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Background: Soil macro- and mesofauna play a critical role in regulating (mixed-)litter decomposition. In shrub-encroached temperate graminoid wetlands, shrub and graminoid litters, with contrasting chemical quality, often interact to affect decomposition. However, little is known about how fauna contribute to decomposition and mixing effects in situ.We collected litters of two graminoid species (Deyeuxia angustifolia and Carex schmidtii) and two shrubs (Betula fruticosa and Salix floderusii) in a shrub-encroached wetland. By a one-year field microcosm experiment involving 8 mm- and 0.5 mm-mesh sizes to control soil fauna sizes in B. fruticosa and S. floderusii islands, we measured litter mass loss of graminoid species, shrubs, and their mixtures.In both islands, the 8-mm treatment increased mass loss by 11.4% ~ 35.9% relative to the 0.5-mm, irrespective of monospecific and mixed-species litter. For mixed-species litter, positive non-additive effects on mass loss were common, especially in the 8-mm treatment (in three of four mixtures in the S. floderusii island, and in all mixtures in the B. fruticose island). Specifically, graminoid litters generally had greater mass loss in the shrub-graminoid mixtures than that decomposing alone, with a higher incidence in the 8-mm treatment. For the mixtures, the mesh size explained most variation (26.9%, followed by species composition and litter chemical dissimilarity) in mass loss.This study provides field evidences for the critical role of macro- and mesofauna in regulating litter decomposition in freshwater wetlands. Following shrub encroachment, the fauna contributes greatly to positive mixing effects on decomposition of shrub-graminoid litter assemblages.Methods: Soil macro- and mesofauna play a critical role in regulating (mixed-)litter decomposition. In shrub-encroached temperate graminoid wetlands, shrub and graminoid litters, with contrasting chemical quality, often interact to affect decomposition. However, little is known about how fauna contribute to decomposition and mixing effects in situ.We collected litters of two graminoid species (Deyeuxia angustifolia and Carex schmidtii) and two shrubs (Betula fruticosa and Salix floderusii) in a shrub-encroached wetland. By a one-year field microcosm experiment involving 8 mm- and 0.5 mm-mesh sizes to control soil fauna sizes in B. fruticosa and S. floderusii islands, we measured litter mass loss of graminoid species, shrubs, and their mixtures.In both islands, the 8-mm treatment increased mass loss by 11.4% ~ 35.9% relative to the 0.5-mm, irrespective of monospecific and mixed-species litter. For mixed-species litter, positive non-additive effects on mass loss were common, especially in the 8-mm treatment (in three of four mixtures in the S. floderusii island, and in all mixtures in the B. fruticose island). Specifically, graminoid litters generally had greater mass loss in the shrub-graminoid mixtures than that decomposing alone, with a higher incidence in the 8-mm treatment. For the mixtures, the mesh size explained most variation (26.9%, followed by species composition and litter chemical dissimilarity) in mass loss.This study provides field evidences for the critical role of macro- and mesofauna in regulating litter decomposition in freshwater wetlands. Following shrub encroachment, the fauna contributes greatly to positive mixing effects on decomposition of shrub-graminoid litter assemblages.Results: Soil macro- and mesofauna play a critical role in regulating (mixed-)litter decomposition. In shrub-encroached temperate graminoid wetlands, shrub and graminoid litters, with contrasting chemical quality, often interact to affect decomposition. However, little is known about how fauna contribute to decomposition and mixing effects in situ.We collected litters of two graminoid species (Deyeuxia angustifolia and Carex schmidtii) and two shrubs (Betula fruticosa and Salix floderusii) in a shrub-encroached wetland. By a one-year field microcosm experiment involving 8 mm- and 0.5 mm-mesh sizes to control soil fauna sizes in B. fruticosa and S. floderusii islands, we measured litter mass loss of graminoid species, shrubs, and their mixtures.In both islands, the 8-mm treatment increased mass loss by 11.4% ~ 35.9% relative to the 0.5-mm, irrespective of monospecific and mixed-species litter. For mixed-species litter, positive non-additive effects on mass loss were common, especially in the 8-mm treatment (in three of four mixtures in the S. floderusii island, and in all mixtures in the B. fruticose island). Specifically, graminoid litters generally had greater mass loss in the shrub-graminoid mixtures than that decomposing alone, with a higher incidence in the 8-mm treatment. For the mixtures, the mesh size explained most variation (26.9%, followed by species composition and litter chemical dissimilarity) in mass loss.This study provides field evidences for the critical role of macro- and mesofauna in regulating litter decomposition in freshwater wetlands. Following shrub encroachment, the fauna contributes greatly to positive mixing effects on decomposition of shrub-graminoid litter assemblages.Conclusions: Soil macro- and mesofauna play a critical role in regulating (mixed-)litter decomposition. In shrub-encroached temperate graminoid wetlands, shrub and graminoid litters, with contrasting chemical quality, often interact to affect decomposition. However, little is known about how fauna contribute to decomposition and mixing effects in situ.We collected litters of two graminoid species (Deyeuxia angustifolia and Carex schmidtii) and two shrubs (Betula fruticosa and Salix floderusii) in a shrub-encroached wetland. By a one-year field microcosm experiment involving 8 mm- and 0.5 mm-mesh sizes to control soil fauna sizes in B. fruticosa and S. floderusii islands, we measured litter mass loss of graminoid species, shrubs, and their mixtures.In both islands, the 8-mm treatment increased mass loss by 11.4% ~ 35.9% relative to the 0.5-mm, irrespective of monospecific and mixed-species litter. For mixed-species litter, positive non-additive effects on mass loss were common, especially in the 8-mm treatment (in three of four mixtures in the S. floderusii island, and in all mixtures in the B. fruticose island). Specifically, graminoid litters generally had greater mass loss in the shrub-graminoid mixtures than that decomposing alone, with a higher incidence in the 8-mm treatment. For the mixtures, the mesh size explained most variation (26.9%, followed by species composition and litter chemical dissimilarity) in mass loss.This study provides field evidences for the critical role of macro- and mesofauna in regulating litter decomposition in freshwater wetlands. Following shrub encroachment, the fauna contributes greatly to positive mixing effects on decomposition of shrub-graminoid litter assemblages. [ABSTRACT FROM AUTHOR]

Background: In boreal peatlands, climate warming and associated soil drying facilitate the growth of vascular plants at the cost of moss species, resulting in an alteration of species dominance in plant communities. However, how altered dominant species and evenness affect litter mixture decomposition is still unclear in these ecosystems. Methods: We collected fresh litter from Larix gmelinii (tree), Betula fruticosa (shrub), Eriophorum vaginatum (sedge), and Sphagnum magellanicum (moss), and determined mass loss and nitrogen (N) release of four-species mixtures with varying dominant species and evenness at 10 and 20 oC during 360-day decomposition. Results: Irrespective of the incubation temperature, B. fruticosa-dominated litter mixtures had greatest mass loss and N release throughout decomposition, while S. magellanicum-dominated litter mixtures had lowest values. Moreover, mass loss and N release of B. fruticosa-dominated litter mixtures decreased with elevating evenness after 360 days of decomposition, but the opposite trends were observed for litter mixtures dominated by the other three species. Increasing incubation temperature facilitated decomposition of all litter mixtures, with the lowest magnitude for S. magellanicum-dominated mixtures. Non-additive effects, especially positive effects, on mass loss and N release were common, which played a key role in enhancing the influences of dominant species and evenness on litter mixture decomposition. Moreover, the incidence of positive non-additive effects on mass loss decreased at 20 oC as litter decomposition proceeded. Conclusions: Warming-induced increased dominance of vascular plants, especially shrubs, will amplify the warming effect on litter decomposition and N availability in boreal peatlands, thus generating positive feedback to climate warming. [ABSTRACT FROM AUTHOR]

Litter decomposition plays a critical role in both nutrient cycling and the interspecific relationships between tree species. In this study, leaf litter from Robinia pseudoacacia was mixed with litter from 10 other species, this mixture was then ground and incubated in soil. The soil indexes (i.e., quantity of microbes, activities of enzymes, and chemical properties) were analyzed to study the effects of litter decomposition on soil properties and the interaction between the litters. If mixed separately with Larix principis-rupprechtii or Betula platyphylla, R. pseudoacacia litter exerted synergistic effects on the activities of most enzymes. The mixed litters of R. pseudoacacia and Pinus sylvestris var. mongolica or Ulmus pumila exerted synergistic effects on the soil available P. With regard to the soil properties as a whole, the mixed litters of R. pseudoacacia and B. platyphylla, Pinus tabulaeformis, P. sylvestris var. mongolica, or L. principis-rupprechtii exerted synergistic effects on soil during their decomposition. However, the mixed litters of R. pseudoacacia and Populus simonii, Quercus liaotungensis, U. pumila, or Caragana microphylla did not. This indicated that R. pseudoacacia mixed with the litter of other needle-leaf tree species benefits the development and regeneration of soil and thus can be used for sustainable forest management. [ABSTRACT FROM AUTHOR]

Litter decomposition, an important component of nutrient cycling, is often one of the limiting factors for the development of monoculture tree plantations for restoration, and how to improve the litter decomposition rate remains as a major challenge. To help resolve this issue, we developed a mixed-litter transplantation approach to improve the litter decomposition and nutrient cycling in Schima superba, Cunninghamia lanceolata, Eucalyptus urophylla, and Acacia mangium monoculture plantations in China. The monospecific leaf litters of the four species were collected and their possible two-, three- and four-species combinations were transplanted between plantations. We examined the influences of home/away field, litter species richness, and litter composition on litter decomposition during 24 months treatment. A significant effect of litter composition on litter decomposition (Duration × Composition effect) was detected in E. urophylla plantation. The influence of litter richness on litter decomposition was significant in A. mangium plantation (Duration × Richness effect). The litter of C. lanceolata and A. mangium had a distinct home-field advantage, while the litter of S. superba had a distinct away-field advantage in decomposition. We observed a positive relationship between richness and litter decomposition in C. lanceolate plantation. The effect of Duration × Species Interaction on litter decomposition, was significant in E. urophylla plantation, indicating a non-additive effect. Litter decomposition in E. urophylla plantation could be explained by idiosyncratic model, and the rivet model may be appropriate to illustrate the litter decomposition in A. mangium plantation. Finally, since the litter decomposition in degraded A. mangium plantations had a distinct home-field advantage and was significantly affected by litter richness, transplanting mixed litters of neighboring plantations may be beneficial to improve its litter decomposition rate. Transplanting of S. superba litters due to the distinct home-field advantage to neighboring plantations such as E. urophylla plantation whose litter decomposition is significantly affected by litter composition, may be an effective management method for improving litters decomposition. [ABSTRACT FROM AUTHOR]

Background: Litter decomposition is a fundamental process of biogeochemical cycles, and there is a strong consensus that litter mixture interactions are one of the factors driving the decomposition process. A better understanding of how climate change can alter interactions between species and the litter decomposition process could facilitate projections of ecosystem functioning into the future. Methods: A 24-month litterbag decomposition experiment was carried out in a Mediterranean forest to analyze the effects of climate and species diversity changes on litter mixture interactions and the decomposition process. Results: In the control plot, synergistic interactions increased with time and species diversity in litter mixtures, leading to more efficient litter decomposition. Drier conditions obtained in the field with a rain exclusion device decreased decomposition rates, resulting in three-fold less synergistic interactions and five-fold more antagonistic interactions during the decomposition process. Furthermore, synergistic interactions were better preserved in the drought conditions with increasing number of species. Conclusions: Our findings underline how a longer drought season could strongly affect the relationship between biodiversity and ecosystem functioning. Drier climate led to slower mass loss rates and a strong shift in the litter mixture interactions, with fewer synergistic interactions and more antagonistic interactions. [ABSTRACT FROM AUTHOR]

Purpose: The rate of litter decomposition can be affected by a suite of factors, including the diversity of litter type in the environment. The effect of mixing different litter types on decomposition rates is increasingly being studied but is still poorly understood. We investigated the effect of mixing either litter material with high nitrogen (N) and phosphorus (P) concentrations or those with low N and P concentrations on litter decomposition and nutrient release in the context of agroforestry systems. Materials and methods: Poplar leaf litter, wheat straw, peanut leaf, peanut straw, and mixtures of poplar leaf litter-wheat straw, poplar leaf litter-peanut leaf, and poplar leaf litter-peanut straw litter samples were placed in litter bags, and their rates of decomposition and changes in nutrient concentrations were studied for 12 months in poplar-based agroforestry systems at two sites with contrasting soil textures (clay loam vs silt loam). Results and discussion: Mixing of different litter types increased the decomposition rate of litter, more so for the site with a clay loam soil texture, representing site differences, and in mixtures that included litter with high N and P concentrations (i.e., peanut leaf). The decomposition rate was highest in the peanut leaf that had the highest N and P concentrations among the tested litter materials. Initial N and P immobilization may have occurred in litter of high carbon (C) to N or C to P ratios, with net mineralization occurring in the later stage of the decomposition process. For litter materials with a low C to N or P ratios, net mineralization and nutrient release may occur quickly over the course of the litter decomposition. Conclusions: Non-additive effects were clearly demonstrated for decomposition rates and nutrient release when different types of litter were mixed, and such effects were moderated by site differences. The implications from this study are that it may be possible to manage plant species composition to affect litter decomposition and nutrient biogeochemistry; mixed species agroforestry systems can be used to enhance nutrient cycling, soil fertility, and site productivity in land-use systems. [ABSTRACT FROM AUTHOR]

Litter decomposition is strongly controlled by litter quality, but the composition of litter mixtures and potential interactions with live plants through root activity may also influence decomposers. In a greenhouse experiment in French Guiana we studied the combined effects of the presence of tropical tree seedlings and of distinct litter composition on mass and nitrogen (N) loss from decomposing litter and on microbial biomass. Different litter mixtures decomposed for 435 days in pots filled with sand and containing an individual seedling from one of four different tree species. We found both additive and negative non-additive effects (NAE) of litter mixing on mass loss, whereas N loss showed negative and positive NAE of litter mixing. If litter from the two tree species, Platonia insignis and Goupia glabra were present, litter mixtures showed more positive and more negative NAE on N loss, respectively. Overall, decomposition, and in particular non-additive effects, were only weakly affected by the presence of tree seedlings. Litter mass loss weakly yet significantly decreased with increasing fine root biomass in presence of Goupia seedlings, but not in the presence of seedlings of any other tree species. Our results showed strong litter composition effects and also clear, mostly negative, non-additive effects on mass loss and N loss. Species identity of tree seedlings can modify litter decomposition, but these live plant effects remain quantitatively inferior to litter composition effects. [ABSTRACT FROM AUTHOR]