm aperture of mesh bag,non-fertile hole > fertile hole,underground group > ground group. During the entire process of decomposition,the quantity of bacteria holed absolute superiority,then actinomycetes,finally fungi.(3) Through the correlation analysis,the total number of bacteria,fungi and microorganism in aboveground group was significantly associated with the decomposition rate,but there was little correlation to actinomycetes. It's suggested that fungi and bacteria are the main participants in litter decomposition on the ground. In underground group,the microbial groups were significantly or extremely significantly related to the dry weight of residues,but was not correlated to decomposition rate significantly,which suggested that litter provided food for underground microbes,and litter decomposition was more dependent on comprehensive effect of microbes,soil animals and soil environments.展开更多
Exotic tree Melaleuca quinquenervia (melaleuca) deposits large quantities of slowly decomposing litter biomass that accumulates over time and covers forest floors in its adventive habitats in Florida (USA). Herein, we...Exotic tree Melaleuca quinquenervia (melaleuca) deposits large quantities of slowly decomposing litter biomass that accumulates over time and covers forest floors in its adventive habitats in Florida (USA). Herein, we assessed the influence of melaleuca litter cover, seed addition, and seeding date on seedling emergence and survival. The assessment was conducted by ma-nipulating litter cover and seed inputs of melaleuca and two native species at different dates in two soil types. Litter cover was either removed or left in place in organic and arenaceous soils within melaleuca stands. Each of the three treatment plots were seeded with melaleuca, wax myrtle or sawgrass, while the fourth plot was not seeded and served as the control. Seedlings were counted at 2-wk intervals to determine cumulative seedling emergence and survival during the experimental period. The experiment was repeated four times within a year. Soil type did not influence seedling emergence of all three species but influenced survival of wax myrtle. Litter removal increased the emergence of melaleuca, sawgrass, and wax myrtle and increased the survival of melaleuca. Seed addition increased the emergence and survival of sawgrass and wax myrtle but made no difference for melaleuca. Seeding during the periods of high soil moisture content had positive effects on the emergence and survival of melaleuca, wax myrtle, and sawgrass seedlings. These findings are deemed useful in planning active restoration for melaleuca invaded sites.展开更多
基金the framework of the FunDivEUROPE project and has received funding from the European Union Seventh Framework Programme(FP7/2007–2013)under grant agreement n°265171.Dries Landuyt was supported by a postdoctoral fellowship of the Research Foundation-Flanders(FWO).Kris Verheyen was supported by the ERC Consolidator Grant 614839 that is linked with the project PASTFORWARD.
文摘Background:In contrast with the negligible contribution of the forest understorey to the total aboveground phytobiomass of a forest,its share in annual litter production and nutrient cycling may be more important.Whether and how this functional role of the understorey differs across forest types and depends upon overstorey characteristics remains to be investigated.Methods:We sampled 209 plots of the FunDivEUROPE Exploratory Platform,a network of study plots covering local gradients of tree diversity spread over six contrasting forest types in Europe.To estimate the relative contribution of the understorey to carbon and nutrient cycling,we sampled non-lignified aboveground understorey biomass and overstorey leaf litterfall in all plots.Understorey samples were analysed for C,N and P concentrations,overstorey leaf litterfall for C and N concentrations.We additionally quantified a set of overstorey attributes,including species richness,proportion of evergreen species,light availability(representing crown density)and litter quality,and investigated whether they drive the understorey’s contribution to carbon and nutrient cycling.Results and conclusions:Overstorey litter production and nutrient stocks in litterfall clearly exceeded the contribution of the understorey for all forest types,and the share of the understorey was higher in forests at the extremes of the climatic gradient.In most of the investigated forest types,it was mainly light availability that determined the contribution of the understorey to yearly carbon and nutrient cycling.Overstorey species richness did not affect the contribution of the understorey to carbon and nutrient cycling in any of the investigated forest types.
基金Supported by Special Item of Basic Scientific Research Business Fee of Rubber Research Institute,Chinese Academy of Tropical Agricultural Sciences(1630022014011)
文摘Microorganism plays an irreplaceable role in litter decomposition,and the dynamics of microbial activity in litter is of ecological significance in understanding the mechanism of litter decomposition. Therefore,the dynamic characteristics of microorganism in rubber litter decomposition were studied during 300 and 240 days by mesh bag method under different control measures in plantations. And the results were as following:(1) Microbial populations were closely related to litter residues and decomposition environments. The microbial population has been rising firstly and then falling on the ground but directly dropping under the ground by time.(2) Microbial populations under different environments as follows:0.07 mm aperture of mesh bag > 1 mm aperture of mesh bag,non-fertile hole > fertile hole,underground group > ground group. During the entire process of decomposition,the quantity of bacteria holed absolute superiority,then actinomycetes,finally fungi.(3) Through the correlation analysis,the total number of bacteria,fungi and microorganism in aboveground group was significantly associated with the decomposition rate,but there was little correlation to actinomycetes. It's suggested that fungi and bacteria are the main participants in litter decomposition on the ground. In underground group,the microbial groups were significantly or extremely significantly related to the dry weight of residues,but was not correlated to decomposition rate significantly,which suggested that litter provided food for underground microbes,and litter decomposition was more dependent on comprehensive effect of microbes,soil animals and soil environments.
文摘Exotic tree Melaleuca quinquenervia (melaleuca) deposits large quantities of slowly decomposing litter biomass that accumulates over time and covers forest floors in its adventive habitats in Florida (USA). Herein, we assessed the influence of melaleuca litter cover, seed addition, and seeding date on seedling emergence and survival. The assessment was conducted by ma-nipulating litter cover and seed inputs of melaleuca and two native species at different dates in two soil types. Litter cover was either removed or left in place in organic and arenaceous soils within melaleuca stands. Each of the three treatment plots were seeded with melaleuca, wax myrtle or sawgrass, while the fourth plot was not seeded and served as the control. Seedlings were counted at 2-wk intervals to determine cumulative seedling emergence and survival during the experimental period. The experiment was repeated four times within a year. Soil type did not influence seedling emergence of all three species but influenced survival of wax myrtle. Litter removal increased the emergence of melaleuca, sawgrass, and wax myrtle and increased the survival of melaleuca. Seed addition increased the emergence and survival of sawgrass and wax myrtle but made no difference for melaleuca. Seeding during the periods of high soil moisture content had positive effects on the emergence and survival of melaleuca, wax myrtle, and sawgrass seedlings. These findings are deemed useful in planning active restoration for melaleuca invaded sites.
