WorldWideScience

Sample records for leaf litter decomposition-estimates

  1. Macro-detritivore identity drives leaf litter diversity effects

    NARCIS (Netherlands)

    Vos, V.C.A.; Ruijven, van J.; Berg, M.P.; Peeters, E.T.H.M.; Berendse, F.

    2011-01-01

    The importance of leaf litter diversity for decomposition, an important process in terrestrial ecosystems, is much debated. Previous leaf litter-mixing studies have shown that non-additive leaf litter diversity effects can occur, but it is not clear why they occurred in only half of the studies and

  2. Leaf litter quality drives litter mixing effects through complementary resource use among detritivores

    NARCIS (Netherlands)

    Vos, V.C.A.; Ruijven, van J.; Berg, M.P.; Peeters, E.T.H.M.; Berendse, F.

    2013-01-01

    To comprehend the potential consequences of biodiversity loss on the leaf litter decomposition process, a better understanding of its underlying mechanisms is necessary. Here, we hypothesize that positive litter mixture effects occur via complementary resource use, when litter species complement eac

  3. The emission of volatile compounds from leaf litter

    NARCIS (Netherlands)

    Derendorp, L.

    2012-01-01

    Leaf litter is available at the Earth’s surface in large quantities. During the decomposition of leaf litter, volatile compounds can be released into the atmosphere, where they potentially influence local air quality, atmospheric chemistry or the global climate. In this thesis the focus was on the e

  4. The emission of volatile compounds from leaf litter

    NARCIS (Netherlands)

    Derendorp, L.|info:eu-repo/dai/nl/314016414

    2012-01-01

    Leaf litter is available at the Earth’s surface in large quantities. During the decomposition of leaf litter, volatile compounds can be released into the atmosphere, where they potentially influence local air quality, atmospheric chemistry or the global climate. In this thesis the focus was on the

  5. Litter chemistry prevails over litter consumers in mediating effects of past steel industry activities on leaf litter decomposition.

    Science.gov (United States)

    Lucisine, Pierre; Lecerf, Antoine; Danger, Michaël; Felten, Vincent; Aran, Delphine; Auclerc, Apolline; Gross, Elisabeth M; Huot, Hermine; Morel, Jean-Louis; Muller, Serge; Nahmani, Johanne; Maunoury-Danger, Florence

    2015-12-15

    Soil pollution has adverse effects on the performance and life history traits of microorganisms, plants, and animals, yet evidence indicates that even the most polluted sites can support structurally-complex and dynamic ecosystems. The present study aims at determining whether and how litter decomposition, one of the most important soil ecological processes leaf, is affected in a highly trace-metal polluted site. We postulated that past steel mill activities resulting in soil pollution and associated changes in soil characteristics would influence the rate of litter decomposition through two non-exclusive pathways: altered litter chemistry and responses of decomposers to lethal and sub-lethal toxic stress. We carried out a litter-bag experiment using Populus tremula L. leaf litter collected at, and allowed to decompose in, a trace metal polluted site and in three unpolluted sites used as controls. We designed a fully-factorial transplant experimental design to assess effects of litter origin and exposure site on the rate of litter decomposition. We further determined initial litter chemistry, fungal biomass, mesofauna abundance in litter bags, and the soil macrofauna community. Irrespective of the site of litter exposure, litter originating from the polluted site had a two-fold faster decomposition than litter from the unpolluted sites. Litter chemistry, notably the lignin content, seemed most important in explaining the degradation rate of the leaf litter. Abundance of meso and macro-detritivores was higher at the polluted site than at the unpolluted sites. However, litter decomposition proceeded at similar rates in polluted and unpolluted sites. Our results show that trace metal pollution and associated soil and litter changes do not necessarily weaken consumer control on litter decomposition through lethal and sub-lethal toxic stress.

  6. Leaf Litter Inhibits Growth of an Amphibian Fungal Pathogen.

    Science.gov (United States)

    Stoler, Aaron B; Berven, Keith A; Raffel, Thomas R

    2016-06-01

    Past studies have found a heterogeneous distribution of the amphibian chytrid fungal pathogen, Batrachochytrium dendrobatidis (Bd). Recent studies have accounted for some of this heterogeneity through a positive association between canopy cover and Bd abundance, which is attributed to the cooling effect of canopy cover. We questioned whether leaf litter inputs that are also associated with canopy cover might also alter Bd growth. Leaf litter inputs exhibit tremendous interspecific chemical variation, and we hypothesized that Bd growth varies with leachate chemistry. We also hypothesized that Bd uses leaf litter as a growth substrate. To test these hypotheses, we conducted laboratory trials in which we exposed cultures of Bd to leachate of 12 temperate leaf litter species at varying dilutions. Using a subset of those 12 litter species, we also exposed Bd to pre-leached litter substrate. We found that exposure to litter leachate and substrate reduced Bd spore and sporangia densities, although there was substantial variation among treatments. In particular, Bd densities were inversely correlated with concentrations of phenolic acids. We conducted a field survey of phenolic concentrations in natural wetlands which verified that the leachate concentrations in our lab study are ecologically relevant. Our study reinforces prior indications that positive associations between canopy cover and Bd abundance are likely mediated by water temperature effects, but this phenomenon might be counteracted by changes in aquatic chemistry from leaf litter inputs.

  7. PAHs in decaying Quercus ilex leaf litter: mutual effects on litter decomposition and PAH dynamics.

    Science.gov (United States)

    De Nicola, F; Baldantoni, D; Alfani, A

    2014-11-01

    The investigation of the relationships between litter decomposition and polycyclic aromatic hydrocarbons (PAHs) is important to shed light not only on the effects of these pollutants on fundamental ecosystem processes, such as litter decomposition, but also on the degradation of these pollutants by soil microbial community. This allows to understand the effect of atmospheric PAH contamination on soil PAH content via litterfall. At this aim, we studied mass and PAH dynamics of Quercus ilex leaf litters collected from urban, industrial and remote sites, incubated in mesocosms under controlled conditions for 361d. The results highlighted a litter decomposition rate of leaves sampled in urban>industrial>remote sites; the faster decomposition of litter of the urban site is also related to the low C/N ratio of the leaves. The PAHs showed concentrations at the beginning of the incubation of 887, 650 and 143 ng g(-1)d.w., respectively in leaf litters from urban, industrial and remote sites. The PAHs in litter decreased along the time, with the same trend observed for mass litter, showing the highest decrease at 361 d for the urban leaf litter. Anyway, PAH dynamics in all the litters exhibited two phases of loss, separated by a PAH increase observed at 246 d and mainly linked to benzo[e]pyrene.

  8. Leaf litter mixtures alter microbial community development: mechanisms for non-additive effects in litter decomposition.

    Directory of Open Access Journals (Sweden)

    Samantha K Chapman

    Full Text Available To what extent microbial community composition can explain variability in ecosystem processes remains an open question in ecology. Microbial decomposer communities can change during litter decomposition due to biotic interactions and shifting substrate availability. Though relative abundance of decomposers may change due to mixing leaf litter, linking these shifts to the non-additive patterns often recorded in mixed species litter decomposition rates has been elusive, and links community composition to ecosystem function. We extracted phospholipid fatty acids (PLFAs from single species and mixed species leaf litterbags after 10 and 27 months of decomposition in a mixed conifer forest. Total PLFA concentrations were 70% higher on litter mixtures than single litter types after 10 months, but were only 20% higher after 27 months. Similarly, fungal-to-bacterial ratios differed between mixed and single litter types after 10 months of decomposition, but equalized over time. Microbial community composition, as indicated by principal components analyses, differed due to both litter mixing and stage of litter decomposition. PLFA biomarkers a15∶0 and cy17∶0, which indicate gram-positive and gram-negative bacteria respectively, in particular drove these shifts. Total PLFA correlated significantly with single litter mass loss early in decomposition but not at later stages. We conclude that litter mixing alters microbial community development, which can contribute to synergisms in litter decomposition. These findings advance our understanding of how changing forest biodiversity can alter microbial communities and the ecosystem processes they mediate.

  9. Leaf Litter Mixtures Alter Microbial Community Development: Mechanisms for Non-Additive Effects in Litter Decomposition

    Science.gov (United States)

    Chapman, Samantha K.; Newman, Gregory S.; Hart, Stephen C.; Schweitzer, Jennifer A.; Koch, George W.

    2013-01-01

    To what extent microbial community composition can explain variability in ecosystem processes remains an open question in ecology. Microbial decomposer communities can change during litter decomposition due to biotic interactions and shifting substrate availability. Though relative abundance of decomposers may change due to mixing leaf litter, linking these shifts to the non-additive patterns often recorded in mixed species litter decomposition rates has been elusive, and links community composition to ecosystem function. We extracted phospholipid fatty acids (PLFAs) from single species and mixed species leaf litterbags after 10 and 27 months of decomposition in a mixed conifer forest. Total PLFA concentrations were 70% higher on litter mixtures than single litter types after 10 months, but were only 20% higher after 27 months. Similarly, fungal-to-bacterial ratios differed between mixed and single litter types after 10 months of decomposition, but equalized over time. Microbial community composition, as indicated by principal components analyses, differed due to both litter mixing and stage of litter decomposition. PLFA biomarkers a15∶0 and cy17∶0, which indicate gram-positive and gram-negative bacteria respectively, in particular drove these shifts. Total PLFA correlated significantly with single litter mass loss early in decomposition but not at later stages. We conclude that litter mixing alters microbial community development, which can contribute to synergisms in litter decomposition. These findings advance our understanding of how changing forest biodiversity can alter microbial communities and the ecosystem processes they mediate. PMID:23658639

  10. Photodegradation of Leaf Litter in Water-Limited Ecosystems

    Science.gov (United States)

    Cory, R. M.; Powers, H.; McDowell, N.; Rahn, T.

    2008-12-01

    The longstanding view of terrestrial decomposition holds that heterotrophic respiration drives release of CO2, but recent studies, such as Austin and Vivanco (2006) have shown that in water-limited environments, photochemical decomposition of leaf litter may be equally or more effective than microbial decomposition. Although initial studies have concluded that photochemical degradation can be important in some environments, it has been difficult to quantify and the oxidative mechanisms involved remain unknown. Thus, the objectives of our study were to (1) quantify the CO2 emitted during photochemical degradation of leaf litter and (2) use the stable isotopic signatures of evolved CO2 to elucidate pathways of production. Emitted CO2 and its isotopic signature were measured using a tunable diode laser (TDL) to assess the pool of photochemically-labile plant matter (δ13C-CO2) in a given sample and to assess the source of the oxygen (δ18O-CO2). We quantified the photochemical release of CO2 and its isotopic signature from dried leaf litter of 10 tree and grass species prevalent in major biotic zones of New Mexico. The cumulative CO2 released upon exposure of 0.1-0.3 g of dried leaf litter to three hours of simulated sunlight ranged from 8-25 mg CO2-C g-1 dried litter, corresponding to 1-2% mass loss. Generally, the δ13C-CO2 was more depleted (4-7 ± 2 per mil) than the average δ13C of the respective leaf litter sample. The δ18O-CO2 evolved is approximately equal to δ18O of atmospheric O2, suggesting that the oxidation mechanism involves direct reaction with atmospheric O2.

  11. Evaluation of Methane from Sisal Leaf Residue and Palash Leaf Litter

    Science.gov (United States)

    Arisutha, S.; Baredar, P.; Deshpande, D. M.; Suresh, S.

    2014-12-01

    The aim of this study is to evaluate methane production from sisal leaf residue and palash leaf litter mixed with different bulky materials such as vegetable market waste, hostel kitchen waste and digested biogas slurry in a laboratory scale anaerobic reactor. The mixture was prepared with 1:1 proportion. Maximum methane content of 320 ml/day was observed in the case of sisal leaf residue mixed with vegetable market waste as the feed. Methane content was minimum (47 ml/day), when palash leaf litter was used as feed. This was due to the increased content of lignin and polyphenol in the feedstock which were of complex structure and did not get degraded directly by microorganisms. Sisal leaf residue mixtures also showed highest content of volatile fatty acids (VFAs) as compared to palash leaf litter mixtures. It was observed that VFA concentration in the digester first increased, reached maximum (when pH was minimum) and then decreased.

  12. Climate history shapes contemporary leaf litter decomposition

    Science.gov (United States)

    Michael S. Strickland; Ashley D. Keiser; Mark A. Bradford

    2015-01-01

    Litter decomposition is mediated by multiple variables, of which climate is expected to be a dominant factor at global scales. However, like other organisms, traits of decomposers and their communities are shaped not just by the contemporary climate but also their climate history. Whether or not this affects decomposition rates is underexplored. Here we source...

  13. Biological and climatic controls on leaf litter decomposition across European forests and grasslands revealed by reciprocal litter transplantation experiments

    Science.gov (United States)

    Portillo-Estrada, M.; Pihlatie, M.; Korhonen, J. F. J.; Levula, J.; Frumau, A. K. F.; Ibrom, A.; Lembrechts, J. J.; Morillas, L.; Horváth, L.; Jones, S. K.; Niinemets, Ü.

    2015-11-01

    Projection of carbon and nitrogen cycles to future climates is associated with large uncertainties, in particular due to uncertainties how changes in climate alter soil turnover, including litter decomposition. In addition, future conditions are expected to result in changes in vegetation composition, and accordingly in litter type and quality, but it is unclear how such changes could potentially alter litter decomposition. Litter transplantation experiments were carried out across 6 European sites (4 forest and 2 grasslands) spanning a large geographical and climatic gradient (5.6-11.4 °C in annual temperature 511-878 mm in precipitation) to gain insight into biological (litter origin and type, soil type) and climatic controls on litter decomposition. The decomposition k rates were overall higher in warmer and wetter sites than in colder and drier sites, and positively correlated to the litter total specific leaf area. Also, litter N content increased as less litter mass remained and decay went further. Surprisingly, this study demonstrates that climatic controls on litter decomposition are quantitatively more important than species, litter origin and soil type. Cumulative climatic variables, precipitation and air temperature (ignoring days with air temperatures below 0 °C), were appropriate to predict the litter remaining mass during decomposition (Mr). And Mr and cumulative air temperature were found to be the best predictors for litter carbon and nitrogen remaining during decomposition. We concluded with an equation for predicting the decomposition k rate by using mean annual air temperature and litter total specific leaf area.

  14. SOA Formation Potential of Emissions from Soil and Leaf Litter

    Science.gov (United States)

    Faiola, C. L.; Vanderschelden, G. S.; Wen, M.; Cobos, D. R.; Jobson, B. T.; VanReken, T. M.

    2013-12-01

    In the United States, emissions of volatile organic compounds (VOCs) from natural sources exceed all anthropogenic sources combined. VOCs participate in oxidative chemistry in the atmosphere and impact the concentrations of ozone and particulate material. The formation of secondary organic aerosol (SOA) is particularly complex and is frequently underestimated using state-of-the-art modeling techniques. We present findings that suggest emissions of important SOA precursors from soil and leaf litter are higher than current inventories would suggest, particularly under conditions typical of Fall and Spring. Soil and leaf litter samples were collected at Big Meadow Creek from the University of Idaho Experimental Forest. The dominant tree species in this area of the forest are ponderosa pine, Douglas-fir, and western larch. Samples were transported to the laboratory and housed within a 0.9 cubic meter Teflon dynamic chamber where VOC emissions were continuously monitored with a GC-FID-MS and PTR-MS. Aerosol was generated from soil and leaf litter emissions by pumping the emissions into a 7 cubic meter Teflon aerosol growth chamber where they were oxidized with ozone in the absence of light. The evolution of particle microphysical and chemical characteristics was monitored over the following eight hours. Particle size distribution and chemical composition were measured with a SMPS and HR-ToF-AMS respectively. Monoterpenes dominated the emission profile with emission rates up to 283 micrograms carbon per meter squared per hour. The dominant monoterpenes emitted were beta-pinene, alpha-pinene, and delta-3-carene in descending order. The composition of the SOA produced was similar to biogenic SOA formed from oxidation of ponderosa pine emissions and alpha-pinene. Measured soil/litter monoterpene emission rates were compared with modeled canopy emissions. Results suggest that during fall and spring when tree emissions are lower, monoterpene emissions within forests may be

  15. Litter dynamics in two Sierran mixed conifer forests. II. Nutrient release in decomposing leaf litter

    Science.gov (United States)

    Stohlgren, Thomas J.

    1988-01-01

    The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (r2 = 0.94, p r2 = 0.92, p r2 = 0.80, p incense cedar immobilized N and to a lesser extent P, while sugar pine immobilized Ca. Strong linear or negative exponential relationships existed between initial concentrations of N, P, K, and Ca and percent original mass remaining of those nutrients after 3.6 years. This suggests efficient retention of these nutrients in the litter layer of these ecosystems. Nitrogen concentrations steadily increase in decomposing leaf litter, effectively reducing the C/N ratios from an initial range of 68–96 to 27–45 after 3.6 years.

  16. Allelopathic activity and chemical constituents of walnut (Juglans regia) leaf litter in walnut-winter vegetable agroforestry system.

    Science.gov (United States)

    Wang, Qian; Xu, Zheng; Hu, Tingxing; Rehman, Hafeez Ur; Chen, Hong; Li, Zhongbin; Ding, Bo; Hu, Hongling

    2014-01-01

    Walnut agroforestry systems have many ecological and economic benefits when intercropped with cool-season species. However, decomposing leaf litter is one of the main sources of allelochemicals in such systems. In this study, lettuce (Lactuca sativa var. angustata) was grown in the soil incorporated with walnut leaf litter to assess its allelopathic activity. Lettuce growth and physiological processes were inhibited by walnut leaf litter, especially during early growth stage (1-2 euphylla period) or with large amount of litter addition. The plants treated by small amount of leaf litter recovered their growth afterwards, while the inhibition for 180 g leaf litter persisted until harvest. Twenty-eight compounds were identified in the leaf litter, and several of them were reported to be phytotoxic, which may be responsible for the stress induced by walnut leaf litter. Thus, for highest economic value of vegetables such as lettuce, excessive incorporation of leaf litter should be discouraged.

  17. Climatic controls on leaf litter decomposition across European forests and grasslands revealed by reciprocal litter transplantation experiments

    Science.gov (United States)

    Portillo-Estrada, Miguel; Pihlatie, Mari; Korhonen, Janne F. J.; Levula, Janne; Frumau, Arnoud K. F.; Ibrom, Andreas; Lembrechts, Jonas J.; Morillas, Lourdes; Horváth, László; Jones, Stephanie K.; Niinemets, Ülo

    2016-03-01

    Carbon (C) and nitrogen (N) cycling under future climate change is associated with large uncertainties in litter decomposition and the turnover of soil C and N. In addition, future conditions (especially altered precipitation regimes and warming) are expected to result in changes in vegetation composition, and accordingly in litter species and chemical composition, but it is unclear how such changes could potentially alter litter decomposition. Litter transplantation experiments were carried out across six European sites (four forests and two grasslands) spanning a large geographical and climatic gradient (5.6-11.4 °C in annual temperature 511-878 mm in precipitation) to gain insight into the climatic controls on litter decomposition as well as the effect of litter origin and species. The decomposition k rates were overall higher in warmer and wetter sites than in colder and drier sites, and positively correlated with the litter total specific leaf area. Also, litter N content increased as less litter mass remained and decay went further. Surprisingly, this study demonstrates that climatic controls on litter decomposition are quantitatively more important than species or site of origin. Cumulative climatic variables, precipitation, soil water content and air temperature (ignoring days with air temperatures below zero degrees Celsius), were appropriate to predict the litter remaining mass during decomposition (Mr). Mr and cumulative air temperature were found to be the best predictors for litter carbon and nitrogen remaining during the decomposition. Using mean annual air temperature, precipitation, soil water content and litter total specific leaf area as parameters we were able to predict the annual decomposition rate (k) accurately.

  18. Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests

    Directory of Open Access Journals (Sweden)

    Lori D. Bothwell

    2014-12-01

    Full Text Available Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivity of leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical montane wet forests where the warming trend may be amplified compared to tropical wet forests at lower elevations. We quantified leaf litter decomposition rates along a highly constrained 5.2 °C mean annual temperature (MAT gradient in tropical montane wet forests on the Island of Hawaii. Dominant vegetation, substrate type and age, soil moisture, and disturbance history are all nearly constant across this gradient, allowing us to isolate the effect of rising MAT on leaf litter decomposition and nutrient release. Leaf litter decomposition rates were a positive linear function of MAT, causing the residence time of leaf litter on the forest floor to decline by ∼31 days for each 1 °C increase in MAT. Our estimate of the Q10 temperature coefficient for leaf litter decomposition was 2.17, within the commonly reported range for heterotrophic organic matter decomposition (1.5–2.5 across a broad range of ecosystems. The percentage of leaf litter nitrogen (N remaining after six months declined linearly with increasing MAT from ∼88% of initial N at the coolest site to ∼74% at the warmest site. The lack of net N immobilization during all three litter collection periods at all MAT plots indicates that N was not limiting to leaf litter decomposition, regardless of temperature. These results suggest that leaf litter decay in tropical montane wet forests may be more sensitive to rising MAT than in tropical lowland wet forests, and that increased rates of N release from decomposing litter could delay or prevent progressive N limitation to net primary productivity with climate warming.

  19. Leaf litter nitrogen concentration as related to climatic factors in Eurasian forests

    DEFF Research Database (Denmark)

    Liu, Chunjiang; Berg, Bjørn; Kutsch, Werner

    2006-01-01

    The aim of this study is to determine the patterns of nitrogen (N) concentrations in leaf litter of forest trees as functions of climatic factors, annual average temperature (Temp, °C) and annual precipitation (Precip, dm) and of forest type (coniferous vs. broadleaf, deciduous vs. evergreen, Pinus......, etc.). Location: The review was conducted using data from studies across the Eurasian continent. Methods: Leaf litter N concentration was compiled from 204 sets of published data (81 sets from coniferous and 123 from broadleaf forests in Eurasia). We explored the relationships between leaf litter N...... concentration and Temp and Precip by means of regression analysis. Leaf litter data from N2-fixing species were excluded from the analysis. Results: Over the Eurasian continent, leaf litter N concentration increased with increasing Temp and Precip within functional groups such as conifers, broadleaf, deciduous...

  20. No evidence for leaf-trait dissimilarity effects on litter decomposition, fungal decomposers, and nutrient dynamics.

    Science.gov (United States)

    Frainer, André; Moretti, Marcelo S; Xu, Wenjing; Gessner, Mark O

    2015-02-01

    Biodiversity and ecosystem-functioning theory suggest that litter mixtures composed of dissimilar leaf species can enhance decomposition due to species trait complementarity. Here we created a continuous gradient of litter chemistry trait variability within species mixtures to assess effects of litter dissimilarity on three related processes in a natural stream: litter decomposition, fungal biomass accrual in the litter, and nitrogen and phosphorus immobilization. Litter from a pool of eight leaf species was analyzed for chemistry traits affecting decomposition (lignin, nitrogen, and phosphorus) and assembled in all of the 28 possible two-species combinations. Litter dissimilarity was characterized in terms of a range of trait-diversity measures, using Euclidean and Gower distances and dendrogram-based indices. We found large differences in decomposition rates among leaf species, but no significant relationships between decomposition rate of individual leaf species and litter trait dissimilarity, irrespective of whether decomposition was mediated by microbes alone or by both microbes and litter-consuming invertebrates. Likewise, no effects of trait dissimilarity emerged on either fungal biomass accrual or changes during decomposition of nitrogen or phosphorus concentrations in individual leaf species. In line with recent meta-analyses, these results provide support for the contention that litter diversity effects on decomposition, at least in streams, are less pronounced than effects on terrestrial primary productivity.

  1. Leaf litter decomposition in temperate deciduous forest stands with a decreasing fraction of beech (Fagus sylvatica).

    Science.gov (United States)

    Jacob, Mascha; Viedenz, Karin; Polle, Andrea; Thomas, Frank M

    2010-12-01

    We hypothesised that the decomposition rates of leaf litter will increase along a gradient of decreasing fraction of the European beech (Fagus sylvatica) and increasing tree species diversity in the generally beech-dominated Central European temperate deciduous forests due to an increase in litter quality. We studied the decomposition of leaf litter including its lignin fraction in monospecific (pure beech) stands and in stands with up to five tree genera (Acer spp., Carpinus betulus, Fagus sylvatica, Fraxinus excelsior, Tilia spp.) using a litterbag approach. Litter and lignin decomposition was more rapid in stand-representative litter from multispecific stands than in litter from pure beech stands. Except for beech litter, the decomposition rates of species-specific tree litter did not differ significantly among the stand types, but were most rapid in Fraxinus excelsior and slowest in beech in an interspecific comparison. Pairwise comparisons of the decomposition of beech litter with litter of the other tree species (except for Acer platanoides) revealed a "home field advantage" of up to 20% (more rapid litter decomposition in stands with a high fraction of its own species than in stands with a different tree species composition). Decomposition of stand-representative litter mixtures displayed additive characteristics, not significantly more rapid than predicted by the decomposition of litter from the individual tree species. Leaf litter decomposition rates were positively correlated with the initial N and Ca concentrations of the litter, and negatively with the initial C:N, C:P and lignin:N ratios. The results support our hypothesis that the overall decomposition rates are mainly influenced by the chemical composition of the individual litter species. Thus, the fraction of individual tree species in the species composition seems to be more important for the litter decomposition rates than tree species diversity itself.

  2. Decreased toxicity of Bacillus thuringiensis subsp. israelensis to mosquito larvae after contact with leaf litter.

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    Tetreau, Guillaume; Stalinski, Renaud; Kersusan, Dylann; Veyrenc, Sylvie; David, Jean-Philippe; Reynaud, Stéphane; Després, Laurence

    2012-08-01

    Bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing Cry and Cyt proteins, which are toxic for mosquito larvae. Nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. In the present work, we investigated the behavior of B. thuringiensis subsp. israelensis toxic crystals sprayed on leaf litter. In the presence of leaf litter, a 60% decrease in the amount of Cyt toxin detectable by immunology (enzyme-linked immunosorbent assays [ELISAs]) was observed, while the respective proportions of Cry toxins were not affected. The toxicity of Cry toxins toward Aedes aegypti larvae was not affected by leaf litter, while the synergistic effect of Cyt toxins on all B. thuringiensis subsp. israelensis Cry toxins was decreased by about 20% when mixed with leaf litter. The toxicity of two commercial B. thuringiensis subsp. israelensis strains (VectoBac WG and VectoBac 12AS) and a laboratory-produced B. thuringiensis subsp. israelensis strain decreased by about 70% when mixed with leaf litter. Taken together, these results suggest that Cyt toxins interact with leaf litter, resulting in a decreased toxicity of B. thuringiensis subsp. israelensis in litter-rich environments and thereby dramatically reducing the efficiency of mosquitocidal treatments.

  3. Leaf waxes in litter and topsoils along a European transect

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    Schäfer, Imke K.; Lanny, Verena; Franke, Jörg; Eglinton, Timothy I.; Zech, Michael; Vysloužilová, Barbora; Zech, Roland

    2016-10-01

    Lipid biomarkers are increasingly used to reconstruct past environmental and climate conditions. Leaf-wax-derived long-chain n-alkanes and n-alkanoic acids may have great potential for reconstructing past changes in vegetation, but the factors that affect the leaf wax distribution in fresh plant material, as well as in soils and sediments, are not yet fully understood and need further research. We systematically investigated the influence of vegetation and soil depth on leaf waxes in litter and topsoils along a European transect. The deciduous forest sites are often dominated by the n-C27 alkane and n-C28 alkanoic acid. Conifers produce few n-alkanes but show high abundances of the C24 n-alkanoic acid. Grasslands are characterized by relatively high amounts of C31 and C33 n-alkanes and C32 and C34 n-alkanoic acids. Chain length ratios thus may allow for distinguishing between different vegetation types, but caution must be exercised given the large species-specific variability in chain length patterns. An updated endmember model with the new n-alkane ratio (n-C31 + n-C33) / (n-C27 + n-C31 + n-C33) is provided to illustrate, and tentatively account for, degradation effects on n-alkanes.

  4. The effect of temperature and moisture on trace gas emissions from deciduous and coniferous leaf litter

    Science.gov (United States)

    Gritsch, Christine; Egger, Florian; Zehetner, Franz; Zechmeister-Boltenstern, Sophie

    2016-05-01

    The forest litter layer lies at the boundary between soil and atmosphere and is a major factor in biogeochemical cycles. While there are several studies on how the litter layer controls soil trace gas emissions, litter emissions itself are less well understood, and it is still unclear how important gases respond to changing temperature and moisture. In order to assess leaf litter gas exchange, we conducted laboratory incubation experiments in which the full set of climate relevant gases, i.e., carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and nitric oxide (NO) coming from deciduous and coniferous leaf litter were measured at five temperatures and seven moisture contents. In addition, we compared litter and soil from different origin in terms of temperature/moisture responses of gas fluxes and investigated possible interactions between the two climate factors. Deciduous litter emitted more CO2 (up to 335 mg CO2-C kg-1 h-1) than coniferous litter, whereas coniferous litter released maximum amounts of NO (207 µg NO-N kg-1 h-1). N2O was only emitted from litter under very moist and warm conditions (>70% wet weight, >10°C). CH4 emissions were close to zero. Temperature sensitivities of litter emissions were generally lower than for soil emissions. Nevertheless, wet and warm conditions always enhanced litter emissions, suggesting a strong feedback effect of the litter layer to predicted future climate change.

  5. Chemical constituents of Cinnamomum septentrionale leaf litter and its allelopathic activity on the growth of maize (Zea mays).

    Science.gov (United States)

    Yang, Shanshan; Hu, Hongling; Hu, Tingxing; Wang, Qian; Ye, Mao; Luo, Jie; Peng, Yong; Zhang, Ruyi

    2017-06-01

    A pot experiment was conducted to study the effect of decomposing Cinnamomum septentrionale leaf litter on the growth of maize. In this study, the morphological traits of maize were significantly inhibited when the leaf litter amount reached or exceeded 40 g per pot; Furthermore, during the early growth stage or with a large amount of litter addition, the pigment contents were inhibited by C. septentrionale leaf litter. Gas chromatography-mass spectrometry was used to determine the volatile substances of leaf litter and 34 compounds were identified, several of which were reported to be phytotoxic. In conclusion, the leaf litter of C. septentrionale showed a strong allelopathic effect on the growth of maize. Thus, it is better to avoid the growing of maize under or near the C. septentrionale plantation unless the leaf litter could be eliminated in time or other effective leaf litter processing methods could be implemented.

  6. Carbon input belowground is the major C flux contributing to leaf litter mass loss

    DEFF Research Database (Denmark)

    Rubino, Mauro; Dungait; Evershed

    2010-01-01

    Partitioning of the quantities of C lost by leaf litter through decomposition into (i) CO2 efflux to the atmosphere and (ii) C input to soil organic matter (SOM) is essential in order to develop a deeper understanding of the litter-soil biogeochemical continuum. However, this is a challenging task...... due to the occurrence of many different processes contributing to litter biomass loss. With the aim of quantifying different fluxes of C lost by leaf litter decomposition, a field experiment was performed at a short rotation coppice poplar plantation in central Italy. Populus nigra leaf litter......, enriched in 13C (d13C +160‰) was placed within collars to decompose in direct contact with the soil (d13C -26‰) for 11 months. CO2 efflux from within the collars and its isotopic composition were determined at monthly intervals. After 11 months, remaining litter and soil profiles (0–20 cm) were sampled...

  7. [Applicability analysis of spatially explicit model of leaf litter in evergreen broad-leaved forests].

    Science.gov (United States)

    Zhao, Qing-Qing; Liu, He-Ming; Jonard, Mathieu; Wang, Zhang-Hua; Wang, Xi-Hua

    2014-11-01

    The spatially explicit model of leaf litter can help to understand its dispersal process, which is very important to predict the distribution pattern of leaves on the surface of the earth. In this paper, the spatially explicit model of leaf litter was developed for 20 tree species using litter trap data from the mapped forest plot in an evergreen broad-leaved forest in Tiantong, Zhejiang Pro- vince, eastern China. Applicability of the model was analyzed. The model assumed an allometric equation between diameter at breast height (DBH) and leaf litter amount, and the leaf litter declined exponentially with the distance. Model parameters were estimated by the maximum likelihood method. Results showed that the predicted and measured leaf litter amounts were significantly correlated, but the prediction accuracies varied widely for the different tree species, averaging at 49.3% and ranging from 16.0% and 74.0%. Model qualities of tree species significantly correlated with the standard deviations of the leaf litter amount per trap, DBH of the tree species and the average leaf dry mass of tree species. There were several ways to improve the forecast precision of the model, such as installing the litterfall traps according to the distribution of the tree to cover the different classes of the DBH and distance apart from the parent trees, determining the optimal dispersal function of each tree species, and optimizing the existing dispersal function.

  8. Detritivores enhance the mobilization of {sup 137}Cs from leaf-litter

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Masashi; Suzuki, Takahiro [Community Ecology Lab., Biology Course, Faculty of Science, Chiba University, Chiba, 263-8522 (Japan); Ishii, Nobuyoshi [National Institute of Radiological Sciences, Chiba, 263-8555 (Japan); Ohte, Nobuhito [Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657 (Japan)

    2014-07-01

    A large amount of radioactive material was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident after the disastrous earthquake and subsequent tsunami of March 2011. Since most of the Japanese land area is covered by forest ecosystems, {sup 137}Cs was mostly deposited and accumulated on the land surface of forest. The fate of radioactive materials accumulated on the leaf litters should be conscientiously monitored to understand the future distribution and the spread to the surrounding landscapes. Because the accident took place on 11 March 2011, just before the bud-break of deciduous trees, the {sup 137}Cs are highly accumulated on the surface of leaf litter on the forest floor. This accumulated {sup 137}Cs had transferred to higher trophic organisms mainly through the detritus food chain. However, on the litter surface, {sup 137}Cs considered to be strongly and immediately fixed and highly immobilized. Decomposition processes in the forest floor can re-mobilise the nutritional elements which are contained within detritus and make them available for the organisms. In the present study, the feeding effect of detritivore soil arthropods on the mobilization of {sup 137}Cs from leaf litter was experimentally examined. Furthermore, the effect of detritivores on the plant uptake of {sup 137}Cs was examined by small-scale nursery experiment. Decomposition experiment in the small microcosms was performed using a larvae of Trypoxylus dichotomus, whichis a detritivores feeding on dead plant materials such as wood debris and leaf litters. Contaminated leaf litters were collected in a forest of the Kami-Oguni River catchment in the northern part of Fukushima Prefecture. The leaf litters at A0 layers which are highly contaminated by {sup 137}Cs were utilized for the experiment. The contaminated leaf litter was fed to the larvae for ten days. The litter with larvae excreta was washed by 2 M KCl and deionized water. The {sup 137}Cs concentration was measured

  9. Combined effects of leaf litter and soil microsite on decomposition process in arid rangelands.

    Science.gov (United States)

    Carrera, Analía Lorena; Bertiller, Mónica Beatriz

    2013-01-15

    The objective of this study was to analyze the combined effects of leaf litter quality and soil properties on litter decomposition and soil nitrogen (N) mineralization at conserved (C) and disturbed by sheep grazing (D) vegetation states in arid rangelands of the Patagonian Monte. It was hypothesized that spatial differences in soil inorganic-N levels have larger impact on decomposition processes of non-recalcitrant than recalcitrant leaf litter (low and high concentration of secondary compounds, respectively). Leaf litter and upper soil were extracted from modal size plant patches (patch microsite) and the associated inter-patch area (inter-patch microsite) in C and D. Leaf litter was pooled per vegetation state and soil was pooled combining vegetation state and microsite. Concentrations of N and secondary compounds in leaf litter and total and inorganic-N in soil were assessed at each pooled sample. Leaf litter decay and soil N mineralization at microsites of C and D were estimated in 160 microcosms incubated at field capacity (16 month). C soils had higher total N than D soils (0.58 and 0.41 mg/g, respectively). Patch soil of C and inter-patch soil of D exhibited the highest values of inorganic-N (8.8 and 8.4 μg/g, respectively). Leaf litter of C was less recalcitrant and decomposed faster than that of D. Non-recalcitrant leaf litter decay and induced soil N mineralization had larger variation among microsites (coefficients of variation = 25 and 41%, respectively) than recalcitrant leaf litter (coefficients of variation = 12 and 32%, respectively). Changes in the canopy structure induced by grazing disturbance increased leaf litter recalcitrance, and reduced litter decay and soil N mineralization, independently of soil N levels. This highlights the importance of the combined effects of soil and leaf litter properties on N cycling probably with consequences for vegetation reestablishment and dynamics, rangeland resistance and resilience with implications

  10. Litter mixture dominated by leaf litter of the invasive species, Flaveria bidentis, accelerates decomposition and favors nitrogen release.

    Science.gov (United States)

    Li, Huiyan; Wei, Zishang; Huangfu, Chaohe; Chen, Xinwei; Yang, Dianlin

    2017-01-01

    In natural ecosystems, invasive plant litter is often mixed with that of native species, yet few studies have examined the decomposition dynamics of such mixtures, especially across different degrees of invasion. We conducted a 1-year litterbag experiment using leaf litters from the invasive species Flaveria bidentis (L.) and the dominant co-occurring native species, Setaria viridis (L.). Litters were allowed to decompose either separately or together at different ratios in a mothproof screen house. The mass loss of all litter mixtures was non-additive, and the direction and strength of effects varied with species ratio and decomposition stage. During the initial stages of decomposition, all mixtures had a neutral effect on the mass loss; however, at later stages of decomposition, mixtures containing more invasive litter had synergistic effects on mass loss. Importantly, an increase in F. bidentis litter with a lower C:N ratio in mixtures led to greater net release of N over time. These results highlight the importance of trait dissimilarity in determining the decomposition rates of litter mixtures and suggest that F. bidentis could further synchronize N release from litter as an invasion proceeds, potentially creating a positive feedback linked through invasion as the invader outcompetes the natives for nutrients. Our findings also demonstrate the importance of species composition as well as the identity of dominant species when considering how changes in plant community structure influence plant invasion.

  11. Plant structure predicts leaf litter capture in the tropical montane bromeliad Tillandsia turneri

    Directory of Open Access Journals (Sweden)

    F. Ospina-Bautista

    Full Text Available Abstract Leaves intercepted by bromeliads become an important energy and matter resource for invertebrate communities, bacteria, fungi, and the plant itself. The relationship between bromeliad structure, defined as its size and complexity, and accumulated leaf litter was studied in 55 bromeliads of Tillandsia turneri through multiple regression and the Akaike information criterion. Leaf litter accumulation in bromeliads was best explained by size and complexity variables such as plant cover, sheath length, and leaf number. In conclusion, plant structure determines the amount of litter that enters bromeliads, and changes in its structure could affect important processes within ecosystem functioning or species richness.

  12. The effect of leaf litter cover on surface runoff and soil erosion in Northern China.

    Directory of Open Access Journals (Sweden)

    Xiang Li

    Full Text Available The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter, four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (p<0.05. Average runoff yield was 29.5% and 31.3% less than bare-soil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, p<0.05, and the efficiency in runoff reduction by litter decreased considerably. Runoff yield and the runoff coefficient increased dramatically by 72.9 and 5.4 times, respectively. The period of time before runoff appeared decreased approximately 96.7% when rainfall intensity increased from 5.7 to 75.6 mm h-1. Broadleaf and needle leaf litter showed similarly relevant effects on runoff and soil erosion control, since no significant differences (p≤0.05 were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (p<0.05 with sediment yield. These results suggest that the protective role of leaf litter in runoff and erosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes.

  13. Experimental evidence that the Ornstein-Uhlenbeck model best describes the evolution of leaf litter decomposability.

    Science.gov (United States)

    Pan, Xu; Cornelissen, Johannes H C; Zhao, Wei-Wei; Liu, Guo-Fang; Hu, Yu-Kun; Prinzing, Andreas; Dong, Ming; Cornwell, William K

    2014-09-01

    Leaf litter decomposability is an important effect trait for ecosystem functioning. However, it is unknown how this effect trait evolved through plant history as a leaf 'afterlife' integrator of the evolution of multiple underlying traits upon which adaptive selection must have acted. Did decomposability evolve in a Brownian fashion without any constraints? Was evolution rapid at first and then slowed? Or was there an underlying mean-reverting process that makes the evolution of extreme trait values unlikely? Here, we test the hypothesis that the evolution of decomposability has undergone certain mean-reverting forces due to strong constraints and trade-offs in the leaf traits that have afterlife effects on litter quality to decomposers. In order to test this, we examined the leaf litter decomposability and seven key leaf traits of 48 tree species in the temperate area of China and fitted them to three evolutionary models: Brownian motion model (BM), Early burst model (EB), and Ornstein-Uhlenbeck model (OU). The OU model, which does not allow unlimited trait divergence through time, was the best fit model for leaf litter decomposability and all seven leaf traits. These results support the hypothesis that neither decomposability nor the underlying traits has been able to diverge toward progressively extreme values through evolutionary time. These results have reinforced our understanding of the relationships between leaf litter decomposability and leaf traits in an evolutionary perspective and may be a helpful step toward reconstructing deep-time carbon cycling based on taxonomic composition with more confidence.

  14. [Effects of benthic macro-invertebrate on decomposition of Acer buergerianum leaf litter in streams].

    Science.gov (United States)

    Jiang, Li-Hong; Wang, Bei-Xin; Chen, Ai-Qing; Lan, Ce-Jie

    2009-05-01

    By using composite mesh bag method, the effects of benthic macro-invertebrate in an undisturbed stream and an ecologically restored stream on the decomposition process of Acer buergerianum leaf litter from the Purple Mountain of Nanjing in winter were studied. After 112 days of decomposition, the remaining rate of A. buergerianum leaf litter based on ash-free dry mass was 31-62%, and the decomposition rate followed a declined exponential equation (P Shredders (mainly Asellus sp.) had the highest abundance (70.4%) in the flowing water of undisturbed stream, while filterers (mainly Tanytarsus sp.) were dominant (37.8%) in the flowing water of ecologically restored stream. The decomposition rate of the leaf litter was significantly correlated with the richness and abundance of shredder species in flowing water (P shredders, suggesting that the decomposition of A. buergerianum leaf litter in streams in winter was more dependent on the richness and abundance of shredders.

  15. Photobleaching Kinetics of Chromophoric Dissolved Organic Matter Derived from Mangrove Leaf Litter and Floating Sargassum Colonies

    Science.gov (United States)

    We examined the photoreactivity of chromophoric dissolved organic matter (CDOM) derived from Rhizophora mangle (red mangrove) leaf litter and floating Sargassum colonies as these marine plants can be important contributors to coastal and open ocean CDOM pools, respectively. Mangr...

  16. The effect of temperature and moisture on trace gas emissions from deciduous and coniferous leaf litter

    National Research Council Canada - National Science Library

    Gritsch, Christine; Egger, Florian; Zehetner, Franz; Zechmeister‐Boltenstern, Sophie

    2016-01-01

    ... gases, i.e., carbon dioxide (CO 2 ), nitrous oxide (N 2 O), methane (CH 4 ), and nitric oxide (NO) coming from deciduous and coniferous leaf litter were measured at five temperatures and seven moisture contents...

  17. Indirect effects of precipitation variation on the decomposition process of Mongolian oak (Quercus mongolica) leaf litter

    Institute of Scientific and Technical Information of China (English)

    LI Xuefeng; HAN Shijie; ZHANG Yan

    2007-01-01

    The effect of precipitation variation on the chemistry of Mongolian oak(Quercus mongolica)leaf litters was examined by analyzing litters of Mongolia oak saplings under four precipitation gradients.The decomposing process of these leaf litters in the Mongolian oak dominated forest was assessed using litter bag method.Compared with the litters of the Mongolian oak saplings from the natural precipitation site(A),litters produced by Mongolian oak from the driest precipitation gradient(A450)had significantly higher concentrations of nitrogen(N),phosphorus(P)and potassium(K)while lower acid-insoluble fraction(A/F)concentration.The decomposition study showed that A450 exhibited significantly higher decomposition rate,mineralization rates of N,P and K as well as much shorter N and P net immobilization periods.On the contrary,litters produced by seedlings from wettest gradient(Ass0)showed a totally opposite pattern.Litters from saplings that received comparable precipitation(A650)to those at the natural site(A)had significantly higher N concentration and faster decomposition rate as well as release rates of N,P and K.The mass loss patterns for the four litter types fitted the exponential model and the decay constant(k)can be well predicted by initial AIF/N.During the decomposition period,N concentration was best related to the percentage of mass remaining of the litters with relatively higher AIF concentrations and lower N concentrations,but the percentage of mass remaining of litters with lower AIF concentrations and higher N concentrations correlates strongly with AIF concentration.Our study proved that changes in precipitation significantly altered the litter quality,and therefore indirectly changed the decay process of leaf litters.

  18. Exotic or not, leaf trait dissimilarity modulates the effect of dominant species on mixed litter decomposition

    NARCIS (Netherlands)

    Finerty, Genevieve E.; de Bello, Francesco; Bílá, Karolína; Berg, Matty P.; Dias, André T C; Pezzatti, Gianni B.; Moretti, Marco

    2016-01-01

    It has long been recognized that leaf traits exert a crucial control on litter decomposition, a key process for nutrient cycling, and that invading species can greatly alter such soil processes via changes in mixed litter trait composition. Trait effects on ecosystem processes are hypothesized to op

  19. Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests

    Science.gov (United States)

    Lori D. Bothwell; Paul C. Selmants; Christian P. Giardina; Creighton M. Litton

    2014-01-01

    Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivityof leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical...

  20. Global synthesis of the temperature sensitivity of leaf litter breakdown in streams and rivers

    Science.gov (United States)

    Jennifer J. Follstad Shah; John S. Kominoski; Marcelo Ardón; Walter K. Dodds; Mark O. Gessner; Natalie A. Griffiths; Charles P. Hawkins; Sherri L. Johnson; Antoine Lecerf; Carri J. LeRoy; David W. P. Manning; Amy D. Rosemond; Robert L. Sinsabaugh; Christopher M. Swan; Jackson R. Webster; Lydia H. Zeglin

    2017-01-01

    Streams and rivers are important conduits of terrestrially derived carbon (C) to atmospheric and marine reservoirs. Leaf litter breakdown rates are expected to increase as water temperatures rise in response to climate change. The magnitude of increase in breakdown rates is uncertain, given differences in litter quality and microbial and detritivore community...

  1. The effect of leaf litter cover on surface runoff and soil erosion in Northern China.

    Science.gov (United States)

    Li, Xiang; Niu, Jianzhi; Xie, Baoyuan

    2014-01-01

    The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter), four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (psoil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, psoil erosion control, since no significant differences (p≤0.05) were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (perosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes.

  2. Leaf litter ecological fate in the Schelde estuary in Belgium

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two dominant species of Willow (Salix triandra) and Reed(Phragmites australis) along the Schelde estuary (in Belgium) wereselected in this research. The pigments of higher plant was used asbiomarkers, the decomposition process of the two species werestudied after they fall into the Schelde estuary. After statisticalanalysis (Spearman rank order correlation, p<0.05), the results hasshown the decomposition dynamics pattern of the pigments, and thewillow showed different pattern in comparing with the reed, eg.Chlorophyll-a decomposition dynamics for willow is: y1 = 12196x2 -175895x + 1E + 06 + k, R2 = 0.5706 while for reed is: y2 = -37878x2+ 229782x + 734282 + k, R2 = 0.9065. The precise time of the leaflitter spent in the water was also calculated as were less than 24days, 24-37 days, longer than 37 days (willow) and less than 24days, longer than 24 days (reed), the leaf litter fate of the two -Process, Institute of Applied Ecology, Chinese Academy of Sciencesdominant species in the Schelde estuary was also compared.

  3. Relationships among leaf functional traits, litter traits, and mass loss during early phases of leaf litter decomposition in 12 woody plant species.

    Science.gov (United States)

    Zukswert, Jenna M; Prescott, Cindy E

    2017-09-08

    Litter 'quality' or decomposability has historically been estimated through measuring chemical attributes, such as concentrations of nitrogen or 'lignin'. More recently, foliar functional traits, which may incorporate indications of the physical structures of tissues, have been found to correlate with litter mass loss rates. However, these traits may not be adequate to predict early rates of mass loss, in which two factors are crucial: the amount of material quickly lost through leaching, and the ease of access of decomposer organisms to the more labile tissues in the interior of the litter. We investigated relationships among physical and chemical traits in foliage and litter of 12 species native to British Columbia and then observed how these traits related to mass loss during the first 3 months (Phase I) and between 3 and 12 months (Phase II). Novel traits measured in this study include cuticle thickness, litter leaching loss, and litter water uptake. Foliar and litter traits both co-varied along spectra, but several chemical traits, such as nitrogen concentration, changed from foliage to litter, i.e., during senescence. Phase I mass loss was best predicted by leaching loss and traits relating to leaching, such as cuticle thickness and specific leaf area. Phase II mass loss was predicted by traits that may relate to decomposer access and activity, such as leaf dry matter content and foliar nitrogen. Physical traits predicted mass loss as well or better than chemical traits, suggesting that physical characteristics of litter are important in determining early rates of decomposition.

  4. [Leaf litter decomposition in six Cloud Forest streams of the upper La Antigua watershed, Veracruz, Mexico].

    Science.gov (United States)

    Astudillo, Manuel R; Ramírez, Alonso; Novelo-Gutiérrez, Rodolfo; Vázquez, Gabriela

    2014-04-01

    Leaf litter decomposition is an important stream ecosystem process. To understand factors controlling leaf decomposition in cloud forest in Mexico, we incubated leaf packs in different streams along a land use cover gradient for 35 days during the dry and wet seasons. We assessed relations between leaf decomposition rates (k), stream physicochemistry, and macroinvertebrates colonizing leaf packs. Physicochemical parameters showed a clear seasonal difference at all study streams. Leaves were colonized by collector-gatherer insects, followed by shredders. Assessment of factors related to k indicated that only forest cover was negatively related to leaf decomposition rates. Thus stream physicochemistry and seasonality had no impact on decomposition rates. We concluded that leaf litter decomposition at our study streams is a stable process over the year. However, it is possible that this stability is the result of factors regulating decomposition during the different seasons and streams.

  5. Mercury in leaf litter in typical suburban and urban broadleaf forests in China

    Institute of Scientific and Technical Information of China (English)

    Zhenchuan Niu; Xiaoshan Zhang; Zhangwei Wang; Zhijia Ci

    2011-01-01

    To study the role of leaf litter in the mercury (Hg) cycle in suburban broadleaf forests and the distribution of Hg in urban forests,we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing.The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g,with an average (avg) of (49.7 ± 36.9) ng/g.The average Hg concentration in evergreen broadleaf forest leaf litter (50.8 ± 39.4) ng/g was higher than that in deciduous broadleaf forest leaf litter (25.8 + 10.1) ng/g.The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/(ha.yr),respectively.The Hg concentration in organic horizons (O horizons) ((263.1 + 237.2) ng/g) was higher than that in eluvial horizons (A horizons) ((83.9 + 52.0) ng/g).These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests.For urban forests in Beijing,the Hg concentrations in leaf litter ranged from 8.8-119.0 (avg 28.1 ± 16.6) ng/g,with higher concentrations at urban sites than at suburban sites for each tree.The Hg concentrations in surface soil in Beijing were 32.0-25300.0 ng/g and increased from suburban sites to urban sites,with the highest value from Jingshan (JS) Park at the centre of Beijing.Therefore,the distribution of Hg in Beijing urban forests appeared to be strongly influenced by anthropogenic activities.

  6. Can species-specific differences in foliar chemistry influence leaf litter decomposition in grassland species?

    Science.gov (United States)

    Sanaullah, M.; Chabbi, A.; Rumpel, C.

    2009-04-01

    The influence of litter quality on its rate of decomposition is a crucial aspect of C cycle. In this study we concentrated on grassland ecosystems where leaf litter is one of the major sources of C input. To quantify the contribution of initial leaf chemistry within different plant species, the decomposition of chemically different leaf litter of three grassland species (Lolium perenne, Festuca arundinacea and Dactylis glomerata) was monitored, using the litter bag technique. Litter of different maturity stages i.e. green (fresh leaves) and brown litter (brown leaves were still attached to the plant), were incubated on bare soil surface. Samples were taken at different time intervals (0, 2, 4, 8, 20 and 44 weeks) and were analyzed for mass loss, organic C and N contents and stable isotopic signatures (C and N). Changes in litter chemistry were addressed by determining lignin-derived phenols after CuO oxidation and non-cellulosic polysaccharides after acid hydrolysis followed by gas chromatography. Green litter was chemically different from brown litter due to higher initial N and lower lignin contents. While in grassland species, both L. perenne and D. glomerata were similar in their initial chemical composition compared with F. arundinacea. Green litter showed higher rate of degradation. In green litter, Percent lignin remaining of initial (% OI) followed the similar decomposition pattern as of C remaining indicating lignin as controlling factor in decomposition. Constant Acid-to-Aldehyde ratios of lignin-derived phenols (vanillyl and syringyl) did not suggest any transformation in lignin structures. In green litter, increase in non-cellulosic polysaccharides ratios (C6/C5 and deoxy/C5) proposed microbial-derived sugars, while there was no significant increase in these ratios in brown litter. In conclusion, due to the differences in initial chemical composition (initial N and lignin contents), green litter decomposition was higher than brown litter in all

  7. Allelopathic effects of Leucaena leucocephala leaf litter on some forest and agricultural crops grown in nursery

    Institute of Scientific and Technical Information of China (English)

    Romel Ahmed; A. T. M. Rafiqul Hoque; Mohammed Kamal Hossain

    2008-01-01

    An experiment was conducted to assess the effect of leaf litter of Leucaena leucocephala on two forest crops Sada koroi (Albizia procera),Ipil ipil (L.leucocephala) and three agricultural crops Falen (Vigna unguiculata),Chickpea (Cicer arietinum) and Arhor (Cajanus cajan) in the nursery of the Institute of Forestry and Environmental Sciences,Chittagong University,Bangladesh,in a Randomized Block Design.Results suggested that leaf litters of L.leucocephala induced inhibitory effects on germination and growth of bioassay.It was also found that the effect depended on concentration of extract and litterfall,type of receptor species.Higher concentration of the materials had the higher effect and vice versa.Growth response of receptor crops varied with the variation of leaf litter application.The study revealed that application of low-dose leaf litter specially litter of 10 g(m-2 had stimulating effect on shoot growth of C.arietinum,V.unguiculata and A.procera.While in all other cases significant inhibitory effect was observed and it was significantly increased with the increase of leaf litter application.However,the trend of inhibition was uneven with treatments.Root growth was found to be more affected than shoot growth.

  8. Effects of terrestrial isopods (Crustacea: Oniscidea on leaf litter decomposition processes

    Directory of Open Access Journals (Sweden)

    Khaleid F. Abd El-Wakeil

    2015-03-01

    Full Text Available The leaf litter decomposition is carried out by the combined action of microorganisms and decomposer invertebrates such as earthworms, diplopods and isopods. The present work aimed to evaluate the impact of terrestrial isopod on leaf litter decomposition process. In Lab experimental food sources from oak and magnolia leaves litter were prepared. Air dried leaf litter were cut to 9 mm discs and sterilized in an autoclave then soaked in distilled water or water percolated through soil and left to decompose for 2, 4 and 6 weeks. 12 groups from two isopods species Porcellio scaber and Armadillidium vulgare, were prepared with each one containing 9 isopods. They were fed individually on the prepared food for 2 weeks. The prepared food differed in Carbon stable isotope ratio (δ13C, C%, N% and C/N ratios. At the end of the experiment, isopods were dissected and separated into gut, gut content and rest of the body. The δ13C for the prepared food, faecal pellets, remaining food, gut content, gut and rest of isopod were compared. The feeding activities of the two isopods were significantly different among isopods groups. Consumption and egestion ratios of magnolia leaf were higher than oak leaf. P. scaber consumed and egested litter higher than A. vulgare. The present results suggested that the impact of isopods and decomposition processes is species and litter specific.

  9. Decomposition of oak leaf litter and millipede faecal pellets in soil under temperate mixed oak forest

    Science.gov (United States)

    Tajovský, Karel; Šimek, Miloslav; Háněl, Ladislav; Šantrůčková, Hana; Frouz, Jan

    2015-04-01

    The millipedes Glomeris hexasticha (Diplopoda, Glomerida) were maintained under laboratory conditions and fed on oak leaf litter collected from a mixed oak forest (Abieto-Quercetum) in South Bohemia, Czech Republic. Every fourth day litter was changed and produced faecal pellets were separated and afterwards analysed. Content of organic carbon and C:N ratio lowered in faecal pellets as compared with consumed litter. Changes in content of chemical elements (P, K, Ca, Mg, Na) were recognised as those characteristic for the first stage of degradation of plant material. Samples of faecal pellets and oak leaf litter were then exposed in mesh bags between the F and H layers of forest soil for up to one year, subsequently harvested and analysed. A higher rate of decomposition of exposed litter than that of faecal pellets was found during the first two weeks. After 1-year exposure, the weight of litter was reduced to 51%, while that of pellets to 58% only, although the observed activity of present biotic components (algae, protozoans, nematodes; CO2 production, nitrogenase activity) in faecal pellets was higher as compared with litter. Different micro-morphological changes were observed in exposed litter and in pellets although these materials originated from the same initial sources. Comparing to intact leaf litter, another structural and functional processes occurred in pellets due to the fragmentation of plant material by millipedes. Both laboratory and field experiments showed that the millipede faecal pellets are not only a focal point of biodegradation activity in upper soil layers, but also confirmed that millipede feces undergo a slower decomposition than original leaf litter.

  10. Leaf Chemical and Structural Traits Control Variation in Leaf Litter Water Absorption

    Science.gov (United States)

    Talhelm, A. F.; Smith, A. M.

    2016-12-01

    The ability of plant litter to absorb moisture from precipitation or atmospheric humidity is well known to vary among plant species and is an important trait for wildland fire science, hydrology, and litter decomposition. This variation among species is thought to be function of litter physical and chemical traits, but there has been little systematic investigation of these relationships. To test the influence of chemical and structural traits on water absorption, we collected recently senesced leaves of 23 temperate species that represented a range of habitats and plant functional types and then quantified a suite of biochemical (gross energy, lignin, lipid, and ash content), elemental (C, N, O, and H %, C oxidation state), and structural (specific leaf area) characteristics as well as the maximum water absorption capacity of whole leaves and the amount of water vapor absorbed by whole leaves and finely-ground leaves. Maximum water absorption of whole leaves was positively related to both average C oxidation state (r = 0.55) and specific leaf area (r = 0.58) and negatively related to lignin (r = -0.67) and energy content (r = -0.57). The amount water vapor absorbed over an hour after being removed from a drying oven for whole leaves and ground leaves was positively correlated with tissue C oxidation state (r = 0.63, r = 0.53, respectively) and energy content (r = 0.41, r = 0.48). Because moist fuels release less energy when burned, our observation that litter energy content is linked to moisture absorption represents a mechanism that widens the gap between comparatively flammable and non-flammable species. Also, because lignin and lipid content were each positively correlated with energy content (r > 0.66) and negatively correlated with C oxidation state (r traits in water absorption could be used to help predict shifts in ecosystem function as plant communities reassemble as result of climate change. The views expressed in this work are those of the authors and

  11. Heavy Metals and Polycyclic Aromatic Hydrocarbons in Urban Leaf Litter Designated for Combustion

    Directory of Open Access Journals (Sweden)

    Meike Nitsche

    2017-03-01

    Full Text Available Vast amounts of leaf litter have to be disposed of by city administrations. This biomass has the potential for energy conversion, but contamination with pollutants can adversely affect this usage. We investigated leaf litter samples from the city of Kassel by analyzing their heavy metal and polycyclic aromatic hydrocarbon (PAH concentrations. Leaf samples were indeed contaminated with heavy metals and PAHs and contamination was influenced by provenience and collection technique. A simple cleaning system of washing and subsequent mechanical dewatering significantly reduced heavy metal concentration. Regression models were developed for contamination with heavy metals which showed that contamination could be successfully estimated using the total ash content of the sample as a predictor, with an R2 of up to 0.77. It can be concluded that leaf litter from cities is a possible feedstock for energetic conversion, provided a cleaning step is applied.

  12. Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes.

    Science.gov (United States)

    Cornelissen, Johannes H C; van Bodegom, Peter M; Aerts, Rien; Callaghan, Terry V; van Logtestijn, Richard S P; Alatalo, Juha; Chapin, F Stuart; Gerdol, Renato; Gudmundsson, Jon; Gwynn-Jones, Dylan; Hartley, Anne E; Hik, David S; Hofgaard, Annika; Jónsdóttir, Ingibjörg S; Karlsson, Staffan; Klein, Julia A; Laundre, Jim; Magnusson, Borgthor; Michelsen, Anders; Molau, Ulf; Onipchenko, Vladimir G; Quested, Helen M; Sandvik, Sylvi M; Schmidt, Inger K; Shaver, Gus R; Solheim, Bjørn; Soudzilovskaia, Nadejda A; Stenström, Anna; Tolvanen, Anne; Totland, Ørjan; Wada, Naoya; Welker, Jeffrey M; Zhao, Xinquan

    2007-07-01

    Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern biomes worldwide. Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.

  13. Leaf litter nutrient uptake in an intermittent blackwater river: influence of tree species and associated biotic and abiotic drivers

    National Research Council Canada - National Science Library

    Mehring, Andrew S; Kuehn, Kevin A; Thompson, Aaron; Pringle, Catherine M; Rosemond, Amy D; First, Matthew R; Lowrance, R Richard; Vellidis, George; Whitehead, David

    2015-01-01

    .... During leaf litter decomposition, microbial biomass and accumulated inorganic materials immobilize and retain nutrients, and therefore, both biotic and abiotic drivers may influence detrital nutrient content...

  14. Do climate and soil influence phenotypic variability in leaf litter, microbial decomposition and shredder consumption?

    Science.gov (United States)

    Graça, M A S; Poquet, J M

    2014-03-01

    We tested the hypothesis that water stress and soil nutrient availability drive leaf-litter quality for decomposers and detritivores by relating chemical and physical leaf-litter properties and decomposability of Alnus glutinosa and Quercus robur, sampled together with edaphic parameters, across wide European climatic gradients. By regressing principal components analysis of leaf traits [N, P, condensed tannins, lignin, specific leaf area (SLA)] against environmental and soil parameters, we found that: (1) In Q. robur the condensed tannin and lignin contents increased and SLA decreased with precipitation, annual range of temperature, and soil N content, whereas leaf P increased with soil P and temperature; (2) In A. glutinosa leaves N, P, and SLA decreased and condensed tannins increased with temperature, annual range of temperature, and decreasing soil P. On the other hand, leaf P and condensed tannins increased and SLA decreased with minimum annual precipitation and towards sites with low temperature. We selected contrasting leaves in terms of quality to test decomposition and invertebrate consumption. There were intraspecific differences in microbial decomposition rates (field, Q. robur) and consumption by shredders (laboratory, A. glutinosa). We conclude that decomposition rates across ecosystems could be partially governed by climate and soil properties, affecting litter quality and therefore decomposers and detritivores. Under scenarios of global warming and increased nutrients, these results suggest we can expect species-specific changes in leaf-litter properties most likely resulting in slow decomposition with increased variance in temperatures and accelerated decomposition with P increase.

  15. Increasing shrub abundance and N addition in Arctic tundra affect leaf and root litter decomposition differently

    Science.gov (United States)

    McLaren, J.; van de Weg, M. J.; Shaver, G. R.; Gough, L.

    2013-12-01

    Changes in global climate have resulted in a ';greening' of the Arctic as the abundance of deciduous shrub species increases. Consequently, not only the living plant community, but also the litter composition changes, which in turn can affect carbon turnover patterns in the Arctic. We examined effects of changing litter composition (both root and leaf litter) on decomposition rates with a litter bag study, and specifically focused on the impact of deciduous shrub Betula nana litter on litter decomposition from two evergreen shrubs (Ledum palustre, and Vaccinium vitis-idaea) and one graminoid (Eriophorum vaginatum) species. Additionally, we investigated how decomposition was affected by nutrient availability by placing the litterbags in an ambient and a fertilized moist acidic tundra environment. Measurements were carried out seasonally over 2 years (after snow melt, mid-growing season, end growing season). We measured litter mass loss over time, as well as the respiration rates (standardized for temperature and moisture) and temperature sensitivity of litter respiration at the time of harvesting the litter bags. For leaves, Betula litter decomposed faster than the other three species, with Eriophorum leaves decomposing the slowest. This pattern was observed for both mass loss and litter respiration rates, although the differences in respiration became smaller over time. Surprisingly, combining Betula with any other species resulted in slower overall weight loss rates than would be predicted based on monoculture weight loss rates. This contrasted with litter respiration at the time of sampling, which showed a positive mixing effect of adding Betula leaf liter to the other species. Apparently, during the first winter months (September - May) Betula litter decomposition is negatively affected by mixing the species and this legacy can still be observed in the total mass loss results later in the year. For root litter there were fewer effects of species identity on root

  16. The effects of leaf litter nutrient pulses on Alliaria petiolata performance

    Directory of Open Access Journals (Sweden)

    Robert W. Heckman

    2015-08-01

    Full Text Available Nutrient pulses can facilitate species establishment and spread in new habitats, particularly when one species more effectively uses that nutrient pulse. Biological differences in nutrient acquisition between native and exotic species may facilitate invasions into a variety of habitats including deciduous forest understories. Alliaria petiolata (Bieb. Cavara & Grande is an important invader of deciduous forest understories throughout much of North America. These understory communities contain many species which perform the majority of their growth and reproduction before canopy closure in spring. Because A. petiolata is a wintergreen biennial that can be active during autumn and winter, it may utilize nutrients released from decaying leaf litter before its competitors. To investigate this we manipulated the timing of leaf litter addition (fall or spring and experimentally simulated the nutrient pulse from decaying leaves using artificial fertilizer. To determine whether A. petiolata affected the abundance of understory competitors, we also removed A. petiolata from one treatment. A. petiolata that received early nutrients exhibited greater growth. Treatments receiving fall leaf litter or artificial nutrients had greater A. petiolata adult biomass than plots receiving spring nutrient additions (leaf litter or artificial nutrients. However, fall leaf litter addition had no effect on the richness of competitor species. Thus, wintergreen phenology may contribute to the spread of A. petiolata through deciduous forest understories, but may not explain community-level impacts of A. petiolata in deciduous forests.

  17. Bleaching of leaf litter and associated microfungi in subboreal and subalpine forests.

    Science.gov (United States)

    Hagiwara, Yusuke; Matsuoka, Shunsuke; Hobara, Satoru; Mori, Akira S; Hirose, Dai; Osono, Takashi

    2015-10-01

    Fungal decomposition of lignin leads to the whitening, or bleaching, of leaf litter, especially in temperate and tropical forests, but less is known about such bleaching in forests of cooler regions, such as boreal and subalpine forests. The purposes of the present study were to examine the extent of bleached area on the surface of leaf litter and its variation with environmental conditions in subboreal and subalpine forests in Japan and to examine the microfungi associated with the bleaching of leaf litter by isolating fungi from the bleached portions of the litter. Bleached area accounted for 21.7%-32.7% and 2.0%-10.0% of total leaf area of Quercus crispula and Betula ermanii, respectively, in subboreal forests, and for 6.3% and 18.6% of total leaf area of B. ermanii and Picea jezoensis var. hondoensis, respectively, in a subalpine forest. In subboreal forests, elevation, C/N ratio and pH of the FH layer, and slope aspect were selected as predictor variables for the bleached leaf area. Leaf mass per area and lignin content were consistently lower in the bleached area than in the nonbleached area of the same leaves, indicating that the selective decomposition of acid unhydrolyzable residue (recalcitrant compounds such as lignin, tannins, and cutins) enhanced the mass loss of leaf tissues in the bleached portions. Isolates of a total of 11 fungal species (6 species of Ascomycota and 5 of Basidiomycota) exhibited leaf-litter-bleaching activity under pure culture conditions. Two fungal species (Coccomyces sp. and Mycena sp.) occurred in both subboreal and subalpine forests, which were separated from each other by approximately 1100 km.

  18. Shifts in leaf litter breakdown along a forest-pasture-urban gradient in Andean streams.

    Science.gov (United States)

    Iñiguez-Armijos, Carlos; Rausche, Sirkka; Cueva, Augusta; Sánchez-Rodríguez, Aminael; Espinosa, Carlos; Breuer, Lutz

    2016-07-01

    Tropical montane ecosystems of the Andes are critically threatened by a rapid land-use change which can potentially affect stream variables, aquatic communities, and ecosystem processes such as leaf litter breakdown. However, these effects have not been sufficiently investigated in the Andean region and at high altitude locations in general. Here, we studied the influence of land use (forest-pasture-urban) on stream physico-chemical variables (e.g., water temperature, nutrient concentration, and pH), aquatic communities (macroinvertebrates and aquatic fungi) and leaf litter breakdown rates in Andean streams (southern Ecuador), and how variation in those stream physico-chemical variables affect macroinvertebrates and fungi related to leaf litter breakdown. We found that pH, water temperature, and nutrient concentration increased along the land-use gradient. Macroinvertebrate communities were significantly different between land uses. Shredder richness and abundance were lower in pasture than forest sites and totally absent in urban sites, and fungal richness and biomass were higher in forest sites than in pasture and urban sites. Leaf litter breakdown rates became slower as riparian land use changed from natural to anthropogenically disturbed conditions and were largely determined by pH, water temperature, phosphate concentration, fungal activity, and single species of leaf-shredding invertebrates. Our findings provide evidence that leaf litter breakdown in Andean streams is sensitive to riparian land-use change, with urban streams being the most affected. In addition, this study highlights the role of fungal biomass and shredder species (Phylloicus; Trichoptera and Anchytarsus; Coleoptera) on leaf litter breakdown in Andean streams and the contribution of aquatic fungi in supporting this ecosystem process when shredders are absent or present low abundance in streams affected by urbanization. Finally, we summarize important implications in terms of managing of

  19. Impacts of pesticides and natural stressors on leaf litter decomposition in agricultural streams

    DEFF Research Database (Denmark)

    Rasmussen, Jes; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette

    2012-01-01

    surveyed pesticide contamination and rates of leaf litter decomposition in 14 1st and 2nd order Danish streams using litter bags with coarse and ¿ne mesh sizes. Two sites differing in physical habitat complexity were sampled in each stream, and we used this approach to differentiate the effects...... of pesticides between sites with uniform (silt and sand) and more heterogeneous physical properties. Microbial litter decomposition was reduced by a factor two to four in agricultural streams compared to forested streams, and we found that the rate of microbial litter decomposition responded most strongly...... to pesticide toxicity for microorganisms and not to eutrophication. Moreover, the rate of microbial litter decomposition was generally 50% lower at sites with uniform physical habitats dominated by soft substrate compared to the sites with more heterogeneous physical habitats. The rate of macroinvertebrate...

  20. Carbon redistribution during interrill erosion in subtropical forests: Effects of leaf litter diversity and soil fauna

    Science.gov (United States)

    Goebes, Philipp; Seitz, Steffen; Kühn, Peter; Scholten, Thomas

    2016-04-01

    Soil erosion is crucial for degradation of carbon (C) from their pools in the soil. If C of the eroded sediment and runoff are not only related to soil pools but also resulting additively from decomposition of litter cover, the system gets more complex. The role of these amounts for C cycling in a forest environment is not yet known properly and thus, the aim of this study was to investigate the role of leaf litter diversity, litter cover and soil fauna on C redistribution during interrill erosion. We established 96 runoff plots that were deployed with seven domestic leaf litter species resulting in none species (bare ground), 1-species, 2-species and 4-species mixtures. Every second runoff plot was equipped with a fauna extinction feature to investigate the role of soil meso- and macrofauna. Erosion processes were initiated using a rainfall simulator at two time steps (summer 2012 and autumn 2012) to investigate the role of leaf litter decomposition on C redistribution. C fluxes during 20 min rainfall simulation were 99.13 ± 94.98 g/m². C fluxes and C contents both were affected by soil fauna. C fluxes were higher with presence of soil fauna due to loosening and slackening of the soil surface rather than due to faster decomposition of leaves. In contrast, C contents were higher in the absence of soil fauna possibly resulting from a missing dilution effect in the top soil layer. Leaf litter diversity did not affect C fluxes, but indirectly affected C contents as it increased the soil fauna effect with higher leaf litter diversity due to superior food supply. Initial C contents in the soil mainly determined those of the eroded sediment. For future research, it will be essential to introduce a long-term decomposition experiment to get further insights into the processes of C redistribution.

  1. Breakdown of Leaf Litter in a Neotropical Stream

    OpenAIRE

    Mathuriau, Catherine; Chauvet, Eric

    2002-01-01

    International audience; We investigated the breakdown of 2 leaf species, Croton gossypifolius (Euphorbiaceae) and Clidemia sp. (Melastomataceae), in a 4th-order neotropical stream (Andean Mountains, southwestern Colombia) using leaf bags over a 6-wk period. We determined the initial leaf chemical composition and followed the change in content of organic matter, C, N, and ergosterol, the sporulation activity of aquatic hyphomy cetes, and the structure and composition of leaf-associated aquatic...

  2. Leaf litter breakdown, microbial respiration and shredder production in metal-polluted streams

    Science.gov (United States)

    Carlisle, D.M.; Clements, W.H.

    2005-01-01

    1. If species disproportionately influence ecosystem functioning and also differ in their sensitivities to environmental conditions, the selective removal of species by anthropogenic stressors may lead to strong effects on ecosystem processes. We evaluated whether these circumstances held for several Colorado, U.S.A. streams stressed by Zn. 2. Benthic invertebrates and chemistry were sampled in five second-third order streams for 1 year. Study streams differed in dissolved metal concentrations, but were otherwise similar in chemical and physical characteristics. Secondary production of leaf-shredding insects was estimated using the increment summation and size-frequency methods. Leaf litter breakdown rates were estimated by retrieving litter-bags over a 171 day period. Microbial activity on leaf litter was measured in the laboratory using changes in oxygen concentration over a 48 h incubation period. 3. Dissolved Zn concentrations varied eightfold among two reference and three polluted streams. Total secondary production of shredders was negatively associated with metal contamination. Secondary production in reference streams was dominated by Taenionema pallidum. Results of previous studies and the current investigation demonstrate that this shredder is highly sensitive to metals in Colorado headwater streams. Leaf litter breakdown rates were similar between reference streams and declined significantly in the polluted streams. Microbial respiration at the most contaminated site was significantly lower than at reference sites. 4. Our results supported the hypothesis that some shredder species contribute disproportionately to leaf litter breakdown. Furthermore, the functionally dominant taxon was also the most sensitive to metal contamination. We conclude that leaf litter breakdown in our study streams lacked functional redundancy and was therefore highly sensitive to contaminant-induced alterations in community structure. We argue for the necessity of simultaneously

  3. Measuring feeding traits of a range of litter-consuming terrestrial snails : Leaf litter consumption, faeces production and scaling with body size

    NARCIS (Netherlands)

    Astor, Tina; Lenoir, Lisette; Berg, Matty P.

    2015-01-01

    Plant litter decomposition is an essential ecosystem function that contributes to energy and nutrient cycling above- and belowground. Terrestrial gastropods can affect this process in various ways: they consume and fragment leaf litter and create suitable habitats for microorganisms through the prod

  4. Differences in leaf litter, ascospore production and infection of pear scab (Venturia pirina) in Dutch organic orchards

    NARCIS (Netherlands)

    Timmermans, B.G.H.; Jansonius, P.J.

    2012-01-01

    In 2010 and 2011 the amounts of leaf litter and ascospore production per unit of leaf litter area in 7 organic pear orchards throughout the Netherlands were measured. In one of the orchards, adapted managements strategies were implemented, being grass/clover that is grown as ground cover on the tree

  5. Dissolved organic carbon biodegradability from leaf litter leachates of riparian tropical trees

    Science.gov (United States)

    Bastianoni, A.; Montoya, J. V.; Mendez, C.; Paolini, J.

    2012-04-01

    It is generally assumed that leaf litter with varying chemical composition may show different rates of mass loss, dissolved organic carbon (DOC) release, and DOC biodegradability. Leaf litter is composed of different organic compounds, which may differ in their release rates. Some authors consider leaf litter chemical quality (carbon to nitrogen ratio (C:N) and polyphenolics content) as an indicator of leaf litter mass losses and DOC released into stream water through leaching. In this research, we determined if leachate's DOC biodegradability exhibited a positive relationship with leaf litter chemical quality and leaf litter mass loss due to leaching. In order to test these hypotheses, leaf litter from six riparian tree species (Bambusa vulgaris; Castilla elastica; Artocarpus altilis; Cecropia peltata; Hura crepitans and Ficus maxima), present in the lower reaches of a fifth-order stream in northern Venezuela was collected during the dry season of 2010. To evaluate leaf litter mass loss, air-dried leaves were incubated in Milli-Q water at room temperature in the dark. After 1h, 6h, 1d, 2d, 4d, 8d and 15d, microcosms were removed from the assay to determine remaining mass. DOC biodegradability was measured using 24 h leachates that were added into a 1L glass flask containing 250mL of unfiltered stream water, 4g of stream sediment, and nutrient amendments until all incubations had equal initial DOC concentrations. Biodegradability of DOC was measured at 0, 1, 2, 5 and 7 days as the decrease in DOC concentration through time. Chemical characterization of leaf litter involved the determination of total concentrations of C, N, and poliphenolics. Three replicates were used for all analyses. Initial chemical characterization of leaf litter showed that only two species (C. elastica and A. altilis), had similar C:N ratios (~31). The other four species, showed different C and N contents but presented C:N ratios between 21 and 23. Total polyphenolics content varied greatly

  6. Response of leaf litter decomposition to rises in atmospheric CO2 and temperature

    Science.gov (United States)

    Hammrich, A.; Flury, S.; Gessner, M. O.

    2007-05-01

    Atmospheric concentrations of CO2 have considerably increased in the last century and are expected to rise further. Elevated CO2 concentrations not only increase global temperature but also have potential to change plant litter quality, for example by increasing lignin content, changing C:N ratios and altering tannin contents. These chemical changes may interact with increased temperature to alter litter decomposition. To test whether changes in litter quality and warming affect decomposition, we conducted a field experiment with leaf litter collected from six species of mature deciduous trees exposed to either ambient or elevated CO2 levels. We used a set of 16 enclosures installed in four blocks in a freshwater marsh in a prealpine lake to test for the effects of CO2-mediated litter quality and temperature and the interaction of both factors. We measured leaf mass loss of the twelve litter types in control and heated enclosures (4 °C above ambient) and also in the open marsh. In contrast to expectations, species decomposing at low (oak and beech) and medium (hornbeam and maple) rates showed faster mass loss when leaves were grown under elevated CO2 conditions, whereas fast-decomposing species (cherry and basswood) showed no clear response. The accelerated decomposition of CO2-enriched litter could be due to higher amounts of nonstructural carbohydrates, which may have been either leached or readily degraded. Warming had a surprisingly small influence on mass loss of the tested litter species, and interactive effects were weak. These results suggest that direct and indirect effects of elevated CO2 levels on litter decomposition may not be readily predictable from first principles.

  7. Tea polyphenols dominate the short-term tea (Camellia sinensis) leaf litter decomposition*

    Science.gov (United States)

    Fan, Dong-mei; Fan, Kai; Yu, Cui-ping; Lu, Ya-ting; Wang, Xiao-chang

    2017-01-01

    Polyphenols are one of the most important secondary metabolites, and affect the decomposition of litter and soil organic matter. This study aims to monitor the mass loss rate of tea leaf litter and nutrient release pattern, and investigate the role of tea polyphenols played in this process. High-performance liquid chromatography (HPLC) and classical litter bag method were used to simulate the decomposition process of tea leaf litter and track the changes occurring in major polyphenols over eight months. The release patterns of nitrogen, potassium, calcium, and magnesium were also determined. The decomposition pattern of tea leaf litter could be described by a two-phase decomposition model, and the polyphenol/N ratio effectively regulated the degradation process. Most of the catechins decreased dramatically within two months; gallic acid (GA), catechin gallate (CG), and gallocatechin (GC) were faintly detected, while others were outside the detection limits by the end of the experiment. These results demonstrated that tea polyphenols transformed quickly and catechins had an effect on the individual conversion rate. The nutrient release pattern was different from other plants which might be due to the existence of tea polyphenols. PMID:28124839

  8. Ecohydrology of the wetland-forestland interface: hydrophobicity in leaf litter and its potential effect on surface evaporation

    Science.gov (United States)

    Probert, Samantha; Kettridge, Nicholas; Devito, Kevin; Hurley, Alexander

    2017-04-01

    Riparian wetlands represent an important ecotone at the interface of peatlands and forests within the Western Boreal Plain of Canada. Water storage and negative feedbacks to evaporation in these systems is crucial for the conservation and redistribution of water during dry periods and providing ecosystem resilience to disturbance. Litter cover can alter the relative importance of the physical processes that drive soil evaporation. Negative feedbacks to drying are created as the hydrophysical properties of the litter and soil override atmospheric controls on evaporation in dry conditions, subsequently dampening the effects of external forcings on the wetland moisture balance. In this study, water repellency in leaf litter has been shown to significantly correlate with surface-atmosphere interactions, whereby severely hydrophobic leaf litter is linked to the highest surface resistances to evaporation, and therefore lowest instantaneous evaporation. Decreasing moisture is associated with increasing hydrophobicity, which may reduce the evaporative flux further as the dry hydrophobic litter creates a hydrological disconnect between soil moisture and the atmosphere. In contrast, hydrophilic litter layers exhibited higher litter moistures, which is associated with reduced resistances to evaporation and enhanced evaporative fluxes. Water repellency of the litter layer has a greater control on evaporation than the presence or absence of litter itself. Litter removal had no significant effect on instantaneous evaporation or surface resistance to evaporation except under the highest evaporation conditions, where litter layers produced higher resistance values than bare peat soils. However, litter removal modified the dominant physical controls on evaporation: moisture loss in plots with leaf litter was driven by leaf and soil hydrophysical properties. Contrastingly, bare peat soils following litter removal exhibited cooler, wetter surfaces and were more strongly correlated to

  9. CDOM PRODUCTION BY MANGROVE LEAF LITTER AND SARGASSUM COLONIES IN FLORIDA KEYS COASTAL WATERS

    Science.gov (United States)

    We have investigated the importance of leaf litter from red mangroves (Rhizophora mangle) and living Sargassum plants as sources of chromophoric dissolved organic matter (CDOM) to the coastal ocean waters and coral reef system of the Florida Keys. The magnitude of UVB exposure t...

  10. Leaf economics traits predict litter decomposition of tropical plants and differ among land use types

    NARCIS (Netherlands)

    Bakker, M.A.; Carreño Rocabado, G.; Poorter, L.

    2011-01-01

    1. Decomposition is a key ecosystem process that determines nutrient and carbon cycling. Individual leaf and litter characteristics are good predictors of decomposition rates within biomes worldwide, but knowledge of which traits are the best predictors for tropical species remains scarce. Also, the

  11. Four novel Talaromyces species isolated from leaf litter from Colombian Amazon rain forests

    NARCIS (Netherlands)

    Yilmaz, Neriman; López-Quintero, Carlos A.; Vasco-Palacios, Aída Marcela; Frisvad, Jens C.; Theelen, Bart; Boekhout, Teun; Samson, Robert A.; Houbraken, Jos

    2016-01-01

    Various Talaromyces strains were isolated during a survey of fungi involved in leaf litter decomposition in tropical lowland forests in the Caquetá and Amacayacu areas of the Colombian Amazon. Four new Talaromyces species are described using a polyphasic approach, which includes phenotypic character

  12. Effects of forest fragmentation and habitat degradation on West African leaf-litter frogs

    NARCIS (Netherlands)

    Hillers, A.; Veith, M.; Rödel, M.-O.

    2008-01-01

    Habitat degradation alters the dynamics and composition of anuran assemblages in tropical forests. The effects of forest fragmentation on the composition of anuran assemblages are so far poorly known. We studied the joint influence of forest fragmentation and degradation on leaf-litter frogs. We spe

  13. Effect of Leaf Litters and Soils on Viability of Entomopathogenic Fungi Beauveria bassiana (Bals. Vuill

    Directory of Open Access Journals (Sweden)

    LISDAR IDWAN SUDIRMAN

    2008-09-01

    Full Text Available Viability of Beauveria bassiana is extremely low due to toxic compounds in soils. This research was aimed to study the effect of four groups of media on viability of B. bassiana Bb-Pb2. The first group was leaf litters of onion, flowering white cabbage, cabbage, and chinese mustard, respectively; the second group was the soils containing decomposed residues of each plant of the first group; the third group was the mixtures of each media of both groups above (1:1, and the fourth group was natural top soil as a control. Each plastic bag filled with one kg of each medium was inoculated with ten ml of B. bassiana conidia (106/ml of concentration and incubated in open area for 8 weeks. The results showed that all leaf litters of those plants and their compost soils affected the fungal viability. The highest decreasing number of colony was found on onion’s leaf litters, soil containing of decomposed onion, and the mixtures of both media. The treated B. bassiana showed significant reducing abilities of growth, conidia production and conidia germination on PDA media, except the one of control. It is suggested that the Bb-Pb2 isolate might not be effective as bioinsecticide in the soils containing either those leaf litters or composts.

  14. Effects of forest fragmentation and habitat degradation on West African leaf-litter frogs

    NARCIS (Netherlands)

    Hillers, A.; Veith, M.; Rödel, M.-O.

    2008-01-01

    Habitat degradation alters the dynamics and composition of anuran assemblages in tropical forests. The effects of forest fragmentation on the composition of anuran assemblages are so far poorly known. We studied the joint influence of forest fragmentation and degradation on leaf-litter frogs. We

  15. VOC emission into the atmosphere by trees and leaf litter in Polish forests

    Science.gov (United States)

    Isidorov, V.; Smolewska, M.; Tyszkiewicz, Z.

    2009-04-01

    It is generally recognized at present that the vegetation of continents is the principal source of reactive volatile organic compounds (VOC) of the atmosphere. The upper limit of the evaluation of global phytogenic VOC is 1100-1500 Tg/yr (Isidorov, 1990; Guenther et al., 1995). Although these global evaluations showing the place of phytogenic emission among of other VOC sources are important, evaluations for individual countries are also very important. This poster represents the results of the estimation of VOC emission from Polish forests. Calculations took into account the composition and age of forests. According to our estimation, the total VOC emission by the arboreal vegetation differs from 190 to 750 kt/yr, depending of weather conditions in different years. There are only few studies conducted on decaying plant material as a source of atmospheric VOCs, but still they are able to give evidence of the importance of this source. For Polish forests, the litter mass is estimated to be (16-19)106 t/yr. These organic materials undergo decomposition by mesofauna and microorganisms. In these processes volatile organic compounds (VOC) stored in the litter and secondary metabolites of litter-destroying fungi are emitted into the atmosphere. The scale of the phenomenon makes leaf litter an important VOC source in the atmosphere. The filling of numerous gaps in researches of VOC emissions from decomposing leaf litter demands carrying out of long term field experiments in various climatic conditions. In this communication we report also the results of 3.5-year experiment on qualitative and quantitative GC-MS investigations of VOC emitted into the gas phase from leaves litter of some species of deciduous and coniferous trees of Polish forests. Apart from terpenes and their oxygenated derivatives, which are usual in plant tissues, leaf litter intensively emits vast amounts of lower alcohols and carbonyl compounds. We suppose that these volatile substances are products

  16. Impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings.

    Science.gov (United States)

    Huang, Weiwei; Hu, Tingxing; Chen, Hong; Wang, Qian; Hu, Hongling; Tu, Lihua; Jing, Liao

    2013-09-01

    A pot experiment was performed to study the impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings. The experimental design scheme was 0 (CK), 40 (A1), 80 (A2) and 120 g pot(-1) (A3) of E. grandis leaves, and changes in the volatile oil chemical composition during litter decomposition were assessed in the present study. The results showed that C. septentrionale leaf litter inhibited the growth of E. grandis saplings, as determined by the height, basal diameter and chlorophyll content, after 69 d (T1). Five months after transplantation (T2), the height growth rate of the E. grandis saplings increased and then gradually reduced (A1: 40 g pot(-1) > A2: 80 g pot(-1) > A3: 120 g pot(-1) > CK: 0 g pot(-1)). After eleven months (T3), the variations in the height and basal diameter were the same as observed at T2, and the inhibition on leaf, branch, root and stem biomass increased with increasing leaf litter content. Gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile compound composition. The results indicated that the C. septentrionale original leaf litter (S1) contained thirty-one volatile compounds, but the treated leaf litter S2 (which was mixed with soil for eleven months to simultaneously plant E. grandis saplings) only possessed fourteen volatile compounds, releasing many secondary metabolites in the soil during decomposition. Most of the volatile compounds were alcohols, monoterpenoids, sesquiterpenes, alkanes, alkene, esters and ketones. Most of the allelochemicals of C. septentrionale might be released during the initial decomposing process, inhibiting the growth of other plants, whereas some nutrients might be released later, promoting the height growth of plants. In conclusion, decomposing C. septentrionale leaf litter release of many allelochemicals in the soil that significantly inhibit the growth of E. grandis.

  17. The effects of fire severity on macroinvertebrate detritivores and leaf litter decomposition.

    Science.gov (United States)

    Buckingham, Sebastian; Murphy, Nick; Gibb, Heloise

    2015-01-01

    High severity wildfire events are a feature of forests globally and are likely to be more prevalent with climate change. As a disturbance process, fire has the potential to change important ecological functions, such as decomposition, through its impact on biodiversity. Despite the recognised importance of decomposition in terms of fuel loads and energy flow, little is known about the post-fire effects of fire severity on decomposition by litter-dwelling macroinvertebrate detritivores. We tested the hypotheses that: 1) increasing fire severity is associated with decreased rates of leaf litter decomposition by macroinvertebrate detritivores; and 2) the abundance and biomass of macroinvertebrate detritivores decreases with increasing fire severity, while body size increases. We used a litterbag experiment at long-unburnt, ground-burnt and crown-burnt sites (n = 7 for all treatments) to test the effect of fire severity on: a) macroinvertebrate-driven break-down of litter fuel loads; and b) the size and abundance of macroinvertebrate detritivores three years after fire. Microhabitat conditions differed among fire severity classes. Macroinvertebrate exclusion reduced litter decomposition by 34.7%. Macroinvertebrate detritivores were larger and less abundant following higher severity fires, possibly as a result of fire-induced changes in habitat structure. Opposing effects of fire severity on macroinvertebrate abundance and body size resulted in both similar detritivore biomass and, most interestingly, no differences in leaf litter decomposition under different fire severities. This suggests that the diversity of macroinvertebrates enhances functional resilience of litter decomposition to fire and that litter-breakdown is not inhibited within three years following a high severity fire in this forest type and where recolonisation sources are readily available. We found no support for the hypothesis that high severity fires reduce litter decomposition and therefore

  18. Tadpoles of Early Breeding Amphibians are Negatively Affected by Leaf Litter From Invasive Chinese Tallow Trees

    Science.gov (United States)

    Leonard, N. E.

    2005-05-01

    As wetlands are invaded by Chinese tallow trees (Triadica sebifera), native trees are displaced and detrital inputs to amphibian breeding ponds are altered. I used a mesocosm experiment to examine the effect of Chinese tallow leaf litter on the survival to, size at, and time to metamorphosis of amphibian larvae. Fifty 1000-L cattle watering tanks were treated with 1500 g dry weight of one of five leaf litter treatments: Chinese tallow, laurel oak (Quercus laurifolia), water tupelo (Nyssa aquatica), slash pine (Pinus elliottii), or a 3:1:1:1 mixture. Each tank received 45 tadpoles of Pseudacris feriarum, Bufo terrestris, and Hyla cinerea in sequence according to their natural breeding phonologies. Every Pseudacris feriarum and Bufo terrestris tadpole exposed to Chinese tallow died prior to metamorphosis. Hyla cinerea survival in tanks with tallow-only was significantly lower than that observed for all other leaf treatments. Hyla cinerea tadpoles from tallow-only and mixed-leaf treatments were larger at metamorphosis and transformed faster than those in tanks with native leaves only. These results suggest that Chinese tallow leaf litter may negatively affect tadpoles of early breeding frogs and that Chinese tallow invasion may change the structure of amphibian communities in temporary ponds.

  19. Ecological process of leaf litter decomposition in tropical rainforest in Xishuangbanna, southwest China. Ⅲ. Enzyme dynamics

    Institute of Scientific and Technical Information of China (English)

    Ruiqing ZHANG; Zhenjun SUN; Chong WANG; Tangyu YUAN

    2009-01-01

    We tested the dynamics of nine enzymes during leaf litter decomposition in Xishuangbanna tropical rain-forest both in the field and laboratory to explore the response of enzyme dynamics to decomposition under different food-web structures. We used coarse and fine (1 mm and 100 μm mesh size, respectively) litterbags in the field to create different food-web structures during litter decomposition. Most soil macrofauna such as nematodes could access only the coarse mesh litterbags, leaving only microbiota, such as mites, in the fine mesh litterbags. In the laboratory, sterilization and inoculation were adopted to investigate different enzyme dynamics with nematodes or only microbiota participating in litter decomposition.Invertase and amylase increased more for shorter food webs at the early stages of decomposition, while activities of endocellulase, β-glucosidase, xylanase and polypheno-loxydase increased to their maxima at the later stages, but greater increase occurred with extended food webs.Invertase and amylase had negative relationships and endocellulase, β-glucosidase, xylanase and polyphenolox-ydase had positive relationships with litter decomposition (mass loss). The activities of enzymes responded to the process of litter decomposition. Invertase and amylase played key roles for microbiota utilizing the substrates at early stages of decomposition, while endocellulase, β-glucosidase, xylanase and polyphenoloxydase worked on the further decay of recalcitrant compounds at later stages.All enzymes related to carbon decay acted as effective indicators of litter decomposition. The decomposition of plant organic matter was essentially an enzymatic process.

  20. Evolutionary Position and Leaf Toughness Control Chemical Transformation of Litter, and Drought Reinforces This Control: Evidence from a Common Garden Experiment across 48 Species

    OpenAIRE

    Xu Pan; Yao-Bin Song; Can Jiang; Guo-Fang Liu; Xue-Hua Ye; Xiu-Fang Xie; Yu-Kun Hu; Wei-Wei Zhao; Lijuan Cui; Johannes H. C. Cornelissen; Ming Dong; Andreas Prinzing

    2015-01-01

    Plant leaf litter is an important source of soil chemicals that are essential for the ecosystem and changes in leaf litter chemical traits during decomposition will determine the availability of multiple chemical elements recycling in the ecosystem. However, it is unclear whether the changes in litter chemical traits during decomposition and their similarities across species can be predicted, respectively, using other leaf traits or using the phylogenetic relatedness of the litter species. He...

  1. Direct and indirect effects of an invasive omnivore crayfish on leaf litter decomposition.

    Science.gov (United States)

    Carvalho, Francisco; Pascoal, Cláudia; Cássio, Fernanda; Sousa, Ronaldo

    2016-01-15

    Invasive alien species (IAS) can disrupt important ecological functions in aquatic ecosystems; however, many of these effects are not quantified and remain speculative. In this study, we assessed the effects of the invasive crayfish Procambarus clarkii (Girard, 1852) on leaf litter decomposition (a key ecosystem process) and associated invertebrates using laboratory and field manipulative experiments. The crayfish had significant impacts on leaf decomposition due to direct consumption of leaf litter and production of fine particulate organic matter, and indirectly due to consumption of invertebrate shredders. The invertebrate community did not appear to recognize P. clarkii as a predator, at least in the first stages after its introduction in the system; but this situation might change with time. Overall, results suggested that the omnivore invader P. clarkii has the potential to affect detritus-based food webs through consumption of basal resources (leaf litter) and/or consumers. Recognizing that this IAS is widespread in Europe, Asia and Africa, and may attain high density and biomass in aquatic ecosystems, our results are important to develop strategies for improving stream ecosystem functioning and to support management actions aiming to control the invasive omnivore P. clarkii.

  2. Leaf litter decomposition in Torna stream before and after a red mud disaster.

    Science.gov (United States)

    Kucserka, T; Karádi-Kovács, Kata; Vass, M; Selmeczy, G B; Hubai, Katalin Eszter; Üveges, Viktória; Kacsala, I; Törő, N; Padisák, Judit

    2014-03-01

    The aim of the study was to estimate the breakdown of the allochthonous litter in an artificial stream running in an agricultural area and compare it with the same values following a toxic mud spill into the same stream. Litter bags were filled with three types of leaves (Quercus robur, Populus tremula and Salix alba) and placed to the bottom of the river. Ergosterol was used to detect fungal biomass. We supposed the absence of fungi and the retardation of leaf litter decomposition. Only pH and conductivity increased significantly. Leaf mass loss after the catastrophe was much slower than in 2009 and the decay curves did not follow the exponential decay model. Prior to the catastrophe, leaf mass loss was fast in Torna, compared to other streams in the area. The reason is that the stream is modified, the bed is trapezoid and covered with concrete stones. Fungal biomass was lower, than in the pre-disaster experiment, because fungi did not have enough leaves to sporulate. Leaf mass loss followed the exponential decay curve before the disaster, but after that it was possible only after a non-change period.

  3. Leaf litter resource quality induces morphological changes in wood frog (Lithobates sylvaticus) metamorphs.

    Science.gov (United States)

    Stoler, Aaron B; Stephens, Jeffrey P; Relyea, Rick A; Berven, Keith A; Tiegs, Scott D

    2015-11-01

    For organisms that exhibit complex life cycles, resource conditions experienced by individuals before metamorphosis can strongly affect phenotypes later in life. Such resource-induced effects are known to arise from variation in resource quantity, yet little is known regarding effects stemming from variation in resource quality (e.g., chemistry). For larval anurans, we hypothesized that variation in resource quality will induce a gradient of effects on metamorph morphology. We conducted an outdoor mesocosm experiment in which we manipulated resource quality by rearing larval wood frogs (Lithobates sylvaticus) under 11 leaf litter treatments. The litter species represented plant species found in open- and closed-canopy wetlands and included many plant species of current conservation concern (e.g., green ash, common reed). Consistent with our hypothesis, we found a gradient of responses for nearly all mass-adjusted morphological dimensions. Hindlimb dimensions and gut mass were positively associated with litter nutrient content and decomposition rate. In contrast, forelimb length and head width were positively associated with concentrations of phenolic acids and dissolved organic carbon. Limb lengths and widths were positively related with the duration of larval period, and we discuss possible hormonal mechanisms underlying this relationship. There were very few, broad differences in morphological traits of metamorphs between open- and closed-canopy litter species or between litter and no-litter treatments. This suggests that the effects of litter on metamorph morphology are litter species-specific, indicating that the effects of changing plant community structure in and around wetlands will largely depend on plant species composition.

  4. Bioinsecticide and leaf litter combination increases oviposition and reduces adult recruitment to create an effective ovitrap for Culex mosquitoes.

    Science.gov (United States)

    Bellile, Katie G; Vonesh, James R

    2016-06-01

    Mosquito egg traps, aquatic habitats baited with oviposition attractant and insecticide, are important tools for surveillance and control efforts in integrated vector management programs. The bioinsecticide Bacillus thuringiensis subsp. israelensis (Bti) is increasingly used as an environmentally friendly alternative to chemical insecticides and the combination of Bti with a simple oviposition attractant like leaf litter to create an effective egg trap seems appealing. However, previous research suggests that Bti may itself alter oviposition, and that leaf litter may dramatically reduce Bti toxicity. Here we present results from field experiment designed to link the effects of litter and Bti on mosquito oviposition habitat selection and post-colonization survival to production of adult mosquitoes. Tripling litter increased Culex spp. oviposition nearly nine-fold, while Bti had no effect on oviposition. Neither factor altered egg survival, thus larval abundance reflected the effects of litter on oviposition. Both Bti and litter reduced larval survival by ∼60%. We found no evidence that increased litter reduced Bti toxicity. Adult production was dependent upon both litter and Bti. In the absence of Bti, effects of litter on oviposition translated into three-fold more adults. However, in the presence of Bti, initial increases in oviposition were erased by the combined negative effects of Bti and litter on post-colonization survival. Thus, our study provides field evidence that combined litter and Bti application creates an effective ovitrap. This combined treatment had the highest oviposition and the lowest survival, and thus removed the greatest number of mosquitoes from the landscape.

  5. Decomposition and nitrogen dynamics of (15)N-labeled leaf, root, and twig litter in temperate coniferous forests.

    Science.gov (United States)

    van Huysen, Tiff L; Harmon, Mark E; Perakis, Steven S; Chen, Hua

    2013-12-01

    Litter nutrient dynamics contribute significantly to biogeochemical cycling in forest ecosystems. We examined how site environment and initial substrate quality influence decomposition and nitrogen (N) dynamics of multiple litter types. A 2.5-year decomposition study was installed in the Oregon Coast Range and West Cascades using (15)N-labeled litter from Acer macrophyllum, Picea sitchensis, and Pseudotsuga menziesii. Mass loss for leaf litter was similar between the two sites, while root and twig litter exhibited greater mass loss in the Coast Range. Mass loss was greatest from leaves and roots, and species differences in mass loss were more prominent in the Coast Range. All litter types and species mineralized N early in the decomposition process; only A. macrophyllum leaves exhibited a net N immobilization phase. There were no site differences with respect to litter N dynamics despite differences in site N availability, and litter N mineralization patterns were species-specific. For multiple litter × species combinations, the difference between gross and net N mineralization was significant, and gross mineralization was 7-20 % greater than net mineralization. The mineralization results suggest that initial litter chemistry may be an important driver of litter N dynamics. Our study demonstrates that greater amounts of N are cycling through these systems than may be quantified by only measuring net mineralization and challenges current leaf-based biogeochemical theory regarding patterns of N immobilization and mineralization.

  6. Decomposition and nitrogen dynamics of 15N-labeled leaf, root, and twig litter in temperate coniferous forests

    Science.gov (United States)

    van Huysen, Tiff L.; Harmon, Mark E.; Perakis, Steven S.; Chen, Hua

    2013-01-01

    Litter nutrient dynamics contribute significantly to biogeochemical cycling in forest ecosystems. We examined how site environment and initial substrate quality influence decomposition and nitrogen (N) dynamics of multiple litter types. A 2.5-year decomposition study was installed in the Oregon Coast Range and West Cascades using 15N-labeled litter from Acer macrophyllum, Picea sitchensis, and Pseudotsuga menziesii. Mass loss for leaf litter was similar between the two sites, while root and twig litter exhibited greater mass loss in the Coast Range. Mass loss was greatest from leaves and roots, and species differences in mass loss were more prominent in the Coast Range. All litter types and species mineralized N early in the decomposition process; only A. macrophyllum leaves exhibited a net N immobilization phase. There were no site differences with respect to litter N dynamics despite differences in site N availability, and litter N mineralization patterns were species-specific. For multiple litter × species combinations, the difference between gross and net N mineralization was significant, and gross mineralization was 7–20 % greater than net mineralization. The mineralization results suggest that initial litter chemistry may be an important driver of litter N dynamics. Our study demonstrates that greater amounts of N are cycling through these systems than may be quantified by only measuring net mineralization and challenges current leaf-based biogeochemical theory regarding patterns of N immobilization and mineralization.

  7. Effects of radionuclide contamination on leaf litter decomposition in the Chernobyl exclusion zone

    Energy Technology Data Exchange (ETDEWEB)

    Bonzom, Jean-Marc, E-mail: jean-marc.bonzom@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS, Cadarache, Bât. 183, BP 3, 13115 St Paul-lez-Durance (France); Hättenschwiler, Stephan [Centre d' Ecologie Fonctionnelle et Evolutive (CEFE UMR 5175, CNRS–Université de Montpellier–Université Paul-Valéry Montpellier–EPHE), 1919 Route de Mende, F-34293 Montpellier (France); Lecomte-Pradines, Catherine [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS, Cadarache, Bât. 183, BP 3, 13115 St Paul-lez-Durance (France); Chauvet, Eric [EcoLab, Université de Toulouse, CNRS, UPS, INPT, 118 Route de Narbonne, 31062 Toulouse cedex (France); Gaschak, Sergey [Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, International Radioecology Laboratory, 07100 Slavutych (Ukraine); Beaugelin-Seiller, Karine; Della-Vedova, Claire; Dubourg, Nicolas [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS, Cadarache, Bât. 183, BP 3, 13115 St Paul-lez-Durance (France); Maksimenko, Andrey [Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, International Radioecology Laboratory, 07100 Slavutych (Ukraine); and others

    2016-08-15

    The effects of radioactive contamination on ecosystem processes such as litter decomposition remain largely unknown. Because radionuclides accumulated in soil and plant biomass can be harmful for organisms, the functioning of ecosystems may be altered by radioactive contamination. Here, we tested the hypothesis that decomposition is impaired by increasing levels of radioactivity in the environment by exposing uncontaminated leaf litter from silver birch and black alder at (i) eleven distant forest sites differing in ambient radiation levels (0.22–15 μGy h{sup −1}) and (ii) along a short distance gradient of radioactive contamination (1.2–29 μGy h{sup −1}) within a single forest in the Chernobyl exclusion zone. In addition to measuring ambient external dose rates, we estimated the average total dose rates (ATDRs) absorbed by decomposers for an accurate estimate of dose-induced ecological consequences of radioactive pollution. Taking into account potential confounding factors (soil pH, moisture, texture, and organic carbon content), the results from the eleven distant forest sites, and from the single forest, showed increased litter mass loss with increasing ATDRs from 0.3 to 150 μGy h{sup −1}. This unexpected result may be due to (i) overcompensation of decomposer organisms exposed to radionuclides leading to a higher decomposer abundance (hormetic effect), and/or (ii) from preferred feeding by decomposers on the uncontaminated leaf litter used for our experiment compared to locally produced, contaminated leaf litter. Our data indicate that radio-contamination of forest ecosystems over more than two decades does not necessarily have detrimental effects on organic matter decay. However, further studies are needed to unravel the underlying mechanisms of the results reported here, in order to draw firmer conclusions on how radio-contamination affects decomposition and associated ecosystem processes. - Highlights: • The effects of radioactivity on

  8. Isolation and identification mould micoflora inhabiting plant leaf litter from Mount Lawu, Surakarta, Central Java

    Directory of Open Access Journals (Sweden)

    MUHAMMAD ILYAS

    2007-04-01

    Full Text Available A study on isolation and identification mould inhabiting plant leaf litter had been conducted. The objective of the study was to isolate and identify mould inhabiting plant leaf litter from Mount Lawu, Surakarta, Central Java. The mould isolation was based on washing and filtering with membrane isolation method. The result showed that 39 moulds generas with 55 species varians, one group identified in class level, and three groups of unidentified mould isolates had been isolated. Taxas distributions showed that there were endophyte and phytopatogen mould isolates had been isolated such as Fusarium, Pestalotiopsis, Phoma, and Coelomycetes. However, typical soil taxa and common saprobic fungi such as Aspergillus, Cunninghamella, Mucor, Paecilomyces, Penicillium, Rhizopus, and Trichoderma remain dominated the resulted isolates.

  9. Effect of elevated atmospheric CO2 concentration on growth and leaf litter decomposition of Quercus acutissima and Fraxinus rhynchophylla.

    Science.gov (United States)

    Cha, Sangsub; Chae, Hee-Myung; Lee, Sang-Hoon; Shim, Jae-Kuk

    2017-01-01

    The atmospheric carbon dioxide (CO2) level is expected to increase substantially, which may change the global climate and carbon dynamics in ecosystems. We examined the effects of an elevated atmospheric CO2 level on the growth of Quercus acutissima and Fraxinus rhynchophylla seedlings. We investigated changes in the chemical composition of leaf litter, as well as litter decomposition. Q. acutissima and F. rhynchophylla did not show differences in dry weight between ambient CO2 and enriched CO2 treatments, but they exhibited different patterns of carbon allocation, namely, lower shoot/root ratio (S/R) and decreased specific leaf area (SLA) under CO2-enriched conditions. The elevated CO2 concentration significantly reduced the nitrogen concentration in leaf litter while increasing lignin concentrations and carbon/nitrogen (C/N) and lignin/N ratios. The microbial biomass associated with decomposing Q. acutissima leaf litter was suppressed in CO2 enrichment chambers, while that of F. rhynchophylla was not. The leaf litter of Q. acutissima from the CO2-enriched chambers, in contrast with F. rhynchophylla, contained much lower nutrient concentrations than that of the litter in the ambient air chambers. Consequently, poorer litter quality suppressed decomposition.

  10. Interactions between hyphosphere-associated bacteria and the fungus Cladosporium herbarum on aquatic leaf litter.

    Science.gov (United States)

    Baschien, Christiane; Rode, Georg; Böckelmann, Uta; Götz, Peter; Szewzyk, Ulrich

    2009-10-01

    We investigated microbial interactions of aquatic bacteria associated with hyphae (the hyphosphere) of freshwater fungi on leaf litter. Bacteria were isolated directly from the hyphae of fungi from sedimented leaves of a small stream in the National Park "Lower Oder," Germany. To investigate interactions, bacteria and fungi were pairwise co-cultivated on leaf-extract medium and in microcosms loaded with leaves. The performance of fungi and bacteria was monitored by measuring growth, enzyme production, and respiration of mono- and co-cultures. Growth inhibition of the fungus Cladosporium herbarum by Ralstonia pickettii was detected on leaf extract agar plates. In microcosms, the presence of Chryseobacterium sp. lowered the exocellulase, endocellulase, and cellobiase activity of the fungus. Additionally, the conversion of leaf material into microbial biomass was retarded in co-cultures. The respiration of the fungus was uninfluenced by the presence of the bacterium.

  11. Drought and detritivores determine leaf litter decomposition in calcareous streams of the Ebro catchment (Spain).

    Science.gov (United States)

    Monroy, Silvia; Menéndez, Margarita; Basaguren, Ana; Pérez, Javier; Elosegi, Arturo; Pozo, Jesús

    2016-12-15

    Drought, an important environmental factor affecting the functioning of stream ecosystems, is likely to become more prevalent in the Mediterranean region as a consequence of climate change and enhanced water demand. Drought can have profound impacts on leaf litter decomposition, a key ecosystem process in headwater streams, but there is still limited information on its effects at the regional scale. We measured leaf litter decomposition across a gradient of aridity in the Ebro River basin. We deployed coarse- and fine-mesh bags with alder and oak leaves in 11 Mediterranean calcareous streams spanning a range of over 400km, and determined changes in discharge, water quality, leaf-associated macroinvertebrates, leaf quality and decomposition rates. The study streams were subject to different degrees of drought, specific discharge (Ls(-1)km(-2)) ranging from 0.62 to 9.99. One of the streams dried out during the experiment, another one reached residual flow, whereas the rest registered uninterrupted flow but with different degrees of flow variability. Decomposition rates differed among sites, being lowest in the 2 most water-stressed sites, but showed no general correlation with specific discharge. Microbial decomposition rates were not correlated with final nutrient content of litter nor to fungal biomass. Total decomposition rate of alder was positively correlated to the density and biomass of shredders; that of oak was not. Shredder density in alder bags showed a positive relationship with specific discharge during the decomposition experiment. Overall, the results point to a complex pattern of litter decomposition at the regional scale, as drought affects decomposition directly by emersion of bags and indirectly by affecting the functional composition and density of detritivores.

  12. Impacts of pesticides and natural stressors on leaf litter decomposition in agricultural streams.

    Science.gov (United States)

    Rasmussen, Jes Jesssen; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette; Monberg, Rikke Juul; Kronvang, Brian

    2012-02-01

    Agricultural pesticides are known to significantly impact the composition of communities in stream ecosystems. Moreover, agricultural streams are often characterised by loss of physical habitat diversity which may impose additional stress resulting from suboptimal environmental conditions. We surveyed pesticide contamination and rates of leaf litter decomposition in 14 1st and 2nd order Danish streams using litter bags with coarse and fine mesh sizes. Two sites differing in physical habitat complexity were sampled in each stream, and we used this approach to differentiate the effects of pesticides between sites with uniform (silt and sand) and more heterogeneous physical properties. Microbial litter decomposition was reduced by a factor two to four in agricultural streams compared to forested streams, and we found that the rate of microbial litter decomposition responded most strongly to pesticide toxicity for microorganisms and not to eutrophication. Moreover, the rate of microbial litter decomposition was generally 50% lower at sites with uniform physical habitats dominated by soft substrate compared to the sites with more heterogeneous physical habitats. The rate of macroinvertebrate shredding activity was governed by the density of shredders, and the density of shredders was not correlated to pesticide contamination mainly due to high abundances of the amphipod Gammarus pulex at all sites. Our study provides the first field based results on the importance of multiple stressors and their potential to increase the effect of agricultural pesticides on important ecosystem processes.

  13. Allelopathic effects of leaf litters of Eucalyptus camaldulensis on some forest and agricultural crops

    Institute of Scientific and Technical Information of China (English)

    Romel Ahmed; A. T. M. Rafiqul Hoque; Mohammed Kamal Hossain

    2008-01-01

    Allelopathic effects of different doses of Eucalyptus camaldulensis leaf litters were investigated through an experiment in the green house of Institute of Forestry and Environmental Sciences, Chittagong, Bangladesh. Three popular agricultural crops: Falen (Vigna unguiculata), Chickpea (Cicer arietinum), Arhor (Cajanus cajan) and two widely used plantation trees: Sada koroi (Albizia procera) and Ipil ipil (Leucaena leucocephala) were selected as bioassay species. Experiment was set on tray at room temperature 27℃. The effects of different doses of leaf litter extracts were compared to the control. Results suggest that leaf litters of E. camaldulesis induced inhibitory effects. It was also found that the effect depend on concentration of extract and litterfall, type of receiver species. Higher concentration of the materials had the higher effect and vice versa. Though all the bioassay species were suppressed some of them showed better performance. Vigna unguiculata, Cicer arietinum are recommended in agroforestry based on this present Experiment output. In mixed plantation, Leucaena leucochephala is a better choice while compared to Albizia procera.

  14. The impact of coffee and pasture agriculture on predatory and omnivorous leaf-litter ants.

    Science.gov (United States)

    Dias, Nivia da Silva; Zanetti, Ronald; Santos, Mônica Silva; Peñaflor, Maria Fernanda Gomes Villalba; Broglio, Sônia Maria Forti; Delabie, Jacques Hubert Charles

    2013-01-01

    Ants are known to function as reliable biological indicators for habitat impact assessment. They play a wide range of ecological roles depending on their feeding and nesting habits. By clustering ants in guilds, it is possible both to assess how agriculture and forest fragmentation can disturb ant communities and to predict the ecological impacts due to losses of a specific guild. This study aimed at determining the impact of non-shaded coffee and pasture agriculture on predatory and omnivorous guilds of leaf-litter ants of Atlantic Forest fragments in Minas Gerais, Brazil. Both coffee and pasture agriculture influenced leaf-litter ant community, although coffee was more disruptive than pasture. Coffee agriculture not only disturbed the diversity of predatory ants, but also negatively affected the number of predatory and omnivorous ants when compared to forest fragments. In contrast, pasture agriculture only disrupted the abundance of predatory ants. Fragment edges skirting crops were negatively affected in terms of leaf-litter ant abundance, but not diversity. Cluster analysis showed that forest fragments were similar irrespective of the cultivation, but the borders were similar to the crop. The study assessed agriculture impact by surveying ant guilds, and revealed that the predatory guild is more susceptible than omnivorous ants.

  15. Effects of forest management practices in temperate beech forests on bacterial and fungal communities involved in leaf litter degradation.

    Science.gov (United States)

    Purahong, Witoon; Kapturska, Danuta; Pecyna, Marek J; Jariyavidyanont, Katalee; Kaunzner, Jennifer; Juncheed, Kantida; Uengwetwanit, Tanaporn; Rudloff, Renate; Schulz, Elke; Hofrichter, Martin; Schloter, Michael; Krüger, Dirk; Buscot, François

    2015-05-01

    Forest management practices (FMPs) significantly influence important ecological processes and services in Central European forests, such as leaf litter decomposition and nutrient cycling. Changes in leaf litter diversity, and thus, its quality as well as microbial community structure and function induced by different FMPs were hypothesized to be the main drivers causing shifts in decomposition rates and nutrient release in managed forests. In a litterbag experiment lasting 473 days, we aimed to investigate the effects of FMPs (even-aged timber management, selective logging and unmanaged) on bacterial and fungal communities involved in leaf litter degradation over time. Our results showed that microbial communities in leaf litter were strongly influenced by both FMPs and sampling date. The results from nonmetric multidimensional scaling (NMDS) ordination revealed distinct patterns of bacterial and fungal successions over time in leaf litter. We demonstrated that FMPs and sampling dates can influence a range of factors, including leaf litter quality, microbial macronutrients, and pH, which significantly correlate with microbial community successions.

  16. Highly Active Ice Nuclei from Tree Leaf Litters Retain Activity for Decades

    Science.gov (United States)

    Schnell, R. C.; Hill, T. C. J.

    2015-12-01

    Biogenic ice nuclei (IN) studied since the 1960s were first observed in tree leaf litters, in a few bacteria species and later in fungi and lichens. Recently, viable IN bacteria in precipitation have been used as a metric of their possible role in precipitation formation. Although bacterial IN activity is deactivated by a variety of common environmental stresses, we present data showing that IN found in a potpourri of decayed plant leaves, bacteria, molds and fungi etc. in plant litters are exceptionally stable and active over decades while in storage. As such, their atmospheric IN potential is worthy of further study due to their environmental persistence. In August 1970 litter collected in a grove of deciduous trees near Red Deer, AB, Canada was tested for IN (drop freezing technique). The sample initiated ice at -4C with 109 IN per gram of litter active at -10C. A few kilograms were stored in a plastic bag and tested every few years for IN content; the IN activity remained essentially unchanged over 40 years. In 2011, litter collected in the same grove had the same IN activity as the sample tested over the intervening 40 years. Boiling a gram sample of this litter in 100 grams of water deactivated 99 % of the IN activity down to -13C. None of 88 different bacteria cultures several of which appeared to Pseudomonads (common IN producing bacteria) from the fresh litter produced any active IN. A sample of the litter was placed on the top of a 15 cm column of laboratory grade kaolin and water dripped onto the litter. Ten days later the water reached the bottom of the column. The kaolin was dried and tested for IN. The prior essentially IN free kaolin now exhibited IN activity at -4C with 105 IN active at -10C. The litter exposed kaolin retained the IN activity for 25 years. Baking the kaolin removed the active IN. This suggests that IN activity attributed to kaolin particles sometimes seen at the nucleus of snow crystals could be of biological origin.

  17. Molecular characteristics of continuously released DOM during one year of root and leaf litter decomposition

    Science.gov (United States)

    Altmann, Jens; Jansen, Boris; Kalbitz, Karsten; Filley, Timothy

    2013-04-01

    Dissolved organic matter (DOM) is one of the most dynamic carbon pools linking the terrestrial with the aquatic carbon cycle. Besides the insecure contribution of terrestrial DOM to the greenhouse effect, DOM also plays an important role for the mobility and availability of heavy metals and organic pollutants in soils. These processes depend very much on the molecular characteristics of the DOM. Surprisingly the processes that determine the molecular composition of DOM are only poorly understood. DOM can originate from various sources, which influence its molecular composition. It has been recognized that DOM formation is not a static process and DOM characteristics vary not only between different carbon sources. However, molecular characteristics of DOM extracts have scarcely been studied continuously over a longer period of time. Due to constant molecular changes of the parent litter material or soil organic matter during microbial degradation, we assumed that also the molecular characteristics of litter derived DOM varies at different stages during root and needle decomposition. For this study we analyzed the chemical composition of root and leaf samples of 6 temperate tree species during one year of litter decomposition in a laboratory incubation. During this long-term experiment we measured continuously carbon and nitrogen contents of the water extracts and the remaining residues, C mineralization rates, and the chemical composition of water extracts and residues by Curie-point pyrolysis mass spectrometry with TMAH We focused on the following questions: (I) How mobile are molecules derived from plant polymers like tannin, lignin, suberin and cutin? (II) How does the composition of root and leaf derived DOM change over time in dependence on the stage of decomposition and species? Litter derived DOM was generally dominated by aromatic compounds. Substituded fatty acids as typically cutin or suberin derived were not detected in the water extracts. Fresh leaf and

  18. Decomposition of leaf litter from a native tree and an actinorhizal invasive across riparian habitats.

    Science.gov (United States)

    Harner, Mary J; Crenshaw, Chelsea L; Abelho, Manuela; Stursova, Martina; Shah, Jennifer J Follstad; Sinsabaugh, Robert L

    2009-07-01

    Dynamics of nutrient exchange between floodplains and rivers have been altered by changes in flow management and proliferation of nonnative plants. We tested the hypothesis that the nonnative, actinorhizal tree, Russian olive (Elaeagnus angustifolia), alters dynamics of leaf litter decomposition compared to native cottonwood (Populus deltoides ssp. wislizeni) along the Rio Grande, a river with a modified flow regime, in central New Mexico (U.S.A.). Leaf litter was placed in the river channel and the surface and subsurface horizons of forest soil at seven riparian sites that differed in their hydrologic connection to the river. All sites had a cottonwood canopy with a Russian olive-dominated understory. Mass loss rates, nutrient content, fungal biomass, extracellular enzyme activities (EEA), and macroinvertebrate colonization were followed for three months in the river and one year in forests. Initial nitrogen (N) content of Russian olive litter (2.2%) was more than four times that of cottonwood (0.5%). Mass loss rates (k; in units of d(-1)) were greatest in the river (Russian olive, k = 0.0249; cottonwood, k = 0.0226), intermediate in subsurface soil (Russian olive, k = 0.0072; cottonwood, k = 0.0031), and slowest on the soil surface (Russian olive, k = 0.0034; cottonwood, k = 0.0012) in a ratio of about 10:2:1. Rates of mass loss in the river were indistinguishable between species and proportional to macroinvertebrate colonization. In the riparian forest, Russian olive decayed significantly faster than cottonwood in both soil horizons. Terrestrial decomposition rates were related positively to EEA, fungal biomass, and litter N, whereas differences among floodplain sites were related to hydrologic connectivity with the river. Because nutrient exchanges between riparian forests and the river have been constrained by flow management, Russian olive litter represents a significant annual input of N to riparian forests, which now retain a large portion of slowly

  19. Influences of leaf litter replacement on soil biochemical characteristics of main planted forests in Qinling Mountains of China

    Institute of Scientific and Technical Information of China (English)

    Zengwen LIU; Erjun DUAN; Wenjun GAO

    2009-01-01

    Long-term continuous growth of the same tree species in planted pure forest will lead to soil polarization and degradation. Mixed forestation or litter replacement between different needle- and broad-leaved forests are effective measures, except fertilization, to control soil polarization according to the mutual compensation principle of different tree species. Through a two-year leaf litter replacement experiment in 4 typical planted pure forests of Larix kaempferi, Pinus tabulaeformis, Catalpa fargesii and Quercus aliena var. acuteserrata in Qinling Mountains of China, influences of leaf litter replacement on soil biochemical characteristics and their interspecific relationships were studied and main conclusions were reached as follows. (1) Annual leaf litter decomposition rate of broadleaved forests was 33.70% higher than those of needleleaved forests and increased by 8.35%-12.15% when needle-leaved litter was replaced with broad-leaved forests, whereas it decreased by 5.38%-9.49% when broad-leaved litter was replaced with needle-leaved forests. (2) Leaf litter replacement between needle- and broad-leaved forests popularly raised the contents of organic C, available N, P and K in soil, whose content increments in the needle-leaved forests (8.70%-35.84%) were obviously more than those in the broad-leaved forests (3.73%-10.44%), and in the former, the content increments after replacement with the litter of Catalpa fargesii (24.63%-35.84%) were more than those after replacement with the litter ofQuercus aliena var. acuteserrata (8.70% 28.15%). Furthermore, the litter replacement was found to make the soil pH of needle-leaved forests developed from light-acid to neutral. (3) Litter replacement of the needleleaved forests with the broad-leaved litter popularly raised enzyme activities, amounts of microorganisms and contents of micro-biomass C and N in soil, the increments of which after replacement with the litter of Catalpa fargesii were also more than those after

  20. Restoration of Tidal Flow to Impounded Salt Marsh Exerts Mixed Effect on Leaf Litter Decomposition

    Science.gov (United States)

    Henry, B. A.; Schade, J. D.; Foreman, K.

    2015-12-01

    Salt marsh impoundments (e.g. roads, levees) disconnect marshes from ocean tides, which impairs ecosystem services and often promotes invasive species. Numerous restoration projects now focus on removing impoundments. Leaf litter decomposition is a central process in salt marsh carbon and nutrient cycles, and this study investigated the extent to which marsh restoration alters litter decomposition rates. We considered three environmental factors that can potentially change during restoration: salinity, tidal regime, and dominant plant species. A one-month field experiment (Cape Cod, MA) measured decay of litter bags in impounded, restored, and natural marshes under ambient conditions. A two-week lab experiment measured litter decay in controlled incubations under experimental treatments for salinity (1ppt and 30 ppt), tidal regime (inundated and 12 hr wet-dry cycles), and plant species (native Spartina alterniflora and invasive Phragmites australis). S. alterniflora decomposed faster in situ than P. australis (14±1.0% mass loss versus 0.74±0.69%). Corroborating this difference in decomposition, S. alterniflora supported greater microbial respiration during lab incubation, measured as CO2 flux from leaf litter and biological oxygen demand of water containing leached organic matter (OM). However, nutrient analysis of plant tissue and leached OM show P. australis released more nitrogen than S. alterniflora. Low salinity treatments in both lab and field experiments decayed more rapidly than high salinity treatments, suggesting that salinity inhibited microbial activity. Manipulation of inundation regime did not affect decomposition. These findings suggest the reintroduction of tidal flow to an impounded salt marsh can have mixed effects; recolonization by the native cordgrass could supply labile OM to sediment and slow carbon sequestration, while an increase in salinity might inhibit decomposition and accelerate sequestration.

  1. Radiocesium immobilization to leaf litter by fungi during first-year decomposition in a deciduous forest in Fukushima.

    Science.gov (United States)

    Huang, Yao; Kaneko, Nobuhiro; Nakamori, Taizo; Miura, Toshiko; Tanaka, Yoichiro; Nonaka, Masanori; Takenaka, Chisato

    2016-02-01

    Vast forest areas in eastern Japan have been contaminated with radio-isotopes by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Radiocesium (radioCs) is known to remain bioavailable in forest ecosystems for a long time, and it is necessary to terminate the cycling process to decontaminate the forest ecosystem. We observed radiocesium concentrations of leaf litter during decomposition on a forest floor where radiocesium ((137)Cs) contamination was ∼155 kBq/m(2). Litter bag experiments were conducted with newly fallen mixed deciduous leaf litter in a deciduous forest (alt. 610 m) about 50 km from the FDNPP. Litter bags were retrieved in April, June, August, October, and December 2012. Fresh litter (137)Cs concentration was ∼3000 Bq/kg in December 2011. During the decomposition process on the forest floor, litter (137)Cs concentration increased rapidly and exceeded 25,000 Bq/kg after 6 months, whereas potassium (K) concentration in the litter was rather stable, indicating that radiocesium and K showed contrasting dynamics during the early decomposition phase. Nitrogen, phosphorus, and (137)Cs contents were positively correlated to fungal biomass, evaluated by phospholipid fatty acids in the litter during decomposition. The increase of radiocesium concentration mainly occurred during from April to October, when fungal growth peaked. Therefore, this suggests fungal translocation of nutrients from outside the litter substrate (immobilization) is the mechanism to increase radiocesium in the decomposing litter. The amount of (137)Cs contained in the 1-year-old decomposed leaf litter was estimated to be 4% per area of the soil-contaminated (137)Cs.

  2. The influence of leaf morphology on litter flammability and its utility for interpreting palaeofire.

    Science.gov (United States)

    Belcher, Claire M

    2016-06-05

    Studies of palaeofire rely on quantifying the abundance of fossil charcoals in sediments to estimate changes in fire activity. However, gaining an understanding of the behaviour of palaeofires is also essential if we are to determine the palaeoecological impact of wildfires. Here, I use experimental approaches to explore relationships between litter fire behaviour and leaf traits that are observable in the fossil record. Fire calorimetry was used to assess the flammability of 15 species of conifer litter and indicated that leaf morphology related to litter bulk density and fuel load that determined the duration of burning and the total energy released. These data were applied to a fossil case study that couples estimates of palaeolitter fire behaviour to charcoal-based estimates of fire activity and observations of palaeoecological changes. The case study reveals that significant changes in fire activity and behaviour likely fed back to determine ecosystem composition. This work highlights that we can recognize and measure plant traits in the fossil record that relate to fire behaviour and therefore that further research is warranted towards estimating palaeofire behaviour as it can enhance our ability to interpret the palaeoecological impact of palaeofires throughout Earth's long evolutionary history.This article is part of the themed issue 'The interaction of fire and mankind'.

  3. Effects of flow scarcity on leaf-litter processing under oceanic climate conditions in calcareous streams.

    Science.gov (United States)

    Martínez, Aingeru; Pérez, Javier; Molinero, Jon; Sagarduy, Mikel; Pozo, Jesús

    2015-01-15

    Although temporary streams represent a high proportion of the total number and length of running waters, historically the study of intermittent streams has received less attention than that of perennial ones. The goal of the present study was to assess the effects of flow cessation on litter decomposition in calcareous streams under oceanic climate conditions. For this, leaf litter of alder was incubated in four streams (S1, S2, S3 and S4) with different flow regimes (S3 and S4 with zero-flow periods) from northern Spain. To distinguish the relative importance and contribution of decomposers and detritivores, fine- and coarse-mesh litter bags were used. We determined processing rates, leaf-C, -N and -P concentrations, invertebrate colonization in coarse bags and benthic invertebrates. Decomposition rates in fine bags were similar among streams. In coarse bags, only one of the intermittent streams, S4, showed a lower rate than that in the other ones as a consequence of lower invertebrate colonization. The material incubated in fine bags presented higher leaf-N and -P concentrations than those in the coarse ones, except in S4, pointing out that the decomposition in this stream was driven mainly by microorganisms. Benthic macroinvertebrate and shredder density and biomass were lower in intermittent streams than those in perennial ones. However, the bags in S3 presented a greater amount of total macroinvertebrates and shredders comparing with the benthos. The most suitable explanation is that the fauna find a food substrate in bags less affected by calcite precipitation, which is common in the streambed at this site. Decomposition rate in coarse bags was positively related to associated shredder biomass. Thus, droughts in streams under oceanic climate conditions affect mainly the macroinvertebrate detritivore activity, although macroinvertebrates may show distinct behavior imposed by the physicochemical properties of water, mainly travertine precipitation, which can

  4. The surrounding landscape influences the diversity of leaf-litter ants in riparian cloud forest remnants

    Science.gov (United States)

    Valenzuela-González, Jorge E.; Escobar-Sarria, Federico; López-Barrera, Fabiola; Castaño-Meneses, Gabriela

    2017-01-01

    Riparian vegetation is a distinctive and ecologically important element of landscapes worldwide. However, the relative influence of the surrounding landscape on the conservation of the biodiversity of riparian remnants in human-modified tropical landscapes is poorly understood. We studied the surrounding landscape to evaluate its influence on leaf-litter-ant alpha and beta diversity in riparian remnants in the tropical montane cloud forest region of central Veracruz, Mexico. Sampling was carried out in 12 sites with riparian vegetation during both rainy (2011) and dry (2012) seasons. Ten leaf-litter samples were collected along a 100-m transect per site and processed with Berlese-Tullgren funnels and Winkler sacks. Using remotely-sensed and ground-collected data, we characterized the landscape around each site according to nine land cover types and computed metrics of landscape composition and configuration. We collected a total of 8,684 ant individuals belonging to 53 species, 22 genera, 11 tribes, and 7 subfamilies. Species richness and the diversity of Shannon and Simpson increased significantly in remnants immersed in landscapes with a high percentage of riparian land cover and a low percentage of land covers with areas reforested with Pinus, cattle pastures, and human settlements and infrastructure. The composition of ant assemblages was a function of the percentage of riparian land cover in the landscape. This study found evidence that leaf-litter ants, a highly specialized guild of arthropods, are mainly impacted by landscape composition and the configuration of the focal remnant. Maintaining or improving the surrounding landscape quality of riparian vegetation remnants can stimulate the movement of biodiversity among forest and riparian remnants and foster the provision of ecosystem services by these ecosystems. Effective outcomes may be achieved by considering scientific knowledge during the early stages of riparian policy formulation, in addition to

  5. Conspecific Leaf Litter-Mediated Effect of Conspecific Adult Neighborhood on Early-Stage Seedling Survival in A Subtropical Forest

    Science.gov (United States)

    Liu, Heming; Shen, Guochun; Ma, Zunping; Yang, Qingsong; Xia, Jianyang; Fang, Xiaofeng; Wang, Xihua

    2016-11-01

    Conspecific adults have strong negative effect on the survival of nearby early-stage seedlings and thus can promote species coexistence by providing space for the regeneration of heterospecifics. The leaf litter fall from the conspecific adults, and it could mediate this conspecific negative adult effect. However, field evidence for such effect of conspecific leaf litter remains absent. In this study, we used generalized linear mixed models to assess the effects of conspecific leaf litter on the early-stage seedling survival of four dominant species (Machilus leptophylla, Litsea elongate, Acer pubinerve and Distylium myricoides) in early-stage seedlings in a subtropical evergreen broad-leaved forest in eastern China. Our results consistently showed that the conspecific leaf litter of three species negatively affected the seedling survival. Meanwhile, the traditional conspecific adult neighborhood indices failed to detect this negative conspecific adult effect. Our study revealed that the accumulation of conspecific leaf litter around adults can largely reduce the survival rate of nearby seedlings. Ignoring it could result in underestimation of the importance of negative density dependence and negative species interactions in the natural forest communities.

  6. Evolutionary Position and Leaf Toughness Control Chemical Transformation of Litter, and Drought Reinforces This Control: Evidence from a Common Garden Experiment across 48 Species.

    Science.gov (United States)

    Pan, Xu; Song, Yao-Bin; Jiang, Can; Liu, Guo-Fang; Ye, Xue-Hua; Xie, Xiu-Fang; Hu, Yu-Kun; Zhao, Wei-Wei; Cui, Lijuan; Cornelissen, Johannes H C; Dong, Ming; Prinzing, Andreas

    2015-01-01

    Plant leaf litter is an important source of soil chemicals that are essential for the ecosystem and changes in leaf litter chemical traits during decomposition will determine the availability of multiple chemical elements recycling in the ecosystem. However, it is unclear whether the changes in litter chemical traits during decomposition and their similarities across species can be predicted, respectively, using other leaf traits or using the phylogenetic relatedness of the litter species. Here we examined the fragmentation levels, mass losses, and the changes of 10 litter chemical traits during 1-yr decomposition under different environmental conditions (within/above surrounding litter layer) for 48 temperate tree species and related them to an important leaf functional trait, i.e. leaf toughness. Leaf toughness could predict the changes well in terms of amounts, but poorly in terms of concentrations. Changes of 7 out of 10 litter chemical traits during decomposition showed a significant phylogenetic signal notably when litter was exposed above surrounding litter. These phylogenetic signals in element dynamics were stronger than those of initial elementary composition. Overall, relatively hard-to-measure ecosystem processes like element dynamics during decomposition could be partly predicted simply from phylogenies and leaf toughness measures. We suggest that the strong phylogenetic signals in chemical ecosystem functioning of species may reflect the concerted control by multiple moderately conserved traits, notably if interacting biota suffer microclimatic stress and spatial isolation from ambient litter.

  7. Evolutionary Position and Leaf Toughness Control Chemical Transformation of Litter, and Drought Reinforces This Control: Evidence from a Common Garden Experiment across 48 Species.

    Directory of Open Access Journals (Sweden)

    Xu Pan

    Full Text Available Plant leaf litter is an important source of soil chemicals that are essential for the ecosystem and changes in leaf litter chemical traits during decomposition will determine the availability of multiple chemical elements recycling in the ecosystem. However, it is unclear whether the changes in litter chemical traits during decomposition and their similarities across species can be predicted, respectively, using other leaf traits or using the phylogenetic relatedness of the litter species. Here we examined the fragmentation levels, mass losses, and the changes of 10 litter chemical traits during 1-yr decomposition under different environmental conditions (within/above surrounding litter layer for 48 temperate tree species and related them to an important leaf functional trait, i.e. leaf toughness. Leaf toughness could predict the changes well in terms of amounts, but poorly in terms of concentrations. Changes of 7 out of 10 litter chemical traits during decomposition showed a significant phylogenetic signal notably when litter was exposed above surrounding litter. These phylogenetic signals in element dynamics were stronger than those of initial elementary composition. Overall, relatively hard-to-measure ecosystem processes like element dynamics during decomposition could be partly predicted simply from phylogenies and leaf toughness measures. We suggest that the strong phylogenetic signals in chemical ecosystem functioning of species may reflect the concerted control by multiple moderately conserved traits, notably if interacting biota suffer microclimatic stress and spatial isolation from ambient litter.

  8. Intrapopulation Genotypic Variation of Foliar Secondary Chemistry during Leaf Senescence and Litter Decomposition in Silver Birch (Betula pendula).

    Science.gov (United States)

    Paaso, Ulla; Keski-Saari, Sarita; Keinänen, Markku; Karvinen, Heini; Silfver, Tarja; Rousi, Matti; Mikola, Juha

    2017-01-01

    Abundant secondary metabolites, such as condensed tannins, and their interpopulation genotypic variation can remain through plant leaf senescence and affect litter decomposition. Whether the intrapopulation genotypic variation of a more diverse assortment of secondary metabolites equally persists through leaf senescence and litter decomposition is not well understood. We analyzed concentrations of intracellular phenolics, epicuticular flavonoid aglycones, epicuticular triterpenoids, condensed tannins, and lignin in green leaves, senescent leaves and partly decomposed litter of silver birch, Betula pendula. Broad-sense heritability (H(2)) and coefficient of genotypic variation (CVG) were estimated for metabolites in senescent leaves and litter using 19 genotypes selected from a B. pendula population in southern Finland. We found that most of the secondary metabolites remained through senescence and decomposition and that their persistence was related to their chemical properties. Intrapopulation H(2) and CVG for intracellular phenolics, epicuticular flavonoid aglycones and condensed tannins were high and remarkably, increased from senescent leaves to decomposed litter. The rank of genotypes in metabolite concentrations was persistent through litter decomposition. Lignin was an exception, however, with a diminishing genotypic variation during decomposition, and the concentrations of lignin and condensed tannins had a negative genotypic correlation in the senescent leaves. Our results show that secondary metabolites and their intrapopulation genotypic variation can for the most part remain through leaf senescence and early decomposition, which is a prerequisite for initial litter quality to predict variation in litter decomposition rates. Persistent genotypic variation also opens an avenue for selection to impact litter decomposition in B. pendula populations through acting on their green foliage secondary chemistry. The negative genotypic correlations and diminishing

  9. Climatic controls on leaf litter decomposition across European forests and grasslands revealed by reciprocal litter transplantation experiments

    DEFF Research Database (Denmark)

    Portillo-Estrada, Miguel; Pihlatie, Mari; Korhonen, Janne F. J.

    2016-01-01

    Carbon (C) and nitrogen (N) cycling under future climate change is associated with large uncertainties in litter decomposition and the turnover of soil C and N. In addition, future conditions (especially altered precipitation regimes and warming) are expected to result in changes in vegetation...... composition, and accordingly in litter species and chemical composition, but it is unclear how such changes could potentially alter litter decomposition. Litter transplantation experiments were carried out across six European sites (four forests and two grasslands) spanning a large geographical and climatic...... gradient (5.6-11.4 degrees C in annual temperature 511-878mm in precipitation) to gain insight into the climatic controls on litter decomposition as well as the effect of litter origin and species.The decomposition k rates were overall higher in warmer and wetter sites than in colder and drier sites...

  10. Effect of brushwood transposition on the leaf litter arthropod fauna in a cerrado area

    Directory of Open Access Journals (Sweden)

    Paula Cristina Benetton Vergílio

    2013-10-01

    Full Text Available The results of ecological restoration techniques can be monitored through biological indicators of soil quality such as the leaf litter arthropod fauna. This study aimed to determine the immediate effect of brushwood transposition transferred from an area of native vegetation to a disturbed area, on the leaf litter arthropod fauna in a degraded cerrado area. The arthropod fauna of four areas was compared: a degraded area with signal grass, two experimental brushwood transposition areas, with and without castor oil plants, and an area of native cerrado. In total, 7,660 individuals belonging to 23 taxa were sampled. Acari and Collembola were the most abundant taxa in all studied areas, followed by Coleoptera, Diptera, Hemiptera, Hymenoptera, and Symphyla. The brushwood transposition area without castor oil plants had the lowest abundance and dominance and the highest diversity of all areas, providing evidence of changes in the soil community. Conversely, the results showed that the presence of castor oil plants hampered early succession, negatively affecting ecological restoration in this area.

  11. Contribution of Leaf Litter to Nutrient Export during Winter Months in an Urban Residential Watershed.

    Science.gov (United States)

    Bratt, Anika R; Finlay, Jacques C; Hobbie, Sarah E; Janke, Benjamin D; Worm, Adam C; Kemmitt, Kathrine L

    2017-03-03

    Identification of nonpoint sources of nitrogen (N) and phosphorus (P) in urban systems is imperative to improving water quality and better managing eutrophication. Winter contributions and sources of annual N and P loads from urban watersheds are poorly characterized in northern cities because monitoring is often limited to warm-weather periods. To determine the winter export of N and P, we monitored stormwater outflow in a residential watershed in Saint Paul, Minnesota during 2012-2014. Our data demonstrate that winter melt events contribute a high percentage of annual N and P export (50%). We hypothesized that overwintering leaf litter that is not removed by fall street sweeping could be an important source to winter loads of N and P. We estimated contributions of this source by studying decomposition in lawns, street gutters, and catch basins during two winters. Rates of mass and N loss were negligible during both winters. However, P was quickly solubilized from decomposing leaves. Using mass balances and estimates of P leaching losses, we estimated that leaf litter could contribute 80% of winter total dissolved phosphorus (TDP) loading in this watershed (∼40% of annual TDP loading). Our work indicates that urban trees adjacent to streets likely represent a major source of P pollution in northern cities. Management that targets important winter sources such as tree leaves could be highly effective for reducing P loading and may mitigate eutrophication in urban lakes and streams in developed cities.

  12. Prior Hydrologic Disturbance Affects Competition between Aedes Mosquitoes via Changes in Leaf Litter.

    Science.gov (United States)

    Smith, Cassandra D; Freed, T Zachary; Leisnham, Paul T

    2015-01-01

    Allochthonous leaf litter is often the main resource base for invertebrate communities in ephemeral water-filled containers, and detritus quality can be affected by hydrologic conditions. The invasive mosquito Aedes albopictus utilizes container habitats for its development where it competes as larvae for detritus and associated microorganisms with the native Aedes triseriatus. Different hydrologic conditions that containers are exposed to prior to mosquito utilization affect litter decay and associated water quality. We tested the hypothesis that larval competition between A. albopictus and A. triseriatus would be differentially affected by prior hydrologic conditions. Experimental microcosms provisioned with Quercus alba L. litter were subjected to one of three different hydrologic treatments prior to the addition of water and mosquito larvae: dry, flooded, and a wet/dry cycle. Interspecific competition between A. albopictus and A. triseriatus was mediated by hydrologic treatment, and was strongest in the dry treatment vs. the flooded or wet/dry treatments. Aedes triseriatus estimated rate of population change (λ') was lowest in the dry treatment. Aedes albopictus λ' was unaffected by hydrologic treatment, and was on average always increasing (i.e., > 1). Aedes triseriatus λ' was affected by the interaction of hydrologic treatment with interspecific competition, and was on average declining (i.e., litter had the slowest decay rate and leached the highest concentration of tannin-lignin, but supported more total bacteria than the other treatments. These results suggest that dry conditions negatively impact A. triseriatus population performance and may result in the competitive exclusion of A. triseriatus by A. albopictus, possibly by reducing microbial taxa that Aedes species browse. Changing rainfall patterns with climate change are likely to affect competition between A. triseriatus and A. albopictus, probably enhancing negative competitive effects of A

  13. Interspecific variations in mangrove leaf litter decomposition are related to labile nitrogenous compounds

    Science.gov (United States)

    Nordhaus, Inga; Salewski, Tabea; Jennerjahn, Tim C.

    2017-06-01

    Mangrove leaves form a large pool of carbon, nitrogen and energy that is a major driver of element cycles and detrital food webs inside mangrove forests as well as in adjacent coastal waters. However, there are large gaps in knowledge on the transformation pathways and ultimate fate of leaf nitrogen. Therefore, the main objective of this study was to determine the amount and composition of nitrogenous organic matter and possible species-specific differences during the decomposition of mangrove leaf litter. For that purpose a three month decomposition experiment with litterbags was conducted using leaves of Aegiceras corniculatum, Avicennia alba, Ceriops decandra, Rhizophora apiculata, and Sonneratia caseolaris in the mangrove forest of the Segara Anakan Lagoon, Java, Indonesia. Detrital leaves were analyzed for bulk carbon and total nitrogen (N), stable carbon and nitrogen isotope composition (δ13C, δ15N), total hydrolyzable amino acids (THAA) and total hydrolyzable hexosamines (THHA). Decomposition rates (k d-1) were highest and tM50 values (when 50% of the original mass had been degraded) lowest in S. caseolaris (k = 0.0382 d-1; tM50 = 18 days), followed by A. alba, C. decandra, A. corniculatum, and R. apiculata (k = 0.0098 d-1; tM50 = 71 days). The biochemical composition of detrital leaves differed significantly among species and over time. S. caseolaris and A. alba had higher concentrations of N, THAA and THHA and a lower C/N ratio than the other three species. For most of the species concentrations of N, THAA and THHA increased during decomposition. The hexosamine galactosamine, indicative of bacterial cell walls, was first found in leaves after 5-7 days of decomposition and increased afterwards. Our findings suggest an increasing, but species-specific varying, portion of labile nitrogenous OM and total N in decomposing leaves over time that is partly related to the activity of leaf-colonizing bacteria. Despite a higher relative nitrogen content in the

  14. Zinc oxide nanoparticles affect carbon and nitrogen mineralization of Phoenix dactylifera leaf litter in a sandy soil.

    Science.gov (United States)

    Rashid, Muhammad Imtiaz; Shahzad, Tanvir; Shahid, Muhammad; Ismail, Iqbal M I; Shah, Ghulam Mustafa; Almeelbi, Talal

    2017-02-15

    We investigated the impact of zinc oxide nanoparticles (ZnO NPs; 1000mgkg(-1) soil) on soil microbes and their associated soil functions such as date palm (Phoenix dactylifera) leaf litter (5gkg(-1) soil) carbon and nitrogen mineralization in mesocosms containing sandy soil. Nanoparticles application in litter-amended soil significantly decreased the cultivable heterotrophic bacterial and fungal colony forming units (cfu) compared to only litter-amended soil. The decrease in cfu could be related to lower microbial biomass carbon in nanoparticles-litter amended soil. Likewise, ZnO NPs also reduced CO2 emission by 10% in aforementioned treatment but this was higher than control (soil only). Labile Zn was only detected in the microbial biomass of nanoparticles-litter applied soil indicating that microorganisms consumed this element from freely available nutrients in the soil. In this treatment, dissolved organic carbon and mineral nitrogen were 25 and 34% lower respectively compared to litter-amended soil. Such toxic effects of nanoparticles on litter decomposition resulted in 130 and 122% lower carbon and nitrogen mineralization efficiency respectively. Hence, our results entail that ZnO NPs are toxic to soil microbes and affect their function i.e., carbon and nitrogen mineralization of applied litter thus confirming their toxicity to microbial associated soil functions.

  15. Litter decomposition and heavy metal dynamics (Pb, Cd) in leaf and needle litter of forest ecosystems close to urban agglomerations. Streuabbau und Schwermetalldynamik (Pb, Cd) in Blatt- und Nadelstreu in ballungsraumnahen Waldoekosystemen

    Energy Technology Data Exchange (ETDEWEB)

    Kratz, W. (FU Berlin (Germany). AG Bodenzoologie und Oekologie, Inst. fuer Tierphysiologie); Bielitz, K. (FU Berlin (Germany). AG Bodenzoologie und Oekologie, Inst. fuer Tierphysiologie)

    1989-01-01

    Litter containers are used to investigate the decomposition of polluted leaf and needle litter in forest ecosystems close to Berlin (West). Black cherry leaves decomposed faster than hornbeam and oak leaves. After 19 months the black cherry litter lost 85%, hornbeam 58% and oak litter 37% of its biomass. The pine needle litter decomposition ranged between 48 and 51%. In all cases an increase of lead and cadmium content and concentration is remarkable. There was a 3 to 14 fold increase of lead concentration in the forest sites. The cadmium concentration also increased 1.3 to 6.5 fold during litter decomposition. At the edge of a highway a comparison of absolute lead and cadmium litter content from the beginning and end of a period of litter exposure demonstrates a heavy input of lead and cadmium from external sources. (orig.)

  16. Metaproteome analysis of the microbial community during leaf litter decomposition - the impact of stoichiometry and temperature perturbations

    Science.gov (United States)

    Keiblinger, K. M.; Schneider, T.; Leitner, S.; Hämmerle, I.; Riedel, K.; Zechmeister-Boltenstern, S.

    2012-04-01

    Leaf litter decomposition is the breakdown of dead plant material, a terrestrial ecosystem process of paramount importance. Nutrients released during decomposition play a key role for microbial growth and plant productivity. These processes are controlled by abiotic factors, such as climate, and by biotic factors, such as litter nutrient concentration and stoichiometry (carbon:nutrient ratio) and activity of soil organisms. Future climate change scenarios predict temperature perturbations, therefore following changes of microbial community composition and possible feedbacks on ecosystem processes are of key interest; especially as our knowledge about the microbial regulation of these processes is still scarce. Our aim was to elucidate how temperature perturbations and leaf litter stoichiometry affect the composition of the microbial decomposer community. To this end a terrestrial microcosm experiment using beech (Fagus sylvatica) litter with different stoichiometry was conducted. In a semi-quantitative metaproteomics approach (1D-SDS PAGE combined with liquid chromatography and tandem mass spectrometry; unique spectral counting) we used the intrinsic metabolic function of proteins to relate specific microbial activities to their phylogenetic origin in multispecies communities. Decomposer communities varied on litter with different stoichiometry so that microbial decomposers (fungi and bacteria) were favoured in litter with narrow C:nutrient ratios. The fungal community was dominated by Ascomycota (Eurotiomycetes, Sordariomycetes) and Basidiomycota (Agaricomycetes) and the bacterial community was dominated by Proteobacteria, Actinobacteria and Firmicutes. The extracellular enzymes we detected belonged mainly to classes of xylanases, pectinases, cellulases and proteases and were almost exclusively of fungal origin (particularly Ascomycota). Temperature stress (heat and frost) evoked strong changes in community composition, enzyme activities, dissolved organic

  17. Leaf litter copepods from a cloud forest mountain top in Honduras (Copepoda: Cyclopidae, Canthocamptidae).

    Science.gov (United States)

    Fiers, Frank; Jocque, Merlijn

    2013-01-01

    Five different species of Copepoda were extracted from a leaf litter sample collected on the top (at 2000 m a.s.l.) of a cloud forested mountain in El Cusuco National Park, Honduras. Three of them, one Cyclopidae and two Canthocamptidae are new to science, and are described herein. Olmeccyclops hondo sp. nov. is the second representative thus far known of this New World genus. Moraria catracha sp. nov. and Moraria cusuca sp. nov. are the first formally described members of the genus occurring in Central America. The concept of a "Moraria-group" is considered to be an artificial grouping and is limited here to the genera Moraria and Morariopsis only. The distributional range of this group is essentially Holarctic, with the mountainous regions in Honduras, and probably in west Nicaragua, as the southernmost limits in the New World.

  18. The effects of high-tannin leaf litter from transgenic poplars on microbial communities in microcosm soils.

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    Richard S. Winder

    2013-09-01

    Full Text Available The impacts of leaf litter from genetically-modified hybrid poplar accumulating high levels of condensed tannins (proanthocyanidins were examined in soil microcosms consisting of moss growing on sieved soil. Moss preferentially proliferated in microcosms with lower tannin content; DGGE detected increased fungal diversity in microcosms with low-tannin litter. The proportion of cloned rDNA sequences from Actinobacteria decreased with litter addition while Bacteroidetes, Chloroflexi, Cyanobacteria, and α-Proteobacteria significantly increased. β–Proteobacteria were proportionally more numerous at high tannin levels. Tannins had no significant impact on overall diversity of bacterial communities analyzed with various estimators. There was an increased proportion of N-fixing bacteria corresponding to the addition of litter with low tannin levels. The addition of litter increased the proportion of Ascomycota/Basidiomycota. Dothideomycetes, Pucciniomycetes, and Tremellomycetes also increased and Agaricomycetes decreased. Agaricomycetes and Sordariomycetes were significantly more abundant in controls, whereas Pucciniomycetes increased in soil with litter from transformed trees (P = 0.051. Richness estimators and diversity indices revealed no significant difference in the composition of fungal communities; PCoA partitioned the fungal communities into three groups: (i those with higher amounts of added tannin from both transformed and untransformed treatments, (ii those corresponding to soils without litter, and (iii those corresponding to microcosms with litter added from trees transformed only with a β-glucuronidase (GUS control vector. While the litter from transformed poplars had significant effects on soil microbe communities, the observed impacts reflected known impacts on soil processes associated with tannins, and were similar to changes that would be expected from natural variation in tannin levels.

  19. Weighted Decomposition Estimates for Differential Forms

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    Yong Wang

    2010-01-01

    Full Text Available After introducing the definition of Ar,λβ-weights, we establish the Ar(Ω-weighted decomposition estimates and Ar,λβ(Ω-weighted Caccioppoli-type estimates for A-harmonic tensors. Furthermore, by Whitney covering lemma, we obtain the global results in domain Ω⊂Rn. These results can be used to study the integrability of differential forms and to estimate the integrals for differential forms.

  20. Differences in water depth determine leaf-litter decomposition in streams: implications on impact assessment reliability

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    Martínez A.

    2016-01-01

    Full Text Available Leaf-litter decomposition is a widespread functional indicator to assess the stream ecosystem status. However, the spatial location of leaf-bags could distort the impact assessment since intrinsic features of a given site have an important role in the spatial distribution of macroinvertebrates, which could affect decomposition rate. A source of variability that can be easily controlled is the water depth at which bags are incubated in stream bed. Therefore, we tested if water depth within a same mesohabitat (riffles can determine decomposition rates. Due to the seasonal variability of macroinvertebrate assemblages in temperate regions, the study was performed in autumn-winter and spring to test the consistency of the findings. In three streams from North of Spain 15 mesh bags with alder leaves were placed in riffles covering a gradient of depths. Depth had a positive effect on decomposition rates and biomass of associated total invertebrates and shredders in autumn-winter, fauna variables helping to explain the differences in rates. In spring, depth affected negatively rates, the observed variability being weakly explained by invertebrates, which did not show differences along depth. Despite the opposite trend between seasons, water depth influences the decomposition rates, which may reduce or increase differences among systems if the water depth distribution is greatly biased. Our study highlights the importance of covering a similar range of water depths in the different systems being compared.

  1. Leaf litter decomposition of native and introduced tree species of contrasting quality in headwater streams: how does the regional setting matter?

    Science.gov (United States)

    Casas, J Jesús; Larrañaga, Aitor; Menéndez, Margarita; Pozo, Jesús; Basaguren, Ana; Martínez, Aingeru; Pérez, Javier; González, José M; Mollá, Salvador; Casado, Carmen; Descals, Enrique; Roblas, Neftalí; López-González, J Antonio; Valenzuela, J Luis

    2013-08-01

    Terrestrial plant litter is important in sustaining stream food webs in forested headwaters. Leaf litter quality often decreases when native species are replaced by introduced species, and a lower quality of leaf litter inputs may alter litter decomposition at sites afforested with non-native species. However, since detritivore composition and resource use plasticity may depend on the prevalent litter inputs, the extent of the alteration in decomposition can vary between streams. We tested 2 hypotheses using 2 native and 3 introduced species of tree differing in quality in 4 Iberian regions with contrasting vegetational traits: 1) decomposition rates of all plant species would be higher in regions where streams normally receive litter inputs of lower rather than higher quality; 2) a higher resource-use plasticity of detritivores in regions vegetated with plants of lower litter quality will cause a greater evenness in decomposition rates among plant species compared to regions where streams normally receive higher-quality plant litter inputs. Results showed a highly consistent interspecific ranking of decomposition rates across regions driven by litter quality, and a significant regional effect. Hypothesis 1 was supported: decomposition rates of the five litter types were generally higher in streams from regions vegetated with species producing leaf litter of low quality, possibly due to the profusion of caddisfly shredders in their communities. Hypothesis 2 was not supported: the relative differences in decomposition rates among leaf litter species remained essentially unaltered across regions. Our results suggest that, even in regions where detritivores can be comparatively efficient using resources of low quality, caution is needed particularly when afforestation programs introduce plant species of lower litter quality than the native species.

  2. Functional traits drive the contribution of solar radiation to leaf litter decomposition among multiple arid-zone species.

    Science.gov (United States)

    Pan, Xu; Song, Yao-Bin; Liu, Guo-Fang; Hu, Yu-Kun; Ye, Xue-Hua; Cornwell, William K; Prinzing, Andreas; Dong, Ming; Cornelissen, Johannes H C

    2015-08-18

    In arid zones, strong solar radiation has important consequences for ecosystem processes. To better understand carbon and nutrient dynamics, it is important to know the contribution of solar radiation to leaf litter decomposition of different arid-zone species. Here we investigated: (1) whether such contribution varies among plant species at given irradiance regime, (2) whether interspecific variation in such contribution correlates with interspecific variation in the decomposition rate under shade; and (3) whether this correlation can be explained by leaf traits. We conducted a factorial experiment to determine the effects of solar radiation and environmental moisture for the mass loss and the decomposition constant k-values of 13 species litters collected in Northern China. The contribution of solar radiation to leaf litter decomposition varied significantly among species. Solar radiation accelerated decomposition in particular in the species that already decompose quickly under shade. Functional traits, notably specific leaf area, might predict the interspecific variation in that contribution. Our results provide the first empirical evidence for how the effect of solar radiation on decomposition varies among multiple species. Thus, the effect of solar radiation on the carbon flux between biosphere and atmosphere may depend on the species composition of the vegetation.

  3. Sympodial bamboo species differ in carbon bio-sequestration and stocks within phytoliths of leaf litters and living leaves.

    Science.gov (United States)

    Xiang, Tingting; Ying, Yuqi; Teng, Jiangnan; Huang, Zhangting; Wu, Jiasen; Meng, Cifu; Jiang, Peikun; Tang, Caixian; Li, Jianmin; Zheng, Rong

    2016-10-01

    Phytolith-occluded carbon (PhytOC) with high resistance against decomposition is an important carbon (C) sink in many ecosystems. This study compared concentrations of phytolith in plants and the PhytOC production of seven sympodial bamboo species in southern China, aiming to provide the information for the managed bamboo plantation and selection of bamboo species to maximize phytolith C sequestration. Leaf litters and living leaves of seven sympodial bamboo species were collected from the field sites. Concentrations of phytoliths, silicon (Si), and PhytOC in leaf litters and living leaves were measured. Carbon sequestration as PhytOC was estimated. There was a considerable variation in the PhytOC concentrations in the leaf litters and living leaves among the seven bamboo species. The mean concentrations of PhytOC ranged from 3.4 to 6.9 g kg(-1) in leaf litters and from 1.6 to 5.9 g kg(-1) in living leaves, with the PhytOC production rates ranging from 5.7 to 52.3 kg e-CO2 ha(-1) year(-1) as leaf litters. Dendrocalamopsis oldhami (Munro) Keng f. had the highest PhytOC production rate. Based on a bio-sequestration rate of 52.3 kg e-CO2 ha(-1) year(-1), we estimated that the current 8 × 10(5) ha of sympodial bamboo stands in China could potentially acquire 4.2 × 10(4) t e-CO2 yearly via phytolith carbon. Furthermore, the seven sympodial bamboo species stored 5.38 × 10(5) t e-CO2 as PhytOC in living leaves and leaf litters in China. It is concluded that sympodial bamboos make a significant contribution to C sequestration and that to maximize the PhytOC accumulation, the bamboo species with the highest PhytOC production rate should be selected for plantation.

  4. Effects of fungal inocula and habitat conditions on alder and eucalyptus leaf litter decomposition in streams of northern Spain.

    Science.gov (United States)

    Pérez, Javier; Galán, Javier; Descals, Enrique; Pozo, Jesús

    2014-02-01

    We investigated how fungal decomposer (aquatic hyphomycetes) communities colonizing alder and eucalyptus leaf litter respond to changes in habitat characteristics (transplantation experiment). We examined the breakdown of leaf materials and the associated fungal communities at two contrasting sites, a headwater stream (H) and a midreach (M). Agroforestry increased from headwater to midreach. One month after the start of experiments at both sites, some leaf samples from the midreach site were transplanted to the headwater site (M-H treatment). Although both sites showed similar dissolved inorganic nutrient concentrations, eucalyptus leaves initially incubated at the midreach site (M, M-H) increased their breakdown rate compared to those incubated along the experiment at the headwater site (H). Alder breakdown rate was not enhanced, suggesting that their consumption was not limited by nutrient availability. Sporulation rates clearly differed between leaf types (alder > eucalyptus) and streams (H > M), but no transplantation effect was detected. When comparing conidial assemblages after transplantation, an inoculum effect (persistence of early colonizing species) was clear in both leaf species. Substrate preference and shifts in the relative importance of some fungal species along the process were also observed. Overall, our results support the determining role of the initial conditioning phase on the whole litter breakdown process, highlighting the importance of intrinsic leaf characteristics and those of the incubation habitat.

  5. Leaf litter variation influences invasion dynamics in the invasive wetland grass Phalaris arundinacea

    NARCIS (Netherlands)

    Kaproth, M.A.; Eppinga, M.B.; Molofsky, J.

    2013-01-01

    High litter mass is hypothesized to produce an invader-directed invasion by changing ecosystem properties such as nutrient cycling rates and light availability. An invasive plant species that stimulates litter accumulation may induce a positive feedback when it benefits from high litter conditions.

  6. Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition.

    Science.gov (United States)

    Pesce, Stéphane; Zoghlami, Olfa; Margoum, Christelle; Artigas, Joan; Chaumot, Arnaud; Foulquier, Arnaud

    2016-04-01

    Loss of biodiversity and altered ecosystem functioning are driven by the cumulative effects of multiple natural and anthropogenic stressors affecting both quantity and quality of water resources. Here we performed a 40-day laboratory microcosm experiment to assess the individual and combined effects of drought and the model fungicide tebuconazole (TBZ) on leaf litter decomposition (LLD), a fundamental biogeochemical process in freshwater ecosystems. Starting out from a worst-case scenario perspective, leaf-associated microbial communities were exposed to severe drought conditions (four 5-day drought periods alternated with 4-day immersion periods) and/or a chronic exposure to TBZ (nominal concentration of 20μgL(-1)). We assessed the direct effects of drought and fungicide on the structure (biomass, diversity) and activity (extracellular enzymatic potential) of fungal and bacterial assemblages colonizing leaves. We also investigated indirect effects on the feeding rates of the amphipod Gammarus fossarum on leaves previously exposed to drought and/or TBZ contamination. Results indicate a stronger effect of drought stress than fungicide contamination under the experimental conditions applied. Indeed, the drought stress strongly impacted microbial community structure and activities, inhibiting the LLD process and leading to cascading effects on macroinvertebrate feeding. However, despite the lack of significant effect of TBZ applied alone, the effects of drought on microbial functions (i.e., decrease in LLD and in enzymatic activities) and on Gammarus feeding rates were more pronounced when drought and TBZ stresses were applied together. In a perspective of ecological risk assessment and ecosystem management for sustainability, these findings stress the need for deeper insight into how multiple stressors can affect the functioning of aquatic ecosystems and associated services.

  7. Comparison of the chemical alteration trajectory of Liriodendron tulipifera L. leaf litter among forests with different earthworm abundance

    Science.gov (United States)

    Filley, Timothy R.; McCormick, Melissa K.; Crow, Susan E.; Szlavecz, Katalin; Whigham, Dennis F.; Johnston, Cliff T.; van den Heuvel, Ronald N.

    2008-03-01

    To investigate the control of earthworm populations on leaf litter biopolymer decay dynamics, we analyzed the residues of Liriodendron tulipifera L. (tulip poplar) leaves after six months of decay, comparing open surface litter and litter bag experiments among forests with different native and invasive earthworm abundances. Six plots were established in successional tulip poplar forests where sites varied in earthworm density and biomass, roughly 4-10 fold, of nonnative lumbricid species. Analysis of residues by diffuse reflectance Fourier transform infrared spectroscopy and alkaline CuO extraction indicated that open decay in sites with abundant earthworms resulted in residues depleted in cuticular aliphatic and polysaccharide components and enriched in ether-linked lignin relative to open decay in low earthworm abundance plots. Decay within earthworm-excluding litter bags resulted in an increase in aliphatic components relative to initial amendment and similar chemical trajectory to low earthworm open decay experiments. All litter exhibited a decline in cinnamyl-based lignin and an increase in nitrogen content. The influence of earthworm density on the chemical trajectory of litter decay was primarily a manifestation of the physical separation and concentration of lignin-rich and cutin-poor petioles with additional changes promoted by either microorganisms and/or mesofauna resulting in nitrogen addition and polysaccharide loss. These results illustrate how projected increases in invasive earthworm activity in northern North American forests could alter the chemical composition of organic matter in litter residues and potentially organic matter reaching the soil which may result in shifts in the aromatic and aliphatic composition of soils in different systems.

  8. Organic Carbon Accumulation in Topsoil Following Afforestation with Willow: Emphasis on Leaf Litter Decomposition and Soil Organic Matter Quality

    Directory of Open Access Journals (Sweden)

    Benoit Lafleur

    2015-03-01

    Full Text Available Short-rotation intensive cultures (SRICs of willows can potentially sequester carbon (C in soil. However, there is limited information regarding the factors governing soil organic C (Corg accumulation following afforestation. The objectives of this study were to: (i determine whether willow leads to Corg accumulation in the topsoil (0–10 cm two to six years after establishment in five SRICs located along a large climatic/productivity gradient in southern Quebec, and (ii assess the influence of leaf litter decomposition and soil organic matter (OM quality on Corg accumulation in the topsoil. Topsoil Corg concentrations and pools under SRICs were, on average, 25% greater than reference fields, and alkyls concentrations were higher under SRICs. On an annualized basis, Corg accumulation rates in the topsoil varied between 0.4 and 4.5 Mg ha−1 yr−1. Estimated annual litterfall C fluxes were in the same order of magnitude, suggesting that SRICs can accumulate Corg in the topsoil during early years due to high growth rates. Leaf litter decomposition was also related to Corg accumulation rates in the topsoil. It was positively correlated to growing season length, degree-days, and growing season average air and topsoil temperature (r > 0.70, and negatively correlated to topsoil volumetric water content (r = −0.55. Leaf litter decomposition likely occurred more quickly than that of plants in reference fields, and as it progressed, OM became more decay resistant, more stable and accumulated as Corg in the topsoil.

  9. Aquatic hyphomycete communities associated with decomposing alder leaf litter in reference headwater streams of the Basque Country (northern Spain).

    Science.gov (United States)

    Pérez, Javier; Descals, Enrique; Pozo, Jesús

    2012-08-01

    The community of aquatic hyphomycetes associated with decomposing alder leaf litter was studied during autumn-winter in nine headwater reference streams of the Basque Country (northern Spain). In order to study the spatial variability in composition and community structure, three streams from each of three different river basins were compared. The colonization dynamics and community changes throughout the decomposition process were also followed in three of the rivers (one per basin). The taxonomic richness and community structure of these fungi varied among rivers, including similar streams of a given watershed. However, neither species diversity nor total abundance was statistically related to environmental variables. Only the conidial production of two of the species, Flagellospora curvula and Lunulospora curvula appeared to be enhanced by nitrate availability in the water. The taxonomic richness and the reproductive activity (sporulation rate) were positively related to the leaf litter decomposition rate. The changes in conidial production along the process were similar for all the streams and helped explain leaf litter quality dynamics.

  10. Characterization saprobic fungi on leaf litter of two species of trees in the Atlantic Forest, Brazil

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    Loise Araujo Costa

    2015-01-01

    Full Text Available AbstractWe investigated the composition and structure of fungal communities associated with leaf litter generated by Clusia nemorosa and Vismia guianensis that belong to phylogenetically-related botanical families and exist together in a remnant of the Atlantic Forest in Bahia, Brazil. Samplings were conducted during wet (June 2011 and dry (January 2013 seasons in Serra da Jibóia. The fungi were isolated using particle filtration and the 1,832 isolates represented 92 taxa. The wet season yielded the largest number of isolates (1,141 and taxa (76 compared with the dry season (641 isolates and 37 taxa. The richness and diversity of fungal species associated with C. nemorosa (64 taxa, Simpson=0.95were higher compared with those of V.guianensis (59 taxa, Simpson =0.90. Analysis of similarity (ANOSIM revealed significant variations in the composition and community structure of fungi isolated from the two plants as a function of seasons. In contrast, nonmetric multidimensional scaling (NMDS analysis show that the seasonality was an important influence on the distribution of fungal species. However, the populations of the saprobic fungal communities were dynamic, and several factors may influence such communities in the Atlantic Forest.

  11. New leaf- and litter-dwelling species of the genus Pholcus from Southeast Asia (Araneae, Pholcidae

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    Bernhard Huber

    2016-05-01

    Full Text Available We describe eight new species of the genus Pholcus, and document their microhabitats. Four species are assigned to the previously described Pholcus ethagala group: P. tanahrata Huber sp. nov., P. uludong Huber sp. nov., and P. bukittimah Huber sp. nov. from the Malay Peninsula, and P. barisan Huber sp. nov. from Sumatra. These species are all litter-dwellers that build domed sheet webs on the undersides of large dead leaves on the ground. The other four species are assigned to newly created species groups: the P. tambunan group with two species from northern Borneo: P. tambunan Huber sp. nov. and P. bario Huber sp. nov.; and the P. domingo group with two species from the Philippines, Mindanao: P. domingo Huber sp. nov. and P. matutum Huber sp. nov. These latter four species are leaf-dwellers that build barely visible silk platforms tightly attached to the undersides of live leaves. The main rationale for this paper is to provide part of the taxonomic and natural history background for upcoming phylogenetic and evolutionary (microhabitat shifts analyses.

  12. Evidence for an intrinsic factor promoting landscape divergence in Madagascan leaf-litter frogs

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    Katharina C. Wollenberg Valero

    2015-05-01

    Full Text Available The endemic Malagasy frog radiations are an ideal model system to study patterns and processes of speciation in amphibians. Large-scale diversity patterns of these frogs, together with other endemic animal radiations, led to the postulation of new and the application of known hypotheses of species diversification causing diversity patterns in this biodiversity hotspot. Both extrinsic and intrinsic factors have been studied in a comparative framework, with extrinsic factors usually being related to the physical environment (landscape, climate, river catchments, mountain chains, and intrinsic factors being clade-specific traits or constraints (reproduction, ecology, morphology, physiology. Despite some general patterns emerging from such large-scale comparative analyses, it became clear that the mechanism of diversification in Madagascar may vary among clades, and may be a multifactorial process. In this contribution, I test for intrinsic factors promoting population-level divergence within a clade of terrestrial, diurnal leaf-litter frogs (genus Gephyromantis that has previously been shown to diversify according to extrinsic factors. Landscape genetic analyses of the microendemic species G. enki and its widely distributed, larger sister species G. boulengeri over a rugged landscape in the Ranomafana area shows that genetic variance of the smaller species cannot be explained by landscape resistance alone. Both topographic and riverine barriers are found to be important in generating this divergence. This case study yields additional evidence for the probable importance of body size in lineage diversification.

  13. Evidence for an intrinsic factor promoting landscape genetic divergence in Madagascan leaf-litter frogs.

    Science.gov (United States)

    Wollenberg Valero, Katharina C

    2015-01-01

    The endemic Malagasy frog radiations are an ideal model system to study patterns and processes of speciation in amphibians. Large-scale diversity patterns of these frogs, together with other endemic animal radiations, led to the postulation of new and the application of known hypotheses of species diversification causing diversity patterns in this biodiversity hotspot. Both extrinsic and intrinsic factors have been studied in a comparative framework, with extrinsic factors usually being related to the physical environment (landscape, climate, river catchments, mountain chains), and intrinsic factors being clade-specific traits or constraints (reproduction, ecology, morphology, physiology). Despite some general patterns emerging from such large-scale comparative analyses, it became clear that the mechanism of diversification in Madagascar may vary among clades, and may be a multifactorial process. In this contribution, I test for intrinsic factors promoting population-level divergence within a clade of terrestrial, diurnal leaf-litter frogs (genus Gephyromantis) that has previously been shown to diversify according to extrinsic factors. Landscape genetic analyses of the microendemic species Gephyromantis enki and its widely distributed, larger sister species Gephyromantis boulengeri over a rugged landscape in the Ranomafana area shows that genetic variance of the smaller species cannot be explained by landscape resistance alone. Both topographic and riverine barriers are found to be important in generating this divergence. This case study yields additional evidence for the probable importance of body size in lineage diversification.

  14. Creating 13C- and 15N-enriched tree leaf litter for decomposition experiments

    Science.gov (United States)

    Szlavecz, K. A.; Pitz, S.; Chang, C.; Bernard, M.

    2013-12-01

    Labeling plant material with heavy isotopes of carbon and nitrogen can produce a traceable nutrient signal that can be followed into the different trophic levels and decomposer food web. We treated 60 tree saplings with 13C-enriched CO2 gas and 15N-enriched ammonium nitrate over a three-month period to create dually-labeled plant material for future decomposition experiments. The trees included both early (Red maple, Sweetgum, Tulip poplar) and late (American beech, White oak) successional deciduous tree species, and a conifer, White pine. We constructed a 2.4 m × 2.4 m × 2.4 m environmental chamber that was climate-controlled using an air conditioning system. An Arduino microcontroller interfaced with a Vaisala GMP343 CO2 probe maintained a CO2 concentration between 500-520 ppm by controlling a solenoid valve on the CO2 tank regulator. The trees were placed into the chamber in August 2012 and remained until senescence unless they were lost to death or disease. Ammonium nitrate was added twice, in September and October. Leaf samples were collected prior to the start of the experiment and after senescence, whereas root samples were collected only in December. Samples were dried, ground and analyzed using an isotope ratio mass spectrometer. American beech and White oak had 40% mortality, and 34% of tulip poplar trees were removed because of powdery mildew overgrowth or death. Most tulip poplar trees exhibited a second leaf out following senescence in late September. Nearly 1 kg of litter was produced with tulip poplar representing over half of the total mass. Levels of enrichment varied greatly by species. Beech (-14.2‰) and White oak (-4.8‰) had low levels of enrichment in comparison to early successional species such as Sweetgum (41.7‰) and Tulip poplar (30.7‰ [first leaf fall] and 238.0‰ [second leaf fall]). Leaf enrichment with 15N followed a similar pattern, though it was achieved at a higher level with δ15N values varying from 271.6‰ to 1354.2

  15. Leaf litter decomposition of four different deciduous tree species - resource stoichiometry, nutrient release and microbial community composition

    Science.gov (United States)

    Leitner, S.; Keiblinger, K. M.; Zechmeister-Boltenstern, S.

    2012-04-01

    Recently, there has been increasing interest in the role of microbial communities for ecosystem processes like litter decomposition and nutrient cycling. For example, fungi are thought to be key players during litter decomposition in terrestrial ecosystems because they are able to degrade recalcitrant compounds like lignin and also dominate the decomposition of cellulose and hemicellulose, whereas bacteria seem to play an important role for lignin decomposition especially under anaerobic conditions. However, our knowledge about the contribution of bacteria and fungi to decomposition is still scarce. The aim of the present study was to elucidate how the microbial decomposer community is affected by resource stoichiometry and how changes in community composition affect litter decomposition and nutrient cycling. To this end, we collected leaf litter of four deciduous tree species (beech (Fagus), oak (Quercus), alder (Alnus) and ash tree (Fraxinus)) at four different seasons (winter, spring, summer and autumn) in an Austrian forest (Schottenwald, 48°14'N16°15'E; MAT=9°C; soil type: dystric cambiosol; soil C:N=16) in 2010. We determined litter nutrient content (micro- and macronutrients) and extractable nutrients and assessed the microbial community by PFLA analysis to test the following hypotheses: (i) tree species affects microbial community composition, (ii) microbial community composition changes over the course of the year, and (iii) narrow litter C:nutrient ratios favour nutrient release. Our data show that litter of different tree species varied in their stoichiometry, with C:N ratios between 16 (alder) and 46 (beech) and C:P ratios between 309 (ash) and 1234 (alder). Tree species had a significant impact on microbial community composition: highest amounts of actinomycetes and protozoa were observed for alder, while arbuscular mycorrhizae were lowest for oak. Bacteria were favoured by litter with narrow C:N shortly after litterfall. During litter decomposition

  16. Fate of Bacillus thuringiensis subsp. israelensis in the Field: Evidence for Spore Recycling and Differential Persistence of Toxins in Leaf Litter

    Science.gov (United States)

    Alessi, Mattia; Veyrenc, Sylvie; Périgon, Sophie; David, Jean-Philippe; Reynaud, Stéphane; Després, Laurence

    2012-01-01

    Bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. Despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of B. thuringiensis subsp. israelensis can occur under specific, unknown conditions. Decaying leaf litters sampled in mosquito breeding sites in the French Rhône-Alpes region several months after a treatment were shown to exhibit a high level of larval toxicity and contained large amounts of spores. In the present article, we show that the high concentration of toxins found in these litters is consistent with spore recycling in the field, which gave rise to the production of new crystal toxins. Furthermore, in these toxic leaf litter samples, Cry4Aa and Cry4Ba toxins became the major toxins instead of Cyt1Aa in the commercial mixture. In a microcosm experiment performed in the laboratory, we also demonstrated that the toxins, when added in their crystal form to nontoxic leaf litter, exhibited patterns of differential persistence consistent with the proportions of toxins observed in the field-collected toxic leaf litter samples (Cry4 > Cry11 > Cyt). These results give strong evidence that B. thuringiensis subsp. israelensis recycled in specific breeding sites containing leaf litters, and one would be justified in asking whether mosquitoes can become resistant when exposed to field-persistent B. thuringiensis subsp. israelensis for several generations. PMID:23001669

  17. Fate of Bacillus thuringiensis subsp. israelensis in the field: evidence for spore recycling and differential persistence of toxins in leaf litter.

    Science.gov (United States)

    Tetreau, Guillaume; Alessi, Mattia; Veyrenc, Sylvie; Périgon, Sophie; David, Jean-Philippe; Reynaud, Stéphane; Després, Laurence

    2012-12-01

    Bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. Despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of B. thuringiensis subsp. israelensis can occur under specific, unknown conditions. Decaying leaf litters sampled in mosquito breeding sites in the French Rhône-Alpes region several months after a treatment were shown to exhibit a high level of larval toxicity and contained large amounts of spores. In the present article, we show that the high concentration of toxins found in these litters is consistent with spore recycling in the field, which gave rise to the production of new crystal toxins. Furthermore, in these toxic leaf litter samples, Cry4Aa and Cry4Ba toxins became the major toxins instead of Cyt1Aa in the commercial mixture. In a microcosm experiment performed in the laboratory, we also demonstrated that the toxins, when added in their crystal form to nontoxic leaf litter, exhibited patterns of differential persistence consistent with the proportions of toxins observed in the field-collected toxic leaf litter samples (Cry4 > Cry11 > Cyt). These results give strong evidence that B. thuringiensis subsp. israelensis recycled in specific breeding sites containing leaf litters, and one would be justified in asking whether mosquitoes can become resistant when exposed to field-persistent B. thuringiensis subsp. israelensis for several generations.

  18. Allellopathic Impacts of Leaf Litters Decomposition from Intercrop Tree Species on Soybean

    OpenAIRE

    Xiaoxi Zhang; Zengwen Liu; Nan Tian; Kehao Chen; Nhu Trung Luc

    2015-01-01

    Foliar litters from 5 commonly planted intercorpped trees were collected and decayed within soil of local farm. These soil samples containing different amount of decomposed litters were then used as culture medium for a germination and seedlings growth testing of soybean. The allelopathic effects of intercropped trees on soybean were assessed. The results indicated that Eucommia ulmoides, Paulownia fortunei and Acer truncatum litters showed promotional effects at relative low concentration (7...

  19. Dynamics of leaf litter humidity, depth and quantity: two restoration strategies failed to mimic ground microhabitat conditions of a low montane and premontane forest in Costa Rica.

    Science.gov (United States)

    Barrientos, Zaidett

    2012-09-01

    Little is known about how restoration strategies affect aspects like leaf litter's quantity, depth and humidity. I analyzed leaf litter's quantity, depth and humidity yearly patterns in a primary tropical lower montane wet forest and two restored areas: a 15 year old secondary forest (unassisted restoration) and a 40 year old Cupressus lusitanica plantation (natural understory). The three habitats are located in the Rio Macho Forest Reserve, Costa Rica. Twenty litter samples were taken every three months (April 2009-April 2010) in each habitat; humidity was measured in 439g samples (average), depth and quantity were measured in five points inside 50x50cm plots. None of the restoration strategies reproduced the primary forest leaf litter humidity, depth and quantity yearly patterns. Primary forest leaf litter humidity was higher and more stable (mean=73.2), followed by secondary forest (mean=63.3) and cypress plantation (mean=52.9) (Kruskall-Wallis=77.93, n=232, p=0.00). In the primary (Kruskal-Wallis=31.63, n=78, p<0.001) and secondary (Kruskal-Wallis=11.79, n=75, p=0.008) forest litter accumulation was higher during April due to strong winds. In the primary forest (Kruskal-wallis=21.83, n=78, p<0.001) and the cypress plantation (Kruskal-wallis=39.99, n=80, p<0.001) leaf litter depth was shallow in October because heavy rains compacted it. Depth patterns were different from quantity patterns and described the leaf litter's structure in different ecosystems though the year. September 01.

  20. The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests.

    Science.gov (United States)

    Salinas, N; Malhi, Y; Meir, P; Silman, M; Roman Cuesta, R; Huaman, J; Salinas, D; Huaman, V; Gibaja, A; Mamani, M; Farfan, F

    2011-03-01

    • We present the results from a litter translocation experiment along a 2800-m elevation gradient in Peruvian tropical forests. The understanding of the environmental factors controlling litter decomposition is important in the description of the carbon and nutrient cycles of tropical ecosystems, and in predicting their response to long-term increases in temperature. • Samples of litter from 15 species were transplanted across all five sites in the study, and decomposition was tracked over 448 d. • Species' type had a large influence on the decomposition rate (k), most probably through its influence on leaf quality and morphology. When samples were pooled across species and elevations, soil temperature explained 95% of the variation in the decomposition rate, but no direct relationship was observed with either soil moisture or rainfall. The sensitivity of the decay rate to temperature (κ(T)) varied seven-fold across species, between 0.024 and 0.169 °C⁻¹, with a mean value of 0.118 ± 0.009 °C⁻¹ (SE). This is equivalent to a temperature sensitivity parameter (Q₁₀) for litter decay of 3.06 ± 0.28, higher than that frequently assumed for heterotrophic processes. • Our results suggest that the warming of approx. 0.9 °C experienced in the region in recent decades may have increased decomposition and nutrient mineralization rates by c. 10%.

  1. Effects of copper on production of periphyton, nitrogen fixation and processing of leaf litter in a Sierra Nevada, California, stream

    Energy Technology Data Exchange (ETDEWEB)

    Leland, H.V.; Carter, J.L.

    1985-04-01

    The production of periphyton, nitrogen fixation and processing of leaf litter were examined in an oligotrophic Sierra Nevada stream and the responses of these processes to copper (2.5, 5 and 10..mu..g l/sup -1/ Cu/sub T/ (total filterable copper); approximately 12, 25 and 50 ng l/sup -1/ Cu/sup 2 +/) were determined. The specific rate of photosynthesis (mg C mg chlorophyll a/sup -1/ h/sup -1/) of mature periphyton communities declined at all test concentrations of copper, but the rate for periphyton on newly-colonized surfaces did not change. The species composition of benthic algae shifted during exposure to an assemblage more tolerant of copper. Achnanthes minutissima and Fragilaria crotonensis were the primary replacement species on newly-colonized surfaces. The nitrogenase activity of blue-green algae was low, with controls ranging from 2.4 to 12 mnol C/sub 2/H/sub 2/ m/sup -2/ h/sup -1/. Nitrogenase activity was inhibited during the initial weeks of exposure by 5 and 10 ..mu..g l/sup -1/ Cu/sub T/. However, after 9 months of exposure, control and copper-treated sections did not differ. The rate of processing of leaf litter, estimated by microbial respiration and nutrient quality of litter of resident riparian woodland taxa, was inhibited at all test concentrations of copper.

  2. Nutrient dynamics associated with leaf litter decomposition of three agroforestry tree species (Azadirachta indica, Dalbergia sissoo, and Melia azedarach) of Bangladesh

    Institute of Scientific and Technical Information of China (English)

    Mahmood Hossain; Mohammad Raqibul Hasan Siddique; Md. Saidur Rahman; Md. Zaber Hossain; Md. Mahedi Hasan

    2011-01-01

    Azadirachta indica A.Juss,Dalbergia sissoo Roxb.,and Melia azedarach L.are little studied species in nutrient return capabilities from leaf litter decomposition to maintenance of the soil fertility despite their importance in agroforestry practices of Bangladesh.A leaf litter decomposition experiment was conducted using a litterbag technique to assess the nutrient return efficiency of these species.The decomposition rate of leaf liter was highest for M.azedarach and lowest for D.sissoo.Rainfall and temperature of study sites showed a significant (p<0.05) positive relationship with the rate of leaf litter decomposition.The highest decay constant was observed for M.azedarach (6.67).Nitrogen and Phosphorus concentration in leaf litter showed a decreased trend sharply at the end of the first month,whereas rapid decrease of Potassium concentration was reported within 10 days.Conversely,higher concentration of nutrient was observed at the later stages of decomposition.All three species showed a similar pattern of nutrient release (K > N> P) during the decomposition process of leaf litter.Among the studied species,D.sissoo was best in terms of N and P return and A.indica was best in terms of K return.

  3. Dynamics of the leaf-litter arthropod fauna following fire in a neotropical woodland savanna.

    Directory of Open Access Journals (Sweden)

    Heraldo L Vasconcelos

    Full Text Available Fire is an important agent of disturbance in tropical savannas, but relatively few studies have analyzed how soil-and-litter dwelling arthropods respond to fire disturbance despite the critical role these organisms play in nutrient cycling and other biogeochemical processes. Following the incursion of a fire into a woodland savanna ecological reserve in Central Brazil, we monitored the dynamics of litter-arthropod populations for nearly two years in one burned and one unburned area of the reserve. We also performed a reciprocal transplant experiment to determine the effects of fire and litter type on the dynamics of litter colonization by arthropods. Overall arthropod abundance, the abundance of individual taxa, the richness of taxonomic groups, and the species richness of individual taxa (Formiciade were lower in the burned site. However, both the ordinal-level composition of the litter arthropod fauna and the species-level composition of the litter ant fauna were not dramatically different in the burned and unburned sites. There is evidence that seasonality of rainfall interacts with fire, as differences in arthropod abundance and diversity were more pronounced in the dry than in the wet season. For many taxa the differences in abundance between burned and unburned sites were maintained even when controlling for litter availability and quality. In contrast, differences in abundance for Collembola, Formicidae, and Thysanoptera were only detected in the unmanipulated samples, which had a lower amount of litter in the burned than in the unburned site throughout most of our study period. Together these results suggest that arthropod density declines in fire-disturbed areas as a result of direct mortality, diminished resources (i.e., reduced litter cover and less favorable microclimate (i.e., increased litter desiccation due to reduction in tree cover. Although these effects were transitory, there is evidence that the increasingly prevalent fire

  4. Fungal diversity of Norway spruce litter: effects of site conditions and premature leaf fall caused by bark beetle outbreak.

    Science.gov (United States)

    Przybył, K; Karolewski, P; Oleksyn, J; Labedzki, A; Reich, P B

    2008-08-01

    Fungi play an important role in leaf litter decomposition due to their ability to break down the lignocellulose matrix, which other organisms are unable to digest. However, little is known regarding the factors affecting components of fungal diversity. Here, we quantified richness of internal fungi in relation to litter nutrient and phenolic concentrations, sampling season (spring or fall), and premature leaf shedding due to low precipitation and infestation of bark beetles (mainly Ips typographus and Ips duplicatus). The study was conducted in 37-year-old Norway spruce [Picea abies (L.) Karst.] stands, with three plots each in mixed forest (MF) and coniferous forest (CF) site conditions in south-central Poland. Fifty-four species of sporulating fungi were identified in 2,330 freshly fallen needles sampled during 2003-2005, including 45 species in MF and 31 in CF. The significantly higher number of species in MF was likely related to moister conditions at that site. Among isolated fungi, 22% (12 species) were identified as endophytes of Norway spruce in prior studies. During spring of 2005, we found less than half the number of isolates and fungal species at each forest site as compared to fall for the two prior years. This pattern was observed in typical soil fungi (e.g., Penicillium daleae, Penicillium purpurogenum) and endophytes/epiphytes (e.g., Aureobasidium pullulans, Alternaria alternata, Cladosporium spp., and Lophodermium piceae). Premature shedding of needles was the most likely cause of this decline because it shortened the time period for fungi to infect green needles while on the tree. For all sites and sampling periods, richness of internal fungi was strongly and positively related to the age of freshly fallen litter (assessed using needle Ca concentration as a needle age tracer) and was also negatively related to litter phenolic concentration. Richness of internal fungi in freshly fallen litter may be adversely affected by low soil moisture status

  5. Colonization of leaf litter of two aquatic macrophytes, Mayaca fluviatilis Aublet and Salvinia auriculata Aublet by aquatic macroinvertebrates in a tropical reservoir

    OpenAIRE

    Marcia Cristina de Paula; Alaide Aparecida Fonseca-Gessner; Fabio Laurindo da Silva; Heliana Rosely Neves Oliveira; Suzana Cunha Escarpinati

    2011-01-01

    Decomposition and colonization of S. auriculata and M. fluviatilis by macroinvertebrates were analyzed during 40 days to determine whether differences existed on colonization by aquatic macroinvertebrates of two macrophytes with distinct habits (submerged versus fluctuant). Leaf litter of S. auriculata and M. fluviatilis were incubated in 24 litter bags (12 of each species), in a small reservoir surrounded by a cerrado fragment with low level of anthropic impact. After 10, 20, 30 and 40 days,...

  6. Allellopathic Impacts of Leaf Litters Decomposition from Intercrop Tree Species on Soybean

    Directory of Open Access Journals (Sweden)

    Xiaoxi Zhang

    2015-04-01

    Full Text Available Foliar litters from 5 commonly planted intercorpped trees were collected and decayed within soil of local farm. These soil samples containing different amount of decomposed litters were then used as culture medium for a germination and seedlings growth testing of soybean. The allelopathic effects of intercropped trees on soybean were assessed. The results indicated that Eucommia ulmoides, Paulownia fortunei and Acer truncatum litters showed promotional effects at relative low concentration (75-150 g litters decomposed in 6.5 kg soil, that is 75-150 g/pot, but inhibitory effects at high concentration (300 g/pot, thus these trees should be planted with soybean with a low intercrop proportion. Populus canadensis litters showed promotional effects at low and high concentration (75 or 300 g/pot, but inhibitory effects at moderate concentration (150 g/pot and this tree should be planted with a moderate intercrop proportion. Zanthoxylum bungeanum litters exhibited promoting effects at all concentrations, thus this tree was recommened to be planted with soybean with any tested intercrop proportion.

  7. Effects of invasive European bird cherry (Prunus padus) on leaf litter processing by aquatic invertebrate shredder communities in urban Alaskan streams

    Science.gov (United States)

    Roon, David A.; Wipfli, Mark S.; Wurtz, Tricia L.

    2014-01-01

    European bird cherry (Prunus padus) (EBC) is an invasive ornamental tree that is spreading rapidly in riparian forests of urban Alaska. To determine how the spread of EBC affects leaf litter processing by aquatic invertebrate shredders, we conducted complementary leaf pack experiments in two streams located in Anchorage, Alaska. The first experiment contrasted invasive EBC with three native tree species—thin-leaf alder (Alnus tenuifolia), paper birch (Betula neoalaskana), and black cottonwood (Populus trichocarpa)—in one reach of Chester Creek; finding that EBC leaf litter broke down significantly faster than birch and cottonwood, but at a similar rate to alder. The second experiment contrasted EBC with alder in four reaches of Campbell and Chester creeks; finding that while EBC leaf litter broke down significantly faster than alder in Chester Creek, EBC broke down at a similar rate to alder in Campbell Creek. Although EBC sometimes supported fewer shredders by both count and mass, shredder communities did not differ significantly between EBC and native plants. Collectively, these data suggest that invasive EBC is not currently exhibiting strong negative impacts on leaf litter processing in these streams, but could if it continues to spread and further displaces native species over time.

  8. Comparison Between Ground Ant (Hymenoptera: Formicidae) Communities Foraging in the Straw Mulch of Sugarcane Crops and in the Leaf Litter of Neighboring Forests.

    Science.gov (United States)

    Silva, N S; Saad, L P; Souza-Campana, D R; Bueno, O C; Morini, M S C

    2017-02-01

    In many sugarcane plantations in Brazil, the straw is left on the soil after harvesting, and vinasse, a by-product of the production of sugar and ethanol, is used for fertigation. Our goal was to compare ant community composition and species richness in the straw mulch of sugarcane crops with the leaf litter of neighboring forests. We tested the hypothesis that ant communities in the straw mulch of vinasse-irrigated sugarcane crops and in the forest leaf litter were similar, because the combination of straw mulching and vinasse irrigation has a positive effect on soil fauna. Straw mulch and leaf litter were collected from 21 sites and placed in Berlese funnels. In total, 61 species were found in the forest leaf litter, whereas 34 and 28 species were found in the straw mulch of sugarcane fields with and without vinasse, respectively. Ant communities differed between forest and crop fields, but the species in the sugarcane straw mulch were a subset of the species found in the forest leaf litter. Although vinasse is rich in organic matter, it did not increase ant diversity. Seven feeding and/or foraging types were identified and, among the different types, surface-foraging omnivorous ants were the most prevalent in all habitats. Vinasse-irrigated sugarcane straw mulch had more predatory species than mulch from vinasse-free fields, but fewer than forest leaf litter. However, this positive effect of vinasse irrigation should be carefully evaluated because vinasse has negative effects on the environment. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Effects of decaying leaf litter and inorganic fertilizer on growth and development of maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Chukwuka Kanayo S.

    2014-01-01

    Full Text Available The effects of decaying leaf litter of Tithonia diversifolia and Vernonia amygdalina as organic fertilizer, inorganic fertilizer (NPK 15-15-15 and their combination effects on the growth and development of maize were studied in a screen house. Twenty-four experimental bags filled with 20 kg of loamy soil were laid out in a completely randomized design with six treatments and four replications for each treatment which included: 250 g of decaying leaves of T. diversifolia as mulch (T1, 250 g of decaying leaves of V. amygdalina (T2, 1.52 g of NPK (inorganic fertilizer (T3, a mixture of 250 g of decaying leaves of T. diversifolia and 1.52 g of NPK 15-15-15 fertilizer (T4, a mixture of V. amygdalina and 1.52 g of NPK 15-15-15 fertilizer (T5 and control (T6. The significant growth as well as maize yields were obtained from T3 treated maize seedlings, and this was closely followed by T4 treated seedlings. The study showed that the decaying leaf litter as an organic fertilizer in maize production in a screen house conditions did not give better yield than NPK treatment alone.

  10. Effect of temperature and moisture on the mineralization and humification of leaf litter in a model incubation experiment

    Science.gov (United States)

    Larionova, A. A.; Maltseva, A. N.; Lopes de Gerenyu, V. O.; Kvitkina, A. K.; Bykhovets, S. S.; Zolotareva, B. N.; Kudeyarov, V. N.

    2017-04-01

    The mineralization and humification of leaf litter collected in a mixed forest of the Prioksko-Terrasny Reserve depending on temperature (2, 12, and 22°C) and moisture (15, 30, 70, 100, and 150% of water holding capacity ( WHC)) has been studied in long-term incubation experiments. Mineralization is the most sensitive to temperature changes at the early stage of decomposition; the Q 10 value at the beginning of the experiment (1.5-2.7) is higher than at the later decomposition stages (0.3-1.3). Carbon losses usually exceed nitrogen losses during decomposition. Intensive nitrogen losses are observed only at the high temperature and moisture of litter (22°C and 100% WHC). Humification determined from the accumulation of humic substances in the end of incubation decreases from 34 to 9% with increasing moisture and temperature. The degree of humification CHA/CFA is maximum (1.14) at 12°C and 15% WHC; therefore, these temperature and moisture conditions are considered optimal for humification. Humification calculated from the limit value of litter mineralization is almost independent of temperature, but it significantly decreases from 70 to 3% with increasing moisture. A possible reason for the difference between the humification values measured by two methods is the conservation of a significant part of hemicelluloses, cellulose, and lignin during the transformation of litter and the formation of a complex of humic substances with plant residues, where HSs fulfill a protectoral role and decrease the decomposition rate of plant biopolymers.

  11. Factors affecting the abundance of leaf-litter arthropods in unburned and thrice-burned seasonally-dry Amazonian forests.

    Directory of Open Access Journals (Sweden)

    Juliana M Silveira

    Full Text Available Fire is frequently used as a land management tool for cattle ranching and annual crops in the Amazon. However, these maintenance fires often escape into surrounding forests, with potentially severe impacts for forest biodiversity. We examined the effect of experimental fires on leaf-litter arthropod abundance in a seasonally-dry forest in the Brazilian Amazon. The study plots (50 ha each included a thrice-burned forest and an unburned control forest. Pitfall-trap samples were collected at 160 randomly selected points in both plots, with sampling stratified across four intra-annual replicates across the dry and wet seasons, corresponding to 6, 8, 10 and 12 months after the most recent fire. Arthropods were identified to the level of order (separating Formicidae. In order to better understand the processes that determine arthropod abundance in thrice-burned forests, we measured canopy openness, understory density and litter depth. All arthropod taxa were significantly affected by fire and season. In addition, the interactions between burn treatment and season were highly significant for all taxa but Isoptera. The burned plot was characterized by a more open canopy, lower understory density and shallower litter depth. Hierarchical partitioning revealed that canopy openness was the most important factor explaining arthropod order abundances in the thrice-burned plot, whereas all three environmental variables were significant in the unburned control plot. These results reveal the marked impact of recurrent wildfires and seasonality on litter arthropods in this transitional forest, and demonstrate the overwhelming importance of canopy-openness in driving post-fire arthropod abundance.

  12. Effect of climate-related change in vegetation on leaf litter consumption and energy storage by Gammarus pulex from Continental or Mediterranean populations.

    Directory of Open Access Journals (Sweden)

    Natacha Foucreau

    Full Text Available As a consequence of global warming, it is important to characterise the potential changes occurring for some functional processes through the intra-specific study of key species. Changes in species distribution, particularly when key or engineer species are affected, should contribute to global changes in ecosystem functioning. In this study, we examined the potential consequences induced by global warming on ecosystem functioning in term of organic matter recycling. We compared consumption of leaf litter by some shredder populations (Gammarus pulex between five tree species inhabiting continental (i.e., the northern region of the Rhône River Valley and/or Mediterranean (i.e., the southern region of the Rhône River Valley conditions. To consider any potential adaptation of the gammarid population to vegetation in the same climate conditions, three populations of the key shredder Gammarus pulex from the northern region and three from the southern region of the Rhône River Valley were used. We experimentally compared the effects of the geographical origin of both the gammarid populations and the leaf litter species on the shredding activity and the physiological state of animals (through body triglyceride content. This study demonstrated that leaf toughness is more important than geographical origin for determining shredder leaf litter consumption. The overall consumption rate of the gammarid populations from the southern region of Rhône Valley was much higher than that of the populations from the northern region, but no clear differences between the origins of the leaf litter (i.e., continental vs. Mediterranean were observed. The northwards shift of G. pulex populations adapted to warmer conditions might significantly modify organic matter recycling in continental streams. As gammarid populations can demonstrate local adaptations to certain leaf species as a trophic resource, changes in riparian vegetation associated with climate change

  13. Molecular diversity of myxomycetes associated with decaying wood and forest floor leaf litter.

    Science.gov (United States)

    Ko, Thida Win Ko; Stephenson, Steven L; Jeewon, Rajesh; Lumyong, Saisamorn; Hyde, Kevin D

    2009-01-01

    Denaturing gradient gel electrophoresis (DGGE) fingerprinting was used to assess the molecular diversity of myxomycetes from environmental samples (decaying wood and forest floor litter) collected at the Mushroom Research Centre in northern Thailand. Total genomic DNA was extracted directly from environmental samples on which myxomycetes were not apparent. Part of the small subunit ribosomal RNA gene (SSU rDNA) was amplified and DNA sequences analyzed. DGGE gels revealed up to 17 operational taxonomic units (OTU) from decaying wood and 10 OTU from forest floor litter samples, but only seven (wood) and six (litter) OTU could be re-amplified and/or sequenced. Based on results obtained with the BLAST analysis program, the species involved appeared to correspond most closely to Diderma saundersii, Didymium iridis, Stemonitis flavogenita and Hyperamoeba sp. strain W2i on decaying wood and to Diderma saundersii and Physarum didermoides on forest floor litter. Our results suggest that then PCR-DGGE can be used to obtain data on the presence of myxomycetes in their primary microhabitats without the need to observe the sporocarps of these organisms. As such the technique would seem to have considerable potential for contributing to a more complete understanding of myxomycete diversity and ecology in terrestrial ecosystems.

  14. Leaf litter is an important mediator of soil respiration in an oak-dominated forest

    Science.gov (United States)

    Jared L. DeForest; Jiquan Chen; Steve G. McNulty

    2009-01-01

    The contribution of the organic (O) horizon to total soil respiration is poorly understood even though it can represent a large source of uncertainty due to seasonal changes in microclimate and O horizon properties due to plant phenology. Our objectives were to partition the CO2 effluxes of litter layer and mineral soil from total soil...

  15. Changes in the structural composition and reactivity of Acer rubrum leaf litter tannins exposed to warming and altered precipitation: climatic stress-induced tannins are more reactive.

    Science.gov (United States)

    Tharayil, Nishanth; Suseela, Vidya; Triebwasser, Daniella J; Preston, Caroline M; Gerard, Patrick D; Dukes, Jeffrey S

    2011-07-01

    • Climate change could increase the frequency with which plants experience abiotic stresses, leading to changes in their metabolic pathways. These stresses may induce the production of compounds that are structurally and biologically different from constitutive compounds. • We studied how warming and altered precipitation affected the composition, structure, and biological reactivity of leaf litter tannins in Acer rubrum at the Boston-Area Climate Experiment, in Massachusetts, USA. • Warmer and drier climatic conditions led to higher concentrations of protective compounds, including flavonoids and cutin. The abundance and structure of leaf tannins also responded consistently to climatic treatments. Drought and warming in combination doubled the concentration of total tannins, which reached 30% of leaf-litter DW. This treatment also produced condensed tannins with lower polymerization and a greater proportion of procyanidin units, which in turn reduced sequestration of tannins by litter fiber. Furthermore, because of the structural flexibility of these tannins, litter from this treatment exhibited five times more enzyme (β-glucosidase) complexation capacity on a per-weight basis. Warmer and wetter conditions decreased the amount of foliar condensed tannins. • Our finding that warming and drought result in the production of highly reactive tannins is novel, and highly relevant to climate change research as these tannins, by immobilizing microbial enzymes, could slow litter decomposition and thus carbon and nutrient cycling in a warmer, drier world.

  16. Penicillium araracuarense sp. nov., Penicillium elleniae sp. nov., Penicillium penarojense sp. nov., Penicillium vanderhammenii sp. nov. and Penicillium wotroi sp. nov., isolated from leaf litter

    DEFF Research Database (Denmark)

    Houbraken, Jos; López-Quintero, Carlos A.; Frisvad, Jens Christian

    2011-01-01

    Several species of the genus Penicillium were isolated during a survey of the mycobiota of leaf litter and soil in Colombian Amazon forest. Five species, Penicillium penarojense sp. nov. (type strain CBS 113178T = IBT 23262T), Penicillium wotroi sp. nov. (type strain CBS 118171T = IBT 23253T...

  17. Aboveground biomass, wood volume, nutrient stocks and leaf litter in novel forests compared to native forests and tree plantations in Puerto Rico

    Science.gov (United States)

    A.E. Lugo; O. Abelleira Martínez; J. Fonseca da Silva

    2012-01-01

    The article presents comparative data for aboveground biomass, wood volume, nutirent stocks (N, P, K) and leaf litter in different types of forests in Puerto Rico. The aim of the study is to assess how novel forests of Castilla elastica, Panama Rubber Tree, and Spathodea campanulata, African Tulip Tree, compare with tree plantations and native historical forests (both...

  18. Variable role of aquatic macroinvertebrates in initial breakdown of seasonal leaf litter inputs to a cold-desert river

    Science.gov (United States)

    Nelson, S.M.; Andersen, D.C.

    2007-01-01

    We used coarse-mesh and fine-mesh leafpacks to examine the importance of aquatic macroinvertebrates in the breakdown of floodplain tree leaf litter that seasonally entered a sand-bedded reach of the sixth-order Yampa River in semiarid Colorado. Leafpacks were positioned off the easily mobilized channel bed, mimicking litter trapped in debris piles. Organic matter (OM) loss was fastest for leaves collected from the floodplain and placed in the river in spring (k = 0.029/day) and slowest for leaves collected and placed in the river in winter (0.006/day). Macroinvertebrates were most abundant in winter and spring leaves, but seemed important to processing only in spring, when exclusion by fine mesh reduced OM loss by 25% and nitrogen loss by 65% in spring leaves. Macroinvertebrates seemed to have little role in processing of autumn, winter, or summer leaves over the 50-day to 104-day monitoring periods. Desiccation during bouts of low discharge and sediment deposition on leaves limited invertebrate processing in summer and autumn, whereas processing of winter leaves, which supported relatively large numbers of shredders, might have been restricted by ice formation and low water temperatures. These results were consistent with the concept that microbial processing dominates in higher-order rivers, but suggested that macroinvertebrate processing can be locally important in higher-order desert rivers in seasons or years with favorable discharge and water quality conditions.

  19. Litter Breakdown and Microbial Succession on Two Submerged Leaf Species in a Small Forested Stream

    National Research Council Canada - National Science Library

    Newman, Molli M; Liles, Mark R; Feminella, Jack W

    2015-01-01

    Microbial succession during leaf breakdown was investigated in a small forested stream in west-central Georgia, USA, using multiple culture-independent techniques. Red maple (Acer rubrum) and water oak (Quercus nigra...

  20. Colonization of leaf litter of two aquatic macrophytes, Mayaca fluviatilis Aublet and Salvinia auriculata Aublet by aquatic macroinvertebrates in a tropical reservoir

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    Marcia Cristina de Paula

    2011-04-01

    Full Text Available Decomposition and colonization of S. auriculata and M. fluviatilis by macroinvertebrates were analyzed during 40 days to determine whether differences existed on colonization by aquatic macroinvertebrates of two macrophytes with distinct habits (submerged versus fluctuant. Leaf litter of S. auriculata and M. fluviatilis were incubated in 24 litter bags (12 of each species, in a small reservoir surrounded by a cerrado fragment with low level of anthropic impact. After 10, 20, 30 and 40 days, the litter bags were removed and aquatic macroinvertebrates community was analyzed. Two hundred twenty macroinvertebrates were associated with S. auriculata and 261 were associated with M. fluviatilis, identified in 24 taxa. Both macrophyte species were colonized mainly by macroinvertebrate predators. Ablabesmyia with predator and collector food mechanisms was present in all sampling. The data showed an expressive increase of abundance during the process of decomposition and a decrease at the end of the experiment, in both macrophytes. Cluster analysis permitted inference that the colonization of the leaf liter by macroinvertebrates was determinated by incubation time of leaf litter not by the habit of macrophytes (submerged or fluctuant.

  1. Influence of different forest system management practices on leaf litter decomposition rates, nutrient dynamics and the activity of ligninolytic enzymes: a case study from central European forests.

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    Witoon Purahong

    Full Text Available Leaf litter decomposition is the key ecological process that determines the sustainability of managed forest ecosystems, however very few studies hitherto have investigated this process with respect to silvicultural management practices. The aims of the present study were to investigate the effects of forest management practices on leaf litter decomposition rates, nutrient dynamics (C, N, Mg, K, Ca, P and the activity of ligninolytic enzymes. We approached these questions using a 473 day long litterbag experiment. We found that age-class beech and spruce forests (high forest management intensity had significantly higher decomposition rates and nutrient release (most nutrients than unmanaged deciduous forest reserves (P<0.05. The site with near-to-nature forest management (low forest management intensity exhibited no significant differences in litter decomposition rate, C release, lignin decomposition, and C/N, lignin/N and ligninolytic enzyme patterns compared to the unmanaged deciduous forest reserves, but most nutrient dynamics examined in this study were significantly faster under such near-to-nature forest management practices. Analyzing the activities of ligninolytic enzymes provided evidence that different forest system management practices affect litter decomposition by changing microbial enzyme activities, at least over the investigated time frame of 473 days (laccase, P<0.0001; manganese peroxidase (MnP, P = 0.0260. Our results also indicate that lignin decomposition is the rate limiting step in leaf litter decomposition and that MnP is one of the key oxidative enzymes of litter degradation. We demonstrate here that forest system management practices can significantly affect important ecological processes and services such as decomposition and nutrient cycling.

  2. Segregation and Alteration of Phenolic and Aliphatic Components of Root and Leaf Litter by Detritivores and Microbes

    Science.gov (United States)

    Filley, T. R.; Altmann, J.; Szlavecz, K. A.; Kalbitz, K.; Gamblin, D.; Nierop, K.

    2012-12-01

    The physical and microbial transformation of plant detritus in the litter layer and soil is accompanied by chemical separation of progressively soluble fractions and their movement into the rhizosphere driving subsequent soil processes. We investigated the combined action of specific detritivores, microbial decay, and leaching on the chemical separation of plant aromatic and aliphatic components from root, wood, and leaf tissue using 13C-TMAH thermochemolysis. This method enabled the simultaneous analysis of hydrolyzable tannin and lignin fragments, substituted fatty acids, and condensed tannin composition and revealed process-specific chemical transformations to plant secondary compounds. Long-term incubation and field sampling demonstrated how plant residues are progressively leached of the water soluble, oxidized fragments generated through decay. The residues appeared only slightly altered, in the case of brown rot wood, or enriched in aliphatic fragments, in the case of leaf and root tissue. Water extractable fractions were always selectively dominated by polyphenolics, either as demethylated lignin or tannins, and nearly devoid of aliphatic materials, despite high concentrations in the starting materials. Additionally, for plant materials with high tannin contents, such as pine needles, consumption and passage through some arthropod guts revealed what appeared to be microbially-mediated methylation of phenols, and a loss of tannins in leachates. These findings are indications for an in-situ phenol detoxification mechanism. This research provides important information regarding the links between biochemical decay and the chemical nature of organic matter removed and remaining in the soil profile.

  3. Leaf litter input and electrical conductivity may change density of Phylloicus sp. (Trichoptera: Calamoceratidae in a Brazilian savannah stream

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    Gustavo Figueiredo Marques Leite

    Full Text Available Abstract Aim Shredders are generally not abundant in tropical streams, and there is considerable evidence suggesting that the food supply drives this pattern in headwaters. The aim of this study was to assess the effect of variation in the availability of food resources, over one year, on the density of Phylloicus sp. (Trichoptera: Calamoceratidae, which is one of the main shredders in Neotropical headwaters. Methods We measured the relative importance of organic matter in terms of vertical input (VI and benthic standing stock (BS on Phylloicus sp. density from October 2012 to September 2013 in a preserved third order stream in the Cerrado savannah biome, Federal District, Brazil. Results Leaves were abundant (monthly biomass of 24.2 g.m–2 ±23.1 SD in VI and 46.1 g.m–2 ±76.7 SD in BS, increasing at the end of dry season (August to October and comprised the most abundant fraction in VI and BS (~ 70%. Phylloicus sp. had a low density throughout the year (2.4 ind.m–2 ±4.9 SD and its peak (13.7 ind.m–2 ±17.1 SD in October was associated with greater leaf biomass in VI and high electrical conductivity in the stream. The well-defined peak of Phylloicus sp. density in October suggests interplay between the increase in Phylloicus density and the leaf litter that enters the stream at the end of the dry season. Electrical conductivity was also higher in October, reflecting an increase in nutrient concentrations in the water during this period. Conclusions The availability of leaf litter may be a determinant factor for the seasonal variation in Phylloicus sp. density in tropical streams, suggesting a bottom-up effect. Changes in the supply of allochthonous resources to the stream can lead to modification in populations of shredders, such as Phylloicus sp., and anthropogenic influences on the riparian vegetation can affect ecological processes of great importance to streams.

  4. Evaluation of a method for removing cesium and reducing the volume of leaf litter from broad-leaved trees contaminated by the Fukushima Daiichi nuclear accident during the Great East Japan Earthquake.

    Science.gov (United States)

    Harada, Shigeki; Yanagisawa, Mitsunori

    2017-04-01

    The town of Marumori in southern Miyagi Prefecture borders on Fukushima Prefecture, and following the accident at the Fukushima Daiichi nuclear power plant, there were concerns about cesium deposition in forested areas. One of the authors of this paper has continually surveyed leaf litter from the forested areas. As leaf litter may be a source of cesium contamination from the forest to downstream areas, we considered a simplified version of wet oxidation, a method previously presented by one of the authors of this study, as a technology to reduce leaf litter weight and cesium concentration, separating radioactive nuclides from non-radioactive ones, in leaf litter. We tested our method in three experiments. Experiment 1 used new leaf litter (232 Bq/kg) from the surface of a small stream at the forest edge nearby an area with air dose level higher than the national standard threshold of 0.23 μSv/h for the implementation of governmental decontamination works. Experiment 2 applied wet oxidation to older leaf litter (705 Bq/kg) harvested from a pasture nearby the stream mentioned above. We also used the same leaf litter in experiment 3 for a cesium release tests using pure water. In experiment 1 and 2 we treated leaf litter with a sodium hypochlorite solution, optimizing sodium hypochlorite concentration and reaction temperature. We measured a 50-60% decrease in the leaf litter weight and a 60% decrease in the cesium concentration. Moreover, we also measured the amount of cesium washout. The cesium budget of experiment 1 showed no cesium gasification (wet oxidation avoids airborne cesium as this element is prone to be volatile at 600 °C), and that high sodium hypochlorite concentration and high temperature had a strong positive effect on leaf litter volume reduction and cesium decontamination. Experiment 2 confirmed the reproducibility of these results in leaves with different cesium concentration and harvested in different conditions. We could also explain the

  5. Leaf-litter microfungal community on poor fen plant debris in Torfy Lake area (Central Poland

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    Mateusz Wilk

    2014-06-01

    Full Text Available The purpose of this study was to initially evaluate the species diversity of microfungi growing on litter of 15 plant species occurring on the poor fen and neighbouring area of the Torfy Lake, Masovian voivodeship, Poland. The lake is located near the planned road investment (construction of the Warsaw southern express ring road S2. The place is biologically valuable as there are rare plant communities from Rhynchosporion albae alliance protected under the Habitats Directive adopted by the European Union. On the examined plant debris 73 taxa of fungi were recorded (3 basidiomycetes, 13 ascomycetes, 2 zygomycetes, 43 anamorphic ascomycetes, 12 unidentified. Two of them, Dicranidion sp. and Wentiomyces sp. are presented here as new to Poland. Among the plant species examined, the litter of Rhododendron tomentosum harbored the highest number of fungal taxa (16. The highest percents of substrate-specific microfungi (i.e. recorded only on one plant species was noted on R. tomentosum (81.3 %, and Pteridium aquilinum (75%. It is emphasized that the lake area should be protected not only because of rare plant community but also because of the uniqueness and diversity of mycobiota.

  6. Short communication: A laboratory study to validate the impact of the addition of Alnus nepalensis leaf litter on carbon and nutrients mineralization in soil

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    GAURAV MISHRA

    2016-04-01

    Full Text Available Abstract. Mishra G, Giri K, Dutta A, Hazarika S and Borgohain P. 2015. A laboratory study to validate the impact of the addition of Alnus nepalensis leaf litter on carbon and nutrients mineralization in soil. Nusantara Bioscience 8: 5-7. Plant litter or residues can be used as soil amendment to maintain the carbon stock and soil fertility. The amount and rate of mineralization depends on biochemical composition of plant litter. Alnus nepalensis (Alder is known for its symbiotic nitrogen fixation and capability to restore fertility of degraded lands. A laboratory incubation experiment was conducted for 60 days under controlled conditions to validate the carbon and nutrients mineralization potential of alder litter. Soil fertility indicators, i.e. soil organic carbon (SOC, available nitrogen (N, available phosphorus (P, and available potassium (K were analyzed using standard procedures. Significant differences were observed in the soil properties after addition of litter. Nutrient composition of alder litter was found superior by providing significantly higher organic matter and helped in better nutrient cycling. Therefore, alder based land use system may be replicated in other degraded lands or areas for productivity enhancement which is important for sustaining biodiversity and soil fertility.

  7. Leaf and twig litter decomposition of main species in different forests along the north slope of Changbai Mountain,northeast China

    Institute of Scientific and Technical Information of China (English)

    GUO Zhongling; LI Qingkang; ZHENG Jinping; LIU Wande; FAN Chunnan; MA Yuandan; YU Guirui; HAN Shijie

    2007-01-01

    From 2001 to 2003,the litter decomposition dynamics of dominant tree species were conducted using a litterbag burying method in the broadleaf-Korean pine forest,spruce-fir forest and Ermans birch forest,which represents three altitudinal belts in Changbai Mountain,northeast China.The spatial and temporal dynamics of litter decomposition and the effects of litter properties were examined.Furthermore,the decomposition trend of different species was simulated by the Olson model,and results showed that annual mass loss rates increased over time,but was not significantly correlated.Leaf decomposition rates increased after decomposing for 638 days (1.75 years),and the order of dry weight remaining rates of leaf litter for different species is:Asian white birch (Betula platyphylla) (24.56%)<Amur linden (Tilia amurensis) (24.81%) < Korean pine (Pinus koraiensis)(38.48%)<spruce (Picea jezoensis var. microsperma)(41.15%)< Ermans birch (Betula ermanii) (41.53%)<fir (Abies nephrolepis) (42.62%).The dry weight remaining rates of twig litter was smaller than that of leaf litter,and followed the order of Amur linden (44.98%)<fir (64.62%)<Korean pine (72.07%)<spruce (73.51%)<Asian white birch (77.37%)<Ermans birch (80.35%).The simulation results by the Olson model showed that,in leaf,the 95%-decomposition rates ranged from 4.5 to 8.0 years,and annual decomposition rate (k) followed the order of Amur linden (0.686)>Asian white birch (0.624)>Korean pine (0.441)>spruce (0.406)>fir (0.397)>Ermans birch (0.385);in twig,it ranged from 7.8 to 29.3 years,and k follows the order:Amur linden (0.391)>fir (0.204)>Korean pine (0.176)>spruce (0.157)>Asian white birch (0.148)>Ermans birch (0.102).In general,the differences of decomposition rate are evident between leaf and twig litter and among species,and were higher in broad-leaved species compared with coniferous species at the same elevation,and decreased with the ascending of elevation.

  8. Variation in leaf litter production and resorption of nutrients in abundant tree species in Nyungwe tropical montane rainforest in Rwanda

    Science.gov (United States)

    Nyirambangutse, Brigitte; Mirindi Dusenge, Eric; Nsabimana, Donat; Bizuru, Elias; Pleijel, Håkan; Uddling, Johan; Wallin, Göran

    2014-05-01

    African tropical rainforests play many roles from local to global scale as providers of resources and ecosystem services. Although covering 30% of the global rainforest, only few studies aiming to better understand the storage and fluxes of carbon and nutrients in these forests have been conducted. To answer questions related to these issues, we have established 15 permanent 0.5 ha plots where we compare carbon and nutrient fluxes of primary and secondary forest tree communities in a tropical montane forest in central Africa. The studies are conducted in Nyungwe montane tropical rain forest gazetted as a National Park to protect its extensive floral and faunal diversity covering an area of 970 km2. Nyungwe is located in Southwest Rwanda (2o17'-2o50'S, 29o07'-29o26A'E). The forest is ranging between 1600-2950 m.a.s.l. and is one of the most biologically important rainforest in Albertine Rift region in terms of Biodiversity. Nyungwe consists of a mixture of primary and secondary forest communities supporting a richness of plant and animal life. More than 260 species of trees and shrubs have been found in Nyungwe, including species endemic to the Albertine Rift. The forest has a climate with a mean annual temperature of 15.5oC and annual rainfall of ca 1850 mm yr-1, with July and August being the only months when rainfall drops. A part of this study is focusing on the dynamics of nutrients through leaf turnover. This turnover of leaves is regulated to maximize the carbon gain through canopy photosynthesis and resource-use efficiency of the plant. It is known that about half of leaf nitrogen is invested in photosynthetic apparatus and that there normally is a strong correlation between the photosynthetic capacity and leaf nitrogen per unit area. Hence leaf nitrogen is an important factor for canopy photosynthesis. However, leaves are produced, senesce and fall. Some nitrogen in the leaf is lost when leaves senesce but other is resorbed. The resorption of nitrogen

  9. Diversity of shrub tree layer, leaf litter decomposition and N release in a Brazilian Cerrado under N, P and N plus P additions

    Energy Technology Data Exchange (ETDEWEB)

    Khan Baiocchi Jacobson, Tamiel, E-mail: tamiel@unb.br [Departamento de Ecologia, Universidade de Brasilia, Brasilia-DF 70919-970 (Brazil); Cunha Bustamante, Mercedes Maria da, E-mail: mercedes@unb.br [Departamento de Ecologia, Universidade de Brasilia, Brasilia-DF 70919-970 (Brazil); Rodrigues Kozovits, Alessandra, E-mail: kozovits@icep.ufop.br [Departamento de Ecologia, Universidade de Brasilia, Brasilia-DF 70919-970 (Brazil)

    2011-10-15

    This study investigated changes in diversity of shrub-tree layer, leaf decomposition rates, nutrient release and soil NO fluxes of a Brazilian savanna (cerrado sensu stricto) under N, P and N plus P additions. Simultaneous addition of N and P affected density, dominance, richness and diversity patterns more significantly than addition of N or P separately. Leaf litter decomposition rates increased in P and NP plots but did not differ in N plots in comparison to control plots. N addition increased N mass loss, while the combined addition of N and P resulted in an immobilization of N in leaf litter. Soil NO emissions were also higher when N was applied without P. The results indicate that if the availability of P is not increased proportionally to the availability of N, the losses of N are intensified. - Highlights: > Simultaneous addition of N and P affected richness and diversity of the shrub-tree layer of a Brazilian savanna more significantly than addition of N or P separately. > Leaf litter decomposition rates increased in P and NP plots but did not differ in N plots in comparison to control plots. N addition increased N mass loss, while the combined addition of N and P resulted in an immobilization of N in leaf litter. Soil NO emissions were also higher when N was applied without P. > The results indicated that if increases in N deposition in Cerrado ecosystems are not accompanied by P additions, higher N losses through leaching and gas emissions can occur with other ecosystem impacts. - Shrub-tree diversity and functioning of Brazilian savanna are affected by increasing nutrient availability.

  10. LEAF LITTER BREAKDOWN RATES AND ASSOCIATED FAUNA OF NATIVE AND EXOTIC TREES USED IN NEOTROPICAL RIPARIA REFORESTATION

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    Nataly Gutiérrez Isaza

    2013-09-01

    Full Text Available ABSTRACT A signature of globalization is the prevalence of exotic trees along reforested urban and rural riparian zones in the Neotropics, but little is known about the instream processing of its leaf litter. In this study, leaf litter breakdown rates were measured during 35 days using mesh bags within a reference headwater stream for seven exotic and three native tree species commonly used in urban and rural reforestation. Artocarpus altilis, Schefflera actinophylla and Terminalia catappa scored the highest mass loss rates (>85 %; mean life: t50 85 %; vida media: t50 <15 d, mientras que las menores tasas las obtuvieron Cecropia sp. y Cespedesia macrophylla (pérdida de masa =36 y 15 %; t50 =58 y 153 d, respectivamente. Sin embargo, se observó una amplia gama de tasas de pérdida de masa entre las diez especies estudiadas. La proporción carbono:fósforo (C:P y la dureza de la hojarasca fueron los mejores predictores de las tasas de pérdida de masa. Sin embargo, estas características no se correlacionaron con los muy bajos valores de abundancia y diversidad de macroinvertebrados, y la escasez de morfotipos de insectos clasificados como fragmentadores. Por lo tanto, los controles físicos parecen ser más importantes que los biológicos para explicar la variabilidad de las tasas de pérdida de masa; y, las especies con tasas más bajas podrían estar proveyendo hábitat, más que alimento para las especies de insectos acuáticos, principalmente los recolectores. Este estudio sugiere que la reforestación ribereña propagará efectos específicos sobre los procesos dentro del cauce dependiendo de las especies de árbol plantadas mediados por la calidad de la hojarasca, los cuales deberían ser considerados para mejorar las estrategias de reforestación. Estudios futuros deben someter a prueba si existen diferencias en las tasas de fragmentación y colonización de macroinvertebrados entre especies de hojarasca de diferente origen (nativa vs. exótica.

  11. Riparian reserves within oil palm plantations conserve logged forest leaf litter ant communities and maintain associated scavenging rates.

    Science.gov (United States)

    Gray, Claudia L; Lewis, Owen T; Chung, Arthur Y C; Fayle, Tom M

    2015-02-01

    The expansion of oil palm plantations at the expense of tropical forests is causing declines in many species and altering ecosystem functions. Maintaining forest-dependent species and processes in these landscapes may therefore limit the negative impacts of this economically important industry. Protecting riparian vegetation may be one such opportunity; forest buffer strips are commonly protected for hydrological reasons, but can also conserve functionally important taxa and the processes they support.We surveyed leaf litter ant communities within oil palm-dominated landscapes in Sabah, Malaysia, using protein baits. As the scavenging activity of ants influences important ecological characteristics such as nutrient cycling and soil structure, we quantified species-specific rates of bait removal to examine how this process may change across land uses and establish which changes in community structure underlie observed shifts in activity.Riparian reserves had similar ant species richness, community composition and scavenging rates to nearby continuous logged forest. Reserve width and vegetation structure did not affect ant species richness significantly. However, the number of foraging individuals decreased with increasing reserve width, and scavenging rate increased with vegetation complexity.Oil palm ant communities were characterized by significantly lower species richness than logged forest and riparian reserves and also by altered community composition and reduced scavenging rates.Reduced scavenging activity in oil palm was not explained by a reduction in ant species richness, nor by replacement of forest ant species by those with lower per species scavenging rates. There was also no significant effect of land use on the scavenging activity of the forest species that persisted in oil palm. Rather, changes in scavenging activity were best explained by a reduction in the mean rate of bait removal per individual ant across all species in the community.Synthesis and

  12. 杉木与楠木凋落叶混合分解及其P、K动态%Decomposition Characteristics and Dynamics of Phosphorus and Potassium of Leaf Litter Mixtures of Both Cunninghamia lanceolata and Phoeba bournei

    Institute of Scientific and Technical Information of China (English)

    江淼华; 程徐冰; 杨建忠; 郭剑芬

    2012-01-01

    将杉木、楠木凋落叶及以二者不同比例混合的凋落叶置于果园林内进行分解和P、K动态的研究,结果表明:杉木和楠木凋落叶混合处理的分解速率均大于单独分解的纯杉木和纯楠木凋落叶.各凋落叶分解过程中,P浓度略有增加,而K浓度基本呈下降趋势.纯杉木凋落叶分解过程中P、K残留率均比纯楠木叶的低.杉楠混合分解的P、K释放率基本上大于单独的纯楠木叶.杉木与楠木凋落叶混合分解对其P和K的释放有一定的促进作用.%Decomposition and the dynamics of P and K of single Cunninghamia lanceolata and Phoeba bournei leaf litter and their different mixtures were studied in an orchard.The results showed that the decomposition rates of litter mixtures between Cunninghamia lanceolata and Phoeba bournei were faster than those of single leaf litter.Concentrations of P in single and mixture of leaf litter appeared to increase and concentrations of K appeared to decrease during the decomposition.Percentages of P and K remaining were lower in single Cunninghamia lanceolata needle litter compared to single Phoeba bournei leaf litter.P and K release rates of leaf litter mixtures were faster than those of single Phoeba bournei leaf litter.Release rates of P and K were increased when leaf litter of Cunninghamia lanceolata and Phoeba bournei were mixed together.

  13. A study of lignin degradation in leaf and needle litter using 13C-labelled tetramethylammonium hydroxide (TMAH) thermochemolysis: comparison with CuO oxidation and van Soest methods.

    NARCIS (Netherlands)

    Klotzbücher, T.; Filley, T.R.; Kaiser, K.; Kalbitz, K.

    2011-01-01

    We studied the degradation of lignin in leaf and needle litter of ash, beech, maple, pine and spruce using 13C-labelled tetramethylammonium hydroxide (13C TMAH) thermochemolysis. Samples were allowed to decompose for 27 months in litter bags at a German spruce forest site, resulting in a range of

  14. Influence of different forest system management practices on leaf litter decomposition rates, nutrient dynamics and the activity of ligninolytic enzymes: a case study from central European forests.

    Science.gov (United States)

    Purahong, Witoon; Kapturska, Danuta; Pecyna, Marek J; Schulz, Elke; Schloter, Michael; Buscot, François; Hofrichter, Martin; Krüger, Dirk

    2014-01-01

    Leaf litter decomposition is the key ecological process that determines the sustainability of managed forest ecosystems, however very few studies hitherto have investigated this process with respect to silvicultural management practices. The aims of the present study were to investigate the effects of forest management practices on leaf litter decomposition rates, nutrient dynamics (C, N, Mg, K, Ca, P) and the activity of ligninolytic enzymes. We approached these questions using a 473 day long litterbag experiment. We found that age-class beech and spruce forests (high forest management intensity) had significantly higher decomposition rates and nutrient release (most nutrients) than unmanaged deciduous forest reserves (Pforest management (low forest management intensity) exhibited no significant differences in litter decomposition rate, C release, lignin decomposition, and C/N, lignin/N and ligninolytic enzyme patterns compared to the unmanaged deciduous forest reserves, but most nutrient dynamics examined in this study were significantly faster under such near-to-nature forest management practices. Analyzing the activities of ligninolytic enzymes provided evidence that different forest system management practices affect litter decomposition by changing microbial enzyme activities, at least over the investigated time frame of 473 days (laccase, Pforest system management practices can significantly affect important ecological processes and services such as decomposition and nutrient cycling.

  15. Two new families (Acari: Alicorhagiidae and Platyhelminthes: Prorhynchidae reported for the Hungarian fauna From leaf litter in the Bükk Mountains

    Directory of Open Access Journals (Sweden)

    Pfliegler, W.

    2016-06-01

    Full Text Available Two new members of the Hungarian fauna are reported, both of them were collected in beech forest leaf litter in the Bükk Mountains, North-East Hungary: Alicorhagia fragilis Berlese, 1910 (Arthropoda: Arachnida: Acari: Sarcoptiformes: Endeostigmata: Alicorhagiidae and Geocentrophora baltica (Kennel, 1883 (Platyhelminthes: Rhabditophora: Trepaxonemata: Amplimatricata: 'Lecithoepitheliata': Prorhynchida: Prorhynchidae. The families Alicorhagiidae and Prorhynchidae both represent new taxa in the fauna of the country.

  16. Impacts of microbial activity on the optical and copper-binding properties of leaf-litter leachate

    Directory of Open Access Journals (Sweden)

    Chad eCuss

    2012-05-01

    Full Text Available Dissolved organic matter (DOM is a universal part of all aquatic systems that largely originates with the decay of plant and animal tissue. Its polyelectrolytic and heterogeneous characters make it an effective metal-complexing agent with highly diverse characteristics. Microbes utilize DOM as a source of nutrients and energy and their enzymatic activity may change its composition, thereby altering the bioavailability and toxicity of metals. This study investigated the impacts of microbial inoculation upon the optical and copper-binding properties of freshly-produced leaf-litter leachate over 168 hours. Copper speciation was measured using voltammetry, and using fluorescence quenching analysis of independent fluorophores determined using parallel factor analysis (PARAFAC. Four distinct components were detected. Thirty-five percent of total protein/polyphenol-like fluorescence was removed after 168-hr of exposure to riverine microbes. Using voltammetry, a 6-fold increase in copper-complexing (CC capacity (130 - 770 μmol Cu/g C was observed over the exposure period, while the conditional binding constant (log K decreased from 7.2 to 5.8. Binding parameters were significantly different for all four PARAFAC components and were generally in agreement with voltammetric results in the microbially-degraded samples, but they were significantly different in leachate. These results suggest that non-fluorescent moieties may exert a significant influence upon binding characteristics. Three of four binding sites corresponding to independent PARAFAC components, which had distinct characteristics in the leachate, retained significantly different log K values (p<0.05 after 168 hours of incubation, while their complexing capacities became similar. It was concluded that the microbial metabolization of maple leaf leachate has a significant impact upon DOM composition and its copper-binding characteristics.

  17. Impacts of microbial activity on the optical and copper-binding properties of leaf-litter leachate.

    Science.gov (United States)

    Cuss, Chad W; Guéguen, Celine

    2012-01-01

    Dissolved organic matter (DOM) is a universal part of all aquatic systems that largely originates with the decay of plant and animal tissue. Its polyelectrolytic and heterogeneous characters make it an effective metal-complexing agent with highly diverse characteristics. Microbes utilize DOM as a source of nutrients and energy and their enzymatic activity may change its composition, thereby altering the bioavailability and toxicity of metals. This study investigated the impacts of microbial inoculation upon the optical and copper-binding properties of freshly produced leaf-litter leachate over 168 h. Copper speciation was measured using voltammetry, and using fluorescence quenching analysis of independent fluorophores determined using parallel factor analysis (PARAFAC). Two protein/polyphenol-like and two fulvic/humic-like components were detected. Thirty-five percent of total protein/polyphenol-like fluorescence was removed after 168-h of exposure to riverine microbes. The microbial humic-like and tryptophan-like PARAFAC components retained significantly different log K values after 168 h of incubation (p complexing capacities were similar. Using voltammetry, a sixfold increase in copper-complexing capacity (CC, from 130 to 770 μmol Cu g C(-1)) was observed over the exposure period, while the conditional binding constant (log K) decreased from 7.2 to 5.8. Overall binding parameters determined using voltammetry and fluorescence quenching were in agreement. However, the electrochemically based binding strength was significantly greater than that exhibited by any of the PARAFAC components, which may be due to the impact of non-fluorescent DOM, or differences in the concentration ranges of metals analyzed (i.e., different analytical windows). It was concluded that the microbial metabolization of maple leaf leachate has a significant impact upon DOM composition and its copper-binding characteristics.

  18. Effects of different proportion mixed Phyllostachys pubescens leaf litter on litter decomposition in P.pubescens forest%毛竹凋落叶组成对叶凋落物分解的影响

    Institute of Scientific and Technical Information of China (English)

    刘广路; 范少辉; 官凤英; 杜满义; 郭宝华

    2011-01-01

    Mixed Phyllostachys pubescens forest has high productivity and good ecological functions, which is possibly related to the nutrient return characteristics of mixed litter. By using litterbag method, a one-year experiment was conducted to study the decomposition characteristics of different proportion mixed P. pubescens leaf litters in P. pubescens forest in the Yangkou National Forest Farm, Fujian Province of Southeast China. Five treatments were installed, i. e. , pure P. pubescens leaf litters ( Ⅰ ) , P. pubescens+Phoebe bournei litters ( mass ratio 8:2, Ⅱ ) , P. pubescens+Cunninghamia lanceolata litters ( 8 :2, Ⅲ ) , P. pubescens +P. bournei litters (5 :5 , Ⅳ ) , and P. pubescens+C. lanceolata litters (5 :5, Ⅴ ) . The litter decomposition rates of different treatments were all compatible with the exponential decomposition model of Olson ( R2 >0. 92 , P<0. 01). The decomposition rate in treatments Ⅰ and Ⅱ was significantly higher than that in other treatments, and the coefficient of decomposition was in the order of Ⅱ > Ⅰ > Ⅲ > Ⅴ > Ⅳ , being 0. 68 , 0. 66, 0. 58, 0. 55 , and 0. 49 , respectively, which illustrated that only appropriate proportions of mixed tree species leaf litters could promote the litter decomposition. The litter of mixed bamboo-broadleaved forest had higher decomposition rate than that of mixed bambooconifer forest. Therefore, the mixed bamboo-broadleaved forest could benefit the persistent productivity of bamboo forest. During decomposition, the N, P, and K in the litters had different release patterns. The N followed the pattern of alternate enrichment and release; the P was rapidly enriched in the first four month, released from the fourth month to fifth month, and then enriched; the K was released in the first three months, and then enriched. The nutrient return of the litters was closely related to the nutrient contents of the litters. The litter C/N ratio and P content could be the key indices

  19. Effects of Nitrogen Addition on Leaf Decomposition of Single-Species and Litter Mixture in Pinus tabulaeformis Forests

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    Jinsong Wang

    2015-12-01

    Full Text Available The litter decomposition process is closely correlated with nutrient cycling and the maintenance of soil fertility in the forest ecosystem. In particular, the intense environmental concern about atmospheric nitrogen (N deposition requires a better understanding of its influence on the litter decomposition process. This study examines the responses of single-species litter and litter mixture decomposition processes to N addition in Chinese pine (Pinus tabulaeformis Carr. ecosystems. Chinese pine litter, Mongolian oak (Quercus mongolica Fisch. ex Ledeb. litter, and a pine–oak mixture were selected from a plantation and a natural forest of Chinese pine. Four N addition treatments, i.e., control (N0: 0 kg N ha−1·year−1, low-N (N1: 5 kg N ha−1·year−1, medium-N (N2: 10 kg N ha−1·year−1, and high-N (N3: 15 kg N ha−1·year−1, were applied starting May 2010. In the plantation, N addition significantly stimulated the decomposition of the Chinese pine litter. In the natural forest, N addition had variable effects on the decomposition of single-species litter and the litter mixture. A stimulatory effect of the high-N treatment on the Chinese pine litter decomposition could be attributed to a decrease in the substrate C:N ratio. However, an opposite effect was found for the Mongolian oak litter decomposition. The stimulating effect of N addition on the Chinese pine litter may offset the suppressive effect on the Mongolian oak litter, resulting in a neutral effect on the litter mixture. These results suggest that the different responses in decomposition of single-species litter and the litter mixture to N addition are mainly attributed to litter chemical composition. Further investigations are required to characterize the effect of long-term high-level N addition on the litter decomposition as N deposition is likely to increase rapidly in the region where this study was conducted.

  20. Removal of PFOA and PFOS from aqueous solutions using activated carbon produced from Vitis vinifera leaf litter.

    Science.gov (United States)

    Fagbayigbo, Bamidele Oladapo; Opeolu, Beatrice Olutoyin; Fatoki, Olalekan Siyanbola; Akenga, Terresa Ayuko; Olatunji, Olatunde Stephen

    2017-05-01

    The removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from aqueous solutions using agro-waste biomass of Vitis vinifera (grape) leaf litter was studied. Activated carbons were produced from the biomass and chemical activation achieved by using phosphoric acid (H3PO4) and potassium hydroxide (KOH) for the modification of the carbons' surface morphology. Activated carbons were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer-Emmett-Teller (BET) in order to understand removal mechanisms of the contaminants by activated carbons. The effect of solution concentration, pH, adsorbent dosage, contact time and temperature was evaluated to optimize the removal efficiency of activated carbons. Adsorption isotherm models were used to analyse the equilibrium data obtained, and kinetic models were applied to study sorption mechanisms. The results fitted well into Freundlich isotherm with both AC-KOH and AC-H3PO4 having high K f values. Maximum adsorption capacities for AC-H3PO4 were 78.90 and 75.13 mg/g for PFOA and PFOS, respectively. Equilibrium was reached before 60 min on both adsorbents, and thermodynamic studies indicated that the process was exothermic and spontaneous. Surface morphology showed the abundance of microspores (>60%) with BET total surface area of 295.488 and 158.67 m(2)/g for AC-H3PO4 and AC-KOH activated carbons, respectively. Removal efficiencies were 95 and 90% for PFOA using AC-H3PO4 and AC-KOH, respectively; corresponding values for PFOS were 94 and 88%. Adsorbents' removal capacities depended on the physicochemical characteristics of adsorbents.

  1. Detrital stoichiometry as a critical nexus for the effects of streamwater nutrients on leaf litter breakdown rates.

    Science.gov (United States)

    Manning, David W P; Rosemond, Amy D; Kominoski, John S; Gulis, Vladislav; Benstead, Jonathan P; Maerz, John C

    2015-08-01

    Nitrogen (N) and phosphorus (P) concentrations are elevated in many freshwater systems, stimulating breakdown rates of terrestrially derived plant litter; however, the relative importance of N and P in driving litter breakdown via microbial and detritivore processing are not fully understood. Here, we determined breakdown rates of two litter species, Acer rubrum (maple) and Rhododendron maximum (rhododendron), before (PRE) and during two years (YR1, YR2) of experimental N and P additions to five streams, and quantified the relative importance of hypothesized factors contributing to breakdown. Treatment streams received a gradient of P additions (low to high soluble reactive phosphorus [SRP]; ~10-85 µg/L) crossed with a gradient of N additions (high to low dissolved inorganic nitrogen [DIN]; ~472-96 µg/L) to achieve target molar N:P ratios ranging from 128 to 2. Litter breakdown rates increased above pre-treatment levels by an average of 1.1-2.2x for maple, and 2.7-4.9x for rhododendron in YR1 and YR2. We used path analysis to compare fungal biomass, shredder biomass, litter stoichiometry (nutrient content as C:N or C:P), discharge, and streamwater temperature as predictors of breakdown rates and compared models containing streamwater N, P or N + P and litter C:N or C:P using model selection criteria. Litter breakdown rates were predicted equally with either streamwater N or P (R2 = 0.57). In models with N or P, fungal biomass, litter stoichiometry, discharge, and shredder biomass predicted breakdown rates; litter stoichiometry and fungal biomass were most important for model fit. However, N and P effects may have occurred via subtly different pathways. Litter N content increased with fungal biomass (N-driven effects) and litter P content increased with streamwater P availability (P-driven effects), presumably via P storage in fungal biomass. In either case, the effects of N and P through these pathways were associated with higher shredder biomass and breakdown

  2. [C and N allocation patterns in planted forests and their release patterns during leaf litter decomposition in subalpine area of west Sichuan].

    Science.gov (United States)

    Liu, Zeng-wen; Duan, Er-jun; Pan, Kai-wen; Zhang, Li-ping; Du, Hong-xia

    2009-01-01

    With the planted forest ecosystems of Cercidiphyllum japonicum, Betula utilis, Pinus yunnansinsis, and Picea asperata in subalpine area of west Sichuan as test objects, their total biomass and the C and N contents in soils and tree organs were determined. The results showed that the allocation of C in tree organs had less correlation with the age of the organs, while that of N and C/N ratio had closer relationship with the age. The N content in young organs was higher than that in aged ones, whereas the C/N ratio was higher in aged organs than in young organs, and higher in the leaf litters of needle-leaved forests than in those of broad-leaved forests. There was an obvious enrichment of C and N in the topsoil of test forests. The accumulated amounts of C and N in the whole planted forest ecosystem, including tree, litter, and 0-40 cm soil layer, were 176.75-228.05 t x hm(-2) and 11.06-16.54 t x hm(-2), respectively, and the nutrients allocation ratio between soil-litter and tree was (1.9-3.3):1 for C and (15.6-41.5):1 for N. Needle-leaved forests functioned as a stronger "C-sink" than broad-leaved forests. The decomposition rate of the leaf litters in needle-leaved forests was larger than that in broad-leaved forests, with the turnover rate being 2.2-3.7 years and 3.9-4.2 years, respectively. During the decomposition of leaf litter, the C in all of the four forests released at super-speed, with the turnover rate being 1.9-3.4 years. As for N, it also released at super-speed in C. japonicum and B. utilis forests, with the turnover rate being 1.9-3.2 years, but released at low speed in P. yunnansinsis and P. asperata forests, with the turnover rate being 6.7-8.5 years.

  3. Relationship between leaf litter identity, expression of cytochrome P450 genes and life history traits of Aedes aegypti and Aedes albopictus.

    Science.gov (United States)

    Kim, Chang-Hyun; Muturi, Ephantus J

    2012-04-01

    The role of toxic component of leaf litter in mediating the outcome of mosquito species interactions is not well documented. To examine the effect of leaf litter toxins on mosquito performance and interspecific interactions, we reared monospecific and heterospecific cultures of Aedes aegypti L. and Aedes albopictus Skuse larvae in microcosms with one of five leaf species and measured the expression of five cytochrome P450 genes and life history traits of the two mosquito species. For both mosquito species, survival to adulthood was significantly higher in black alder, black walnut, and cypress infusion compared to sugar maple and eastern white pine infusion. In pine but not in other leaf treatments, the presence of A. albopictus had significant positive effects on A. aegypti wing length and development time to adulthood. A. albopictus from heterospecific cultures were larger than those from monospecific cultures and were smaller and took longer to develop in pine and sugar maple infusions than in the other infusions. Up regulation of CYP6Z6 and CYP9M9 in A. aegypti and A. albopictus respectively appeared to be closely associated with the deleterious effects of sugar maple infusion on mosquito performance as was the down regulation of CYP6N12 (in A. aegypti) and lack of induction of CYP6Z6 and CYP9M9 (in A. aegypti and A. albopictus respectively) in pine infusion. Results suggest that metabolic capabilities that enable the two species to tolerate natural xenobiotics are associated with a fitness cost. Published by Elsevier B.V.

  4. Sources and modes of action of invasive knotweed allelopathy: the effects of leaf litter and trained soil on the germination and growth of native plants

    Directory of Open Access Journals (Sweden)

    Madalin Parepa

    2012-05-01

    Full Text Available Invasive knotweeds, native to Eastern Asia, are among the most dominant plant invaders of European and North American temperate ecosystems. Recent studies indicate that one cause of this dominance might be allelopathy, but the possible sources and modes of action of this allelopathy are insufficiently understood. Here, we asked whether the invasive knotweed Fallopia × bohemica can exert allelopathic effects on native plants also through its leaf litter, or through persistent soil contaminants, and whether these affect the germination or growth of native plants. In a germination experiment with nine native species neither litter leachate, an aqueous extract of knotweed leaves added to the soil, nor trained soil with a history of Fallopia pre-cultivation suppressed the germination or early growth of natives. A mesocosm study with experimental native communities showed that the presence of F. × bohemica, although not a dominant in these communities, caused significant shifts of life-history strategy in two dominant natives, and that similar effects could be elicited through litter leachates or trained soil alone. However, there were hardly any effects on the biomass of natives. Our study indicates that knotweed allelopathy acts on the growth rather than germination of natives, and that soil contamination through persistent allelochemicals may not be a significant problem in habitat restoration. It also shows that allelopathic effects can sometimes be subtle changes in life-history and allocation patterns of the affected species.

  5. Decomposition dynamics of Pinus tabulaeformis leaf litter at urban and suburban sites of Shenyang, Northeast China%沈阳城市和城郊油松凋落叶的分解动态

    Institute of Scientific and Technical Information of China (English)

    郭芳琴; 何兴元; 陈玮; 黄彦青

    2012-01-01

    To examine the effects of site location and litter type on litter decomposition, a reciprocal decomposition experiment was conducted to study the effects of contrasting sites ( urban vs. suburban) and leaf litter types ( urban leaf litter vs. suburban leaf litter) on the mass loss rate and N- and P remaining percentages of Pinus tabulaeformis leaf litters when decomposing in urban stand and suburban stand, respectively. The one year experiment showed that different sites had significant effects on the decomposition rate of P. tabulaeformis leaf litters (P<0.05). The leaf litters decomposed faster at suburban site than at urban site, suggesting that environmental conditions had significant effects on the decomposition. In the same stands, different litter types had significant effects on the litter decomposition (P<0. 05). The decomposition rate of the litters was faster at urban site than at suburban site, suggesting the significant effects of inherent characters of the litters. Site had no significant effects on the N- and P remaining percentages, but litter type had significant effects. Urban leaf litter, due to its higher initial C/N and C/P, were easy to enrich N and P during decomposition, as compared with suburban leaf litter.%为了检测分解地点和凋落物类型对分解的影响,采用交互分解实验分析了油松凋落叶在城市林分和城郊林分中分解时不同立地条件(城市和城郊)以及不同油松凋落叶类型(城市油松凋落物和城郊油松凋落物)对凋落物的分解速率以及N、P残留率的相对作用.结果表明:不同的立地条件对油松凋落叶分解速率有显著影响(P<0.05):城郊林分中的油松凋落叶比城市林分中分解快,说明外在环境条件对分解的影响显著;在同一林分里,凋落物类型对凋落叶分解速率也有显著影响(P<0.05):城市凋落物分解快于城郊凋落物,说明凋落物内在特性对分解的影响显著.分解地点对

  6. Value of Riparian Vegetation Remnants for Leaf-Litter Ants (Hymenoptera: Formicidae) in a Human-Dominated Landscape in Central Veracruz, Mexico.

    Science.gov (United States)

    García-Martínez, Miguel Á; Escobar-Sarria, Federico; López-Barrera, Fabiola; Castaño-Meneses, Gabriela; Valenzuela-González, Jorge E

    2015-12-01

    Riparian remnants are linear strips of vegetation immediately adjacent to rivers that may act as refuges for biodiversity, depending on their habitat quality. In this study, we evaluated the role of riparian remnants in contributing to the diversity of leaf-litter ants by determining the relationship between ant diversity and several riparian habitat characteristics within a human-dominated landscape in Veracruz, Mexico. Sampling was carried out in 2012 during both dry and rainy seasons at 12 transects 100 m in length, where 10 leaf-litter samples were collected along each transect and processed with Berlese-Tullgren funnels and Winkler sacks. A total of 8,684 individuals belonging to 53 species, 22 genera, and seven subfamilies were collected. The observed mean alpha diversity accounted for 34.4% of the total species recorded and beta diversity for 65.6%. Species richness and composition were significantly related to litter-layer depth and soil compaction, which could limit the distribution of ant species depending on their nesting, feeding, and foraging habits. Riparian remnants can contribute toward the conservation of ant assemblages and likely other invertebrate communities that are threatened by anthropogenic pressures. In human-dominated landscapes where remnants of riparian vegetation give refuge to a diverse array of myrmecofauna, the protection of the few remaining and well-preserved riparian sites is essential for the long-term maintenance of biodiversity. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Comparative water fluxes through leaf litter of tropical plantation trees and the invasive grass Saccharum spontaneum in the Republic of Panama

    Science.gov (United States)

    Park, Andrew; Friesen, Patrick; Serrud, Aneth Aracelly Sarmiento

    2010-03-01

    SummaryThe hydrological properties of leaf litter layers remain relatively unexplored, especially in tropical vegetation communities. In this paper we explore the hydrological dynamics of litter samples from reforestation plots of tropical hardwoods and the invasive sugar cane Saccharum spontaneum, which these trees were planted to replace. Water holding capacity (WHC) and drying rates were compared under controlled conditions, and throughfall interception, drainage and calculated evaporation were measured in two field experiments (A and B) conducted with different sets of samples. The WHC of samples varied from 3.4 to 6.5 mm in experiment A, and from 1.6 to 7.1 mm in experiment B. Drainage through the litter samples averaged 78.3 ± 34.4% and 61.2 ± 34.70% TF in experiments A and B, respectively. Daily water storage was 70.8 ± 14.25% of total WHC in experiment A and 78.6 ± 25.35% of total WHC in experiment B. Estimated evaporation averaged 34.8 ± 12.52% of WHC in experiment A and 34.3 ± 14.91% of WHC in experiment B. Although significant interspecific differences in WHC, interception of TF and evaporation were recorded, species rankings tended to be different in experiments A and B. The exception was litter from the leguminous tree Gliricidia sepium, which maintained the lowest WHC and water storage in the field in both experiments, but which evaporated water more rapidly than other species. The depth of throughfall draining through litter samples in the field was similar among all species in both experiments. Comparisons of regression slopes also showed that drainage depth increased with increasing throughfall at similar rates among species. On the other hand, both slopes and slope elevations differed among species when drainage was expressed in l kg -1. Patterns of water storage and drainage in our samples were in broad agreement with those of other studies, although WHC and litter necromass in our young tree plantations fell into the lower end of the range

  8. EFECTO DE BORDE SOBRE EL PROCESO DE DESCOMPOSICIÓN DE HOJARASCA EN BOSQUE NUBLADO Edge Effect on the Decomposition Process of Leaf Litter in Cloud Forest

    Directory of Open Access Journals (Sweden)

    MAURICIO ROMERO-TORRES

    2011-08-01

    effect on leaf litter decomposition and its control factors, two fragments of cloud forest in the southwest region of the Bogotá Savannah were selected. Within each, two 64 m long transects were laid out bearing east and west from edge to center respectively, a leaf litter decomposition experiment of a 90 to 180 day duration was set up at seven distances measured from the starting point of each transect. The percentage of leaf litter moisture and decomposition, vegetation density, anamorphic fungi density and carbon:nitrogen ratio were estimated at each point. The maximum distance of the edge effect on the decomposition was determined, and the interaction between orientation, distance and the regulating factors of the decomposition process were ascertained. The results established an effect of the cardinal orientation of the edge on the decomposition and its regulating factors. Marked edge effects on leaf litter moisture extending up to 7 m and up to 30 m on vegetation density were displayedin Eastern border areas. In forest areas, decomposition was regulated by leaf litter moisture and its C:N ratio. The limited penetration of edge effect suggests minor effects regarding nutrient cycles and provides justification and additional value to the use of small fragments.

  9. Alteration of microbial communities colonizing leaf litter in a temperate woodland stream by growth of trees under conditions of elevated atmospheric CO2.

    Science.gov (United States)

    Kelly, John J; Bansal, Amit; Winkelman, Jonathan; Janus, Lori R; Hell, Shannon; Wencel, Marie; Belt, Patricia; Kuehn, Kevin A; Rier, Steven T; Tuchman, Nancy C

    2010-08-01

    Elevated atmospheric CO(2) can cause increased carbon fixation and altered foliar chemical composition in a variety of plants, which has the potential to impact forested headwater streams because they are detritus-based ecosystems that rely on leaf litter as their primary source of organic carbon. Fungi and bacteria play key roles in the entry of terrestrial carbon into aquatic food webs, as they decompose leaf litter and serve as a source of nutrition for invertebrate consumers. This study tested the hypothesis that changes in leaf chemistry caused by elevated atmospheric CO(2) would result in changes in the size and composition of microbial communities colonizing leaves in a woodland stream. Three tree species, Populus tremuloides, Salix alba, and Acer saccharum, were grown under ambient (360 ppm) or elevated (720 ppm) CO(2), and their leaves were incubated in a woodland stream. Elevated-CO(2) treatment resulted in significant increases in the phenolic and tannin contents and C/N ratios of leaves. Microbial effects, which occurred only for P. tremuloides leaves, included decreased fungal biomass and decreased bacterial counts. Analysis of fungal and bacterial communities on P. tremuloides leaves via terminal restriction fragment length polymorphism (T-RFLP) and clone library sequencing revealed that fungal community composition was mostly unchanged by the elevated-CO(2) treatment, whereas bacterial communities showed a significant shift in composition and a significant increase in diversity. Specific changes in bacterial communities included increased numbers of alphaproteobacterial and cytophaga-flavobacter-bacteroides (CFB) group sequences and decreased numbers of betaproteobacterial and firmicutes sequences, as well as a pronounced decrease in overall gram-positive bacterial sequences.

  10. Leaf litter decomposition of Piper aduncum, Gliricidia sepium and Imperata cylindrica in the humid lowlands of Papua New Guinea

    NARCIS (Netherlands)

    Hartemink, A.E.; O'Sullivan, J.N.

    2001-01-01

    No information is available on the decomposition and nutrient release pattern of Piper aduncum and Imperata cylindrica despite their importance in shifting cultivation systems of Papua New Guinea and other tropical regions. We conducted a litter bag study (24 weeks) on a Typic Eutropepts in the humi

  11. Leaf litter decomposition of Piper aduncum, Gliricidia sepium and Imperata cylindrica in the humid lowlands of Papua New Guinea

    NARCIS (Netherlands)

    Hartemink, A.E.; O'Sullivan, J.N.

    2001-01-01

    No information is available on the decomposition and nutrient release pattern of Piper aduncum and Imperata cylindrica despite their importance in shifting cultivation systems of Papua New Guinea and other tropical regions. We conducted a litter bag study (24 weeks) on a Typic Eutropepts in the

  12. Effects of simulated acid rain on leaf litter decomposition of Ginkgo biloba and Taxodium ascendens%模拟酸雨胁迫对银杏与池杉凋落叶分解的影响

    Institute of Scientific and Technical Information of China (English)

    叶龙华; 孙小川; 宋曰钦; 薛立

    2015-01-01

    以硫酸、亚硫酸为原料配制不同 pH 值的酸溶液,采用分解袋法,在室内模拟酸雨处理银杏和池杉凋落叶,研究模拟酸雨胁迫对银杏和池杉凋落叶分解的影响。结果表明:不同 pH 值的模拟酸雨胁迫对银杏和池杉凋落叶的分解率均存在一定的抑制作用,以对照组(pH 值7.0)的凋落叶分解率最高,其次是轻度(pH 值5.6)酸雨胁迫和中度(pH 值4.0)酸雨胁迫处理的,分解率最低的是重度(pH 值2.5)酸雨胁迫处理的,表现为随酸雨胁迫强度增强即 pH 值的减小而减小的趋势。2个不同树种的凋落叶对酸雨胁迫的反应也存在差异,池杉落叶分解受酸雨的影响比银杏落叶的小。%In order to probe the growing problem of acid rain on leaf litter decomposition,the effects of simulated acid rain on leaf litter decomposition of Ginkgo biloba and Taxodium ascendens were studiedby litterbag method in laboratory conditions.The leaf litters of G.biloba and T.ascendens were treated by different pH value of simulated acid rain.The re-sult indecated that the leaf litter decomposition rates of G.biloba and T.ascendens increased with decreasing acid rain in-tensity.The leaf litter decomposition rate of both species was the fastest in the control (pH7.0),followed by mild acid stress (pH5.6),moderate acid rain (pH4.0)and the severe acid rain (pH2.5).There was a difference in respond of leaf litter decomposition of the two species to acid rain.Acid rain influenced on leaf litter decomposition of T.ascendens was smaller than G.biloba.

  13. Araneofauna of the leaf litter in two areas of restinga forest in Capão do Leão, Rio Grande do Sul, Brazil

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    Everton Nei Lopes Rodrigues

    2005-05-01

    Full Text Available The soil spider fauna of a restinga forest in Capão do Leão, Rio Grande do Sul, southern Brazil, was inventoried for a year. Samples were taken in the sandy restinga forest and in the ecotone, monthly, on two 30 m-long transects. Biological material was sampled with 30x30 cm quadrats, four for each transect and eight per monthly sample, with all leaf litter in the quadrats also being collected. Over the 12 samples, dry litter weighed 11.88 kg. Of a total of 96 quadrats, we calculated an annual average of 130.1 spiders/m2. The samples yielded 1124 individuals, of which 335 were adults and 788 were immature, distributed in 26 families with the highest representativity in the Oonopidae (19.57%, Lycosidae (18.06%, Theridiidae (17.08% and Salticidae (10.68% categories. Forty-four morphospecies were distinguished, the most abundant being Euryopis sp. (13.26% and Guaraniella sp. (12.8%. The month with the highest number of individuals was February 2001 (170 spiders and the one with the lowest number was July 2001 (37 specimens. Between the two transects, more spiders were found in the sandy restinga forest Araneofauna de serapilheira em mata de restinga (629 spiders than in the ecotone (495 individuals. The species richness index was 7.39 and the estimated species richness at 53.87 morphospecies.

  14. Identifying Shifts in Leaf-Litter Ant Assemblages (Hymenoptera: Formicidae) across Ecosystem Boundaries Using Multiple Sampling Methods

    Science.gov (United States)

    Wiezik, Michal; Svitok, Marek; Wieziková, Adela; Dovčiak, Martin

    2015-01-01

    Global or regional environmental changes in climate or land use have been increasingly implied in shifts in boundaries (ecotones) between adjacent ecosystems such as beech or oak-dominated forests and forest-steppe ecotones that frequently co-occur near the southern range limits of deciduous forest biome in Europe. Yet, our ability to detect changes in biological communities across these ecosystems, or to understand their environmental drivers, can be hampered when different sampling methods are required to characterize biological communities of the adjacent but ecologically different ecosystems. Ants (Hymenoptera: Formicidae) have been shown to be particularly sensitive to changes in temperature and vegetation and they require different sampling methods in closed vs. open habitats. We compared ant assemblages of closed-forests (beech- or oak-dominated) and open forest-steppe habitats in southwestern Carpathians using methods for closed-forest (litter sifting) and open habitats (pitfall trapping), and developed an integrated sampling approach to characterize changes in ant assemblages across these adjacent ecosystems. Using both methods, we collected 5,328 individual ant workers from 28 species. Neither method represented ant communities completely, but pitfall trapping accounted for more species (24) than litter sifting (16). Although pitfall trapping characterized differences in species richness and composition among the ecosystems better, with beech forest being most species poor and ecotone most species rich, litter sifting was more successful in identifying characteristic litter-dwelling species in oak-dominated forest. The integrated sampling approach using both methods yielded more accurate characterization of species richness and composition, and particularly so in species-rich forest-steppe habitat where the combined sample identified significantly higher number of species compared to either of the two methods on their own. Thus, an integrated sampling

  15. Identifying Shifts in Leaf-Litter Ant Assemblages (Hymenoptera: Formicidae) across Ecosystem Boundaries Using Multiple Sampling Methods.

    Science.gov (United States)

    Wiezik, Michal; Svitok, Marek; Wieziková, Adela; Dovčiak, Martin

    2015-01-01

    Global or regional environmental changes in climate or land use have been increasingly implied in shifts in boundaries (ecotones) between adjacent ecosystems such as beech or oak-dominated forests and forest-steppe ecotones that frequently co-occur near the southern range limits of deciduous forest biome in Europe. Yet, our ability to detect changes in biological communities across these ecosystems, or to understand their environmental drivers, can be hampered when different sampling methods are required to characterize biological communities of the adjacent but ecologically different ecosystems. Ants (Hymenoptera: Formicidae) have been shown to be particularly sensitive to changes in temperature and vegetation and they require different sampling methods in closed vs. open habitats. We compared ant assemblages of closed-forests (beech- or oak-dominated) and open forest-steppe habitats in southwestern Carpathians using methods for closed-forest (litter sifting) and open habitats (pitfall trapping), and developed an integrated sampling approach to characterize changes in ant assemblages across these adjacent ecosystems. Using both methods, we collected 5,328 individual ant workers from 28 species. Neither method represented ant communities completely, but pitfall trapping accounted for more species (24) than litter sifting (16). Although pitfall trapping characterized differences in species richness and composition among the ecosystems better, with beech forest being most species poor and ecotone most species rich, litter sifting was more successful in identifying characteristic litter-dwelling species in oak-dominated forest. The integrated sampling approach using both methods yielded more accurate characterization of species richness and composition, and particularly so in species-rich forest-steppe habitat where the combined sample identified significantly higher number of species compared to either of the two methods on their own. Thus, an integrated sampling

  16. Effects of shallow burial on the decomposition of triploid Populus tomentosa leaf litter.%浅埋对三倍体毛白杨落叶分解的影响

    Institute of Scientific and Technical Information of China (English)

    宋曰钦; 董转年; 程开云; 曹正东

    2011-01-01

    Litter decomposition plays an important role in the nutrient cycling and energy transfer in forest ecosystems. By using Iitterbag method, this paper studied the leaf litter decomposition in 2-, 4-, and 6 years old Populus tomentosa pulp plantations under the condition of shallow burial, aimed to realize the scientific management of nutrients and to accelerate the decomposition of leaf litter in triploid P. Tomentosa pulp plantations. Shallow burial promoted the leaf litter decomposition significantly, as compared to the decomposition on soil surface. The decomposition rate of the leaf litters in 2-, 4-, and 6 years old P. Tomentosa pulp plantations under shallow burial for one year increased significantly, being 130% , 194% , and 186% of that on soil surface, respectively. Compared with the decomposition on soil surface, the days needed for 50% leaf litter decomposition in 2-, 4-, and 6 years old triploid P. Tomentosa pulp plantations under shallow burial were shortened by 58% , 39% , and 38% , and those needed for 95% decomposition were shortened by 60% , 38% and 36% , respectively, indicating that the promotion effect of shallow burial on the leaf litter decomposition differed with triploid P. Tomentosa plantation age.%凋落物分解在森林生态系统养分循环及能量流动中具有十分重要的作用,为实现三倍体毛白杨纸浆林养分的科学管理,加快落叶分解,采用网袋法研究了2、4、6年生3个不同年龄的林分落叶在浅埋条件下的分解情况.结果表明:与在地表分解相比,浅埋显著促进了三倍体毛白杨落叶的分解,1年的分解率显著提高,分别为落叶在地表年分解率的130%、194%和186%;浅埋落叶分解50%所需天数分别只有地表的58%、39%和38%,而分解95%所需的天数分别只有地表的60%、38%和36%;浅埋对不同年龄林分落叶的促进程度不同.

  17. Oribatid mite (Acari: Oribatida contribution to decomposition dynamic of leaf litter in primary forest, second growth, and polyculture in the Central Amazon

    Directory of Open Access Journals (Sweden)

    E. Franklin

    Full Text Available We studied the contribution of oribatid mites in the dynamics of litter decomposition in an experiment using litterbags of three different mesh sizes (20 µm, 250 µm, and 1 cm. The experiment was carried out at a primary forest (FLO, a secondary forest (SEC, and at two polyculture systems (POA and POC. We compared the weight loss of the leaves of Vismia guianensis and the changes of the oribatid mite species community. We processed the samples after 26, 58, 111, 174, 278, and 350 days from the beginning of the experiment by using the Berlese-Tullgren to extract the animals. We hypothesized that: 1. the abundance and diversity of oribatid mites would exert an influence in the decomposition process; 2. there would be a successional changing of the species during decomposition; and 3. there would be differences in the colonization of species in relation to the mesh size of the litterbags. A total of 95 species of oribatid mites was found. The biomass data was the first registered for the Amazon region. The great dominance of oribatid mites did not exert an influence in the decomposition process. There was not a successional changing of the species during the course of the decomposition process, unlike those shown by results obtained in the temperate forest, because we found neither early colonizers nor species that prefer advanced decomposition stages. The oribatid mite community, which developed in the litterbags under tropical conditions, was atypical of the normal stages of leaf litter breakdown and decomposition. There were differences in the colonization of species in relation to the mesh size of the litterbags. These differences were very closely related to the specific habits and habitat of the dominant species.

  18. 巨桉凋落叶分解对菊苣生长及光合特性的影响%Effects of Eucalyptus grandis leaf litter decomposition on the growth and photosynthetic characteristics of Cichorium intybus

    Institute of Scientific and Technical Information of China (English)

    吴秀华; 胡庭兴; 杨万勤; 陈洪; 胡红玲; 涂利华; 泮永祥; 曾凡明

    2012-01-01

    A pot experiment was conducted to study the effects of Eucalyptus grandis leaf litter during its early stage decomposition on the growth and the photosynthesis of Ckhorium intybus. Each pot contained 12 kg soil mixed with different amounts of E. grandis leaf litter (30 g · pot-1, A1; 60 g · pot-1, A2; 90 g · pot-1, A3; and 0 g · pot-1, CK) , and sowed with C. intybus. The growth indicators and the photosynthetic characteristics of C. intybus were measured after the third leaf of C. intybus seedlings fully expanded in treatment A,. At the early stage of leaf litter decomposition , the C. intybus biomass accumulation, leaf area growth, and synthesis of photosynthetic pigments were inhibited significantly, and the inhibition effect was getting stronger with the increasing amount of the leaf litter addition. The intercellular CO2 concentration of C. intybus was increased by litter addition, while the net photosynthetic rate, stomatal conductance, and transpiration rate were significantly lower than those of the control. With the increase of leaf litter addition, all the parameters of C. intybus light response and CO2 response except CO2 compensation point showed an obvious downward trend, and there existed significant differences between the treatments of litter additions and the control. It was suggested that during the decomposition of E. grandis leaf litter, its al-lelopathic substances released gradually and acted on receptor plants, inhibited the synthesis of photosynthetic pigments and the photosynthesis of the receptors, decreased the receptors environmental adaptation ability, and accordingly, inhibited the growth of C. intybus.%采用盆栽试验,研究了巨桉凋落叶分解初期对菊苣幼苗生长和光合生理特性的影响,试验设置A1(30 g·pot-1)、A2(60 g·pot-1)、A3 (90 g·pot-1)和对照(CK)4个凋落叶水平,将各处理的凋落叶分别与12 kg土壤混合后装盆,播种菊苣.待A3处理植株的第3片真叶完全展开后测定

  19. Seasonal variation in the leaf-litter frog community (Amphibia: Anura from an Atlantic Forest Area in the Salto Morato Natural Reserve, southern Brazil

    Directory of Open Access Journals (Sweden)

    Manuela Santos-Pereira

    2011-12-01

    Full Text Available In this study we provide the first data regarding community parameters of leaf-litter anurans inhabiting a forest floor in the state of Paraná, southern Brazil, including information on community species richness, composition, specific density and biomass. Our study was conducted at Salto Morato Natural Reserve using forty plots of 4 x 4 m for each one of the four seasons (winter, spring, summer and autumn, totaling 2.560 m² of forest floor sampled. We sampled a total of 96 frogs inhabiting the forest floor, belonging to seven species: Brachycephalus hermogenesi (Giaretta & Sawaya, 1998, Ischnocnema guentheri (Steindachner, 1864, Haddadus binotatus (Spix, 1824, Leptodactylus gr. marmoratus, Physalaemus spiniger (Miranda-Ribeiro, 1926, Proceratophrys boiei (Wied-Neuwied, 1824, and Rhinella abei (Baldissera, Caramaschi & Haddad, 2004. The overall frog density in the forest floor was 3.73 ind/100m², with I. guentheri (1.37 ind/100 m² being the most common species and R. abei (0.19 ind/100 m², the rarest. The estimated overall frog mass in the community was 3.29 g. The abundance, richness and density varied consistently among the four seasons sampled, with the highest values occurring in the spring and summer seasons.

  20. Effects of the decomposition of poplar and aider mixed leaf litters on soil microbial biomass%杨树和桤木落叶混合分解对土壤微生物生物量的影响

    Institute of Scientific and Technical Information of China (English)

    陈琴; 方升佐; 田野

    2012-01-01

    通过室内培养,研究了杨树和江南桤木落叶混合分解过程中两种落叶的混合比例及落叶添加方式对土壤微生物生物量的影响.结果表明:落叶混合比例对土壤微生物生物量碳(MBC)、氮(MBN)均有显著的影响.培养30 d,江南桤木落叶比例为50%以上的土壤MBC和MBN显著高于纯杨树落叶处理及对照;75 d时,江南桤木落叶比例≥40%的土壤MBC和≥30%的土壤MBN均显著高于纯杨树落叶处理及对照;135 d后,江南桤木落叶比例≥20%的土壤MBC和≥40%的土壤MBN均显著高于纯杨树落叶处理及对照.不同混合比例的土壤MBC/MBN无显著差异,总体呈前期增长后期下降的变化趋势.杨树和江南桤木落叶混合分解对土壤MBC和MBN有显著的协同促进作用.在整个培养过程中,落叶添加方式对土壤MBC、MBN和MBC/MBN无显著影响.%An incubation test was conducted to study the effects of the decomposition of poplar and trabeculate alder leaf litters with different mixed ratios and under different application ways on soil microbial biomass carbon (MBC) and nitrogen (MBN). The mixed ratio of the litters had significant effects on soil MBC and MBN. On the 30th day of incubation, soil MBC and MBN were significantly higher in the treatments with ≥50% of alder litter than in the treatment with poplar litter only and the control. On the 75th day of incubation, the soil MBC in the treatments with ≥40% of alder litter and the soil MBN in the treatments with ≥30% of alder litter were significantly greater than those in the treatment with poplar litter only and the control. After 135 days incubation, soil MBC and MBN were significant higher in the treatments with ≥20% and ≥40% of alder litter than in the treatment with poplar litter only and the control, respectively. There was no significant difference in the soil MBC/MBN between the treatments with different mixed ratios of poplar and alder leaf litters and the

  1. Effects of UV-B radiation on the decomposition of Cunninghamia lanceolata leaf litter%UV-B辐射对杉木凋落叶分解的影响

    Institute of Scientific and Technical Information of China (English)

    张慧玲; 宋新章; 张智婷; 江洪; 王懿祥; 白尚斌

    2011-01-01

    A litterbag experiment was conducted to study the decomposition of Cunninghamia lanceolata leaf litter under ambient and reduced UV-B radiation (22.1% below ambient) . Comparing with ambient treatment. the reduced treatment decreased the decomposition rate of C. lanceolata leaf litter by 69. 6% ( P<0.001 ) . making the relative contents of nitrogen ( N) , phosphorus ( P) ,and lignin in the litter increased by 150% , 83. 3% , and 13. 8% , respectively, and the release of potassium ( K) and carbon ( C) slowed down. In the process of litter decomposition, photo-degradation of lignin didn't play crucial role. The results suggested that UV-B radiation could accelerate the decomposition rate of C. lanceolata leaf litter, promote the release of N. P. K. and C from it.and increase the nutrients turnover rate in litter layer as well as the carbon flux on the ground, giving potential effects on the function of C. lanceolata forest as a carbon source or sink in humid subtropical China.%采用分解袋法对自然和UV-B辐射滤减环境下的杉木凋落叶进行分解试验.结果表明:与对照相比,UV-B辐射滤减处理使杉木凋落叶的分解速率降低了69.6%(P<0.001),凋落叶中氮、磷和木质素的相对含量分别增加150%、83.3%和13.8%,抑制了钾和碳的释放.木质素光降解在杉木凋落叶分解过程中的作用不明显.UV-B辐射可以加快杉木凋落叶的分解,促进氮、磷、钾和碳的释放,以及杉木林凋落物层的营养周转速度,增加地表的碳通量,对杉木林的碳源或碳汇功能具有潜在的影响.

  2. 亚热带溪流中树叶凋落物多酚含量对树叶分解过程的影响%Effect of Polyphenol of leaf litter on the leaf breakdown in a subtropical Stream

    Institute of Scientific and Technical Information of China (English)

    官昭瑛; 赵颖; 童晓立

    2008-01-01

    利用邻二氮菲-铁(Ⅲ)分光光度法测定了蒲桃与人面子树叶在二级溪流中分解时植物多酚含量的变化,并研究了多酚含量对树叶分解速率、底栖动物定殖以及微生物呼吸量的影响. 结果表明,蒲桃叶片中初始多酚含量(19%)比人面子树叶的含量高(6%),其分解速率(分解系数k=0.01 d-1)比人面子树叶慢(k=0.04 d-1).研究还发现,蒲桃叶片上的微生物呼吸量比人面子的低(每克叶片单位时间的耗氧量分别为0.2和0.4毫克),而且底栖动物中撕食者的种类和数量也比人面子树叶少.说明蒲桃叶片中较高的多酚含量抑制了微生物的活性和底栖动物的取食,从而减缓了蒲桃树叶的分解进程,表明叶片中多酚含量与树叶凋落物分解速率呈负相关关系.%We used a spectrophotometry method with 1,10-phenanthroline-Fe(III)to determine the contents of total polyphenol in two species of leaf litter,Dracontomelon duperreanum and Syzygiumjambos.The effects of remaining polyphenolics concentrmion on decomposition rates,colonization of macroinvertibrates and microbial respiratiOn in a subtropical stream were examined.Results showed that total polyphenol was significantly higher in S.jambos(19%)when compared to D.duperreanum(6%),and breakdown rate of S.jambos(k=0.01 day-1)was slower than that of D.duperreanum(k=0.04 day-1).The results also indicated that the average microbial respiration rates(0.2 mg O2 h-1g DM-1)of S.jambos litters Was significantly lower than those of D.duperreanum(0.4 mg O2 h-1g DM-1),and its taxa richness and total density in shredders of macroinvertebrate Was significantly less than in those of D.duperreanum (P<0.05).The low breakdown rate of S.jambos leaves in the early period is mainly as a result of inhibition of microbial activity as well as less palatable to shredders of macroinvertebrates due to high contents of polyphenols,which showed that the leafpolyphenol had a strong negative effect on leaf

  3. UV-B辐射对亚热带森林凋落叶分解的影响%Effects of UV-B Radiation on Leaf Litter Decomposition in Humid Subtropical Region in China

    Institute of Scientific and Technical Information of China (English)

    宋新章; 张慧玲; 江洪; 余树全

    2012-01-01

    The leaf litter decomposition of six representative tree species, Cunninghamia lanceolata, Pinus massoniana, Schima superba, Cinnamomum camphora, Cyclobalanopsis glauca and Castanopsis eyeri, in subtropical region was investigated with litterbag method under ambient and reduced ultraviolet-B ( UV-B ) radiation (22. 1 % below ambient) treatments. The results showed that there were differences in litter mass remaining rates of each species under two UV-B radiation treatments, except for a few decay stages during decomposition, and the difference became more obvious with decay time. The reduced UV-B significantly decreased the litter decomposition rates of six species by an extent from 33.3% for C. Camphora to 69.6% for C. Lanceolata (P < 0.01). Both UV-B radiation treatment and litter type significantly affected litter decomposition rate ( P < 0. 001 ) , with a stronger effect of UV-B radiation than litter type. There were significantly negative correlations between decomposition rate and C = N ratio of leaf litter under both ambient and reduced UV-B radiation treatments (P <0. 05).%采用分解袋法研究自然和UV-B辐射滤减2种环境下6种亚热带代表性树种(杉木、马尾松、木荷、香樟、青冈和甜槠)凋落叶的分解情况.结果表明:除个别分解阶段外,各树种凋落叶在2种UV-B辐射环境下的干质量剩余率均存在显著差异,且随着分解时间延长,差异逐渐加大;与对照相比,UV-B辐射滤减显著降低了6个树种凋落叶的分解速率(P<0.01),降幅为33.3%~69.6%,对香樟凋落叶分解的影响最小,对杉木凋落叶分解的影响最大;UV-B辐射处理和凋落物类型对凋落叶的分解速率均有极显著影响(P<0.001),以UV-B辐射的影响更强烈;自然和UV-B辐射滤减环境下凋落叶的分解速率均与C∶N呈显著负相关(P<0.05).

  4. 侧柏与其他树种枯落叶混合分解对养分释放的影响%IMPACTS OF DECOMPOSITION OF MIXTURE OF LEAF LITTERS FROM PLATYCLADUS ORIENTALIS AND OTHER TREES ON NUTRIENT RELEASE

    Institute of Scientific and Technical Information of China (English)

    张晓曦; 刘增文; 祝振华; 杜良贞

    2013-01-01

    以黄土高原的主要人工林树种侧柏为对象,通过采集侧柏及其他拟混交的8个树种的当年枯落叶,以无林荒草地腐殖质层土壤作为分解介质,在室内将侧柏与不同树种枯落叶剪碎后以一定比例混合装入尼龙网袋并埋人盛土培养钵中,进行恒温恒湿下连续345 d分解培养试验,测定分解前后枯落叶质量及养分含量的变化.结果表明:(1)在枯落叶分解释放养分元素中,K最活跃而易于释出,p一般比较迟钝而难以释出,C、N居中并具有一定的释出同步性,且各种养分的周转期约为1~2a.(2)与侧柏枯落叶混合分解后,在对C释放的影响中白榆表现为促进作用,紫穗槐、白桦和辽东栎表现为抑制作用;在对N释放的影响中小叶杨表现为促进作用,白桦、辽东栎和紫穗槐表现为抑制作用;在对P释放的影响中除小叶杨、白榆不明显之外均表现为抑制作用;在对K释放的影响中白榆表现为促进作用,紫穗槐表现为抑制作用.(3)应用主成分分析法分析不同树种枯落叶混合分解对C、N、P、K释放的综合影响结果表明,与侧柏枯落叶混合分解后总体上促进养分释放的树种以白榆、小叶杨最显著,其次为柠条和辽东栎;而总体上抑制养分释放的树种以紫穗槐的作用最强,白桦、沙棘和刺槐的作用较弱.%For this study,Platycladus orientalis,a major tree species used in afforestation in the Loess Plateau,was chosen.Leaf litters of the current year were gathered from P.orientalis and 8 other tree species that were planned to be planted in mixed forests,and soil from the humus layer (0 ~ 20 cm) of a tract of tree-free waste grassland was used as medium,in which litters were to be decomposed.Mixtures of litter from P.orientalis with others were shredded and packed into nylon mesh bags according to a set ratio,separately.Then the bags were buried into the soil contained in pots for incubation under a

  5. A taxonomic monograph of the leaf-litter inhabiting weevil genus Plumolepilius new genus (Coleoptera: Curculionidae: Molytinae: Conotrachelini) from Mexico, Guatemala, and El Salvador.

    Science.gov (United States)

    Barrios-Izás, Manuel A; Anderson, Robert S; Morrone, Juan J

    2016-09-14

    We describe the Mesoamerican leaf litter weevil genus Plumolepilius Barrios-Izás & Anderson, new genus (Coleoptera: Curculionidae: Molytinae: Conotrachelini) (type species P. trifiniensis Barrios-Izás & Anderson, new species), species of which inhabit mountain ecosystems from the state of Chiapas in southeastern Mexico to northern Panama. In this paper we describe nine new species from Mexico, Guatemala, and El Salvador: P. trifiniensis Barrios-Izás & Anderson, new species (El Salvador and Guatemala); P. branstetteri Barrios-Izás & Anderson, new species (Guatemala and Mexico); P. longinoi Barrios-Izás & Anderson, new species (Guatemala and Mexico); P. cortezi Barrios-Izás & Anderson, new species (Guatemala and Mexico); P. canoi Barrios-Izás & Anderson, new species (Guatemala); P. schusteri Barrios-Izás & Anderson, new species (Guatemala and Mexico); P. daryi Barrios-Izás & Anderson, new species (Guatemala); P. yolnabajensis Barrios-Izás & Anderson, new species (Guatemala); and P. macalajauensis Barrios-Izás & Anderson, new species (Guatemala).        The genus and the species are named and described, information on their geographical distributions is given and images of the habitus of both sexes and the aedeagus are presented. A key to the species of Plumolepilius based on males is included.        The monophyly of Plumolepilius was confirmed by a parsimony analysis of external and male aedeagus morphology and the genus is best characterized by the presence of plumose scales lining the prosternal channel. Phylogenetic analysis supports that Lepilius Champion 1905 is the sister genus of Plumolepilius.

  6. Fate of leaf-litter N in forest and grassland along a pedo-climatic gradient in south-western Siberia: an in situ 15N-labelling experiment

    Science.gov (United States)

    Brédoire, Félix; Zeller, Bernd; Nikitich, Polina; Barsukov, Pavel A.; Rusalimova, Olga; Bakker, Mark R.; Legout, Arnaud; Bashuk, Alexander; Kayler, Zachary E.; Derrien, Delphine

    2017-04-01

    The suitability of Siberia for agriculture is expected to increase in the next decades due to strong and rapid climatic changes, but little is known on the environmental drivers of soil fertility there, especially nitrogen (N). Plant-available N is mainly derived from litter decomposition. South-western (SW) Siberia is located on the transition between several bioclimatic zones that are predicted to shift and extend along with climate change (steppe, forest-steppe, sub-taiga). The soils of this region are formed on a common loess deposit but they are submitted to different climatic conditions and vegetation cover. In the south of the region, typically in steppe/forest-steppe, soil freezes over winter because of a relatively shallow snow-pack, and water shortages are frequent in summer. In the north, typically in sub-taiga, the soil is barely frozen in winter due to a thick snow-pack and sufficient soil moisture in summer. In this study, we characterized the dynamics of leaf litter decomposition and the transfer of N from leaf litter to the soil and back to plants. Four sites were chosen along a climate gradient (temperature, precipitation and snow depth). At each site, we applied 15N-labelled leaf litter on the soil surface in experimental plots in an aspen (Populus tremula L.) forest and in a grassland. Twice a year during three years, we tracked the 15N derived from the decomposing labelled-litter in the organic layers, in the first 15 cm of the soil, and in above-ground vegetation. Soil temperature and moisture were monitored at a daily timestep over three years and soil water budgets were simulated (BILJOU model, Granier et al. 1999). We observed contrasting patterns in the fate of litter-derived 15N between bioclimatic zones. Over three years, along with faster decay rates, the release of leaf litter-N was faster in sub-taiga than in forest-steppe. As such, higher quantities of 15N were transferred into the soil in sub-taiga. The transfer was also deeper there

  7. Decomposition rate of four dominant tree species leaf litters in Qingling Huoditang forests%秦岭火地塘林区四种主要树种凋落叶分解速率

    Institute of Scientific and Technical Information of China (English)

    何帆; 王得祥; 雷瑞德

    2011-01-01

    利用野外分解袋法对秦岭火地塘林区油松、华山松、华北落叶松、锐齿栎凋落叶的分解速率和养分释放趋势进行研究.结果表明,分解2年后,4种树种凋落叶的干物质残留率在35.6%~58.6%,残留率大小顺序为油松>华山松>华北落叶松>锐齿栎.除油松与华山松凋落叶之间残留率差异不显著外,各树种之间凋落叶分解后的残留率差异显著.在2个试验年度中,4-9月凋落叶分解最快,在其他月份保持较平稳的分解速度,分解前12个月凋落叶失重速度明显大干后12个月,呈明显的季节和阶段性差异.利用Olson模型对凋落叶分解50%和95%所需时间进行估测,结果显示,不同树种所需时间差异显著,其中锐齿栎凋落叶95%被分解所需时间最短,为5.43年,油松最长,为9.87年.凋落叶中N、P元素在分解第1年均表现出富集现象,直至1年后达到一个最高值后,开始释放,C含量则呈现出逐步下降的趋势.导致不同树种凋落叶分解速率及养分释放速率差异主要与不同凋落叶的初始质量和性质有关.%By using field litter bag technique, this paper studied the decomposition rate and nutrient release of the leaf litters from Pinus tabulaeformis, P.armandii, Larix principis-rupprechtii, and Quercus aliena var.acuteserrata in Qingling Huoditang forest area.After two years decomposition, the remaining percentage of the leaf litters was 35.6% -58.6% , and ranked as P.tabulaeformis > P.armandii > L.principis-rupprechtii > Q.aliena var.acuteserrata.Except that P.tabulaeformis and P.armandii had no significant difference in their leaf litters remaining percentage, there existed significant differences in the remaining percentage among the test tree species.During the two-year experiment, the leaf litters decomposed fastest during the period from April to September, and kept a stable decomposition rate in other months.Compared the second year, the mass loss rate of the

  8. Litter input controls on soil carbon in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Bowden, Richard D.; Deem, Lauren; Plante, Alain F.

    2014-01-01

    evolution during SOM combustion revealed differences in SOM quality between surface and deeper horizons. Our work shows that the sources of litter are important in controlling soil C. Leaf litter made important contributions to maintaining current stocks of soil C; increased leaf litter did not increase...... in five treatments (control, double litter [DL], no litter [NL], no roots [NR], no inputs [NI]). After two decades of doubled litter addition, soil C and SOM did not increase. However, leaf litter exclusions reduced soil C (O and mineral horizons combined) by 24% in NL and 33% in NI treatments...

  9. Effect of mangrove leaf litter decomposition on soil dissolved organic matter%红树植物凋落叶分解对土壤可溶性有机质的影响

    Institute of Scientific and Technical Information of China (English)

    杨秀虹; 彭琳婧; 李适宇; 王诗忠

    2013-01-01

    Understanding the sources, properties and fates of dissolved organic matter (DOM) in mangrove wetland soils is of signif-icance to reveal the role of DOM in biogeochemical cycles in mangrove wetlands. A 48-day soil incubation experiment was con-ducted with addition of nearly-senesced leaves of mangrove plants (Bruguiera gymnorrhiza, Kandelia candel and Aegiceras cornic-ulatum) to investigate soil DOM changes during mangrove leaf litter decomposition. Soil samples were collected after 6, 12, 18, 26, 36 and 48 days of incubation, and the concentrations of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN), C:N ratio (DOC:TDN) and spectrophotometric absorbance (A280, A240/A420 and A250/A365 ratios) in soil solutions were analyzed. Results show that DOC concentrations in soil solutions were significantly increased by the addition of mangrove leaf litters, and reached the maximum after 6 days with an average increase of between 149%(K. candel) and 196%(A. corniculatum) compared with the control treatment without litter addition, followed by a decrease trend during later incubation periods, while those of control treatment re-mained fairly steady after a drop by day 6. Only slight change was observed for TDN content after input of leaf litter, while the C∶N ratios of soil solutions were significantly higher than those of control treatment (P<0.05) during the early decay of B. gymnorrhiza or A. corniculatum leaf litter. The spectrophotometric absorbances of soil solutions were also influenced by litter addition with an in-crease in A280 value and decrease in A240/A420 or A250/A365 ratio, noticeably for A. corniculatum leaf litter treatment but minimally for K. candel leaf litter treatment after 6-day incubation. These results suggested that litter input and decomposition strongly influenced contents and properties of DOM in soil, especially during the initial decomposition stage, resulting in enhancement of high-er-molecular components and aromatic

  10. 刺槐与其他树种枯落叶混合分解对微量元素释放的影响%Influences of mixed leaf litter decomposition of Robinia pseudoacacia with other trees on microelements release

    Institute of Scientific and Technical Information of China (English)

    杜良贞; 刘增文; 祝振华; 李茜

    2012-01-01

    【目的】检测刺槐分别与其他10个树种枯落叶混合分解后是否对Cu、Zn、Ni和Cd等微量元素的释放产生促进作用,从微量元素的角度研究刺槐与拟混交树种的种间养分关系,为刺槐混交林的树种选择提供科学依据。【方法】在黄土高原,于秋末冬初采集刺槐及其他10个树种的当年枯落叶,并剪成1cm大小的碎片或长1cm的短针叶,同时采集无林荒草地腐殖质层(0-20cm)土壤作为介质,在室内相同温度和湿度条件下,以尼龙网袋埋土法连续345d进行枯落叶混合分解培养试验,并用原子吸收光谱分析法(AAS)测定枯落叶分解前后微量元素Cu、Zn、Ni、Cd的含量。【结果】枯落叶分解过程中,Cu、Zn、Ni和Cd的释放速率均以柠条、小叶杨、沙棘、侧柏、辽东栎较快,周转期略大于1年。刺槐分别与小叶杨、白榆、沙棘枯落叶混合分解,对4种微量元素的释放均呈现出促进作用;而分别与樟子松、侧柏、白桦、拧条枯落叶混合分解,对4种微量元素的释放均呈现出抑制作用;刺槐分别与油松、华北落叶松枯落叶混合分解,对Cu的释放有一定的促进作用,而对Zn、Ni、Cd的释放呈现出抑制作用;刺槐与辽东栎枯落叶混合分解,对Zn、Cd的释放有促进作用,而对Cu、Ni的释放有抑制作用。【结论】选择与刺槐枯落叶混合分解后能促进多数微量元素释放的树种进行混交,将有利于林地微量元素的循环利用。%[Objective] From the standpoint of mieroelements, the interspecific nutrient relationship of Robinia pseudoacacia with other trees were studied through detecting whether the mixed leaf litter decom- position of R. pseudoacacia with other trees would produce promoted or inhibitory actions on release of Cu,Zn,Ni and Cd,in order to provide a scientific basis for selection of tree species mixed with R. pseud- oacacia. [Method] In the

  11. Contribution of soil fauna to the mass loss of Betula albosinensis leaf litter at early decomposition stage of subalpine forest litter in western Sichuan%川西亚高山森林凋落物分解初期土壤动物对红桦凋落叶质量损失的贡献

    Institute of Scientific and Technical Information of China (English)

    夏磊; 吴福忠; 杨万勤; 谭波

    2012-01-01

    2010年10月26日-2011年4月18日在川西亚高山地区季节性冻融期间,选择典型的红桦-岷江冷杉林,采用凋落物分解袋法调查了不同网孔(0.02、0.125、1和3 mm)凋落物分解袋内的凋落物质量损失,分析微型、中型和大型土壤动物对红桦凋落叶分解的贡献.结果表明:在季节性冻融期间,0.02、0.125、1和3 mm分解袋内的红桦凋落叶质量损失率分别为11.8%、13.2%、15.4%和19.5%,不同体径土壤动物对红桦凋落叶质量损失的贡献率为39.5%;不同孔径凋落物袋内土壤动物的类群和个体相对密度与凋落叶的质量损失率的变化趋势相对一致.在季节性冻融的初期、深冻期和融化期,不同土壤动物对红桦凋落叶质量损失的贡献率为大型土壤动物(22.7%)>中型土壤动物(11.9%)>微型土壤动物(7.9%).季节性冻融期间土壤动物活动是影响川西亚高山森林凋落物分解的重要因素之一.%In order to quantify the contribution of soil fauna to the decomposition of birch (Betula albosinensis) leaf litter in subalpine forests in western Sichuan of Southwest China during freeze-thaw season, a field experiment with different mesh sizes (0.02, 0.125 , 1 and 3 mm) of litterbags was conducted in a representative birch-fir (Abies faxoniana) forest to investigate the mass loss rate of the birch leaf litter from 26 October, 2010 to 18 April, 2011, and the contributions of micro-, meso- and macro-fauna to the decomposition of the leaf litter. Over the freeze-thaw season, 11. 8% , 13. 2% , 15. 4% and 19. 5% of the mass loss were detected in the litterbags with 0. 02, 0. 125, 1 and 3 mm mesh sizes, respectively. The total contribution of soil fauna to the litter decomposition accounted for 39.5% of the mass loss, and the taxa and individual relative density of the soil fauna in the litterbags had the similar variation trend with that of the mass loss rate. The contribution rate of soil fauna to the

  12. Allelopathic Potential of Leaf Litter and Forest Soil of Populus yunnanensis Dobe%滇杨枯落叶和林下土壤的化感潜力1)

    Institute of Scientific and Technical Information of China (English)

    王有兵; 严毅; 王亚婷; 李子光; 周庆宏; 袁思安; 何承忠

    2015-01-01

    We studied allelopathic potential of leaf litter and forest soil of Populus yunnanensis Dobe by bioassay.The leaf litter extract of P.yunnanesn is Dobe could delay the seeds germination and inhibit plumule growth of Bidenspi losa L., radicle growth was inhibited when at concentration of 2.5%, and the allelopathic effect sensitivity index ( RI ) was -0.22.Inhibi-tion effects on plant height and biomass were increased with the increasing concentration of extract leaf litter and adding proportion of leaf litter powder, the RI for plant height and biomass were-0.17 and-0.54, respectively, when the concen-tration was at 2.5%, moreover, and adding leaf litter powder proportion of 80%the RI about plant height and biomass were-0.54 and -0.67, respectively.The allelopathic sensitivity degree of biomass was higher than plant height.The forest soil had the promotion effect on the growth of Bidens pilosa L..The soil in >2-10 cm deep had strong stimulated effect, and the RI of plant height and biomass were 0.57 and 0.73, respectively.%采用生物测定法,对滇杨枯落叶和林下土壤的化感潜力进行了研究。结果表明:滇杨枯落叶浸出液会延缓三叶鬼针草种子萌发,抑制胚芽生长,在2.5%的处理质量分数下,对胚根的生长具有抑制作用,化感效应敏感指数RI=-0.22。对株高和生物量的抑制作用,随着浇灌枯落叶浸出液质量分数及添加枯落叶粉比例的增加而增强,质量分数为2.5%时,株高的RI=-0.17,生物量的RI=-0.54。在添加80%枯落叶粉的处理下,株高的RI=-0.54,生物量的RI=-0.67,生物量的化感效应敏感程度高于株高。滇杨林下土壤对三叶鬼针草生长无化感抑制作用,均表现为化感促进作用,>2~10 cm深的土壤促进作用最强,株高和生物量的化感效应敏感指数分别为0.57、0.73。

  13. 不同调控措施下橡胶凋落叶分解速率研究%Study on Decomposition of Rubber Leaf-Litter with Different Control Measures

    Institute of Scientific and Technical Information of China (English)

    金龙; 吴志祥; 杨川; 管利民; 赖华英

    2015-01-01

    通过原位网袋法,研究6、12、20 a 和28 a 4组林龄橡胶凋落叶在不同调控措施下1 a 内的分解过程。结果表明:橡胶凋落叶在0.07 mm 和1.00 mm 孔径网袋内分解趋势基本一致,表现为随时间变化分解呈现先快后慢2个阶段,经1 a 分解后,0.07 mm 和1.00 mm 孔径网袋内残留率分别为36.84%和32.09%。橡胶凋落叶分解速率不仅受埋层位置影响,还与土壤肥力有关。经240 d 分解后,地上组(0 cm)和在保留根系下非肥坑地下组(0~30 cm)、肥坑地下组(0~30 cm)残留率分别为32.09%、7.40%和34.58%。土壤肥力对橡胶凋落物分解的影响主要体现在分解中后期,至240 d 时,4块林地肥坑和非肥坑平均残留率(保留根系组+去除根系组平均值)分别为35.62%和8.46%。6、12、20 a 和28 a 林龄4组橡胶凋落叶原位埋置分解中,前期分解速率差异小,后期分解速率呈显著差异,至240 d 时,残留率分别为2.94%、7.05%、14.62%和2.18%。橡胶根系前期促进凋落物分解,后期转为抑制,但橡胶根系没有显著性改变凋落物的分解速率。%Leaf-litter of 6-year-old,12-year-old,20-year-old and 28-year-old rubber plantations was used to studied the decomposition progress in one year under different control measures by mesh bag method.The results as following:leaf-litter in 0.07 mm and 1.0 mm mesh bags was in a same decomposition dynamic,which was in-creased first and then drop,and the litter residues rates at the end of year were 36.84 % and 32.09 %,respec-tively.Leaf-litter decomposition rates not only by the position of the buried layer influence,but also with soil fertility-related.After 240 d,litter residues of ground plane (0 cm),comparison hole (0 -30 cm)and fertile hole (0 -30 cm)not included roots removed were 32.09%,7.40% and 34.58%,respectively.Litter decomposition of rubber was reflected by soil fertility mainly focus on the

  14. 巨桉凋落叶分解初期对老芒麦幼苗生长和抗性生理的影响%Effects of Eucalyptus grandis leaf litter on growth and resistance physiology of Elymus sibiricus in the initial decomposition process of litter in soil

    Institute of Scientific and Technical Information of China (English)

    陈洪; 胡庭兴; 杨万勤; 吴秀华; 尹丽; 李彬; 米小华; 曾凡明; 弓平

    2011-01-01

    The allelopathic effects of leaf litter (in the initial decomposition process of litter in soil) of Eucalyp tus grandis on growth and resistance physiology of Elymus sibiricus was studied in a pot experiment. Each pot contained 8 kg soil mixed with 0, 25, 50, 100, or 150 g leaf litter. E. sibiricus was sown in September and height, biomass and several indices of resistance physiology were tested at 30, 40, 50, and 90 d after sowing. 1) Height and biomass of E. sibiricus were significantly inhibited after 90 d. 2) The activities of SOD and CAT in leaves of E. sibiricus increased in conditions of low litter content and short decomposition times but were in hibited with higher-contents of litter or longer treatment times. POD was significantly inhibited by different treatments after 90 days. 3) The MDA content rose with the increasing litter content at 50 d, but had de creased in all treatments by 90 d. 4) The soluble carbohydrate content increased considerably, whereas that of soluble protein had considerably reduced by 90 d. 5) The effects of leaf litter decomposition in soil was high at first but then weakened. Faster and stronger allelopathic effects were observed in treatments with higher litter content than those with lower ones. The compound effect of the 150 g treatment was the strongest, while that of 50 -100 g treatments were weaker, and the 25 g treatment was the weakest. On the whole, the leaf litter of E. grandis had a strong allelopathic effect on E. sibiricus in the initial decomposition process of litter in soil.%采用盆栽试验,研究了巨桉凋落叶分解初期对受体植物老芒麦幼苗生长和抗性生理的影响.试验设对照(CK)和4种凋落叶处理,分别将0(CK),25,50,100,150 g巨桉凋落叶与8 kg土壤混合,播种老芒麦.在播种后30,40,50和90 d测定老芒麦株高、生物量和几种抗性生理指标.结果表明,1)凋落叶在施入土壤90 d内,显著抑制了老芒麦幼苗的高生长和生物量;2)在低凋落

  15. 土壤微生物对黄花蒿凋落物或青蒿素的响应%Responses of soil microorganisms to Artemisia annua leaf litter or artemisinin

    Institute of Scientific and Technical Information of China (English)

    李倩; 袁玲; 杨水平; 黄建国

    2015-01-01

    Artemisia annua releases many kinds of allelochemicals into soils via dead plant residues,either by rain leaching or root exudation.Dead leaves of A.annua contribute more than 80% of the total artemisinin that enters soils during the growth period of A.annua.Allelochemicals released by the dead leaves reduce the growth and yields of succeeding and adjacent crops.Soil microbes play roles in nutrient transformation,organic matter recycling,toxicant decomposition,and hormone efflux,and thus,are important for plant growth and development.However,little is known about the effects of these allelochemicals on soil microorganisms.In these experiments,artemisinin and A.annua leaf litter were each added to soil and changes in microbial bio-mass and community structure were evaluated.The growth and reproduction of culturable microorganisms in soils showed wide variations in response to A.annua leaf litter or artemisinin.For example,the number of fungi increased but the numbers of actinomycetes,azotobacteria,nitrobacteria,and nitrite bacteria significantly decreased in soils containing A.annua leaf litter or artemisinin.The results suggested that both leaf litter or artemisinin inhibited organic matter mineralization,nitrogen bio-fixation,mobilization of phosphorus and po-tassium,and nitrification.The soil microbial quotient decreased,while the metabolic quotient increased,after A.annua and artemisinin were added to soils.This result indicated that artemisinin and other allelochemicals in the leaf litter interfered with the metabolism of soil microorganisms.The types and total contents of signa-ture phospholipid fatty acids of microbes such as actinomycetes and protozoa decreased in soils containing leaf litter or artemisinin.The diversity and evenness indices of the microbial community also decreased,suggesting that the soil microbial ecosystem deteriorated as the densities of various microbial groups decreased.Therefore, artemisinin and allelopathic chemicals released from A

  16. 巨桉凋落叶分解对假俭草生长及光合特性的影响%Effects of Eucalyptus grandis leaf litter decomposition on the growth and photosynthetic characteristics of Eremochola ophiuroides

    Institute of Scientific and Technical Information of China (English)

    李羿桥; 李西; 胡庭兴

    2013-01-01

    植物生长的本质是由光能驱动的复杂生理学过程,90%~95%干物质的积累来源于光合产物.本研究采用盆栽试验探讨了巨桉凋落叶分解对假俭草生长及光合特性的影响.4个添加不同凋落叶量的试验组被设置,包括了T1(30 g/盆),T2(60 g/盆),T3(90 g/盆)以及CK(0 g/盆);同时,以添加去除化感物质凋落叶的处理为空白试验.选取晴天测定假俭草光合参数以及在30,60,90 d时的生长指标.结果表明,分解中的巨桉凋落叶明显抑制假俭草的生长、生物量的积累以及光合色素的合成,且随凋落叶含量的增加抑制作用加大;处理组叶片的气孔导度及其对环境中光照和CO2改变的适应能力与对照组相比显著降低(P<0.05).综上,巨桉凋落叶化感作用减弱了假俭草叶片的光合作用,并抑制假俭草的生长.%The essence of crop production is a complex system that is driven by light energy.The accumulation of 90% of the dry matter comes from the production of photosynthesis.In this study,we investigated the effect of Eucalyptus grandis leaf litter decomposition on the growth and photosynthetic characteristics of Eremochola ophiuroides.Four treatments with different amounts of leaf litter were designed,including T1 (30 g/pot),T2 (60 g/pot),T3 (90 g/pot) and control (0 g/pot,CK),and the blank experiment groups with distilled fallen leaves were set as the above.The growth indexes were measured at 30,60 and 90 d after sowing,and the photosynthetic characteristics were tested on the mature leaf in the middle of stolon.The test results showed that increasing amounts of E.grandis leaf litter significantly inhibited the accumulation of biomass,growth,synthesis of photosynthetic pigments of E.ophiuroides seedlings (P<0.05).Meanwhile,the stomatal conductance and the adaptation capacity to the change of light and CO2 in the environment of CK were significantly lower than which of treatments.This demonstrated that the

  17. Effects of snow damage on the leaf litter' s nutrient content and return amount of constructive species in evergreen broadleaved forest in Gutianshan National Natural Reserve,East China%雪灾对古田山常绿阔叶林建群种养分含量及归还量的影响

    Institute of Scientific and Technical Information of China (English)

    晏丽蓉; 刘会; 李铭红; 张磊; 于明坚

    2013-01-01

    在古田山国家级自然保护区24 hm2长期监测样地设置凋落物收集框,对常绿阔叶林的养分归还量进行动态监测.2008年初南方发生特大雪灾,为研究雪灾对建群种甜槠和木荷凋落叶中主要养分含量、归还量的影响提供了契机.结果表明:(1)虽然建群种凋落叶中碳含量受雪灾影响不显著,但雪灾导致其凋落量明显下降,因此碳的归还量在灾后明显减少.(2)建群种凋落叶氮含量在雪灾前后有显著差异,表现为灾前<灾后;但因受凋落量的影响,其归还量仍表现为灾前>灾后.(3)建群种凋落叶磷含量在雪灾前后存在极显著差异(P<0.01),表现为灾前<灾后,导致其归还量也表现为灾前<灾后.%A 24-hm2 plot was installed in the Gutianshan National Natural Reserve, East China to dynamically monitor the leaf litter' s nutrient content and return amount of evergreen broad-leaved forest. In 2008, a serious snow damage event happened in southern China, which gave us an opportunity to study the effects of snow damage on the leaf litter' s nutrient content and return amount of two constructive species (Castanopsis eyrei and Schima superba) in the evergreen broadleaved forest. No obvious difference was observed in the leaf litter' s C content of the constructive species before and after the snow damage, but the leaf litter' s production after the snow damage showed an obvious decrease, and thus, the leaf litter' s C return amount after the snow damage also showed an obvious decrease. As compared with that before the snow damage, the leaf litter' s N content of the constructive species after the snow damage was significantly larger, but the litter' s N return amount was smaller, due to the decrease of the litter' s production after the snow damage. Same as the leaf litter' s N content, the leaf litter' s P content of the constructive species after the snow damage was significantly larger than that before the snow damage ( P< 0

  18. 重庆酸雨区马尾松与木荷的叶凋落物分解特征%Decomposition characteristics of leaf litter of Pinus massoniana and Schima superba in the acid rain region of Chongqing, China

    Institute of Scientific and Technical Information of China (English)

    任来阳; 于澎涛; 刘霞; 王彦辉; 李振华; 王轶浩

    2013-01-01

    The Masson pine (Pinus massoniana) forests grow widely in south China, and are seriously damaged by the long-term acid rain. It is expected that an intercropping with broadleaved tree species, such as Schima superba which can grow well under the canopy of Masson pine forests, can improve the health condition of Masson pine trees damaged by acid rain by accelerating the nutrition cycling of forest ecosystems. In order to assess the possible improving effect of intercropping with Schima superba, a field study of litter decomposition was carried out at Tieshanping forest Farm of Chingqing, a region with severe acid rain and forest damage, to compare the decomposition rate of Masson pine needle litter with that of the broad-leaf litter of Schima superba, and to see if the decomposition rate of Pinus massoniana needle litter can be increased by mixing them with the broad-leaf litter of Schima superba. It was found that the decomposition rate of leaf litter of both tree species was very low because of the severe soil acidification, with the annual decomposition coefficient of 0.345 0 and 0.413 2 for Pinus massoninana and Schima superba respectively. The decomposition rates in Tieshanping amounted to only about half of that reported in the forests of Fuzhou City in Fujian Province (with the annul decomposition coefficient of 0.651 2 and 0.813 3). It needs 2.0 and 1.68 years for a 50%decomposition of the litter of Pinus massoninana and Schima superba, and 8.64 and 7.26 years for a 95%decomposition of them. It was also found that the decomposition rate of Pinus massoniana needles was not increased when it was mixed with the broad-leaf litter of Schima superba, probably because of the decomposer quantity reduction and the change of decomposer composition caused by severe soil acidification. It seems from this study that the intercropping of Schima superba can no more play the role of improving the health condition of Masson pine forests damaged by acid rain. Moreover, it was

  19. Temporal dynamics of abiotic and biotic factors on leaf litter of three plant species in relation to decomposition rate along a subalpine elevation gradient.

    Directory of Open Access Journals (Sweden)

    Jianxiao Zhu

    Full Text Available Relationships between abiotic (soil temperature and number of freeze-thaw cycles or biotic factors (chemical elements, microbial biomass, extracellular enzymes, and decomposer communities in litter and litter decomposition rates were investigated over two years in subalpine forests close to the Qinghai-Tibet Plateau in China. Litterbags with senescent birch, fir, and spruce leaves were placed on the forest floor at 2,704 m, 3,023 m, 3,298 m, and 3,582 m elevation. Results showed that the decomposition rate positively correlated with soil mean temperature during the plant growing season, and with the number of soil freeze-thaw cycles during the winter. Concentrations of soluble nitrogen (N, phosphorus (P and potassium (K had positive effects but C:N and lignin:N ratios had negative effects on the decomposition rate (k, especially during the winter. Meanwhile, microbial biomass carbon (MBC, N (MBN, and P (MBP were positively correlated with k values during the first growing season. These biotic factors accounted for 60.0% and 56.4% of the variation in decomposition rate during the winter and the growing season in the first year, respectively. Specifically, litter chemistry (C, N, P, K, lignin, C:N and lignin:N ratio independently explained 29.6% and 13.3%, and the microbe-related factors (MBC, MBN, MBP, bacterial and fungal biomass, sucrase and ACP activity explained 22.9% and 34.9% during the first winter and the first growing season, respectively. We conclude that frequent freeze-thaw cycles and litter chemical properties determine the winter decomposition while microbe-related factors play more important roles in determining decomposition in the subsequent growing season.

  20. RESPONSES OF MICROBIAL COMMUNITY STRUCTURE TO THE LEAF LITTER COMPOSITION%土壤微生物群落结构对凋落物组成变化的响应

    Institute of Scientific and Technical Information of China (English)

    陈法霖; 郑华; 欧阳志云; 张凯; 屠乃美

    2011-01-01

    carried out to compare mixed litters from massion pine, slash pine, white oak and blue Japanese oak, which are all typical species of the hilly red soil regions in South China, with litter of conifer leaves only in effect of their decomposition on soil microbial community structure with the PLFA method.Results show that ( 1 ) the mixed litter treatment was lower in total PLFA,in relative abundance of fungi and in fungi/bacteria of the soil microbial community, but higher in relative abundance of bacteria and actinomyces than the single litter treatment.And the difference in soil microbial biomass between the treatments was contributed mainly by fungi; (2) The principal component analysis (PCA) of the PLFA data demonstrated that mixed litter treatment differed significantly from the single litter treatment in soil microbial community structure.Principal component one ( PC1 ) explained 65.74% and 89.63% of the variation respectively in the two decomposition periods (9 and 18 months).PC1 consisted mainly of fatty acids of 18∶2ω6,9、18∶1ω9c,17∶0 and 10Me18∶ 0; (3) Soil microbial community structure was affected by initial carbon-nitrogen ratio (C/N)and lignin-nitrogen ratio (lignin/N) of the litter, which were negatively related to relative the abundance of bacteria, but positively to the relative abundance of fungi and fungi/bacteria in the soil microbial community.Decompositions of mixed conifer-broadleaved leaf litters provided a more favorable microenvironment for decomposers by changing the chemical composition of the litters such as carbon-nitrogen ratio and lignin-nitrogen ratio.

  1. Nutrient dynamics of decomposing leaf litter in natural and monoculture plantation forests of Castanopsis kawakamii in subtropical China%格氏栲天然林与人工林凋落叶分解过程中养分动态

    Institute of Scientific and Technical Information of China (English)

    杨玉盛; 郭剑芬; 林鹏; 陈光水; 何宗明; 谢锦升

    2004-01-01

    通过对中亚热带格氏栲天然林 (natural forest of Castanopsis kawakamii, 约150a)、格氏栲和杉木人工林 (monoculture plantations of C. Kawakamii and Cunninghamia lanceolata,33年生) 凋落叶分解过程中养分动态的研究表明,各凋落叶分解过程中N初始浓度均发生不同程度的增加后下降;除格氏栲天然林中其它树种叶和杉木叶P浓度先增加后下降外,其它均随分解过程而下降;除杉木叶外,其它类型凋落叶的Ca和Mg浓度呈上升趋势;凋落叶K浓度均随分解过程不断下降.养分残留率与分解时间之间存在着指数函数关系xt=x0e-kt.凋落叶分解过程中各养分释放常数分别为:N(kN) 0.678~4.088;P (kP) 0.621~4.308;K(kK) 1.408~4.421;Ca (kCa) 0.799~3.756;Mg (kMg) 0.837 ~ 3.894.除杉木叶外,其它凋落叶分解过程中均呈kK>kP>kN>kMg>kCa的顺序变化.各林分凋落叶的年养分释放量分别为N 10.73~48.19kg/(hm2·a),P 0.61~3.70kg/(hm2·a),K 6.66~39.61kg/(hm2·a),Ca 17.90~20.91kg/(hm2·a),Mg 3.21~9.85kg/(hm2·a).与针叶树人工林相比,天然阔叶林凋落叶分解过程中较快的养分释放和较高的养分释放量有利于促进养分再循环,这对地力维持有重要作用.%Nutrient dynamics of decomposing leaf litter was studied in two 33-year-old plantations, Chinese fir (Cunninghamia lanceolata, CF) and Castanopsis kawakamii (CK), and compared with that of an adjacent natural forest of Castanopsis kawakamii (NF, ~150 year old) in Sanming, Fujian, China. During the decomposition, varying degree of initial increase followed by decrease of N concentrations was observed in leaf litter, while initial increase and then decrease of P concentration was only found in leaves of other tree species in the NF and Chinese fir needle. The concentrations of Ca and Mg increased in all leaves except for Chinese fir needle, whereas that of K decreased consistently. Using the model xt=x0e-kt, the decay constants of nutrients

  2. Leaf litter as a possible food source for chironomids (Diptera in Brazilian and Portuguese headwater streams Detritos foliares como possível fonte de alimento para Chironomidae (Diptera em riachos de cabeceira brasileiros e portugueses

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    Marcos Callisto

    2007-06-01

    Full Text Available Our objective was to evaluate the potential use of leaf detritus by chironomid larvae. Field and laboratory experiments were performed using leaves and chironomid species collected in Portugal and Brazil. Laboratory experiments under controlled conditions were done using microbial conditioned senescent leaves of Alnus glutinosa (L. Gaertn, Neriumoleander L., Protium heptaphilum (Aubl. March, Protium brasiliense (Spreng Engl., Myrcia guyanensis(Aubl. DC and Miconia chartacea Triana. Laboratory experiments were performed using specimens collected from leaf litter in local streams. Whenever possible, after the experiments, chironomids were allowed to emerge as adults and identified. In Portugal the following taxa were identified: Micropsectra apposita (Walker, 1856, Polypedilum albicorne (Meigen, 1838,Eukiefferiella claripennis Lundbeck (1898, Rheocricotopus (Psilocricotopus atripes Rempel (1937 and Ablabesmyia Johannsen (1905 (Diptera, Chironomidae. Consumption rates ranged from 0.15 ± 0.10 mg (AFDM of leaf animal-1 day-1 (Micropsectra apposita feeding on Alnus glutinosa up to 0.85 ± 0.33 mg (AFDM of leaf animal-1 day-1 (Polypedilum albicorne feeding on Miconia chartacea. In Brazil, the following taxa were identified from leaves: Phaenopsectra sp., Chironomus spp. and Polypedilum sp. and maximum consumption rates reached 0.47 ± 0.28 (AFDM of leaf mg.animal-1.day-1 (Chironomus Meigen (1803 feeding on Protium heptaphilum. Feeding experiments with laboratory cultured specimens, revealed that some chironomids were unable to feed on decomposing leaves (e.g., C. xanthus Rempel (1939 on P.brasiliensis and M.guyanensis. Our results suggest that some stream chironomids (not typical shredders can use leaf litter of riparian vegetation as a complementary food source.O objetivo foi avaliar o potencial uso de detritos foliares por larvas de Chironomidae. Foram realizados experimentos em campo e em laboratório utilizando folhas e larvas de Chironomidae

  3. Study of the dynamics of Zn, Fe, and Cu in the soil-plant system during leaf litter decomposition using isotopic compositions

    Science.gov (United States)

    Pichat, S.; Fekiacova, Z.

    2013-12-01

    Litter decomposition is a key process in the cycle of the elements in the soil-plant system. We have investigated the dynamics of three essential micronutrients (Zn, Fe, and Cu) in the vegetal cover, litter, organic horizons, and upper soil horizon (0-2 and 5-10 cm) using both element concentrations and isotopic compositions. The study was conducted on the O3HP (Oak Observatory at the Haute-Provence Observatory) experimental field site in southern France. O3HP is located far from pollution sources. It has been a fallow land for 70 years with the tree cover represented mainly by oak trees (Quercus pubescens). The soil is a thin layer of Calcisol developed under Mediterranean climate. The area has been subdivided in four zones as a function of plant cover. The results for two of these zones, dominated by respectively Poaceae and Genista hispanica, are reported here. We found that the concentrations of the three elements increase from the Ol to the Of horizon. Copper concentration in the Of horizon is close to that of the soil, whereas it is lower for Fe and Zn. For isotopic compositions, the behavior of the three elements is, however, different, which suggests different processes of redistribution for these elements. An enrichment in light Fe isotopes was observed from the Ol to the Of horizon, the latter having an isotopic composition similar to that of the soil. Zinc isotopic compositions are also similar in the Of horizon and the soil but they are isotopically heavier than in the Ol horizon. For Cu, the O horizons are isotopically heavier than the soil, with Of being the heaviest horizon. In addition, for Cu and Zn, the profiles in the O-horizons in the Poaceae-dominated and Genista hispanica-dominated areas are similar but their values are offset, suggesting an influence of the vegetal cover. The increase in concentration for Cu, Zn and Fe with age/depth in the O horizons is in agreement with what is commonly observed in litter-bag experiments, e.g. 1,2. Two

  4. Riparian leaf litter processing by benthic macroinvertebrates in a woodland stream of central Chile Procesamiento de detritus ripariano por macroinvertebrados bentónicos en un estero boscoso de Chile central

    Directory of Open Access Journals (Sweden)

    CLAUDIO VALDOVINOS

    2001-06-01

    Full Text Available Leaf litter input from riparian landscapes has been identified as both a major energy flow to stream ecosystems and as a food source for stream macroinvertebrates. In riparian landscapes of woodland streams of central Chile, the native deciduous hardwoods are being artificially replaced by exotic coniferous trees at a large spatial scale. It is suggested that this process has a significant impact on the stream communities of central Chile. Today, exotic plantations occur throughout central Chile, with Pinus radiata (D. Don (Monterrey pine accounting for about 80 % of the more than 1,800,000 ha of exotic forests. The objective of this paper was to analyze the effect of the litter beds of a dominant native species (Nothofagus pumilio and an exotic species (P. radiata on the detritus processing carried out by benthic macroinvertebrates, in an experimental catchment of central Chile (Rucúe Creek; 36° 26'00" S, 71° 35'40" W. Results revealed that processing rates of native leaf packs are higher than rates of coniferous leaf packs, suggesting that the replacement of the native hardwoods by exotic coniferous riparian flora has an important impact on the stream energy flow in central Chile. The decay rate coefficients (k were 0.0072 for N. pumilio, and 0.0027 for P. radiata. The greater abundance and biomass of shredders per gram of leaf pack of native Nothofagus would explain the differences in leaf processing rates, especially through the activity of two Plecoptera Gripopterygidae, Limnoperla jaffueli and Antarctoperla michaelseniLa entrada de detritus foliar procedente de áreas riparianas ha sido reconocido como un componente importante en la energética de ecosistemas fluviales y como fuente de alimento de macroinvertebrados acuáticos. En áreas riparianas de esteros boscosos de Chile central los componentes nativos caducifolios están siendo artificialmente reemplazados a gran escala por coníferas exóticas, sugiriendo que este proceso tiene

  5. 两种落叶分解过程中养分和碳素的行为%Behavior of Carbon and Nutrients Within Two Types of Leaf Litter During 3.5-year Decomposition

    Institute of Scientific and Technical Information of China (English)

    田兴军; 孙书存; 马克平; 安树青

    2003-01-01

    利用分解袋法对日本亚高山针叶林的针叶(Abies veitchii Lindl.and A.mariesiMast.)和阔叶(Betulaermanii Cham.and B.corylifolia Regal.et Maxim.)凋落物进行了分解实验研究.结果表明尽管分解初期的两种凋落物的养分以及分解后期凋落物剩余重量差异很大,但两种凋落物养分浓度在分解后期(30个月以后)趋于一致.这种趋同现象在不同养分中有不同的趋同机制.氮元素浓度升高到分解后期浓度差变小,这种现象是由于分解菌的固持作用及受木质素的束缚所致;钾和镁在分解初期浓度急剧下降,进而浓度差变小,是由于淋溶作用所致.在分解过程中这些元素非常容易被淋溶掉,直到和土壤中的浓度达到一致为止.钙是结构元素,它的行踪和有机物组分有密切关系.由于分解后期有机组分木质化和腐殖质化进而浓度趋同,所以钙的浓度也相应趋同.%A litter bag study of needle (Abies veitchii Lindl. and A. mariesi Mast.) and leaf litter (Betulaermanii Cham. and B. corylifolia Regal. et Maxim.) conducted in a coniferous forest of Mt. Ontake, Japanshowed the similar qualities of two type litters in later stages (after the 30th month). Although thedifference in remaining mass between the two litters was larger in later stage of decomposition and initialconcentration of nutrients was different. The concentrations of carbon (C) fraction and nutrients be-tween the two types of litter tended to similar in the later stages. The similar concentration trend ofnutrients was due to different mechanisms. Nitrogen (N) was due to immobilization of fungi and binding withlignin. K and Mg were leaching elements. They were very easily affected in leaching process. In the laterstage, they reached a similar concentration because of a balance with the soil concentration. Ca is aconstruction element, so its behavior has closely related to that of C fractions. Moreover, C fractionswere lignified or humuified and

  6. Impacts of elevated atmospheric CO2 on litter quality, litter decomposability and nitrogen turnover rate of two oak species in a Mediterranean forest ecosystem

    NARCIS (Netherlands)

    Fayez Raiesi Gahrooee,

    1998-01-01

    Elevated CO2 may affect litter quality of plants, and subsequently C and N cycling in terrestrial ecosystems, but changes in litter quality associated with elevated CO2 are poorly known. Abscised leaf litter of two oak species (Quercus cerris L., and Q. pubescens Willd.) exposed to long-term elevate

  7. 退化红壤丘陵区森林凋落物初始化学组成与分解速率的关系%Relationships between initial chemical composition of forest leaf litters and their decomposition rates in degraded red soil hilly region of Southern China

    Institute of Scientific and Technical Information of China (English)

    陈法霖; 江波; 张凯; 郑华; 肖燚; 欧阳志云; 屠乃美

    2011-01-01

    通过小盆+凋落袋控制试验,研究了我国南方退化红壤丘陵区8种森林凋落物和4种混合凋落物初始化学组成与分解速率的关系.结果表明:阔叶凋落物中的氮、磷、钾、镁含量显著高于针叶凋落物,木质素、碳含量显著低于针叶凋落物;凋落物分解速率与凋落物初始氮、磷、钾、镁含量呈显著正相关,与凋落物初始碳、木质素含量以及木质素/氮、木质素/磷和碳/磷值呈显著负相关;木质素含量解释了凋落物分解速率变异的54.3%,是影响分解速率的最关键因子,凋落物碳、氮、磷含量也与分解速率密切相关,它们与木质素含量一起可解释分解速率变异的81.4%.在退化红壤丘陵区植被恢复过程中,低木质素含量、高氮磷含量的阔叶物种的引入有利于加速凋落物的分解速率和土壤肥力的恢复进程.%A pot experiment with litter bags was conducted to study the relationships between the initial chemical composition of 8 kind forest leaf litters and 4 kind mixed leaf litters and their decomposition rates in degraded red soil hilly region of Southern China. Comparing with needle-leaf litters. broad-leaf litters had significantly higher contents of N, P, K, and Mg, but significantly lower contents of lignin and C. The decomposition rates of test litters were significantly positively correlated with the litters initial contents of N, P, K, and Mg ( P<0.05 ) . and negatively correlated with the initial contents of lignin and C as well as the lignin/N, lignin/P, and C/P ratios (P<0.05 ) . The lignin content explained 54. 3% of the variation in litter decomposition rates, being the key affecting factor. Litters C. N. and P contents also had close correlations with the decomposition rates. and together with lignin content. contributed 81.4% of the variation. It was suggested that in the process of vegetation restoration in degraded red soil hilly region of Southern China, introducing

  8. Temporal dynamics of biotic and abiotic drivers of litter decomposition.

    Science.gov (United States)

    García-Palacios, Pablo; Shaw, E Ashley; Wall, Diana H; Hättenschwiler, Stephan

    2016-05-01

    Climate, litter quality and decomposers drive litter decomposition. However, little is known about whether their relative contribution changes at different decomposition stages. To fill this gap, we evaluated the relative importance of leaf litter polyphenols, decomposer communities and soil moisture for litter C and N loss at different stages throughout the decomposition process. Although both microbial and nematode communities regulated litter C and N loss in the early decomposition stages, soil moisture and legacy effects of initial differences in litter quality played a major role in the late stages of the process. Our results provide strong evidence for substantial shifts in how biotic and abiotic factors control litter C and N dynamics during decomposition. Taking into account such temporal dynamics will increase the predictive power of decomposition models that are currently limited by a single-pool approach applying control variables uniformly to the entire decay process.

  9. 模拟氮沉降对油松林单一及混合叶凋落物分解的影响%Effects of simulated nitrogen deposition on decomposition of single and mixed leaf litters in the plantation and natural forests of Pinus tabulaeformis.

    Institute of Scientific and Technical Information of China (English)

    汪金松; 王晨; 赵秀海; 张春雨; 李化山; 王娜; 赵博

    2015-01-01

    通过长期原位模拟氮沉降试验,研究暖温带油松林单一和混合叶凋落物分解对外源氮添加的响应过程与机制. 氮处理水平分别为对照(0 kg/(hm2·a),N0),低氮(50 kg/(hm2·a),N1),中氮(100 kg/(hm2·a),N2)和高氮(150 kg/(hm2·a),N3). 利用凋落袋法对天然林油松针叶、辽东栎阔叶、油松-辽东栎混合叶以及人工林油松针叶进行原位分解试验. 研究结果表明,自然状态下天然林油松针叶、辽东栎阔叶、油松-辽东栎混合叶、人工林油松针叶分解95%所需时间分别为7. 58、4. 89、6. 92、8. 03 年. 氮沉降显著促进了人工林油松针叶的分解,抑制天然林辽东栎阔叶的分解;分解前期,N沉降促进天然林油松针叶、油松-辽东栎混合叶分解,并在分解后期对油松针叶分解产生抑制作用,而对油松-辽东栎混合叶分解无显著影响. 在氮沉降持续增加的背景下,研究结果可为油松林生态系统物质循环和能量流动提供基础数据.%Through a long-term in situ simulated nitrogen ( N) deposition experiment, we explored the response and mechanism of single and mixed leaf litters decomposition to exogenous nitrogen addition in warm-temperate Chinese pine ( Pinus tabulaeformis) forests. The levels of simulated N deposition were set as control (0 kg/(hm2·a), N0), low N (50 kg/(hm2·a), N1), medium N (100 kg/(hm2·a), N2), and high N ( 150 kg/( hm2·a ) , N3 ) . Litterbag method was used for decomposition of single P. tabulaeformis litter, single Quercus liaotungensis litter, mixed P. tabulaeformis-Q. liaotungensis litter in the natural forest and single P. tabulaeformis litter in the plantation. The results showed that the time of 95% mass loss was 7. 58 years for single P. tabulaeformis litter, 4. 89 years for single Q. liaotungensis litter and 6. 92 years for mixed P. tabulaeformis-Q. liaotungensis litter in the natural forest. And the time of 95% mass loss was 8. 03 years for single P

  10. Screening of Plants with N Fixation Efficiency and High N Concentration in Leaf Litter of Shanghai%上海地区落叶含氮量丰富的高效固氮树种选择

    Institute of Scientific and Technical Information of China (English)

    王振; 张京伟; 张德顺

    2011-01-01

    In order to analyze the N exporting ratio of leaves, the relationship between N fixation efficiency and leaf N concentration of different N-fixing trees, N fixation efficiency and leaf N concentration of 29 N-fixing trees were screened in this experiment. The results showed that the trees with high-N-fixation efficiency usually had high-N-concentration in leaves, and there was significant correlation (correlative coefficient was 0.888**) between them. δ15N values ofAlnus traboculosa, Elaeagnus pungens, Elaeagnus pungens 'Maculata',Mucuna sempervirens, Wisteria sinensis, Genista tinctoria, Albizia julibrissin and Myrica rubra were between -0.632‰ and 1.313‰, and the N concentration values of their leaf litter were between 1.288% and 1.628‰. So they all had high capability of N fixation and were preferable plants for soil fertility enhancement.%对29种固氮树种的固氮效率与叶片含氮量进行测定,分析了两者的关系及叶片氮输出率的大小.以此为据,筛选具有较强固氮能力、落叶含氮量较高的树种.结果表明:大多数固氮能力强的树种鲜叶含氮量较高,两者的相关系数为0.888**,达到极显著水平;江南桤木、胡颓子、花叶胡颓子、常春油麻藤、紫藤、染料木、合欢、杨梅8种树种N自然丰度值介于-0.632%~1.313%,落叶含氮量介于1.288%~1.628%,是筛选出的较好的落叶肥田植物.

  11. Litter-Spinning Retarders

    Science.gov (United States)

    Wilson, John C.

    1995-01-01

    Aerodynamic plates stop litter from spinning during hoisting by helicopter. Features of proposed litter-spinning retarders include convenience of deployment and independence from ground restraint. Retarder plate(s) folded flat against bottom of litter during storage or while litter is loaded. Plate(s) held in storage position by latch that releases manually or automatically as litter is hoisted. Upon release, springs move plates into deployed position.

  12. 格氏栲天然林与人工林凋落物数量、养分归还及凋落叶分解%Litter production, nutrient return and leaf-litter decomposition in natural and monoculture plantation forests of Castanopsis kawakamii in subtropical China

    Institute of Scientific and Technical Information of China (English)

    杨玉盛; 林鹏; 郭剑芬; 林瑞余; 陈光水; 何宗明; 谢锦升

    2003-01-01

    The amount and pattern of litterfall, its nutrient (N, P, K, Ca and Mg) returns, and leaf-litter decomposition associated with its quality were studied in a natural forest of Castanopsis kawakamii (NF) and adjacent monoculture plantations of C. kawakamii (CK) and Chinese fir (Cunninghamia lanceolata, CF) in Sanming, Fujian, China. Mean annual total litterfall over 3 years of observations (from 1999 to 2001) was 11.01 t*hm-2 in the NF, 9.54 t*hm-2 in the CK and 5.47 t*hm-2 in the CF respectively. Of the total annual litterfall in the three forests, leaf contribution constituted 59.70%, 71.98% and 58.29%, respectively. Litterfall in the NF and CK showed similar litterfall pattern with a distinct peak in April of each year. While for the CF, the litterfall peaks occurred in April (or May), August and November, respectively. Except for the highest annual Ca returns in the CF and Mg returns in the CK, the three forests could be arranged in this sequence with respect to annual nutrient returns: NF>CK>CF. The annual percent leaf litter mass loss was the highest for C. kawakamii in the NF (98.16%) and the lowest for Chinese fir (60.78%). Ratios of C/N and lignin/N had significantly negative influences on decay rate coefficients, while initial N and water soluble compounds exerted significantly positive influences. The results of this study demonstrate that the natural forest has a greater capability for maintaining site productivity than monoculture plantations due to higher amount and quality of litter coupled with greater nutrient returns and faster litter decomposition. Therefore, conservation of the natural forest is recommended as a practical measure in forest management to realize sustainable development of forestry in mountainous areas of southern China.%通过对中亚热带格氏栲天然林 ( natural forest of Castanopsis kawakamii, 约150年生)、格氏栲和杉木人工林 (monoculture plantations of C. kawakamii and Cunninghamia lanceolata,33年生) 凋落

  13. In field conditions, commercial pigment grade TiO2 was not harmful to terrestrial isopods but reduced leaf litter fragmentation.

    Science.gov (United States)

    Jemec, Anita; Kos, Monika; Drobne, Damjana; Koponen, Ismo Kalevi; Vukić, Jovan; Ferreira, Nuno G C; Loureiro, Susana; McShane, Heather V A

    2016-11-15

    We investigated the effects of a commercial pigment grade rutile TiO2 on the terrestrial isopod Porcellio scaber in three locations that differed in terms of abiotic and biotic conditions: the laboratory, open air, and the closed barn. Mortality and isopod energy reserves (digestive gland total proteins, lipids and carbohydrates) were not affected following 14days exposure to up to 1000mg TiO2 per kg dry leaves (mg/kg) under any experimental scenario. However, in the field tests, isopods consumption of TiO2-coated leaves was reduced compared to that of uncoated leaves and the decrease was not dose-dependent. The highest reduction was in the closed barn (45-56%) rather than in the open-air (38-40%). In laboratory-based food choice tests, isopods neither preferred nor avoided leaves coated with TiO2, suggesting that rather than sensing the TiO2 on the leaves directly, the isopods under open-air and barn exposure responded to altered attractiveness and/or palatability of the TiO2 amended leaves. We propose that this could be due to altered microbial population on the leaves, a hypothesis that requires further investigation. Although short-term exposure to atmospheric deposition of up to 1000mg/kg commercial TiO2 is unlikely to pose an immediate threat to isopod mortality and energy balance, reduced leaf feeding may have implications for the decomposition of plant material.

  14. Comparison of Major Nutrient Release Patterns of Quercus liaotungensis Leaf Litter Decomposition in Different Climatic Zones%辽东栎叶片凋落物在不同气候带下的分解及其主要元素释放的比较

    Institute of Scientific and Technical Information of China (English)

    王立新; 王瑾; 黄建辉

    2003-01-01

    应用分解网袋法对辽东栎(Quercus liaotungensis Koize)叶片凋落物分别在暖温带的东灵山、亚热带的神农架、热带的西双版纳为期1~2年的分解和K、Ca、Mg、Fe、P、Cu、Mn等营养元素释放动态进行比较研究.三个气候带下辽东栎叶片凋落物质量损失基本符合Olson的指数模型,但降解速率有很大的差别.气候条件对凋落物的分解和营养元素的释放影响很大,降水量增多,年均温增高,凋落物分解速率相应加快.研究还发现影响营养元素释放的因素除了公认的土壤生物(土壤动物和土壤微生物)作用外,对于Fe、Mn等元素遵循的是"化学因素主导"模式,特征在于由于化学螯合作用,其释放过程和凋落物本身失重呈显著负相关.另外,对不同因素占主导的各种分解模式进行了归纳总结.%Leaf litter decomposition of liaotong oak (Quercus liaotungensis Koize) under temperate, subtropical and tropical forests was examined using a litter bag technique. Decomposition rates and release dynamics of nutrients Ca, Cu, Fe, K, Mg, Mn and P were observed separately at all three sites for 1 to 2 a periods. The leaf litter mass loss of liaotong oak was simulated with Olson's exponential model. Significant differences of leaf litter mass loss were found in forests of all three climate zones. Litter decomposition was accelerated with the increase of both annual mean precipitation and temperature. Our results agreed with other studies demonstrating that litter decomposition processes were greatly affected not only by soil organisms (including soil fauna and microorganisms), but also by chemical factors. These chemical factors were important for controlling the release of nutrients, especially elements of Fe and Mn. We also found that Fe and Mn content increased in semi-decayed leaf litter as litter mass decreased. This result was presumably due to chelating process which accumulated soil Fe and Mn ions into the

  15. Size dependent differences in litter consumption of isopods: preliminary results.

    Science.gov (United States)

    Vilisics, Ferenc; Szekeres, Sándor; Hornung, Elisabeth

    2012-01-01

    A series of experiments were applied to test how leaf orientation within microcosms affect consumption rates (Experiment 1), and to discover intra-specific differences in leaf litter consumption (Experiment 2) of the common isopod species Porcellio scaber and Porcellionides pruinosus. A standardised microcosm setup was developed for feeding experiments to maintain standard conditions. A constant amount of freshly fallen black poplar litter was provided to three distinct size class (small, medium, large) of woodlice. We measured litter consumption after a fortnight. We maintained appr. constant isopod biomass for all treatments, and equal densities within each size class. We hypothesized that different size classes differ in their litter consumption, therefore such differences should occur even within populations of the species. We also hypothesized a marked difference in consumption rates for different leaf orientation within microcosms. Our results showed size-specific consumption patterns for Porcellio scaber: small adults showed the highest consumption rates (i.e. litter mass loss / isopod biomass) in high density microcosms, while medium-sized adults of lower densities ate the most litter in containers. Leaf orientation posed no significant effect on litter consumption.

  16. Size dependent differences in litter consumption of isopods: preliminary results

    Directory of Open Access Journals (Sweden)

    Ferenc Vilisics

    2012-03-01

    Full Text Available A series of experiments were applied to test how leaf orientation within microcosms affect consumption rates (Experiment 1, and to discover intra-specific differences in leaf litter consumption (Experiment 2 of the common isopod species Porcellio scaber and Porcellionides pruinosus. A standardised microcosm setup was developed for feeding experiments to maintain standard conditions. A constant amount of freshly fallen black poplar litter was provided to three distinct size class (small, medium, large of woodlice. We measured litter consumption after a fortnight. We maintained appr. constant isopod biomass for all treatments, and equal densities within each size class. We hypothesized that different size classes differ in their litter consumption, therefore such differences should occur even within populations of the species. We also hypothesized a marked difference in consumption rates for different leaf orientation within microcosms. Our results showed size-specific consumption patterns for P. scaber: small adults showed the highest consumption rates (i.e. litter mass loss / isopod biomass in high density microcosms, while medium-sized adults of lower densities ate the most litter in containers. Leaf orientation posed no significant effect on litter consumption.

  17. 沿海沙地厚荚相思和木麻黄凋落叶分解及养分释放%Decomposition Dynamics and Nutrient Release of Leaf Litters for Acacia crassicarpa and Casuarina equisetifolia Forests in Southeast Coastal Area, China

    Institute of Scientific and Technical Information of China (English)

    林宇

    2014-01-01

    Litter decomposition and nutrient release of 9-year-old Acacia crassicarpa and Casuarina equisetifolia plantations on a sandy coastal plain soil in southeast Fujian Province from November 2011 to October 2012 were examined using the litter bag method.The fastest decomposition rates of the two leaf litters were found in June to August.However,differences in residual rate were not significant (p>0.05).The analysis of Olson's exponential decay model showed that it would cost for about 1.10 and 4.73 years to decompose 50% and 95% of A.crassicarpa leaf litter,and to decompose 50% and 95% of C.equisetifolia leaf littler,the time would be 1.14 and 4.93 years.In the late stage of litter decomposition,the contents of the nitrogen (N),phosphorus (P) and calcium (Ca) increased with time,while the contents of carbon (C),potassium (K) and magnesium (Mg) decreased.Release dynamics of nutrients differed in two forest types in different decomposition periods.The litter decomposition rate was significantly and negatively correlated to the initial C,Mg contents and the ratios of,C/N and C/P (p<0.01),and significantly and positively correlated to K content (p<0.05).The orders of releasing speeds of leaf litters were K>Mg>C> Ca>N>P for A.crassicarpa,and Mg>K>C>Ca>N>P for C.equisetifolia plantation.The A.crassicarpa had higher nutrient release rate in leaf litter,and it was more appropriate to be mixed with C.equisetifolia.%采用野外分解网袋法对沿海沙地9年生厚荚相思(Acacia crassicarpa)和木麻黄(Casuarina equisetifolia)林分凋落叶的分解速率和养分释放进行了研究.结果表明:厚荚相思和木麻黄凋落叶6-8月分解速率最快,但残留率差异不显著(p>0.05).用Olson衰减指数模型推算分解50%和95%所需时间,厚荚相思为1.10a和4.73a,木麻黄为1.14a和4.93a.2种凋落叶N、P和Ca元素在分解末期的质量分数均高于初始质量分数,C、K和Mg均低于初始质量分数.凋

  18. Impacto do desmatamento e formação de pastagens sobre a anurofauna de serapilheira em Rondônia The impact of deforestation and pastures on the leaf-litter frog community in Rondônia, Brazil

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Bernarde

    2008-12-01

    Full Text Available A riqueza e a diversidade de anfíbios anuros de serapilheira em áreas de floresta e de pastagem foram estudadas em Rondônia. A eficiência da utilização de armadilhas de interceptação e queda foi analisada. As armadilhas foram instaladas em três ambientes distintos: interior de floresta, distante de ambientes aquáticos permanentes; interior de floresta, a cerca de 100 metros de rio; área de pastagem, distante de ambientes aquáticos permanentes. Foram capturados 1.324 espécimes pertencentes a 27 espécies, distribuídas em nove famílias: Aromobatidae (1 espécie, Brachycephalidae (2, Bufonidae (4, Cycloramphidae (1, Dendrobatidae (1, Hylidae (5, Leiuperidae (1, Leptodactylidae (7 e Microhylidae (5. O emprego de armadilhas de interceptação e queda permitiu registrar 57% das espécies conhecidas para essa localidade, sendo particularmente eficiente para a captura de anuros de hábitos terrícolas e fossoriais. Foram capturados menos indivíduos nos três meses mais secos e houve maior diversidade durante a estação chuvosa. Maior riqueza e diversidade foram registradas nos ambientes florestados, em relação à pastagem, observando-se decréscimo de espécies com o desmatamento. A conversão da floresta em pastagens ocasiona modificações no ambiente (diminuição de locais para reprodução, diminuição da disponibilidade de alimento, perda da serapilheira, compactação do solo, alterações microclimáticas, aumento da abundância de espécies de áreas abertas, etc. criando condições desfavoráveis para a sobrevivência de algumas espécies.Abundance and diversity of leaf-litter frog species were studied in forest and pasture in Rondonia, Brazil. Also, the efficiency of use of pitfall traps was examined. Pitfall traps were established in three treatments: forest interior far (> 100 m from water; forest interior near (< 100 m water; pasture, far from water. Species richness was typical of the Amazon region, with a total of 1

  19. Descomposición de hojarasca de Pinus radiata y tres especies arbóreas nativas Decomposition of leaf litter of Pinus radiata and three native tree species

    Directory of Open Access Journals (Sweden)

    CHRISTOPHER H. LUSK

    2001-09-01

    -central Chile to exotic tree plantations. However, little is known about the effects of these wholesale landuse changes on ecosystem properties and processes, with the notable exception of studies of site water balance. In this brief communication, we present the results of a comparative study of decomposition of leaf litter of Pinus radiata and three common native tree species, beneath exotic and native woody vegetation in south-central Chile. We aimed to assess the nutrient cycling implications of substitution or invasion of native vegetation by P. radiata. Litter samples of the four species were incubated in both environments, registering the percentage of dry weight loss after two and six months. Decomposition rates of all species were much faster during the first two months of incubation than during the four subsequent months. At both dates there were significant differences between species and between sites, with faster decomposition of all species beneath P. radiata. There was no evidence of interaction between species and site. After six months, species rank order for the percentage of weight loss was Nothofagus obliqua > P. radiata > Peumus boldus > Cryptocarya alba. Interspecific variation in decomposition rates was more closely correlated with specific leaf area than with litter nitrogen content. Given that litter of P. radiata decomposed slower than that of the deciduous N. obliqua, but faster than the sclerophyll evergreens, the consequences of substitution or invasion for decomposition processes are likely to depend on the composition of the native vegetation in question

  20. Litter Dynamics of Three Subalpine Forests in Western Sichuan

    Institute of Scientific and Technical Information of China (English)

    YANG Wan-Qin; WANG Kai-Yun; S. KELLOM(A)KI; GONG He-De

    2005-01-01

    Litter production, components and dynamics were investigated and forest floor litter was quantified throughout a whole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF), in Western Sichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in the three forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to the total litterfall was significantly (P < 0.05) greater than that of woody litter, reproductive organs or moss. Regardless of the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October,with smaller peaks occurring in February for SF and FF, and May for BF. The analysis indicated that tree species,stand density, leaf area index (LAI), stand basal area and stand age were the key factors determining litter production.Meanwhile tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter components and dynamics.

  1. Changes in litter quality induced by nutrient addition alter litter decomposition in an alpine meadow on the Qinghai-Tibet Plateau.

    Science.gov (United States)

    Zhu, Wenyan; Wang, Jinzhou; Zhang, Zhenhua; Ren, Fei; Chen, Litong; He, Jin-Sheng

    2016-10-03

    The effects of nitrogen (N) and phosphorus (P) addition on litter decomposition are poorly understood in Tibetan alpine meadows. Leaf litter was collected from plots within a factorial N × P addition experiment and allowed to decompose over 708 days in an unfertilized plot to determine the effects of N and/or P addition on litter decomposition. Results showed that nutrient addition significantly affected initial P and P-related biochemical properties of litter from all four species. However, the responses of litter N and N-related biochemical properties to nutrient addition were quite species-specific. Litter C decomposition and N release were species-specific. However, N and P addition significantly affected litter P release. Ratios of Hemicellulose + Cellulose to N and P were significantly related to litter C decomposition; C:N ratio was a determinant of litter N release; and C:P and (Hemicellulose + Cellulose):P controlled litter P release. Overall, litter C decomposition was controlled by litter quality of different plant species, and strongly affected by P addition. Increasing N availability is likely to affect litter C decomposition more indirectly by shifting plant species composition than directly by improving litter quality, and may accelerate N and P cycles, but shift the ecosystem to P limitation.

  2. 秦岭南坡油松和锐齿栎群落凋落叶碳释放及其与分解的关系%The Relationship between Carbon Release Process and Decomposition Percentages of the Leaf-litter in the Pinus tabulaeformis and Quercus aliena var.acuteserrata Communities in the South Slope of Qinling Mountain

    Institute of Scientific and Technical Information of China (English)

    何帆; 王得祥; 张宋智; 彭舜磊; 沈亚洲; 杜彦昌; 张江涛

    2012-01-01

    The carbon release process of leaf-litter in the Pinus tabulaeformis and Quercus aliena var. Acuteserrata and changes of C/N and C/P values was discussed by using litterbag experiments, which lasted 24 month, in the south slope of Qinling region. Results showed: ( 1) Carbon density in Pinus tabulaeformis litter ( 1265. 580kg/hm2) was 3. 7 times greater than that of Quercus aliena var. Acuteserrata litter ( 3047. 313kg/hm2 )(P<0.001);(2)In beginning of the leaf-litter decomposition,carbon content increased first,then decreased in two communities;carbon release rate in Quercus aliena var. Acuteserrata was significantly faster than in Pinus tabulaeformis (P < 0.001); (3) The change of carbon stock over time was accord with Olson's exposition model during leaf-litter's decomposition process; (4) The C residual percentage appeared a binomial regression correlation with residual percentages of leaf-litter, N and P (except P in Quercus aliena var. Acuteserrata) ,a linear correlation with C/N and C/P values. Carbon release exerts a significant influence on decomposition rate of leaf-litter, release of nutrient elements and material cycle of forest ecosystem.%利用野外分解袋法分别对秦岭南坡油松和锐齿栎群落内凋落叶进行了为期24个月的分解试验.研究了凋落叶C释放过程及其与凋落叶分解过程中N、P释放和C/N、C/P比值变化的关系.研究结果表明:(1)油松群落凋落层( 11265.58kg/hm2)C密度显著大于锐齿栎群落凋落层C密度(3047.31 kg/hm2)(P<0.01),达到了3.7倍;(2)在凋落叶分解初期,2个群落凋落叶中碳含量均呈现先增加后下降的趋势,锐齿栎凋落叶C释放速率大于油松凋落叶C释放速率(P<0.01);(3)在两种群落类型凋落叶分解过程中,碳剩余百分率随时间变化规律符合Olson分解指数模型(R>0.81);(4)凋落叶C剩余百分率与凋落叶和N、P剩余百分率之间具有显著的二项式回归关系(锐齿栎凋落叶P剩余百分率

  3. The effect of saprophagous macrofauna on litter decomposition

    Science.gov (United States)

    Frouz, Jan

    2016-04-01

    Previous experiments show that feeding of the larvae of Bibionidae on lef litter cause short term increase of respiration but in long term the decomposition of bibio feces is slower than decomposition of litter from which feces were produced. To understand why excrements of decompose more slowly than leaf litter, we fed Bibio marci larvae the litter of tree species differing in litter quality (Alnus glutinosa, Salix caprea, and Quercus robur) and then measured respiration induced by litter and excrements. We also measured respiration induced by the same litter artificially modified to mimic faunal effects; the litter was modified by grinding, grinding with alkalinization to pH 11, grinding with coating by kaolinite, and grinding with both alkalinization and coating. Decomposition of excrements tended to be slower for willow and was significantly slower for oak and alder than for the corresponding litter. With oak, decomposition was slower for all artificially modified litter than for non-modified litter. The reduction in the decomposition was similar for excrements and for alder and willow litter that was ground, coated, and alkalinized. In alder, a similar reduction was found in ground and alkalinized litter. 13C NMR indicated that gut passage increases aliphatic components and decreases polysaccharides. Pyrolysis indicated that gut passage increases the ratio of guaiacyl to hydroxymethyl derivatives in lignin. Our findings indicate that the decreased decomposition rate of excrements might result from the removal of easily available polysaccharides, the increase in aliphatic components, an increase in the resistant components of lignin, the accumulation of microbial cell walls, and the binding of nitrogen into complexes with aromatic components. Several of these mechanisms are supported or determined by litter alkalinization during gut passage.

  4. Effects of mixed decomposition of Populus simonii and other tree species leaf litters on soil properties in Loess Plateau%黄土高原小叶杨与其他树种枯落叶混合分解对土壤性质的影响

    Institute of Scientific and Technical Information of China (English)

    李茜; 刘增文; 杜良贞

    2012-01-01

    将小叶杨分别与其他11个树种枯落叶粉碎混合后进行室内分解培养,分析不同树种枯落叶混合分解对土壤性质的影响及其相互作用.结果表明:12个树种枯落叶单独混土分解均明显提高了土壤脲酶、脱氢酶、磷酸酶活性和有机质、碱解N含量,但对土壤速效P含量和土壤阳离子交换量(CEC)的影响差异较大,其中柠条和紫穗槐枯落叶改善土壤性质的效果明显.小叶杨分别与油松、侧柏、刺槐、白榆枯落叶混合分解,对土壤微生物数量的影响存在相互促进作用;小叶杨分别与侧柏、柠条枯落叶混合分解对土壤有机质、速效P、速效K含量和CEC的影响存在相互促进作用,但对土壤大部分酶活性的影响却存在相互抑制作用;小叶杨与落叶松枯落叶混合分解对土壤多数酶活性和养分含量的影响存在相互促进作用,而与樟子松枯落叶混合分解时则有抑制作用.总体上,小叶杨分别与白榆、油松、落叶松和刺槐枯落叶混合分解可促进土壤性质的改善,而与侧柏、柠条、樟子松、沙棘和紫穗槐枯落叶混合分解时则相互抑制.%In this study, the leaf litters of Populus simonii and other 11 tree species were put into soil separately or in mixture after grinding, and incubated in laboratory to analyze the effects of their decomposition on soil properties and the interactions between the litters decomposition. The decomposition of each kind of the leaf litters in soil increased the soil urease, dehydrogenase, and phos-phatase activities and the soil organic matter and available N contents markedly, but had greater differences in the effects on the soil available P content and CEC. The decomposition of the leaf litters of Caragana microphylla and of Amorpha fruticosa showed obvious effects in improving soil properties. The decomposition of the mixed leaf litters of P. simonii and Pinus tabulaeformis, Platy-cladus orientalis, Robinia

  5. Responses of leaf litter decomposition and nutrient release to simulated nitrogen deposition of Castanopsis carlesii%米槠叶凋落物分解及养分释放对模拟N沉降的响应

    Institute of Scientific and Technical Information of China (English)

    王家骏; 程煜; 杨玉盛; 林成芳; 林伟盛; 彭建勤

    2014-01-01

    A field simulated experiment was conducted in Castanopsis carlesii forest in Sanming C.kawakamii Nature Reserve, to study the responses of C.carlesii leaf litter decomposition and nutrients release to increased N deposition .The treatments were designed as CK(0 g· m-2· a-1), LN(5 g· m-2· a-1), MN(10 g· m-2· a-1) and HN(15 g· m-2· a-1), adding N could inhibit those leaf litter′s decompositions , the speeds were CK >MN>LN>HN and slow down after 1 a.In the monitoring period (720 d) , LN and HN could significantly inhibited decomposition (P<0.05).More than 10 g· m-2· a-1 of N deposition could significantly inhibited leaf litter lignin′s decomposition (P<0.05) but not so obviously to cellulose.After 360 d, N deposition could affected its C and N decomposition , and the negative impact of HN was more obvious .The release pattern of P was leaching-enriched-releasing , and in 270-720 d adding N could significantly inhibit their P releasing (P<0.05).The releasing disciplines of K were similar to C and in 0-540 d adding N, especially LN would significantly inhibited K releasing (P<0.05).This may be so that N deposition increased the N availability in subtropical evergreen broad-leaf forest, which changed the original nutrients balance , so that inhibited the activity of microbial , thereby reducing the activity of enzyme and then affected the C.carlesii litter′s decomposition .%通过原位分解研究三明格氏栲保护区内米槠叶凋落物的分解及其对模拟N 沉降的响应。结果表明:高氮( HN)、中氮( MN)、低氮( LN)和对照( CK)4种处理的米槠叶凋落物的分解都呈先快后慢的变化趋势,分解速率为CK>MN>LN>HN,添加N对米槠叶凋落物的分解起到了抑制作用。在监测期(720 d)内,MN处理(10 g· m-2· a-1)对分解速率影响较小, N含量太高(15 g· m-2· a-1),负作用增强,高于10 g· m-2· a-1的N沉降会显著抑制

  6. Trees as templates for tropical litter arthropod diversity.

    Science.gov (United States)

    Donoso, David A; Johnston, Mary K; Kaspari, Michael

    2010-09-01

    Increased tree species diversity in the tropics is associated with even greater herbivore diversity, but few tests of tree effects on litter arthropod diversity exist. We studied whether tree species influence patchiness in diversity and abundance of three common soil arthropod taxa (ants, gamasid mites, and oribatid mites) in a Panama forest. The tree specialization hypothesis proposes that tree-driven habitat heterogeneity maintains litter arthropod diversity. We tested whether tree species differed in resource quality and quantity of their leaf litter and whether more heterogeneous litter supports more arthropod species. Alternatively, the abundance-extinction hypothesis states that arthropod diversity increases with arthropod abundance, which in turn tracks resource quantity (e.g., litter depth). We found little support for the hypothesis that tropical trees are templates for litter arthropod diversity. Ten tree species differed in litter depth, chemistry, and structural variability. However, the extent of specialization of invertebrates on particular tree taxa was low and the more heterogeneous litter between trees failed to support higher arthropod diversity. Furthermore, arthropod diversity did not track abundance or litter depth. The lack of association between tree species and litter arthropods suggests that factors other than tree species diversity may better explain the high arthropod diversity in tropical forests.

  7. 科尔沁沙地不同水分条件下植物叶凋落物 CO2释放研究%The Study on CO2 Release of Leaf Litters in Different Water Conditions in Horqin Sandy Land

    Institute of Scientific and Technical Information of China (English)

    孟庆涛; 李薛飞; 杨宁

    2013-01-01

    This experiment uses laboratory soil incubation experiment that can control environment factor measures the effect on CO 2 re-lease of leaf litters in different water content in fixed dunes .The results showed that:Total CO2 release and litter decomposition were corre-lated to water content of soil .Whether litter added or not , CO2 release rate of low water content was significantly different from that of medi -um and high water contents in the first 4 days.In sand land, either wetness or dryness of soil imposed great influence on litter decomposi -tion, because soil and litter CO2 release amount were significantly different from that of the water content .%采用可以有效控制环境因子的室内土壤培养试验,对固定沙地土壤不同水分作用下叶凋落物释放CO2的情况进行了初步研究。结果表明:土壤CO2的释放量及凋落物的分解均与土壤干湿情况相关。在添加凋落物与不添加凋落物的处理中,培养前4天的低含水条件下CO2释放速率与中高含水处理相比差异均呈极显著,而4天以后不同水分条件下的释放速率无显著差异。在沙地中,土壤过于湿润或干旱均能够阻碍凋落物的分解。

  8. Influence of Nutrient-release of Mix-leaf Litter Decay of Populus simonii with Other Trees in the Loess Plateau%黄土高原小叶杨与其他树种枯落叶混合分解对养分释放的影响

    Institute of Scientific and Technical Information of China (English)

    祝振华; 刘增文; 袁娜; 杜良贞

    2012-01-01

    Soil polarization resulted from continuous growth and planting of pure forest stands is main cause of soil degradation and unbalanced or unsustainable development of artificial forest ecosystem. Fundamental way of controlling soil polarization is to select friendly tree species to form mixed forests. Indoor mixed decomposition experiment was conducted to study the effect of decomposition of mixed leaves of Populus simonii and other species on nutrient release, and to provide theoretical basis for artificial mixed forest formation. The results were as follows. (1). Quercus liaotungensis leaf litter strongly promoted organic carbon release with a promotion percentage of 21. 32%, while Pinus tabulae formi demonstrated suppression effect, and the release rate decreased by 14. 78%. No significant effects on the organic carbon release were observed among the leaves of other tree species. (2) Q. liaotungensis leaf litter strongly increased nitrogen release with a promotion rate of 28. 69%, showing significant promotion effect, for P. sylvestris var. mongolice and Robinia pseudoacacia leaf litters, however, the promotion effects were relatively weaker and nitrogen release rate increased by 14. 98% and 13. 36% respectively. P. Tabulaeformis leaf litter ex-hibited strong inhabiting effect on nitrogen release, the release rate decreased by 20. 33%. For the leaves of other tree species, no significant effects on nitrogen release were observed. (3) R. pseudoacacia, Q. li-aotungensis, and Hippophae rhamnoides leaf litters very strongly promoted the phosphorus release rate with promotion percentages of 57. 60% , 43. 06% , and 38. 60% respectively. Amorpha fruticosa leaf litter strongly promoted phosphorus release, the promotion rate increased by 22. 64%. P. tabulae formis and P. sylvestris var. mongolica leaf litters significantly inhabited phosphorus release, the release rate reduced by 62. 63% and 47. 99%, respectively. The leaf litters of other tree species showed no

  9. 3个树种凋落叶水浸提液对三叶鬼针草生长及抗性生理的影响%Effect of Leaf Litter Water Extract of Three Species on Growth and Resistance Physiology of Bidens pilosa

    Institute of Scientific and Technical Information of China (English)

    廖梦雨; 胡庭兴; 邓承敏; 王茜; 龙华; 柏艺

    2014-01-01

    As an invasive plant, Bidens pilosa imposes great potential harm to agricultural production, biodiversity and safety of ecosystems. Making use of allelopathy to develop new herbicides, is a meaningful way to control and reduce nega⁃tive impact of chemical herbicides to the environment. It has been reported that leaf litters of common species, such as Eu⁃calyptus grandis, Cinnamomum camphora and Juglans regia, could generate secondary metabolites during their growing process, which show comparatively strong allelopathy to plants and microorganism, and might play an important role in the prevention of colonial invasion herbs. Selected leaf litters of E. grandis, C. camphora and J. regia, were made into differ⁃ent concentrations of water extracts. By combining the methods of indoor germination test and potted biological test, indexes such as germination rate, germination speed, aerial parts fresh weight, antioxidant enzyme activity, and osmotic regulation substance of B. pilosa were determined. Finally, comprehensive evaluation and comparison of allelopathy effects of the three species were completed. The water extracts of E. grandis leaf litter significantly inhibited the germination rate and germination speed of B. pilosa, while C. camphora and J. regia showed weaker inhibition. The leaf litter water extracts of the three tree species promoted the activity of peroxidase ( POD) , superoxide dismutase ( SOD) and inhibited the activ⁃ity of catalase ( CAT) in B. pilosa. The antioxidant enzyme system of B. pilosa treated with E. grandis leaf litter extract showed passivation response, and thus lead to obvious increase of malondialdehyde ( MDA) . When treated with leaf litter extracts of E. grandis and C. camphora, the soluble protein and soluble sugar in B. pilosa increased with increasing extract concentration. However, when treated by leaf litter extracts of J. regia, the soluble protein and soluble sugar in B. pilosa showed a trend of promotion at low

  10. Temperature Effects on the Ash Colour of Forest Litter

    Directory of Open Access Journals (Sweden)

    Jolita Dūdaitė

    2011-12-01

    Full Text Available Abstract. Research was carried out to identify the influence of temperature (150, 250, 350, 450, 550ºC on the ash colour of Acer platanoides L. leaf litter and Pinus sylvestris L. needle litter samples collected from deciduous coniferous mixed forest in Lithuania (54º43‘ N 25º19‘ E in April 2010. To achieve the objective, a laboratory experiment was conducted to determine ash samples using the Munsell Colour Chart. The analysis of colours has demonstrated that considering all litter samples, an increase in the temperature of litter heating was found to increase ash colour values (r = 0.92; p = 0.01. All the samples (n = 50 of both litter species were divided into categories 2.5Y (5 samples, 7.5YR (10 samples and 10YR (35 samples. The total black Munsell colour was observed at a temperature of 350ºC for both litter species. Needle ash started turning bright at a temperature of 550ºC while the complete consumption of leaf litter was visible at a temperature of 450ºC. We conclude that the Munsell Colour Chart used for predicting the colour of ash is an informative feature to have the primary classification of ash. It is imperative to analyse the colour of the litter ash of the selected tree species in order to quickly and easily assess and predict their possible impact on the surrounding environment.

  11. Does leaf chemistry differentially affect breakdown in tropical versus temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Science.gov (United States)

    Marcelo Ardon; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to...

  12. 中亚热带主要树种凋落叶在杉木人工林中分解及氮磷释放过程%Decomposition and nitrogen-and phosphorus release of leaf litters from main tree species in a mid-subtropical forest

    Institute of Scientific and Technical Information of China (English)

    仲米财; 王清奎; 高洪; 于小军

    2013-01-01

    By using the standard litter-bag method,an experiment was conducted to study the decomposition rate and the nitrogen (N) and phosphorus (P) release processes of leaf litters derived from Pinus massoniana,Alnus cremastogyne,Schima superba,and Cycloblanopsis glauca in a 21-year Cunninghamia lanceolata forest.By the end of the experiment (13 months incubation),C.glauca litter had the highest decomposition rate,with 33.5% of mass loss,followed by A.cremastogyne and S.superba,and P.massoniana had the lowest decomposition rate,with 29.9% of mass loss.The time for 50% and 95% of the mass loss of the litters from the four tree species ranged from 21 to 26 months and from 94 to 112 months,respectively.During the decomposition,the N concentration in A.cremastogyne litter decreased,whereas that in the other tree species litters increased.The P concentration in the litters decreased rapidly at the first three months of decomposition,and then varied insignificantly.During litter decomposition,the ratio of carbon (C) to N decreased,while the ratio of C to P increased.C.glauca,A.cremastogyne,and S.superba litters had net N release,but P.massoniana litter had N sequestration.In terms of P,the litters from the four tree species had net release during decaying.Among the four tree species,A.cremastogyne was more appropriate to be mixed planted with C.lanceolata.%采用分解网袋法研究了马尾松(Pinus massoniana)、桤木(Alnus cremastogyne)、木荷(Schima superba)、青冈(Cycloblanopsis glauca)等树种凋落叶在21年生杉木人工林内的分解速率和养分释放过程.经过13个月的分解实验,4种供试凋落叶以青冈分解最快,质量失重率为33.5%,其次为桤木和木荷,马尾松分解最慢,其质量失重率仅为29.9%.4种凋落叶分解50%和95%所需要的时间分别为21~26个月和94 ~112个月.在凋落叶分解过程中,除桤木凋落叶中氮含量下降外,其他3种凋落叶的氮含量均增加,但凋落叶的C/N均

  13. Effects of nitrogen addition and water manipulation on leaf litter decomposition%水、氮耦合对阔叶红松林叶凋落物分解的影响

    Institute of Scientific and Technical Information of China (English)

    李东升; 郑俊强; 王秀秀; 郑兴波; 韩士杰

    2016-01-01

    In this study, fivetypes of litter ( Pinus koraiensis, Quercus mongolica, Acer mono, Fraxinus mandsurica and Tilia amurensis) and soil of broadleaf﹣Korean pine mixed forest in Changbai Mountain, northeastern China, were selected to study the effect of nitrogen deposition and water manipulation on the litter decomposition. The results are as follows. The rate of litter decomposition did not change significantly with N addition, but declined when the amount of litter increased. The decomposition rate of Fraxinus mandshurica litter increased with increasing water addition. After 14 weeks of incubation, the N concentration in litter was significantly increased, while the C concentration and C/N ratio of litter were significantly decreased. This phenomenon indicates that both C and N elements in litter may have different migrating patterns. The C and N concentrations of soil increased, the δ15 N value had no significant change, and the δ13 C value and C/N ratio declined after treatment. The δ15 N values of litter residues varied among different water and nitrogen treatments. The δ13 C value of litter residue declined. In addition, there were some interactions among the three factors, i. e. water, nitrogen and litter addition.%以长白山阔叶红松林优势树种红松、蒙古栎、色木槭、水曲柳、紫椴的叶凋落物为研究对象,定量模拟加水、加氮、凋落物量对凋落物分解和土壤碳氮过程的影响。结果表明:加氮处理对凋落物分解没有显著影响;凋落物量增多使分解率下降;加水处理显著促进水曲柳凋落物的分解。培养结束后,凋落物的氮质量分数增加、碳质量分数和C/N降低,凋落物残体的δ15 N值因凋落物种类、水氮处理的不同而不同,δ13 C值下降;土壤的碳、氮质量分数增加,δ15 N值无显著变化,δ13 C值和C/N下降。

  14. Mixing effects of understory plant litter on decomposition and nutrient release of tree litter in two plantations in Northeast China.

    Directory of Open Access Journals (Sweden)

    Lei Zhao

    Full Text Available Understory vegetation plays a crucial role in carbon and nutrient cycling in forest ecosystems; however, it is not clear how understory species affect tree litter decomposition and nutrient dynamics. In this study, we examined the impacts of understory litter on the decomposition and nutrient release of tree litter both in a pine (Pinus sylvestris var. mongolica and a poplar (Populus × xiaozhuanica plantation in Northeast China. Leaf litter of tree species, and senesced aboveground materials from two dominant understory species, Artemisia scoparia and Setaria viridis in the pine stand and Elymus villifer and A. sieversiana in the poplar stand, were collected. Mass loss and N and P fluxes of single-species litter and three-species mixtures in each of the two forests were quantified. Data from single-species litterbags were used to generate predicted mass loss and N and P fluxes for the mixed-species litterbags. In the mixture from the pine stand, the observed mass loss and N release did not differ from the predicted value, whereas the observed P release was greater than the predicted value. However, the presence of understory litter decelerated the mass loss and did not affect N and P releases from the pine litter. In the poplar stand, litter mixture presented a positive non-additive effect on litter mass loss and P release, but an addition effect on N release. The presence of understory species accelerated only N release of poplar litter. Moreover, the responses of mass loss and N and P releases of understory litter in the mixtures varied with species in both pine and poplar plantations. Our results suggest that the effects of understory species on tree litter decomposition vary with tree species, and also highlight the importance of understory species in litter decomposition and nutrient cycles in forest ecosystems.

  15. Carbon and nitrogen dynamics in early stages of forest litter decomposition as affected by nitrogen addition

    Institute of Scientific and Technical Information of China (English)

    DENG Xiao-wen; LIU Ying; HAN Shi-jie

    2009-01-01

    The effects of nitrogen (N) availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment. Fresh litter samples including needle litter (Pinus koraiensis) and two types of broadleaf litters (Quercus mongolica and Tilia amurensis) were collected from a broadleaf-korean pine mixed forest in the northern slope of Changbai Mountain (China). Different doses of N (equal to 0, 30 and 50 kg·ha-1yr-1, respectively, as NH4NO3) were added to litter during the experiment period. The litter decomposition rate expressed as mass loss and respiration rate increased significantly with increasing N availability. The mass loss and cumulative CO2-C emission were higher in leaf litter compared to that in needle litter. The dissolved organic Carbon (DOC) concentrations in litter leachate varied widely between the species, but were not greatly affected by N treatments. Regardless of the N addition rate, both N treatments and species had no significant effect on dissolved organic N (DON) concentrations in litter leachate. About 52·78% of added N was retained in the litter. The percentage of N retention was positively correlated (R2=0.91, p<0.05) with the litter mass loss. This suggested that a forest floor with easily decomposed litter might have higher potential N sink strength than that with more slowly decomposed litter.

  16. Effects of Simulated Nitrogen Deposition on Leaf Litter Decomposition in a Plantation of Eucalyptus grandis, in a Rainy Region of West China%模拟氮沉降对华西雨屏区巨桉林凋落叶分解的影响

    Institute of Scientific and Technical Information of China (English)

    胡红玲; 张健; 刘洋; 涂利华; 向元彬

    2011-01-01

    2008 -01-2010 - 01,对华西雨屏区巨桉人工林进行氮沉降模拟试验,氮沉降水平分别为对照(CK,0 gN·m-2a-1)、低氮(5 g N·m-2a-1)、中氮(15 g N·hm-2a-1)和高氮(30 g N·m-2a-1),把年施氮量分12等份,每月下旬对各处理施氮( NH4 N03),探讨氮沉降持续增加对巨桉凋落叶分解和养分释放过程的影响,及巨桉凋落叶分解过程中是否存在限制值.结果表明:巨桉凋落叶在分解初期存在一个质量快速损失的淋溶期,而分解后期(14个月以后)质量损失极其缓慢,残留凋落物处于较稳定状态;氮沉降显著抑制了巨桉凋落叶后期分解,并且低氮处理抑制作用最强,但氮沉降对凋落物养分释放过程无明显影响;自然分解状态下,巨桉凋落叶分解限制值大约为90% (CK),而氮沉降使得这一限制值降低,并且低氮(限制值大约为72%)与对照之间差异达到显著水平.%To detect the effects of nitrogen deposition on leaf litter decomposition of Eucalyptus grandis, and investigate whether there is a limit value in the decomposition process, a field experiment simulating nitrogen deposition was conducted from January 2008 to January 2010 in a plantation of E. grandis, which is located at a Rainy Region of West China. The levels of nitrogen deposition included control (CK, 0 g N·m-2a-1) , low nitrogen (5 g N·m-2a-1) , medium nitrogen (15 g N·m-2a-1) and high nitrogen (30 g N·m-2a-1). The total annual amount of nitrogen (NH4NO3) application was divided into 12 equal parts, and each part was added to the corresponding N-treated plot by the end of each month started from January of 2008. Results indicated that there was a leaching period at the early stages of leaf litter decomposition of E. grandis. Mass loss became very slow at the late stages after 14 months decomposition, and hereafter the litter was relatively stable. N deposition inhibited the decomposition of litter at the late stages and the inhibiting effect in

  17. Leaf Litter Decomposition of Different Species of Photosynthetic Functional Plant Groups in Karst Area of Central Guizhou%黔中喀斯特区不同光合功能群树种凋落叶分解特性研究

    Institute of Scientific and Technical Information of China (English)

    汪舒雅; 喻理飞; 黄宗胜

    2014-01-01

    通过2013年在黔中喀斯特区采用网袋法进行植物凋落叶的分解实验,比较不同光合功能群树种凋落叶的残留率、分解速率、有机碳释放速率的差异。结果表明,研究区广光耐荫功能群树种(I)、窄光耐荫功能群树种(II)、广光喜光功能群树种(III)、窄光喜光功能群树种(IV)4种功能群树种凋落物在1年的分解过程中,残留率变化趋势分第1~4月、第5~9月、第10~12月3阶段,呈快-慢-快的规律;各光合功能群树种凋落叶分解速率为 III>IV>I>II。有机碳释放速率为 IV>II>III>I。凋落叶分解过程残留率与其有机碳释放速率均呈极显著负相关关系。喜光树种比耐荫树种凋落叶更易分解。%In 2013 by using the litter-bag method,the researchers carried out the plant leaf litter decompo-sition experiment in central Guizhou Karst area,in order to compare differences between residual rates of different photosynthetic functional plant groups’littered leaves,the leaf litter decomposition rates and the organic carbon release rates.There were four species of photosynthetic functional plant groups analyzed in the study area,which were wide-light shade tolerant species (I), narrow-light shade tolerant species (II),wide-light bright light species (III),narrow-light bright light species (IV).Based on analysis of the leaf litter decomposition process in one year,the results showed that tendency of the residual rates presented the fast-slow-fast changes during different periods of time from January to April,May to Sep-tember,and October to December respectively.The leaf litter decomposition rate was III>IV>I>II. The organic carbon release rate was IV>II>III>I.There were negative correlation between the residual rates and the organic carbon release rates.The bright light species were more easier to be decomposed.

  18. Shrub encroachment in Arctic tundra: Betula nana effects on above- and below-ground litter decomposition.

    Science.gov (United States)

    McLaren, Jennie R; Buckeridge, Kate M; van de Weg, Martine J; Shaver, Gaius R; Schimel, Joshua P; Gough, Laura

    2017-03-06

    Rapid arctic vegetation change as a result of global warming includes an increase in the cover and biomass of deciduous shrubs. Increases in shrub abundance will result in a proportional increase of shrub litter in the litter community, potentially affecting carbon turnover rates in arctic ecosystems. We investigated the effects of leaf and root litter of a deciduous shrub, Betula nana, on decomposition, by examining species-specific decomposition patterns, as well as effects of Betula litter on the decomposition of other species. We conducted a two-year decomposition experiment in moist acidic tundra in northern Alaska, where we decomposed three tundra species (Vaccinium vitis-idaea, Rhododendron palustre, and Eriophorum vaginatum) alone and in combination with Betula litter. Decomposition patterns for leaf and root litter were determined using three different measures of decomposition (mass loss, respiration, extracellular enzyme activity). We report faster decomposition of Betula leaf litter compared to other species, with support for species differences coming from all three measures of decomposition. Mixing effects were less consistent among the measures, with negative mixing effects shown only for mass loss. In contrast, there were few species differences or mixing effects for root decomposition. Overall, we attribute longer-term litter mass loss patterns in to patterns created by early decomposition processes in the first winter. We note numerous differences for species patterns between leaf and root decomposition, indicating that conclusions from leaf litter experiments should not be extrapolated to below-ground decomposition. The high decomposition rates of Betula leaf litter aboveground, and relatively similar decomposition rates of multiple species below, suggest a potential for increases in turnover in the fast-decomposing carbon pool of leaves and fine roots as the dominance of deciduous shrubs in the Arctic increases, but this outcome may be tempered

  19. FOREST LITTER DECOMPOSITION AS AFFECTED BY EUCALYPTUS STAND AGE AND TOPOGRAPHY IN SOUTH-EASTERN BRAZIL1

    OpenAIRE

    Alba Lucia Araujo Skorupa; Nairam Félix de Barros; Júlio César Lima Neves

    2015-01-01

    Forest litter decomposition is a major process in returning nutrients to soils and thus promoting wood productivity in the humid tropic. This study aimed to assess decomposition of eucalypt litter in the Rio Doce region, Brazil. Leaf litter was sampled under clonal eucalypt stands aged 2, 4 and 6 years on hillslopes and footslopes. Soil and soil+litter samples were incubated at two levels of soil moisture, temperature and fertilization. C-CO2 emissions from soil measured during 106 days were ...

  20. Fine roots are the dominant source of recalcitrant plant litter in sugar maple-dominated northern hardwood forests.

    Science.gov (United States)

    Xia, Mengxue; Talhelm, Alan F; Pregitzer, Kurt S

    2015-11-01

    Most studies of forest litter dynamics examine the biochemical characteristics and decomposition of leaf litter, but fine roots are also a large source of litter in forests. We quantified the concentrations of eight biochemical fractions and nitrogen (N) in leaf litter and fine roots at four sugar maple (Acer saccharum)-dominated hardwood forests in the north-central United States. We combined these results with litter production data to estimate ecosystem biochemical fluxes to soil. We also compared how leaf litter and fine root biochemistry responded to long-term simulated N deposition. Compared with leaf litter, fine roots contained 2.9-fold higher acid-insoluble fraction (AIF) and 2.3-fold more condensed tannins; both are relatively difficult to decompose. Comparatively, leaf litter had greater quantities of more labile components: nonstructural carbohydrates, cellulose and soluble phenolics. At an ecosystem scale, fine roots contributed over two-thirds of the fluxes of AIF and condensed tannins to soil. Fine root biochemistry was also less responsive than leaf litter to long-term simulated N deposition. Fine roots were the dominant source of difficult-to-decompose plant carbon fractions entering the soil at our four study sites. Based on our synthesis of the literature, this pattern appears to be widespread in boreal and temperate forests.

  1. Effects of snow cover on the decomposition and nutrient dynamics of Sibiraea angustata leaf litter in western Sichuan plateau, Southwest China%川西高原季节性雪被覆盖对窄叶鲜卑花凋落物分解和养分动态的影响

    Institute of Scientific and Technical Information of China (English)

    胡霞; 吴宁; 吴彦; 左万庆; 郭海霞; 王金牛

    2012-01-01

    Soil-borne bag method was adopted to study the decomposition and nutrient dynamics of Sibiraea angustata leaf litter under different depths (0, 30 and 100 cm) of snow cover in western Sichuan plateau in January-May, 2010. In snow-free plot, the mass loss rate of the litter over the five months was 29. 9% ; in the plots with 30 and 100 cm snow cover, the litter mass loss rate was 33.8% and 35.2%, respectively. During the decomposition, definite N enrichment in the litter was observed, while the P enrichment fluctuated. The C content and C/N ratio of the litter decreased sharply at the early stage of decomposition, but increased gradually after then. Snow cover greatly contributed to the rapid decomposition of litter and the N enrichment in the litter, but had little effects on the litter C and P contents. In western Sichuan plateau, durable snow cover with a depth of >30 cm could alter the litter decomposition pattern, and substantially affect the soil nutrient turnover and plant community composition.%2010年1-5月在川西高原采用人工雪厚度梯度试验(0、30和100 cm),应用网袋分解法对窄叶鲜卑花叶片凋落物进行分解试验,测定了凋落物的分解速率及其养分动态.结果表明:在无雪被覆盖的样地上分解5个月后的凋落物质量损失率为29.9%,而中雪和深雪样地的凋落物质量损失率分别为33.8%和35.2%.分解过程中,凋落物氮存在一定的富集现象,磷处于波动的富集状态,碳质量分数和碳氮比均呈现前期急剧下降后期逐渐上升的趋势.雪被覆盖显著增加了凋落物的质量损失率和氮含量,而对碳和磷含量无显著影响.在川西高原地区,30 cm以上的持续雪被覆盖能够改变凋落物的分解过程,从而可能对土壤营养物质转化和植物群落构建产生实质性的影响.

  2. Myxomycetes of the litter

    Directory of Open Access Journals (Sweden)

    Wanda Stojakowska

    2014-08-01

    Full Text Available The litter is a useful substratum for developmen t of the Myxomycetes. On the basis of our own observations and literature data 50 species of the slime molds were found occuring on litter. Species from the order Physarales (33 species are dominant.

  3. 太湖流域上游西苕溪源头溪流中毛竹、石栎和山胡椒落叶分解比较%Leaf litter breakdown of Phyllostachys heterocycla, Lithocarpus glabra and Lindera glauca in a headwater stream of Xitiaoxi watershed, upper reaches of Taihu Basin, China

    Institute of Scientific and Technical Information of China (English)

    卢东琪; 张勇; 刘东晓; 王备新

    2012-01-01

    比较了毛竹、石栎和山胡椒叶片的理化属性,采用粗网叶袋法研究了三种落叶在太湖流域上游西苕溪中的分解过程,探讨了毛竹叶成为溪流优势外来能源后对溪流生态过程和底栖动物群落结构的影响.三种落叶的氮、磷含量及叶片厚度都存在显著差异,毛竹叶的氮含量(30.23 g/kg)远高于石栎(20.98 g/kg)和山胡椒(9.69g/kg),其中毛竹叶的分解速率最快(k =0.00592 d-1),山胡椒(0.00297 d-1)和石栎叶(0.00212 d-1)较慢.三种落叶叶袋间的大型底栖无脊椎动物包括各取食功能团的多度和生物量无显著差异,而4次采样间的差异很显著.大型底栖动物的取食功能团中,撕食者的数量比例最高(40.3%),生物量比例为41.6%,是落叶分解的重要功能类群.撕食者中,利用阔叶筑巢的鳞石蛾Lepidostoma数量最多,占全部底栖动物的14%,是该溪流中主要的撕食者类群.因此,由于毛竹叶具有氮、磷含量较高、叶形较窄,以及两年进行一次换叶的特点,当毛竹叶替代其他阔叶秋季落叶的树种成为源头溪流优势外来能源后,可能会改变源头溪流中的氮磷含量、溪流外来能源的量和滞留时间以及底栖动物群落结构.%In order to explore the impact of the change of the dominant leaf litter source in stream from broad leaf trees to a bamboo tree of Phyllostachys heterocycla on headwater stream ecosystem and their associated benthic macroinvertebrates, we compared the leaf physical and chemical characters of Phyllostachys heterocycla, Luhocarpus glabra and Lindera glauca, and then evaluated the leaf litter breakdown of above three species using coarse-mesh litter bags in a headwater stream of Xitiaoxi watershed, Zhejiang Province. The concentrations of nitrogen , phosphorus and the thickness of the three categories of leaves varied significantly. The nitrogen concentration of bamboo tree leaf (30.23 g/kg) was much higher than that of L. glabra (20

  4. Direct and indirect effects of UV-B exposure on litter decomposition: a meta-analysis.

    Science.gov (United States)

    Song, Xinzhang; Peng, Changhui; Jiang, Hong; Zhu, Qiuan; Wang, Weifeng

    2013-01-01

    Ultraviolet-B (UV-B) exposure in the course of litter decomposition may have a direct effect on decomposition rates via changing states of photodegradation or decomposer constitution in litter while UV-B exposure during growth periods may alter chemical compositions and physical properties of plants. Consequently, these changes will indirectly affect subsequent litter decomposition processes in soil. Although studies are available on both the positive and negative effects (including no observable effects) of UV-B exposure on litter decomposition, a comprehensive analysis leading to an adequate understanding remains unresolved. Using data from 93 studies across six biomes, this introductory meta-analysis found that elevated UV-B directly increased litter decomposition rates by 7% and indirectly by 12% while attenuated UV-B directly decreased litter decomposition rates by 23% and indirectly increased litter decomposition rates by 7%. However, neither positive nor negative effects were statistically significant. Woody plant litter decomposition seemed more sensitive to UV-B than herbaceous plant litter except under conditions of indirect effects of elevated UV-B. Furthermore, levels of UV-B intensity significantly affected litter decomposition response to UV-B (PUV-B effects on litter decomposition were to a large degree compounded by climatic factors (e.g., MAP and MAT) (PUV-B on litter decomposition. No significant differences in UV-B effects on litter decomposition were found between study types (field experiment vs. laboratory incubation), litter forms (leaf vs. needle), and decay duration. Indirect effects of elevated UV-B on litter decomposition significantly increased with decay duration (PUV-B exposure intensity (30%) had significant direct effects on litter decomposition (PUV-B on litter decomposition.

  5. Flower litters of alpine plants affect soil nitrogen and phosphorus rapidly in the eastern Tibetan Plateau

    Science.gov (United States)

    Wang, Jinniu; Xu, Bo; Wu, Yan; Gao, Jing; Shi, Fusun

    2016-10-01

    Litters of reproductive organs have rarely been studied despite their role in allocating nutrients for offspring reproduction. This study determines the mechanism through which flower litters efficiently increase the available soil nutrient pool. Field experiments were conducted to collect plant litters and calculate biomass production in an alpine meadow of the eastern Tibetan Plateau. C, N, P, lignin, cellulose content, and their relevant ratios of litters were analyzed to identify their decomposition features. A pot experiment was performed to determine the effects of litter addition on the soil nutrition pool by comparing the treated and control samples. The litter-bag method was used to verify decomposition rates. The flower litters of phanerophyte plants were comparable with non-flower litters. Biomass partitioning of other herbaceous species accounted for 10-40 % of the aboveground biomass. Flower litter possessed significantly higher N and P levels but less C / N, N / P, lignin / N, and lignin and cellulose concentrations than leaf litter. The litter-bag experiment confirmed that the flower litters of Rhododendron przewalskii and Meconopsis integrifolia decompose approximately 3 times faster than mixed litters within 50 days. Pot experiment findings indicated that flower litter addition significantly increased the available nutrient pool and soil microbial productivity. The time of litter fall significantly influenced soil available N and P, and soil microbial biomass. Flower litters fed the soil nutrition pool and influenced nutrition cycling in alpine ecosystems more efficiently because of their non-ignorable production, faster decomposition rate, and higher nutrient contents compared with non-flower litters. The underlying mechanism can enrich nutrients, which return to the soil, and non-structural carbohydrates, which feed and enhance the transitions of soil microorganisms.

  6. 巨桉凋落叶分解初期对菊苣生长和光合特性的影响%Effects of Eucalyptus grandis leaf litter at its early stage of decomposition on the growth and photosynthetic characteristics of Cichorium intybus

    Institute of Scientific and Technical Information of China (English)

    吴秀华; 李羿桥; 胡庭兴; 陈保军; 杨永贵; 陈洪; 胡红玲

    2013-01-01

    From March to May,2010,a pot experiment was conducted to investigate the effects of Eucalyptus grandis leaf litter at its early stage of decomposition on the growth and photosynthetic characteristics of Cichorium intybus.Four treatments with different application rate of the leaf litter,i.e.,0 g· pot-1(CK),30 g · pot-1(A1),60 g · pot-1(A2),and 90 g · pot-1(A3),were installed.Each pot contained 12 kg soil mixed with the leaf litter,and then,C.intybus was sown.The growth indicators of the C.intybus were measured at the 30,45,60,and 75 d after sowing,and the photosynthetic characteristics of the C.intybus in treatment A3 were studied after the seedlings third leaf fully expanded.At each measured time,the biomass accumulation and leaf area growth of C.intybus in treatments A1,A2,and A3 were inhibited significantly.At the early stage of the leaf litter decomposition,the synthesis of photosynthetic pigments of the C.intybus seedlings was inhibited significantly,and the inhibition effect was getting stronger with the increasing amount of the leaf litter addition.The diurnal change of the seedlings photosynthetic rate in all treatments showed a bimodal curve with midday depression,the stomatal conductance and water use efficiency had the same variation trend with the net photosynthetic rate,and the total diurnal photosynthesis decreased in the order of CK > A1 > A2 > A3.The GC-MS analysis showed there were 33 kinds of small molecule compounds released gradually with the decomposition of the leaf litter,among which,allelopathic substance terpenoid dominated.%采用盆栽试验,于2010年3-5月在四川农业大学教学科研园区内研究了巨桉凋落叶分解初期对受体植物菊苣幼苗生长和光合特性的影响.试验设置CK (0 g·pot-1)、A1(30 g·pot-1)、A2(60 g·pot-1)和A3 (90 g·pot-1)4个凋落叶施用水平,将各处理的凋落叶分别与12 kg土壤混合后装盆,播种菊苣,分别在播种30、45、60和75 d测定菊苣生长指标,

  7. 华西雨屏区亮叶桦凋落叶分解对模拟氮沉降的响应%Response of Betula luminifera leaf litter decomposition to simulated nitrogen deposition in the Rainy Area of West China

    Institute of Scientific and Technical Information of China (English)

    涂利华; 胡红玲; 胡庭兴; 张健; 雒守华; 戴洪忠

    2012-01-01

    Aims Our objective was to determine the effect of simulated increased nitrogen (N) deposition on decomposition of Betula luminifera leaf litter, under a high wet-nitrogen deposition background.Methods From January 2008 to February 2009, a field experiment of simulated N deposition was conducted in a B. Luminifera plantation in the Rainy Area of West China. The levels of nitrogen deposition were control (CK), low, medium and high N (0, 5, 15 and 30 g Nm-2·a-1, respectively). A field experiment using the litterbag method was conducted on the decomposition of leaf litter of B. Luminifera. In the end of each month, NH4NO3 was added into N-treated plots.Important findings Despite the high background N deposition, there were significant effects of simulated increased N deposition on B. Luminifera leaf litter. N treatments significantly slowed the decomposition of B. Luminifera leaf litter through inhibiting the decay of lignin and cellulose. The time of 95% mass loss (r95%) of B. Luminifera leaf litter was increased by 1.14-1.96 a from 2.65 a (T95o/o of CK) caused by simulated N deposition. Simulated N deposition significantly increased the remaining amount of carbon, N, phosphorus, potassium, and magnesium after one year of decomposition. However, calcium release rate was stimulated by simulated N deposition in all three N treatments. The initial chemical characteristics of litter determined the response direction of litter decomposition to simulated N deposition, as well as the nutrient release pattern during litter decomposition.%从2008年1月至2009年2月,对华西雨屏区亮叶桦(Betula luminifera)人工林进行了模拟氮(N)沉降试验,N沉降水平分别为对照(CK,0gN·m-2·a-1)、低N(5 gN·m-2·a-1)、中N(15 g N·m-2·a-1)和高N(30g N·m-2·a-1).利用凋落袋法对亮叶桦凋落叶进行原位分解试验,并在每月下旬定量地对各处理施N (NH4NO3).结果表明,虽然华西雨屏区大气N沉降量较高,但模拟N沉降试验表明:在N

  8. Environmentally friendly animal litter

    Science.gov (United States)

    Chett, Boxley; McKelvie, Jessica

    2013-08-20

    A method of making an animal litter that includes geopolymerized ash, wherein, the animal litter is made from a quantity of a pozzolanic ash mixed with a sufficient quantity of water and an alkaline activator to initiate a geopolymerization reaction that forms geopolymerized ash. After the geopolymerized ash is formed, it is dried, broken into particulates, and sieved to a desired size. These geopolymerized ash particulates are used to make a non-clumping or clumping animal litter. Odor control may be accomplished with the addition of a urease inhibitor, pH buffer, an odor eliminating agent, and/or fragrance.

  9. Littering Behavior in Public Places

    Science.gov (United States)

    Robinson, Stuart N.

    1976-01-01

    This review summarizes the present state of knowledge concerning littering behavior. Available studies are categorized according to the variables that influence littering--individual and environmental. Theoretical issues of attitude-behavior consistency and incentive effectiveness are analyzed with respect to littering and litter control. Results…

  10. Field Experiments in Litter Control

    Science.gov (United States)

    Finnie, William C.

    1973-01-01

    A series of urban and highway litter experiments in Richmond (Virginia), St. Louis, and Philadelphia indicated well-designed litter cans reduced littering about 15 percent along city streets and nearly 30 percent along highways. Also, the propensity to litter is critically affected by the characteristics of the individual and environmental…

  11. 核桃凋落叶分解对3种作物生长、光合及抗性生理特性的影响%Effects of Decomposing Walnut (Juglans regia) Leaf Litter on Growth, Photosynthesis and Resistance Physiology of Three Recipient Plants

    Institute of Scientific and Technical Information of China (English)

    张如义; 胡红玲; 胡庭兴; 杨丽妹; 舒兰; 阮若玉

    2016-01-01

    采用盆栽试验,研究了核桃( Juglans regia)凋落叶在土壤中分解对3种受体作物萝卜( Raphanus sativus)、芥菜( Brassica juncea)和白菜( Brasicca pekinensis)生长、光合及抗性生理特性的影响,并比较不同受体作物对核桃凋落叶化感作用的敏感性,筛选可能与核桃套作的作物。试验设置4�5( T1)、9�0( T2)和18�0 g·盆-1( T3)3个凋落叶添加水平,对照( CK)不添加凋落叶。结果表明:(1)核桃凋落叶在其分解过程中对3种受体作物各项生长指标均表现出抑制作用,随着凋落叶量的增加抑制效应逐渐增强,而随着分解时间的延长抑制效应呈减弱趋势;(2)凋落叶分解80 d时,各处理3种受体作物叶片中的叶绿素和类胡萝卜素含量明显低于CK。各植物叶片净光合速率、气孔导度和蒸腾速率均显著低于CK;(3)与CK相比,各凋落叶处理3种受体作物叶片丙二醛含量增加,过氧化物酶和过氧化氢酶活性表现为受抑制作用,而超氧化物歧化酶活性表现为促进作用,可溶性糖含量增加,可溶性蛋白含量降低;(4)3种受体作物对核桃凋落叶化感综合抑制作用的敏感程度由大到小依次为白菜、萝卜和芥菜。综合各项指标可见,核桃凋落叶在分解初期(约80 d时)对3种受体作物产生了强烈的化感作用,主要通过氧化损伤、抑制叶绿素合成和降低其光合能力来阻碍其生长,之后随着凋落叶的进一步分解,释放的化感物质越来越少,对3种受体作物生长的抑制作用减弱。%A pot experiment was conducted to study effects of decomposing walnut leaf litter on growth, photosynthesis and resistant physiology of three recipient crops, i.e. radish (Raphanus sativus), mustard (Brassica juncea) and Chinese cab⁃bage ( Brasicca pekinensis) , and to compare the three crops in sensibility to allelopathy of the

  12. Variación estacional y potencial enzimático de microhongos asociados con la descomposición de hojarasca de Nothofagus pumilio Seasonal variation and enzymatic potential of microfungi associated with the decomposition of Nothofagus pumilio leaf litter

    Directory of Open Access Journals (Sweden)

    EDUARDO VALENZUELA

    2001-12-01

    Full Text Available Se estudió la variación estacional y el potencial enzimático de microhongos aislados desde el follaje y hojarasca de Nothofagus pumilio sometida a degradación natural durante 1 año. La investigación se realizó en un bosque de N. pumilio ubicado en una microcuenca del Valle de Antillanca, Parque Nacional Puyehue (40° 47' S, 72° 12' O, 1.120 m de altitud. Hojas senescentes colectadas desde árboles de N. pumilio se depositaron en bolsas de malla de nylon ("litter bags" y se sometieron a degradación natural en el piso del bosque durante 1 año (marzo 1997-marzo 1998, realizando muestreos trimestrales. Para el aislamiento de microhongos desde las hojas se utilizó el método de las diluciones, con agar extracto de malta al 2 % como medio de cultivo. Para determinar los potenciales degradativos de los aislamientos, se analizaron in vitro las actividades de amilasa, celulasa, pectinasa, proteasa, lacasa, oxidasa extracelular, peroxidasa, citocromo oxidasa, fosfatasa, esterasa y tirosinasa. Las principales especies aisladas en las hojas senescentes fueron Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Phialophora grupo hoffmannii y Rhodotorula aurantiaca. Las especies dominantes en la hojarasca fueron Hormonema prunorum, Mortierella ramanniana var. angulispora, Penicillium para-herquei y Trichoderma polysporum. El mayor potencial enzimático lo exhibieron Moniliales y micelios estériles, mientras el menor Sphaeropsidales y levaduras. Las especies más activas fueron Alternaria alternata, Cladosporium cladosporioides, Hormonema prunorum y Phialophora malorum. Las actividades de celulasa y amilasa fueron las más importantes. De las enzimas ligninolíticas, oxidasa extracelular y peroxidasa presentaron los más elevados potenciales enzimáticosThe seasonal variation and enzymatic potential of microfungi isolated from senescent leaves and leaf litter of Nothofagus pumilio was studied. The study was performed in a N

  13. Invertebrate grazers affect metal/metalloid fixation during litter decomposition.

    Science.gov (United States)

    Schaller, Jörg; Brackhage, Carsten

    2015-01-01

    Plant litter and organic sediments are main sinks for metals and metalloids in aquatic ecosystems. The effect of invertebrates as key species in aquatic litter decomposition on metal/metalloid fixation by organic matter is described only for shredders, but for grazers as another important animal group less is known. Consequently, a laboratory batch experiment was conducted to examine the effect of invertebrate grazers (Lymnaea stagnalis L.) on metal/metalloid fixation/remobilization during aquatic litter decomposition. It could be shown that invertebrate grazers facilitate significantly the formation of smaller sizes of particulate organic matter (POM), as shown previously for invertebrate shredders. The metal/metalloid binding capacity of these smaller particles of POM is higher compared to leaf litter residuals. But element enrichment is not as high as shown previously for the effect by invertebrate shredders. Invertebrate grazers enhance also the mobilization of selected elements to the water, in the range also proven for invertebrate shredders but different for the different elements. Nonetheless invertebrate grazers activity during aquatic litter decomposition leads to a metal/metalloid fixation into leaf litter as part of sediment organic matter. Hence, the effect of invertebrate grazers on metal/metalloid fixation/remobilization contrasts partly with former assessments revealing the possibility of an enhanced metal/metalloid fixation.

  14. Litter Decomposition Rates, 2015

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set contains decomposition rates for litter of Salicornia pacifica, Distichlis spicata, and Deschampsia cespitosa buried at 7 tidal marsh sites in 2015....

  15. [Litter decomposition of dominant plantations in Guangxi and its effects on leachate quality].

    Science.gov (United States)

    Yang, Gai-Ren; Zhang, Xiu-Qing; Cai, De-Suo; Shi, Xian-Hui; Zhang, Hua; Huang, Cheng-Biao

    2012-01-01

    To understand the decomposition characteristics of the litters in different forest plantations and the effects of released substances during litter decomposition on the leachate quality, litter samples (leaf, shoot, and cortices) were collected from five forest plantations (1 year-old Eucalyptus urophylla x E. grandis, EU1; 4 year-old Eucalyptus urophylla x E. grandis, EU4; 7 year-old Acacia mangium x A. auriculaef, AM; 13 year-old Pinus massoniana Lamb, PL; and mixed broad-leaved softwood, BL), and incubated at 28 degrees C, using water leached for 255 days. In the first 105 days, the litter leachates of EU1 and EU4 had significantly higher coloration and N and P contents and lower pH than those of AM, PL, and BL. On the 255th day, the cumulative chemical oxygen demand (COD) in the leaf litters leachates of EU1 and EU4 was 193.9 and 212.8 g x kg(-1), being 4.2, 4.0, and 4.3 times and 5.3, 4.4, and 4.7 times higher than that of AM, PL, and BL, respectively. The mass loss rate and the N and P leaching rate of the leaf litter of EU1 were significantly higher than those of AM, PL, and BL. The mass loss rate of cortices of EU1 was significantly higher than that of PL. No significant difference was observed for the leaching rate of the shoot litters between AM, PL, and BL. Among the litter samples, leaf litter was easiest to be decomposed, while shoot litter was most difficult to be decomposed. The pH value of the litter leachates of Eucalyptus plantations was significantly negatively correlated with leachate chroma and COD, and the COD had significant positive correlations with the concentrations of total N and P in the leachates.

  16. Litter fall and decomposition of mangrove species Avicennia marina ...

    African Journals Online (AJOL)

    Department of Biological Sciences, Eduardo Mondlane University, PO Box 257, Maputo, ... marina, the average time required to lose half of the initial AFDW (t0,5) was 96 days ... 2008, precipitation varies from the extremes ..... mm) as shown by a 10 year meteorological .... mangrove leaf litter in tropical Australia. J. Exp. Mar.

  17. 紫茎泽兰叶片凋落物对入侵地4种草本植物的化感作用%Allelopathic effect of Ageratina adenophora(Spreng.)leaf litter on four herbaceous plants in invaded regions

    Institute of Scientific and Technical Information of China (English)

    万欢欢; 刘万学; 万方浩

    2011-01-01

    为了明确紫茎泽兰叶片凋落物对入侵地草本植物的化感作用,研究了不同浓度紫茎泽兰叶片凋落物水提液对入侵地草本植物多年生黑麦草、白三叶,辣子草和紫花苜蓿种子萌发和幼苗生长的影响,同时结合土培试验研究了叶片凋落物在入侵地土壤中的化感作用.结果表明,除多年生黑麦草外,水提液对其他3种草本植物种子萌发均产生了显著的化感抑制作用,且水提液的浓度越高抑制效果越强;低浓度水提液对紫花苜蓿和辣子草的幼苗生长存在显著化感促进作用,高浓度的水提液对除多年生黑麦草外的其他3种植物幼苗的生长存在显著化感抑制作用,水提液对多年生黑麦草幼苗生长的影响不显著;土壤中按照50g·kg-1的比例添加叶片凋落物后,显著抑制了白三叶的生长,而添加活性炭后,白三叶的单株生物量相对于未添加活性炭的处理增加71.25%,进一步证实叶片凋落物在土壤中的化感抑制作用.这说明外来入侵植物紫茎泽兰可能通过其叶片凋落物在入侵地土壤中降解,释放化感物质,抑制伴生植物的种子萌发和幼苗生长,为自身创造有利的生长环境,实现其成功入侵和扩张.%The effects of different concentrations of water extracts of A. adenophora leaf litter on the germination and seedling growth of Lolium perenne, Trifoliurn repens, Galinsoga parvifiora and Medicago sativa were determined via laboratory bioassay. The objective of the study was to elucidate allelopathic effects of A. adenophora leaf litter on herbaceous plant in invaded regions. Meanwhile, allelopathic effects ofA. adenophora leaf litter on the invaded soil were examined via pot experiments. Results showed that with the exception of L. perenne, there existed significant allelopathic inhibition effects of the water extracts on herbaceous plant seed germination. Inhibition effect increased with increasing concentration of water

  18. Litter Production, Decomposition, and Nutrient Release in Subalpine Forest Communities of the Northwest Himalaya

    Directory of Open Access Journals (Sweden)

    Vinod K. Bisht

    2014-01-01

    Full Text Available Production, decomposition, and release of nutrients from leaf and nonleaf litter were investigated in four subalpine forests of North-West Himalaya, India. Total annual litter fall in four communities varied from 2950.00 to 4040.00 kg ha−1 and was found significant (CD0.05 = 118.2. Decomposition of leaf litter varied from 1.82–3.5% during autumn-winter to 36.14–45.51 during summer rainy season in all stands and percent of mass loss was significantly varied in stands (CD6.00. Similarly, decomposition in nonleaf litter was varied from 0.3–1.1% during autumn-winter to 19.59–30.05% during summer rainy season and was significantly varied irrespective of seasons. However, percent decomposition of leaf litter and the values of decay constant (k were at par in all stands. Total standing state of nutrients in fresh litter as well as release of total nitrogen (N, phosphorus (P, and potassium (K in due course of decomposition (12 months was also varying significantly. The rate of nonleaf litter decomposition was significantly positively correlated with air temperature (r=0.63–0.74 in all communities. The significant correlation (r=0.85 was observed only in Rhododendron-Sorbus forest community (PRS. Study indicates that the air temperature is a major determinant for nonleaf litter decomposition in this region.

  19. Flammability across the gymnosperm phylogeny: the importance of litter particle size.

    Science.gov (United States)

    Cornwell, William K; Elvira, Alba; van Kempen, Lute; van Logtestijn, Richard S P; Aptroot, André; Cornelissen, J Hans C

    2015-04-01

    Fire is important to climate, element cycles and plant communities, with many fires spreading via surface litter. The influence of species on the spread of surface fire is mediated by their traits which, after senescence and abscission, have 'afterlife' effects on litter flammability. We hypothesized that differences in litter flammability among gymnosperms are determined by litter particle size effects on litterbed packing. We performed a mesocosm fire experiment comparing 39 phylogenetically wide-ranging gymnosperms, followed by litter size and shape manipulations on two chemically contrasting species, to isolate the underlying mechanism. The first-order control on litter flammability was, indeed, litter particle size in both experiments. Most gymnosperms were highly flammable, but a prominent exception was the non-Pinus Pinaceae, in which small leaves abscised singly produced dense, non-flammable litterbeds. There are two important implications: first, ecosystems dominated by gymnosperms that drop small leaves separately will develop dense litter layers, which will be less prone to and inhibit the spread of surface litter fire. Second, some of the needle-leaved species previously considered to be flammable in single-leaf experiments were among the least flammable in litter fuel beds, highlighting the role of the litter traits of species in affecting surface fire regimes.

  20. Metal/metalloid fixation by litter during decomposition affected by silicon availability during plant growth.

    Science.gov (United States)

    Schaller, Jörg

    2013-03-01

    Organic matter is known to accumulate high amounts of metals/metalloids, enhanced during the process of decomposition by heterotrophic biofilms (with high fixation capacity for metals/metalloids). The colonization by microbes and the decay rate of the organic matter depends on different litter properties. Main litter properties affecting the decomposition of organic matter such as the nutrient ratios and the content of cellulose, lignin and phenols are currently described to be changed by silicon availability. But less is known about the impact of silicon availability during plant growth on elemental fixation during decay. Hence, this research focuses on the impact of silicon availability during plant growth on fixation of 42 elements during litter decay, by controlling the litter properties. The results of this experiment are a significantly higher metal/metalloid accumulation during decomposition of plant litter grown under low silicon availability. This may be explained by the altered litter properties (mainly nutrient content) affecting the microbial decomposition of the litter, the microbial growth on the litter and possibly by the silicon double layer, which is evident in leaf litter with high silicon content and reduces the binding sites for metals/metalloids. Furthermore, this silicon double layer may also reduce the growing biofilm by reducing the availability of carbon compounds at the litter surface and has to be elucidated in further research. Hence, low silicon availability during plant growth enhances the metal/metalloid accumulation into plant litter during aquatic decomposition.

  1. Riparian litter inputs to streams in the central Oregon Coast Range

    Science.gov (United States)

    Hart, Stephanie K.; Hibbs, David E.; Perakis, Steven S.

    2013-01-01

    Riparian-zone vegetation can influence terrestrial and aquatic food webs through variation in the amount, timing, and nutritional content of leaf and other litter inputs. We investigated how riparian-forest community composition, understory density, and lateral slope shaped vertical and lateral litter inputs to 16 streams in the Oregon Coast Range. Riparian forests dominated by deciduous red alder delivered greater annual vertical litter inputs to streams (504 g m−2 y−1) than did riparian forests dominated by coniferous Douglas-fir (394 g m−2 y−1). Deciduous forests also contributed greater lateral litter inputs per meter of stream bank on one side (109 g m−1 y−1) than did coniferous forests (63 g m−1 y−1). Total litter inputs from deciduous forests exceeded those from coniferous forests most strongly in November, coincident with an autumn peak in litter inputs. Lateral litter inputs contributed most to total inputs during winter in both forest types. Annual lateral litter movement increased with slope at deciduous sites, but only in spring/summer months at coniferous sites. Neither experimental removal of understory vegetation nor installation of mesh fences to block downslope litter movement affected lateral litter inputs to streams, suggesting that ground litter moves litter fractions were higher at deciduous sites and, when combined with greater litter amounts, yielded twice as much total litter N flux to streams in deciduous than coniferous sites. The presence of red alder in riparian forests along many small streams of the deeply incised and highly dendritic basins of the Oregon Coast Range enhances total fluxes and seasonality of litter delivery to both terrestrial and aquatic food webs in this region and complements the shade and large woody debris provided by large coniferous trees.

  2. Leaf Litter Decomposition and Its Relationship with Soil Properties in Betula alnoides and Eucalyptus urophylla ×E.grandis%西南桦和尾巨桉凋落叶分解及其与土壤性质的相关性

    Institute of Scientific and Technical Information of China (English)

    郝建; 莫慧华; 黄弼昌; 周燕萍; 蔡道雄

    2016-01-01

    Compared with the E.urophylla ×E.grandis stand,the B.alnoides had significantly higher contents of soil or-ganic carbon (SOC),total N,total P,total K as well as higher N /P ratio in 0 -1 0 and 1 0 -20 cm soil depth. However,the litter decomposition had no significant effects on SOC,total K,pH,C /N ratio and N /P ratio in 20-30 cm soil depth.The correlation analysis revealed that the organic C of leaf litter was significantly related to SOC,total N,total P,total K and N /P ratio,whereas the total N of leaf litter was significantly related to soil total N,pH and C /N ratio.[Conclusion]The nutrient contents of leaf litter were found to be significantly correlated with the soil nutrient condition.Compared with the E.urophylla ×E.grandis,the nutrient contents of leaf litter were significantly higher in B.alnoides,and subsequently,faster decomposition rate of leaf litter resulted in high-er soil nutrient contents.%[目的]探讨南亚热带西南桦和尾巨桉人工纯林的凋落叶分解动态及其与土壤化学性质之间的相关关系。[方法]采用原位分解袋法研究凋落叶的分解过程。[结果]表明:西南桦、尾巨桉人工林凋落叶分解系数分别为0.96 a -1和0.88 a -1。在为期12个月的分解试验中,2种凋落叶有机 C 含量在整个分解过程中呈逐渐下降趋势;全K 含量和 C /N 比在分解前期迅速下降,之后趋于平缓;全 N 含量和全 P 含量在整个分解过程中呈逐渐上升趋势;2种凋落叶 N /P 比则呈先升高后下降的趋势。无论是分解前期还是分解后期,凋落叶质量损失与 N 含量均呈显著正相关(前期 R =0.877;后期 R =0.855),与 C /N 均呈显著负相关(前期 R =-0.735;后期 R =-0.697)。与尾巨桉林地土壤性质相比,西南桦凋落叶分解提高了林地010、1020 cm 土壤的有机 C、全 N、全 P、全 K、N /P,对2030 cm 土壤有机 C、全 K、pH 值、C /N、N /P

  3. Does leaf chemistry differentially affect breakdown in tropical vs temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Science.gov (United States)

    Marcelo Ard& #243; n; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to measure leaf chemistry. We used standardized analytical techniques to measure chemistry and breakdown rate of leaves from common riparian tree species at 2 sites, 1...

  4. 黄土高原油松与其他树种枯落叶混合分解对土壤性质的影响%EFFECTS OF DECOMPOSITION OF LEAF LITTERS FROM PINUS TABULAEFORMIS AND OTHER TREES ON SOIL PROPERTIES IN THE LOESS PLATEAU

    Institute of Scientific and Technical Information of China (English)

    李茜; 刘增文; 米彩红; 杜良贞

    2012-01-01

    An indoor experiment was carried out of having leaf litters from Pinus tabulaeformis and from other 10 species of trees decomposed, separately or mixedly to explore effects of the decomposition on soil properties and any synergic or offsetting actions between the two in mixture. It was found that decomposition of the leaf litters separately significantly increased the activities of soil enzymes, like urease, dehydrogenase and phosphatase, and contents of organic matter and available N, but varied sharply in the effect on available P and CEC in the soil. The decomposition of leaf litter from P. tabulaeformis mixed with that from Platycladus orientalis, Populus simonii, Robinia pseudoacacia, or Ulmus pumila, separately showed obvious synergic effects on total soil microbe. In decomposition, its mixture with that from Hippophae rham-noides affected activity of the soil enzyme of phosphatase, synergically, but its mixture with the leaf letter from P. orientalis , Betula platyphylla or U. pumila, separately, did reversely. Its mixture with leaf litters from most of the trees, separately, showed a synergic effect on soil available K content, but, reversely on soil available P content. Its mixture with that from P. simonii,H. rhamnoides or Amorpha fruticosa, separately, displayed a synergic effect on soil organic matter content. In terms of soil properties as a whole in their effects, its mixture with leaf litter from H. rhamnoides, R. pseudoacacia, P. simonii or A. fruticosa, separately, all acted synergically, whereas its mixture with that from P. orientalis, Quercus liao-tungensis,B. platyphylla,Larix principis-rupprechtii, or Caragana microphylla,separately,did reversely.%通过油松及其他10个树种枯落叶单独和混合分解试验,探讨了油松与其他树种枯落叶混合分解对土壤性质的影响及在对土壤性质影响中是否存在相互促进或抑制作用.结果表明:11种枯落叶单独分解均明显提高了土壤脲酶、脱氢酶、

  5. Vegetation patches increase wind-blown litter accumulation in a semi-arid steppe of northern China

    Science.gov (United States)

    Yan, Yuchun; Xin, Xiaoping; Xu, Xingliang; Wang, Xu; Yan, Ruirui; Murray, Philip J.

    2016-12-01

    Litter decomposition is an important source of soil organic matter and nutrients; however, few studies have explored how vegetation patches affect wind-driven litter mobility and accumulation. In this study, we aimed to test the following hypotheses: (1) vegetation patches can reduce litter removal and facilitate litter accumulation, (2) litter mobility results in the heterogeneous redistribution of carbon and nutrients over the land surface, and (3) litter removal rates differ among different litter types (e.g., leaf and stem). Four vegetation patch types and six litter types were used to investigate the impacts of vegetation patches on litter mobility and accumulation. The results show that compared with almost bare ground patches, patches with vegetation cover had significantly higher litter accumulation, with the shrub patch type having the highest accumulation amount. The rate of litter removal due to wind was highest for the almost bare surface type (P4) and lowest for the shrub patch (P1) and Stipa grandis community (P2) types. There were significant differences in the removal rate among the different litter types. These findings indicate that wind-based litter redistribution among bare, S. grandis-dominated, and shrub-dominated patches is at least partially responsible for increasing the spatial heterogeneity of resources on a landscape scale.

  6. DESCOMPOSICIÓN DE LA HOJARASCA Y SU RELACIÓN CON LOS MACROINVERTEBRADOS ACUÁTICOS DEL RÍO GAIRA (SANTA MARTA ­ COLOMBIA Leaf Litter Decomposition and its Relation with Aquatic Macroinvertebrates of the Gaira River (Santa Marta ­ Colombia

    Directory of Open Access Journals (Sweden)

    MELISA EYES-ESCALANTE

    2012-04-01

    Full Text Available Se evaluó la tasa de descomposición de la hojarasca, de cuatro especies nativas y tres especies exóticas, seleccionadas por su mayor frecuencia en la vegetación de la ribera del río Gaira, localizado en la Sierra Nevada de Santa Marta. Se seleccionaron cuatro tramos de muestreo a diferentes alturas. Adicionalmente, se determinaron riqueza, abundancia y función trófica alimenticia de los macroinvertebrados que colonizaron los sustratos artificiales que contenían la hojarasca. En el tramo medio se presentó el mayor coeficiente de descomposición de especies nativas y exóticas (K-W=15,9; n= 23; p= 0,001 y KW=15,5; n=36; p=0,0014 respectivamente. Las especies nativas presentaron la mayor tasa de descomposición (K-W=4; n=47; p=0,04, siendo la especie Pithecellobium longifolium en el tramo medio, la que presentó la mayor pérdida de peso en el tiempo. Se presentan relaciones entre tasa de descomposición, conductividad y temperatura. El ensamblaje de macroinvertebrados estuvo representado por 41 taxones, con una abundancia de 1895 individuos que aportaron una biomasa de 2,27 g. La estructura funcional de los macroinvertebrados asociados a la hojarasca, estuvo representada en los tramos alto, medio y bajo por Plecopteros (Depredadores del género Anacroneuria con 10,14%, 68,43% y 7,60% respectivamente. Dípteros depredadores del taxón Tanypodinae fueron dominantes en la desembocadura con 0,51%. Los resultados de este estudio permiten determinar que la presencia de macroinvertebrados asociados a la hojarasca no está condicionada por la especie vegetal (nativa o exótica, porque no se observaron diferencias entre estas que generen un efecto sobre la tasa de descomposición.The rate of decomposition of leaf litter of four native species and three exotic species were evaluated. They were selected due to the most frequently collected by the bank vegetation Gaira River, located on the Sierra Nevada de Santa Marta. We took four sampling sections

  7. Large litter sizes

    DEFF Research Database (Denmark)

    Sandøe, Peter; Rutherford, K.M.D.; Berg, Peer

    2012-01-01

    This paper presents some key results and conclusions from a review (Rutherford et al. 2011) undertaken regarding the ethical and welfare implications of breeding for large litter size in the domestic pig and about different ways of dealing with these implications. Focus is primarily on the direct...... adverse consequences for animal welfare of Danish breeding for large litter sizes due to increased piglet mortality and the subsequent attempts to reverse these consequences by breeding for number of live piglets at day five rather than number of piglets born. By this change of breeding goal it seems...

  8. The Experimental Control of Littering

    Science.gov (United States)

    Clark, Roger N.; And Others

    1972-01-01

    Behavior, incentives, and education programs were researched as factors relating to littering. Experiments in theaters, forest campgrounds, and hiking and dispersed car camping areas indicate incentive systems are necessary and feasible for curbing litter problems. (BL)

  9. Contribution of soil fauna to mass loss of Abies faxoniana leaf litter during the freeze-thaw season%季节性冻融期间土壤动物对岷江冷杉凋落叶质量损失的贡献

    Institute of Scientific and Technical Information of China (English)

    夏磊; 吴福忠; 杨万勤

    2011-01-01

    -thaw season, DF: the deep frozen period and TS: the thawing stage). The objective was therefore to quantify the contributions of soil fauna to fir (Abies faxoniana) leaf litter decomposition during the freeze-thaw season.Methods A field experiment using litterbags was conducted in an alpine fir forest from October 2010 to April 2011. Samples of air-dried fir leaf litter were placed in nylon litterbags (20 cm x 20 cm, 10 g per bag), and the edges were sealed. We investigated mass loss rates in litterbags with different mesh sizes (0.020, 0.125, 1.000 and 3.000 mm) and simultaneously analyzed contributions of micro-, meso- and macro-fauna to leaf litter decomposition.Important findings Over the freeze-thaw season, the mass loss rates in litterbags with different mesh sizes were 12.13% (0.020 mm), 13.07% (0.125 mm), 14.95% (1.000 mm) and 18.74% (3.000 mm). Contribution percentages of all three body-size soil faunas were about 35.28%. Mass loss rates of fir leaf litter appeared consistent with the taxa and individual relative density of soil fauna. Contribution percentages of mass loss rates showed the order as micro- < meso- < macro-fauna during the three stages of the freeze-thaw season. The highest contribution percentages of micro-fauna (6.56%), meso-fauna (11.77%) and macro-fauna (21.94%) were detected at DF, OF and TS stage, respectively. However, the contribution percentages of meso- and macro-fauna during the DF stagewere lower than the other two stages. The results demonstrated that soil fauna played an important role in litterdecomposition during the freeze-thaw season in alpine forests of western China.

  10. Effects of elevated CO2 on litter chemistry and subsequent invertebrate detritivore feeding responses.

    Directory of Open Access Journals (Sweden)

    Matthew W Dray

    Full Text Available Elevated atmospheric CO2 can change foliar tissue chemistry. This alters leaf litter palatability to macroinvertebrate detritivores with consequences for decomposition, nutrient turnover, and food-web structure. Currently there is no consensus on the link between CO2 enrichment, litter chemistry, and macroinvertebrate-mediated leaf decomposition. To identify any unifying mechanisms, we presented eight invertebrate species from aquatic and terrestrial ecosystems with litter from Alnus glutinosa (common alder or Betula pendula (silver birch trees propagated under ambient (380 ppm or elevated (ambient +200 ppm CO2 concentrations. Alder litter was largely unaffected by CO2 enrichment, but birch litter from leaves grown under elevated CO2 had reduced nitrogen concentrations and greater C/N ratios. Invertebrates were provided individually with either (i two litter discs, one of each CO2 treatment ('choice', or (ii one litter disc of each CO2 treatment alone ('no-choice'. Consumption was recorded. Only Odontocerum albicorne showed a feeding preference in the choice test, consuming more ambient- than elevated-CO2 birch litter. Species' responses to alder were highly idiosyncratic in the no-choice test: Gammarus pulex and O. albicorne consumed more elevated-CO2 than ambient-CO2 litter, indicating compensatory feeding, while Oniscus asellus consumed more of the ambient-CO2 litter. No species responded to CO2 treatment when fed birch litter. Overall, these results show how elevated atmospheric CO2 can alter litter chemistry, affecting invertebrate feeding behaviour in species-specific ways. The data highlight the need for greater species-level information when predicting changes to detrital processing-a key ecosystem function-under atmospheric change.

  11. Large litter sizes

    DEFF Research Database (Denmark)

    Sandøe, Peter; Rutherford, K.M.D.; Berg, Peer

    2012-01-01

    This paper presents some key results and conclusions from a review (Rutherford et al. 2011) undertaken regarding the ethical and welfare implications of breeding for large litter size in the domestic pig and about different ways of dealing with these implications. Focus is primarily on the direct...

  12. Forest composition modifies litter dynamics and decomposition in regenerating tropical dry forest.

    Science.gov (United States)

    Schilling, Erik M; Waring, Bonnie G; Schilling, Jonathan S; Powers, Jennifer S

    2016-09-01

    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.

  13. 甜槠凋落叶分解中土壤节肢动物群落结构动态及其对森林片段化的响应%Dynamics of soil arthropod community structure and its responses to forest fragmentation during the decomposition of Castanopsis eyrei leaf litter

    Institute of Scientific and Technical Information of China (English)

    罗媛媛; 袁金凤; 沈国春; 赵谷风; 于明坚

    2011-01-01

    选取浙、闽、赣交界山地5个不同的常绿阔叶林群落(1处连续森林和4处片段化森林),对优势种甜槠凋落叶分解过程中土壤节肢动物动态进行了研究.5个研究样地共获得土壤节肢动物899头,分属9纲25目,其中鳞翅目占个体总数的10%以上,为优势类群;膜翅目、弹尾目、双翅目、前气门亚目和地蜈蚣目为常见类群.凋落叶分解速率与土壤节肢动物的类群数、个体数随季节动态呈现相一致的变化趋势.8月凋落物分解最快,土壤节肢动物类群和个体数最多;而4至6月和12月情况与之相反.片段化森林和连续森林在土壤节肢动物的类群数、个体数和物种多样性方面均显示出差异,面积效应和边缘效应在其中都起了一定的作用.%Five evergreen broad-leaved forests (one continuous forest and four fragmented forests)in the mountain areas in the juncture of Zhejiang, Fujian, and Jiangxi Provinces, East China were selected as test objects to study the dynamics of soil arthropod community structure and its responses to forest fragmentation during the decomposition of dominant tree species Castanopsis eyrei leaf litter. A total of 899 soil arthropods were collected, belonging to 9 classes and 25 orders. Lepidoptera was the dominant taxon, accounting for 10% of the individual, while Hymenoptera, Collembola,Diptera, Prostigmata, and Geophilomorpha were the common taxa. The decomposition rate of C.eyrei leaf litter was the highest in August and lower in April-June and December, which was in accordance with the seasonal dynamics of the taxa number and individual number of soil arthropods.Meanwhile, the taxa number, individual number, and species diversity of soil arthropods differed between continuous forest and fragmented forests, suggesting that both area effect and edge effect affected the dynamics of soil arthropod community structure during the decomposition of C. eyrei leaf litter.

  14. Production and decomposition of forest litter fall on the Apalachicola River flood plain, Florida

    Science.gov (United States)

    Elder, J.F.; Cairns, D.J.

    1982-01-01

    Measurements of litter fall (leaves and other particulate organic material) and leaf decomposition were made on the Apalachicola River flood plain in 1979-80. Litter fall was collected monthly in five different forest types in swamp and levee areas. Leaves from 42 species of trees and other plants accounted for 58 percent of total litter fall. The remaining 42 percent was nonleaf material. Average litter fall was 800 grams per square meter per year in the flood plain. Tupelo (Nyssa), baldcypress (Taxodium), and ash (Fraxinus), all swamp-adapted trees, produce over 50 percent of the leaf fall. Common levee species such as sweetgum (Liquidambar styraciflua) and diamond-leaf oak (Quercus laurifolia) are also major contributors to total flood-plain litter fall. Annual flooding of the river provides an important mechanism for mobilization of the litter-fall products. Leaf decomposition rates were greatly reduced in dry environments. Carbon loss was nearly linear over a 6-month period, but nitrogen and phosphorus loss was exponential and nearly complete within 1 month. (USGS)

  15. Transformation of Carbon and Nitrogen by Earthworms in the Decomposition Processes of Broad-leaved Litters

    Institute of Scientific and Technical Information of China (English)

    DONG Weihua; YIN Xiuqin

    2007-01-01

    Earthworms are the important constituents in the decayed food web and the main ecological conditioners in the process of decomposition and nutrient mineralization. The transformation of organic carbon (C) and total nitrogen (N) in the broad-leaved litters ingested by earthworms was researched by means of a laboratory experiment. Experimental samples were collected from broad-leaved Korea Pine mixed forest in Liangshui National Natural Reserve (47°10'50"N, 128°53'20"E) in the northeastern Xiao Hinggan Mountains of Northeast China. The contents of organic C and total N in earthworms, leaf litters and earthworm faeces were analyzed. Results show that the organic C content was in the following order: leaf litters>faeces>earthworms, while total N content was contrary to that of the organic C. The organic C contents in the different leaf litters were in the following order: Tilia amurensis>Betula costata>Acer mono, whereas the total N contents in the different leaf litters were: Betula costata>Tilia amurensis>Acer mono. The contents of organic C and total N in the faeces from the different leaf litters were almost consistent with the contents of the leaf litters. After the leaf litters were ingested by earthworms, the organic C, which was transformed to increase earthworms' weights, accounted for 3.90%-13.31% of the total ingestion by earthworms, while that in the earthworm faeces accounted for 6.14%-13.70%. The transformed organic C through the other metabolism (e.g., respiration) of earthworms accounted for 75.04%-89.92%. The ingested organic C by earthworms was mostly used for metabolic activities. The N ingested by earthworms was less than organic C. It is estimated that 37.08% of total N was transformed to increase the earthworm's weight, 19.97% into earthworm faeces and 47.86% for the consumption of the earthworm's activities. The earthworms not only increased the content of organic C and total N in the soil, but also decreased the values of C/N in

  16. The Influence of Plant Litter on Soil Water Repellency: Insight from 13C NMR Spectroscopy.

    Science.gov (United States)

    Cesarano, Gaspare; Incerti, Guido; Bonanomi, Giuliano

    2016-01-01

    Soil water repellency (SWR, i.e. reduced affinity for water owing to the presence of organic hydrophobic coatings on soil particles) has relevant hydrological implications because low rates of infiltration enhance water runoff, and untargeted diffusion of fertilizers and pesticides. Previous studies investigated the occurrence of SWR in ecosystems with different vegetation cover but did not clarify its relationships with litter biochemical quality. Here, we investigated the capability of different plant litter types to induce SWR by using fresh and decomposed leaf materials from 12 species, to amend a model sandy soil over a year-long microcosm experiment. Water repellency, measured by the Molarity of an Ethanol Droplet (MED) test, was tested for the effects of litter species and age, and compared with litter quality assessed by 13C-CPMAS NMR in solid state and elemental chemical parameters. All litter types were highly water repellent, with MED values of 18% or higher. In contrast, when litter was incorporated into the soil, only undecomposed materials induced SWR, but with a large variability of onset and peak dynamics among litter types. Surprisingly, SWR induced by litter addition was unrelated to the aliphatic fraction of litter. In contrast, lignin-poor but labile C-rich litter, as defined by O-alkyl C and N-alkyl and methoxyl C of 13C-CPMAS NMR spectral regions, respectively, induced a stronger SWR. This study suggests that biochemical quality of plant litter is a major controlling factor of SWR and, by defining litter quality with 13C-CPMAS NMR, our results provide a significant novel contribution towards a full understanding of the relationships between plant litter biochemistry and SWR.

  17. The Influence of Plant Litter on Soil Water Repellency: Insight from 13C NMR Spectroscopy.

    Directory of Open Access Journals (Sweden)

    Gaspare Cesarano

    Full Text Available Soil water repellency (SWR, i.e. reduced affinity for water owing to the presence of organic hydrophobic coatings on soil particles has relevant hydrological implications because low rates of infiltration enhance water runoff, and untargeted diffusion of fertilizers and pesticides. Previous studies investigated the occurrence of SWR in ecosystems with different vegetation cover but did not clarify its relationships with litter biochemical quality. Here, we investigated the capability of different plant litter types to induce SWR by using fresh and decomposed leaf materials from 12 species, to amend a model sandy soil over a year-long microcosm experiment. Water repellency, measured by the Molarity of an Ethanol Droplet (MED test, was tested for the effects of litter species and age, and compared with litter quality assessed by 13C-CPMAS NMR in solid state and elemental chemical parameters. All litter types were highly water repellent, with MED values of 18% or higher. In contrast, when litter was incorporated into the soil, only undecomposed materials induced SWR, but with a large variability of onset and peak dynamics among litter types. Surprisingly, SWR induced by litter addition was unrelated to the aliphatic fraction of litter. In contrast, lignin-poor but labile C-rich litter, as defined by O-alkyl C and N-alkyl and methoxyl C of 13C-CPMAS NMR spectral regions, respectively, induced a stronger SWR. This study suggests that biochemical quality of plant litter is a major controlling factor of SWR and, by defining litter quality with 13C-CPMAS NMR, our results provide a significant novel contribution towards a full understanding of the relationships between plant litter biochemistry and SWR.

  18. Interactions of tissue and fertilizer nitrogen on decomposition dynamics of lignin-rich conifer litter

    Science.gov (United States)

    Perakis, Steven S.; Matkins, Joselin J.; Hibbs, David E.

    2012-01-01

    High tissue nitrogen (N) accelerates decomposition of high-quality leaf litter in the early phases of mass loss, but the influence of initial tissue N variation on the decomposition of lignin-rich litter is less resolved. Because environmental changes such as atmospheric N deposition and elevated CO2 can alter tissue N levels within species more rapidly than they alter the species composition of ecosystems, it is important to consider how within-species variation in tissue N may shape litter decomposition and associated N dynamics. Douglas-fir (Pseudotsuga menziesii ) is a widespread lignin-rich conifer that dominates forests of high carbon (C) storage across western North America, and displays wide variation in tissue and litter N that reflects landscape variation in soil N. We collected eight unique Douglas-fir litter sources that spanned a two-fold range in initial N concentrations (0.67–1.31%) with a narrow range of lignin (29–35%), and examined relationships between initial litter chemistry, decomposition, and N dynamics in both ambient and N fertilized plots at four sites over 3 yr. High initial litter N slowed decomposition rates in both early (0.67 yr) and late (3 yr) stages in unfertilized plots. Applications of N fertilizer to litters accelerated early-stage decomposition, but slowed late-stage decomposition, and most strongly affected low-N litters, which equalized decomposition rates across litters regardless of initial N concentrations. Decomposition of N-fertilized litters correlated positively with initial litter manganese (Mn) concentrations, with litter Mn variation reflecting faster turnover of canopy foliage in high N sites, producing younger litterfall with high N and low Mn. Although both internal and external N inhibited decomposition at 3 yr, most litters exhibited net N immobilization, with strongest immobilization in low-N litter and in N-fertilized plots. Our observation for lignin-rich litter that high initial N can slow decomposition

  19. Direct and indirect effects of UV-B exposure on litter decomposition: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Xinzhang Song

    Full Text Available Ultraviolet-B (UV-B exposure in the course of litter decomposition may have a direct effect on decomposition rates via changing states of photodegradation or decomposer constitution in litter while UV-B exposure during growth periods may alter chemical compositions and physical properties of plants. Consequently, these changes will indirectly affect subsequent litter decomposition processes in soil. Although studies are available on both the positive and negative effects (including no observable effects of UV-B exposure on litter decomposition, a comprehensive analysis leading to an adequate understanding remains unresolved. Using data from 93 studies across six biomes, this introductory meta-analysis found that elevated UV-B directly increased litter decomposition rates by 7% and indirectly by 12% while attenuated UV-B directly decreased litter decomposition rates by 23% and indirectly increased litter decomposition rates by 7%. However, neither positive nor negative effects were statistically significant. Woody plant litter decomposition seemed more sensitive to UV-B than herbaceous plant litter except under conditions of indirect effects of elevated UV-B. Furthermore, levels of UV-B intensity significantly affected litter decomposition response to UV-B (P<0.05. UV-B effects on litter decomposition were to a large degree compounded by climatic factors (e.g., MAP and MAT (P<0.05 and litter chemistry (e.g., lignin content (P<0.01. Results suggest these factors likely have a bearing on masking the important role of UV-B on litter decomposition. No significant differences in UV-B effects on litter decomposition were found between study types (field experiment vs. laboratory incubation, litter forms (leaf vs. needle, and decay duration. Indirect effects of elevated UV-B on litter decomposition significantly increased with decay duration (P<0.001. Additionally, relatively small changes in UV-B exposure intensity (30% had significant direct effects

  20. Leaf Litter Decomposition of Main Subtropical Plants with Different Origin Time in the South Subtropical Asia%不同起源时间的亚热带主要树种凋落物在南亚热带的分解研究

    Institute of Scientific and Technical Information of China (English)

    姜小丽; 窦荣鹏; 江洪; 余树全; 马元丹

    2012-01-01

    [ Objective ] Study the leaf litter decomposition of main plants with different origin time in the south subtropical Chinese. [ Method ] Leaf litter decomposition of 9 species with different origin time was studied in the Dinghushan region, using iitterbag method, the time was 840 days, to study the variation of litter dry weight remaining and carbon dynamics in evolutionary process. [ Result ] The range of the annual litter decomposition coefficient(k) was 0.14 to 0. 71. The 95% decomposition time ranged from 4. 22 to 21.40 a, and the 50% decomposition time ranged from 0. 98 to 4. 95 a. The difference of litter decomposition rate with monocotyledon, gymnosperm, pteridophyte was significant( P C. glauca > S. superba > P. massoniana > C. lanceolata > M, glyptostroboides > C. revoluta > A. spinulosa > D. dichotoma. The mean litter decomposition rate of the 4 taxa was monocotyledon > dicotyledon > gymnosperm > pteridophyte. The carbon loss of the 4 taxa was dicotyledon > monocotyledon > gymnosperm > pteridophyte.%[目的]研究不同起源时间的亚热带主要树种凋落物的分解过程.[方法]选择9种起源时间不同的植物的凋落物,采用分解袋法,在南亚热带的鼎湖山地区进行分解实验,实验时间为840d,研究进化过程中凋落物的干重剩余率和碳素动态变化规律.[结果]凋落物分解系数k值的范围在0.14~0.71间.凋落物分解95%所需时间集中在4.22~21.40 a,50%分解时间集中在0.98 ~4.95a.单子叶植物、裸子植物和蕨类植物两两之间分解速率均具有显著差异(P<0.05),但双子叶植物与单子叶植物和裸子植物分解速率之间显著性差异不明显,仅与蕨类植物的分解速率具有显著差异(P<0.05).凋落物总碳量的总体变化趋势表现为下降,在分解过程中均出现2次不同程度的升高过程,出现时间集中在分解的第240天和660天,此时正值冬季,凋落物分解较慢,碳元素出现积累.双子叶植物、裸子植

  1. Annual and Monthly Variations in Litter Macronutrients of Three Subalpine Forests in Western China

    Institute of Scientific and Technical Information of China (English)

    YANG Wan-Qin; WANG Kai-Yun; S.KELLOM(A)KI; ZHANG Jian

    2006-01-01

    Macronutrients (N, P, K, Ca, Mg, and S) in litter of three primarily spruce (Picea purpurea Masters) (SF), fir (Abies faxoniana Rehder & E. H. Wilson) (FF), and birch (Betula platyphylla Sukaczev) (BF) subalpine forests in western China were measured to understand the monthly variations in litter nutrient concentrations and annual and monthly nutrient returns via litterfall. Nutrient concentration in litter showed the rank order of Ca > N > Mg > K > S > P. Monthly variations in nutrient concentrations were greater in leaf litter (LL) than other litter components. The highest and lowest concentrations of N, P, K, and S in LL were found in the growing season and the nongrowing season, respectively, but Ca and Mg were the opposite. Nutrient returns via litterfall showed a marked monthly pattern with a major peak in October and one or two small peaks in February and/or May, varying with the element and stand type, but no marked monthly variations in nutrient returns via woody litter, reproductive litter, except in May for the BF, and moss litter. Not only litter production but also nutrient concentration controlled the annual nutrient return and the monthly nutrient return pattern. The monthly patterns of the nutrient concentration and return were of ecological importance for nutrient cycling and plant growth in the subalpine forest ecosystems.

  2. Decomposição e liberação de nutrientes da serapilheira foliar em povoamentos de Eucalyptus grandis no norte fluminense Decomposition and nutrient release from leaf litter of Eucalyptus grandis in plantations and regrowth sistems in northern Rio de Janeiro state, Brazil

    Directory of Open Access Journals (Sweden)

    Gilmar Santos Costa

    2005-08-01

    Full Text Available O objetivo deste trabalho foi avaliar a decomposição e liberação de nutrientes da serapilheira foliar em um plantio de Eucalyptus grandis de primeira rotação, com 8 anos, e em rebrotas com 2 e 5 anos de idade, por meio da técnica de sacos de serapilheira. A temperatura média anual foi de 19,5 ºC e a precipitação pluvial anual, de 850 mm, com 54% das chuvas concentradas no período de outubro a dezembro. Os resultados indicaram que foi similar o porcentual de perda de massa, bem como a liberação de frações orgânicas (lignina, celulose e polifenol e de nutrientes (N, P, K, Ca e Mg da serapilheira foliar para o plantio de primeira rotação e as rebrotas. O porcentual de perda de massa, média dos três povoamentos, ajustou-se a um modelo quadrático (y = 99,443 + 0,0348x - 0,0003x²; R²=0,92; p=0,0225. Somente no período de maiores precipitações observou-se a efetiva perda de massa (29 - 33%, assim como a liberação de celulose (40 - 51%, de polifenóis (54 - 70% e, em pequena quantidade, de lignina (3 - 14%. Entre os nutrientes avaliados, houve liberação de N (6 - 19%, K (49 - 60%, Ca (18 - 20% e Mg (27 - 39%, enquanto o P foi acumulado (-20 e -40%. Na região norte fluminense, a dinâmica da decomposição e liberação de nutrientes da serapilheira foliar de eucalipto, durante 382 dias, evidenciou a liberação de K > Mg > Ca > N e a imobilização de P, sendo marcadamente influenciada pela precipitação pluvial.This work aimed to evaluate the decomposition and nutrient release of leaf litter in 8-year old Eucalyptus grandis first rotation and 2 and 5-year old regrowth systems through litter bag technique. The annual average temperature was 19.5 ºC and annual rainfall was 848 mm, with 54% of rains concentrated in the period from October to December. The results showed that the dry weight loss, nutrient release (N, K, Ca and Mg and organic fraction release (lignin, cellulose and polyphenols were similar for the first

  3. Reducing Children's Littering on a Nature Trail

    Science.gov (United States)

    LaHart, David E.; Bailey, Jon S.

    1975-01-01

    This study compared incentives and educational methods to motivate children to pick up litter and to prevent littering. Incentives did aid in getting litter picked up. One-sentence anti-litter statements, educational materials, and lectures reduced littering, but incentives did not. (MR)

  4. Effects of applying tree leaf litter on control of soil polarization of continuous cropping wheat land in the Gullied Loess Plateau%利用树木枯落叶防治连作麦田土壤极化的效应

    Institute of Scientific and Technical Information of China (English)

    刘增文; 米彩红; 李茜; 袁娜; 祝振华

    2011-01-01

    【目的】研究不同树木枯落叶对连作麦田土壤性质的影响,为防治麦田土壤性质极化和连作障碍提供依据。【方法】采集黄土残塬区典型连作麦田耕层(0~10cm)土壤,将其与不同森林树种(刺槐、小叶杨、辽东栎、沙棘和柠条)和城市道路绿化树种(法国梧桐、国槐、银杏、垂柳、五角枫、女贞、紫叶李、栾树、广玉兰、梧桐、泡桐、杜仲和七叶树)的当年枯落叶按干质量比100∶2混合后,在20~25℃下进行室内分解培养试验,连续培养120d后,测定土壤的化学性质和生物学性质。【结果】1)连作麦田会引起土壤有效Zn、有机C含量增加和土壤微生物数量、多种酶活性不断提高的正向极化,但也同时引起土壤向贫养化发展、土壤有效Fe和有效Cu含量降低、阳离子交换量(CEC)减少及土壤部分酶活性降低的负向极化趋势;2)根据对连作麦田土壤极化的综合影响效应分析,枯落叶最适合施入麦田土壤的当地森林树种是沙棘、小叶杨,其次是刺槐,而柠条、辽东栎不适宜;枯落叶最适合施入麦田土壤的当地城市道路绿化树种是杜仲、紫叶李,其次是栾树、国槐、垂柳、泡桐,而女贞、法国梧桐、银杏、梧桐、七叶树、玉兰和五角枫均不适宜。【结论】收集一些特定树种的枯落叶施入农田土壤,是防治连作土壤性质极化和连作障碍的一种有效方法。%【Objective】 The study was about the effects of different leaf litters on continuous cropping soil of wheat which can provide scientific basis for controlling soil polarizations and continuous cropping obstacle.【Method】 Through sampling top soil(0-10 cm) of typical wheat land in the gullied Loess Plateau,mixed with different leaf litters of forest trees(Robinia pseudoacia,Populus simonii,Quercus liaotungensis,Hippophae rhamnoides,Caragana microphylla) and urban road trees

  5. Harm caused by Marine Litter

    OpenAIRE

    Werner, S.; Budziak, A.; Franeker, van, J.A.; Galgani, F.; Hanke, G.; Maes, T.; Matiddi, M.; Nilsson, P; Oosterbaan, L.; Priestland, E.; Thompson, R.; Veiga, J.; Vlachogianni, T. (Thomais)

    2016-01-01

    Marine litter is a global concern with a range of problems associated to it, as recognised by the Marine Strategy Framework Directive (MSFD). Marine litter can impact organisms at different levels of biological organization and habitats in a number of ways namely: through entanglement in, or ingestion of, litter items by individuals, resulting in death and/or severe suffering; through chemical and microbial transfer; as a vector for transport of biota and by altering or modifying assemblages ...

  6. Soil microbial responses to forest floor litter manipulation and nitrogen addition in a mixed-wood forest of northern China.

    Science.gov (United States)

    Sun, Xiao-Lu; Zhao, Jing; You, Ye-Ming; Jianxin Sun, Osbert

    2016-01-14

    Changes in litterfall dynamics and soil properties due to anthropogenic or natural perturbations have important implications to soil carbon (C) and nutrient cycling via microbial pathway. Here we determine soil microbial responses to contrasting types of litter inputs (leaf vs. fine woody litter) and nitrogen (N) deposition by conducting a multi-year litter manipulation and N addition experiment in a mixed-wood forest. We found significantly higher soil organic C, total N, microbial biomass C (MBC) and N (MBN), microbial activity (MR), and activities of four soil extracellular enzymes, including β-glucosidase (BG), N-acetyl-β-glucosaminidase (NAG), phenol oxidase (PO), and peroxidase (PER), as well as greater total bacteria biomass and relative abundance of gram-negative bacteria (G-) community, in top soils of plots with presence of leaf litter than of those without litter or with presence of only fine woody litter. No apparent additive or interactive effects of N addition were observed in this study. The occurrence of more labile leaf litter stimulated G-, which may facilitate microbial community growth and soil C stabilization as inferred by findings in literature. A continued treatment with contrasting types of litter inputs is likely to result in divergence in soil microbial community structure and function.

  7. Litter Production and Nutrient Dynamic on a Moso Bamboo Plantation following an Extreme Disturbance of 2008 Ice Storm

    Directory of Open Access Journals (Sweden)

    Xiaogai Ge

    2014-01-01

    Full Text Available Ice storm is known to play a role in determining forest succession and litter dynamics constitute an important aspect of nutrient cycling in forest ecosystems. However, ice storm effects on amount and pattern of litterfall are not clearly understood. We investigated litter production and litter leaf nutrient dynamic in a moso bamboo plantation in China following an extreme disturbance of ice storm in 2008. The litterfall in on-years was significantly lower than in off-years. Ice storm caused total litterfall increasing from 16.68% to 35.60% and greatly disturbed the litterfall peak rhythm especially in the on-year. The litter leaf nutrient concentrations at two latitudes significantly fluctuated after ice-snow disaster in 2008, litter leaf stoichiometric traits indicated that litter leaf chemistry showed more easily decomposition with higher C/P ratio, N/P ratio, and lower C/N ratio. It is clear from this study that litterfall restoration dynamic would result in long-term changes in litter nutrient cycling and may help predicting below ground carbon dynamic in future research as well as subtropical forest inventories following extreme disturbance.

  8. The Effects of Litter on Littering Behavior in a Forest Environment

    Science.gov (United States)

    Crump, S. Larry; And Others

    1977-01-01

    The effects of littered and nonlittered areas on littering behavior were determined in picnic areas in the Uinta National Forest, Utah. Littered and nonlittered conditions were controlled by spreading or removing litter from specified areas. Observations revealed that in the nonlittered areas there was more litter than in the littered areas. (CS)

  9. Mower/Litter Removal

    Science.gov (United States)

    1996-01-01

    The Burg Corporation needed to get more power out of the suction system in their Vac 'N Bag grass mower/litter remover. The president submitted a problem statement to the Marshall Space Flight Center Technology Transfer Office, which devised a way to guide heavier items of trash to a point where suction was greatest, and made changes to the impeller and the exhaust port, based on rocket propulsion technology. The improved system is used by highway departments, city governments and park authorities, reducing work time by combining the tasks of grass cutting and vacuuming trash and grass clippings.

  10. Differential effects of conifer and broadleaf litter inputs on soil organic carbon chemical composition through altered soil microbial community composition

    Science.gov (United States)

    Wang, Hui; Liu, Shi-Rong; Wang, Jing-Xin; Shi, Zuo-Min; Xu, Jia; Hong, Pi-Zheng; Ming, An-Gang; Yu, Hao-Long; Chen, Lin; Lu, Li-Hua; Cai, Dao-Xiong

    2016-06-01

    A strategic selection of tree species will shift the type and quality of litter input, and subsequently magnitude and composition of the soil organic carbon (SOC) through soil microbial community. We conducted a manipulative experiment in randomized block design with leaf litter inputs of four native subtropical tree species in a Pinus massoniana plantation in southern China and found that the chemical composition of SOC did not differ significantly among treatments until after 28 months of the experiment. Contrasting leaf litter inputs had significant impacts on the amounts of total microbial, Gram-positive bacterial, and actinomycic PLFAs, but not on the amounts of total bacterial, Gram-negative bacterial, and fungal PLFAs. There were significant differences in alkyl/O-alkyl C in soils among the leaf litter input treatments, but no apparent differences in the proportions of chemical compositions (alkyl, O-alkyl, aromatic, and carbonyl C) in SOC. Soil alkyl/O-alkyl C was significantly related to the amounts of total microbial, and Gram-positive bacterial PLFAs, but not to the chemical compositions of leaf litter. Our findings suggest that changes in forest leaf litter inputs could result in changes in chemical stability of SOC through the altered microbial community composition.

  11. Influence of packaging design on littering behavior

    OpenAIRE

    Wever, R.

    2006-01-01

    Litter is an environmental and social problem that is closely related to packaging. Many attempts have been made to reduce litter. So far these attempts have mainly focused on influencing littering behavior either through general campaigns or through manipulating the environment. The latter might be done through strategic placement of prompts and litter bins and through cleaning up any previous litter. So far, little or no attention has been paid to the influence of the littered object itself...

  12. Harm caused by Marine Litter

    NARCIS (Netherlands)

    Werner, S.; Budziak, A.; Franeker, van J.A.; Galgani, F.; Hanke, G.; Maes, T.; Matiddi, M.; Nilsson, P.; Oosterbaan, L.; Priestland, E.; Thompson, R.; Veiga, J.; Vlachogianni, T.

    2016-01-01

    Marine litter is a global concern with a range of problems associated to it, as recognised by the Marine Strategy Framework Directive (MSFD). Marine litter can impact organisms at different levels of biological organization and habitats in a number of ways namely: through entanglement in, or

  13. Microbial biomass and activity in litter during the initial development of pure and mixed plantations of Eucalyptus grandis and Acacia mangium

    Directory of Open Access Journals (Sweden)

    Daniel Bini

    2013-02-01

    Full Text Available Studies on microbial activity and biomass in forestry plantations often overlook the role of litter, typically focusing instead on soil nutrient contents to explain plant and microorganism development. However, since the litter is a significant source of recycled nutrients that affect nutrient dynamics in the soil, litter composition may be more strongly correlated with forest growth and development than soil nutrient contents. This study aimed to test this hypothesis by examining correlations between soil C, N, and P; litter C, N, P, lignin content, and polyphenol content; and microbial biomass and activity in pure and mixed second-rotation plantations of Eucalyptus grandis and Acacia mangium before and after senescent leaf drop. The numbers of cultivable fungi and bacteria were also estimated. All properties were correlated with litter C, N, P, lignin and polyphenols, and with soil C and N. We found higher microbial activity (CO2 evolution in litter than in soil. In the E. grandis monoculture before senescent leaf drop, microbial biomass C was 46 % higher in litter than in soil. After leaf drop, this difference decreased to 16 %. In A. mangium plantations, however, microbial biomass C was lower in litter than in soil both before and after leaf drop. Microbial biomass N of litter was approximately 94 % greater than that of the soil in summer and winter in all plantations. The number of cultivable fungi and bacteria increased after leaf drop, especially so in the litter. Fungi were also more abundant in the E. grandis litter. In general, the A. mangium monoculture was associated with higher levels of litter lignin and N, especially after leaf drop. In contrast, the polyphenol and C levels in E. grandis monoculture litter were higher after leaf drop. These properties were negatively correlated with total soil C and N. Litter in the mixed stands had lower C:N and C:P ratios and higher N, P, and C levels in the microbial biomass. This suggests more

  14. Early-stage changes in natural (13)C and (15)N abundance and nutrient dynamics during different litter decomposition.

    Science.gov (United States)

    Gautam, Mukesh Kumar; Lee, Kwang-Sik; Song, Byeong-Yeol; Lee, Dongho; Bong, Yeon-Sik

    2016-05-01

    Decomposition, nutrient, and isotopic (δ(13)C and δ(15)N) dynamics during 1 year were studied for leaf and twig litters of Pinus densiflora, Castanea crenata, Erigeron annuus, and Miscanthus sinensis growing on a highly weathered soil with constrained nutrient supply using litterbags in a cool temperate region of South Korea. Decay constant (k/year) ranged from 0.58 to 1.29/year, and mass loss ranged from 22.36 to 58.43 % among litter types. The results demonstrate that mass loss and nutrient dynamics of decomposing litter were influenced by the seasonality of mineralization and immobilization processes. In general, most nutrients exhibited alternate phases of rapid mineralization followed by gradual immobilization, except K, which was released throughout the field incubation. At the end of study, among all the nutrients only N and P showed net immobilization. Mobility of different nutrients from decomposing litter as the percentage of initial litter nutrient concentration was in the order of K > Mg > Ca > N ≈ P. The δ(13)C (0.32-6.70 ‰) and δ(15)N (0.74-3.90 ‰) values of residual litters showed nonlinear increase and decrease, respectively compared to initial isotopic values during decomposition. Litter of different functional types and chemical quality converged toward a conservative nutrient use strategy through mechanisms of slow decomposition and slow nutrient mobilization. Our results indicate that litter quality and season, are the most important regulators of litter decomposition in these forests. The results revealed significant relationships between litter decomposition rates and N, C:N ratio and P, and seasonality (temperature). These results and the convergence of different litters towards conservative nutrient use in these nutrient constrained ecosystems imply optimization of litter management because litter removal can have cascading effects on litter decomposition and nutrient availability in these systems.

  15. Combined effects of nitrogen addition and litter manipulation on nutrient resorption of Leymus chinensis in a semi-arid grassland of northern China.

    Science.gov (United States)

    Li, X; Liu, J; Fan, J; Ma, Y; Ding, S; Zhong, Z; Wang, D

    2015-01-01

    Plant growth in semi-arid ecosystems is usually severely limited by soil nutrient availability. Alleviation of these resource stresses by fertiliser application and aboveground litter input may affect plant internal nutrient cycling in such regions. We conducted a 4-year field experiment to investigate the effects of nitrogen (N) addition (10 g N·m(-2) ·year(-1)) and plant litter manipulation on nutrient resorption of Leymus chinensis, the dominant native grass in a semi-arid grassland in northern China. Although N addition had no clear effects on N and phosphorus (P) resorption efficiencies in leaves and culms, N fertilisation generally decreased leaf N resorption proficiency by 54%, culm N resorption proficiency by 65%. Moreover, N fertilisation increased leaf P resorption proficiency by 13%, culm P resorption proficiency by 20%. Under ambient or enriched N conditions, litter addition reduced N and P resorption proficiencies in both leaves and culms. The response of P resorption proficiency to litter manipulation was more sensitive than N resorption proficiency: P resorption proficiency in leaves and culms decreased strongly with increasing litter amount under both ambient and enriched N conditions. In contrast, N resorption proficiency was not significantly affected by litter addition, except for leaf N resorption proficiency under ambient N conditions. Furthermore, although litter addition caused a general decrease of leaf and culm nutrient resorption efficiencies under both ambient and enriched N conditions, litter addition effects on nutrient resorption efficiency were much weaker than the effects of litter addition on nutrient resorption proficiency. Taken together, our results show that leaf and non-leaf organs of L. chinensis respond consistently to altered soil N availability. Our study confirms the strong effects of N addition on plant nutrient resorption processes and the potential role of aboveground litter, the most important natural fertiliser in

  16. Losses of soil carbon by converting tropical forest to plantations: erosion and decomposition estimated by δ(13) C.

    Science.gov (United States)

    Guillaume, Thomas; Damris, Muhammad; Kuzyakov, Yakov

    2015-09-01

    Indonesia lost more tropical forest than all of Brazil in 2012, mainly driven by the rubber, oil palm, and timber industries. Nonetheless, the effects of converting forest to oil palm and rubber plantations on soil organic carbon (SOC) stocks remain unclear. We analyzed SOC losses after lowland rainforest conversion to oil palm, intensive rubber, and extensive rubber plantations in Jambi Province on Sumatra Island. The focus was on two processes: (1) erosion and (2) decomposition of soil organic matter. Carbon contents in the Ah horizon under oil palm and rubber plantations were strongly reduced up to 70% and 62%, respectively. The decrease was lower under extensive rubber plantations (41%). On average, converting forest to plantations led to a loss of 10 Mg C ha(-1) after about 15 years of conversion. The C content in the subsoil was similar under the forest and the plantations. We therefore assumed that a shift to higher δ(13) C values in plantation subsoil corresponds to the losses from the upper soil layer by erosion. Erosion was estimated by comparing the δ(13) C profiles in the soils under forest and under plantations. The estimated erosion was the strongest in oil palm (35 ± 8 cm) and rubber (33 ± 10 cm) plantations. The (13) C enrichment of SOC used as a proxy of its turnover indicates a decrease of SOC decomposition rate in the Ah horizon under oil palm plantations after forest conversion. Nonetheless, based on the lack of C input from litter, we expect further losses of SOC in oil palm plantations, which are a less sustainable land use compared to rubber plantations. We conclude that δ(13) C depth profiles may be a powerful tool to disentangle soil erosion and SOC mineralization after the conversion of natural ecosystems conversion to intensive plantations when soils show gradual increase of δ(13) C values with depth. © 2015 The Authors. Global Change Biology published by John Wiley & Sons Ltd.

  17. Environmentally-friendly animal litter

    Energy Technology Data Exchange (ETDEWEB)

    Boxley, Chett; McKelvie, Jessica

    2012-08-28

    An animal litter composition including geopolymerized ash particulates having a network of repeating aluminum-silicon units is described herein. Generally, the animal litter is made from a quantity of a pozzolanic ash mixed with a sufficient quantity of water and an alkaline activator to initiate a geopolymerization reaction that forms geopolymerized ash. After the geopolymerized ash is formed, it is dried, broken into particulates, and sieved to a desired size. These geopolymerized ash particulates are used to make a non-clumping or clumping animal litter. Odor control is accomplished with the addition of a urease inhibitor, pH buffer, an odor eliminating agent, and/or fragrance.

  18. Environmentally-friendly animal litter

    Science.gov (United States)

    Boxley, Chett; McKelvie, Jessica

    2013-09-03

    An animal litter composition that includes geopolymerized ash particulates having a network of repeating aluminum-silicon units is described herein. Generally, the animal litter is made from a quantity of a pozzolanic ash mixed with an alkaline activator to initiate a geopolymerization reaction that forms geopolymerized ash. This geopolymerization reaction may occur within a pelletizer. After the geopolymerized ash is formed, it may be dried and sieved to a desired size. These geopolymerized ash particulates may be used to make a non-clumping or clumping animal litter or other absorbing material. Aluminum sulfate, clinoptilolite, silica gel, sodium alginate and mineral oil may be added as additional ingredients.

  19. Environmentally-friendly animal litter

    Energy Technology Data Exchange (ETDEWEB)

    Boxley, Chett; McKelvie, Jessica

    2013-09-03

    An animal litter composition that includes geopolymerized ash particulates having a network of repeating aluminum-silicon units is described herein. Generally, the animal litter is made from a quantity of a pozzolanic ash mixed with an alkaline activator to initiate a geopolymerization reaction that forms geopolymerized ash. This geopolymerization reaction may occur within a pelletizer. After the geopolymerized ash is formed, it may be dried and sieved to a desired size. These geopolymerized ash particulates may be used to make a non-clumping or clumping animal litter or other absorbing material. Aluminum sulfate, clinoptilolite, silica gel, sodium alginate and mineral oil may be added as additional ingredients.

  20. Influence of litter chemistry and stoichiometry on glucan depolymerization during decomposition of beech (Fagus sylvatica L.) litter.

    Science.gov (United States)

    Leitner, Sonja; Wanek, Wolfgang; Wild, Birgit; Haemmerle, Ieda; Kohl, Lukas; Keiblinger, Katharina M; Zechmeister-Boltenstern, Sophie; Richter, Andreas

    2012-07-01

    Glucans like cellulose and starch are a major source of carbon for decomposer food webs, especially during early- and intermediate-stages of decomposition. Litter quality has previously been suggested to notably influence decomposition processes as it determines the decomposability of organic material and the nutrient availability to the decomposer community. To study the impact of chemical and elemental composition of resources on glucan decomposition, a laboratory experiment was carried out using beech (Fagus sylvatica, L.) litter from four different locations in Austria, differing in composition (concentration of starch, cellulose and acid unhydrolyzable residue or AUR fraction) and elemental stoichiometry (C:N:P ratio). Leaf litter was incubated in mesocosms for six months in the laboratory under controlled conditions. To investigate the process of glucan decomposition and its controls, we developed an isotope pool dilution (IPD) assay using (13)C-glucose to label the pool of free glucose in the litter, and subsequently measured the dilution of label over time. This enabled us to calculate gross rates of glucose production through glucan depolymerization, and glucose consumption by the microbial community. In addition, potential activities of extracellular cellulases and ligninases (peroxidases and phenoloxidases) were measured to identify effects of resource chemistry and stoichiometry on microbial enzyme production. Gross rates of glucan depolymerization and glucose consumption were highly correlated, indicating that both processes are co-regulated and intrinsically linked by the microbial demand for C and energy and thereby to resource allocation to enzymes that depolymerize glucans. At early stages of decomposition, glucan depolymerization rates were correlated with starch content, indicating that starch was the primary source for glucose. With progressing litter decomposition, the correlation with starch diminished and glucan depolymerization rates were

  1. Long-term presence of tree species but not chemical diversity affect litter mixture effects on decomposition in a neotropical rainforest.

    Science.gov (United States)

    Barantal, Sandra; Roy, Jacques; Fromin, Nathalie; Schimann, Heidy; Hättenschwiler, Stephan

    2011-09-01

    Plant litter diversity effects on decomposition rates are frequently reported, but with a strong bias towards temperate ecosystems. Altered decomposition and nutrient recycling with changing litter diversity may be particularly important in tree species-rich tropical rainforests on nutrient-poor soils. Using 28 different mixtures of leaf litter from 16 Amazonian rainforest tree species, we tested the hypothesis that litter mixture effects on decomposition increase with increasing functional litter diversity. Litter mixtures and all single litter species were exposed in the field for 9 months using custom-made microcosms with soil fauna access. In order to test the hypothesis that the long-term presence of tree species contributing to the litter mixtures increases mixture effects on decomposition, microcosms were installed in a plantation at sites including the respective tree species composition and in a nearby natural forest where these tree species are absent. We found that mixture decomposition deviated from predictions based on single species, with predominantly synergistic effects. Functional litter diversity, defined as either richness, evenness, or divergence based on a wide range of chemical traits, did not explain the observed litter mixture effects. However, synergistic effects in litter mixtures increased with the long-term presence of tree species contributing to these mixtures as the home field advantage hypothesis assumes. Our data suggest that complementarity effects on mixed litter decomposition may emerge through long-term interactions between aboveground and belowground biota.

  2. Den litterære blog

    DEFF Research Database (Denmark)

    Serup, Martin Glaz; Kromann, Thomas Hvid

    2012-01-01

    Hvad er en litterær blog og hvordan arbejder den som en aktiv del af den litterære offentlighed.......Hvad er en litterær blog og hvordan arbejder den som en aktiv del af den litterære offentlighed....

  3. 33 CFR 144.01-35 - Litter.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Litter. 144.01-35 Section 144.01... CONTINENTAL SHELF ACTIVITIES LIFESAVING APPLIANCES Manned Platforms § 144.01-35 Litter. On each manned platform a Stokes litter, or other suitable safety litter capable of being safely hoisted with an...

  4. Genetic Based Plant Resistance and Susceptibility Traits to Herbivory Influence Needle and Root Litter Nutrient Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Classen, Aimee T [ORNL; Chapman, Samantha K. [Smithsonian Environmental Research Center, Edgewater, MD; Whitham, Thomas G [Northern Arizona University; Hart, Stephen C [Northern Arizona University; Koch, George W [Northern Arizona University

    2007-01-01

    It is generally assumed that leaf and root litter decomposition have similar drivers and that nutrient release from these substrates is synchronized. Few studies have examined these assumptions, and none has examined how plant genetics (i.e., plant susceptibility to herbivory) could affect these relationships. Here we examine the effects of herbivore susceptibility and resistance on needle and fine root litter decomposition of pi on pine, Pinus edulis. The study population consists of individual trees that are either susceptible or resistant to herbivory by the pi on needle scale, Matsucoccus acalyptus, or the stem-boring moth, Dioryctria albovittella. Genetic analyses and experimental removals and additions of these insects have identified trees that are naturally resistant and susceptible to these insects. These herbivores increase the chemical quality of litter inputs and alter soil microclimate, both of which are important decomposition drivers. Our research leads to four major conclusions: Herbivore susceptibility and resistance effects on 1) needle litter mass loss and phosphorus (P) retention in moth susceptible and resistant litter are governed by microclimate, 2) root litter nitrogen (N) and P retention, and needle litter N retention are governed by litter chemical quality, 3) net nutrient release from litter can reverse over time, 4) root and needle litter mass loss and nutrient release are determined by location (above- vs. belowground), suggesting that the regulators of needle and root decomposition differ at the local scale. Understanding of decomposition and nutrient retention in ecosystems requires consideration of herbivore effects on above- and belowground processes and how these effects may be governed by plant genotype. Because an underlying genetic component to herbivory is common to most ecosystems of the world and herbivory may increase in climatic change scenarios, it is important to evaluate the role of plant genetics in affecting carbon and

  5. Production of mangrove litter in a macrotidal embayment, Darwin Harbour, N.T., Australia

    Science.gov (United States)

    Woodroffe, C. D.; Bardsley, K. N.; Ward, P. J.; Hanley, J. R.

    1988-06-01

    Mangrove forests within a macrotidal embayment, Creek 'H', East Arm, in Darwin Harbour, northern Australia, can be divided into a number of assemblages corresponding to geomorphologically defined habitats. The most widespread of these are: (i) tidal creek, dominated by Camptostemon schultzii, Rhizophora stylosa and Bruguiera parviflora, with occasional massive Avicennia marina; (ii) tidal flat, dominated by mixed Ceriops tagal var. australis and Bruguiera exaristata; and (iii) hinterland margin, with a gently inclined colluvial substrate, dominated by almost monospecific Ceriops tagal var. australis. The average annual litter fall was estimated from two years of observations at a series of locations. The highest rates of litter fall, > 1000 g m -2 year -1 (dry weight), were recorded in tidal creek mangrove forests, with litter fall beneath 13 m tall Avicennia marina of 1400 g m -2 year -1. In tidal flat, mixed Ceriops tagal/Bruguiera exaristata litter fall was 745 g m -2 year -1, with approximately equal contributions from both species. In hinterland margin, litter fall varied between 686 g m -2 year -1 beneath taller Ceriops (up to 7 m) and 300 g m -2 year -1 beneath lower Ceriops (forests and shows considerable spatial variation. Leaf litter was generally low in nitrogen (N) content (litter from traps.

  6. Quantification of litter in the forest fragment national park Serra de Itabaiana, Sergipe State

    Directory of Open Access Journals (Sweden)

    Audenis Fagner de Jesus Nascimento

    2013-12-01

    Full Text Available Natural forests are areas rich in biodiversity that contribute to the maintenance of environmental sustainability through the production of litter and nutrient cycling. Litter is a major route of nutrient return to the system plant – soil – plant and its determination to analyze the restructuring of anthropogenic forest environments. The knowledge of litterfall is critical to determine the potential for regeneration of an area through the intake and nutrient cycling. We quantified litter production in areas of white sand with vegetation in different stages of regeneration the National Park Sierra de Itabaiana, Sergipe State. In each of the areas of white sands open (ABA, white sands intermediary (ABI and white sands closed (ABF was installed 15 litter traps and litter fall was collected monthly from January to December 2011. The total contribution of litter on the White Sand Closed (2092 kg ha-1 was more than double the contribution in Areia Branca Open (881 kg ha-1 and White Sand Intermediate (687 kg ha-1. The leaf fraction contributed the largest mass in all areas and periods, and was the one with greater seasonal variation related to variation in precipitation. Precipitation was one of the factors that determined the seasonality of litter deposition in natural vegetation of the National Park of Sierra de Itabaiana, Sergipe State.

  7. Larger phylogenetic distances in litter mixtures: lower microbial biomass and higher C/N ratios but equal mass loss.

    Science.gov (United States)

    Pan, Xu; Berg, Matty P; Butenschoen, Olaf; Murray, Phil J; Bartish, Igor V; Cornelissen, Johannes H C; Dong, Ming; Prinzing, Andreas

    2015-05-07

    Phylogenetic distances of coexisting species differ greatly within plant communities, but their consequences for decomposers and decomposition remain unknown. We hypothesized that large phylogenetic distance of leaf litter mixtures increases differences of their litter traits, which may, in turn, result in increased resource complementarity or decreased resource concentration for decomposers and hence increased or decreased chemical transformation and reduction of litter. We conducted a litter mixture experiment including 12 common temperate tree species (evolutionarily separated by up to 106 Myr), and sampled after seven months, at which average mass loss was more than 50%. We found no effect of increased phylogenetic distance on litter mass loss or on abundance and diversity of invertebrate decomposers. However, phylogenetic distance decreased microbial biomass and increased carbon/nitrogen (C/N) ratios of litter mixtures. Consistently, four litter traits showed (marginally) significant phylogenetic signal and in three of these traits increasing trait difference decreased microbial biomass and increased C/N. We suggest that phylogenetic proximity of litter favours microbial decomposers and chemical transformation of litter owing to a resource concentration effect. This leads to a new hypothesis: closely related plant species occurring in the same niche should promote and profit from increased nutrient availability.

  8. Mapping litter decomposition by remote-detected indicators

    Directory of Open Access Journals (Sweden)

    L. Rossi

    2006-06-01

    Full Text Available Leaf litter decomposition is a key process for the functioning of natural ecosystems. An important limiting factor for this process is detritus availability, which we have estimated by remote sensed indices of canopy green biomass (NDVI. Here, we describe the use of multivariate geostatistical analysis to couple in situ measures with hyper-spectral and multi-spectral remote-sensed data for producing maps of litter decomposition. A direct relationship between the decomposition rates in four different CORINE habitats and NDVI, calculated at different scales from Landsat ETM+ multi-spectral data and MIVIS hyper-spectral data was found. Variogram analysis was used to evaluate the spatial properties of each single variable and their common interaction. Co-variogram and co-kriging analysis of the two variables turned out to be an effective approach for decomposition mapping from remote-sensed spatial explicit data.

  9. Increased loss of soil-derived carbon in response to litter addition and temperature

    Science.gov (United States)

    Creamer, C.; Krull, E. S.; Sanderman, J.; Farrell, M.

    2013-12-01

    In order to predict the response of soil organic matter (SOM) to increasing temperatures, a mechanistic understanding of the interactions between OM quality, OM availability, and microbial community structure and function is needed. We used short-term incubations of 13C enriched (20 atom%) fresh and pre-incubated eucalyptus leaf litter in an Australian woodland soil to determine changes in allocation of C to various OM pools, as dictated by microbial activity, in response to temperature and substrate quality. The quantity and isotopic composition of microbial phospholipid fatty acids (PLFA) and dissolved organic C (DOC) were measured along with the quantity of dissolved inorganic and organic nitrogen at four destructive time points. The quantity and isotopic composition of respired CO2 was measured throughout the incubation. Although the temperature sensitivities of the two litters were similar (despite different chemical compositions), soil-C was significantly more temperature sensitive than litter-C. We also observed negative priming of soil-C in the fresh litter treatment and positive priming of soil-C in the pre-incubated litter treatment relative to the control (no litter addition). The extent of positive priming in the pre-incubated litter treatment also increased significantly with temperature. The quantity of soil-derived DOC was consistent between both litter treatments and the control, confirming that differences in soil-C availability were not controlling the observed differences in soil-C mineralization. In contrast, dissolved N was significantly higher in the pre-incubated litter treatment and increased with temperature, suggesting enhanced SOM decomposition in the pre-incubated litter treatment resulted in greater N cycling, production, or destabilization from SOM. The pre-incubated litter treatment also had greater proportions of PLFA that predominately cycled soil-derived OM (gram-positive bacteria), and increased in response to elevated temperature

  10. Arbuscular mycorrhizal fungal community composition is altered by long-term litter removal but not litter addition in a lowland tropical forest.

    Science.gov (United States)

    Sheldrake, Merlin; Rosenstock, Nicholas P; Revillini, Daniel; Olsson, Pål Axel; Mangan, Scott; Sayer, Emma J; Wallander, Håkan; Turner, Benjamin L; Tanner, Edmund V J

    2017-04-01

    Tropical forest productivity is sustained by the cycling of nutrients through decomposing organic matter. Arbuscular mycorrhizal (AM) fungi play a key role in the nutrition of tropical trees, yet there has been little experimental investigation into the role of AM fungi in nutrient cycling via decomposing organic material in tropical forests. We evaluated the responses of AM fungi in a long-term leaf litter addition and removal experiment in a tropical forest in Panama. We described AM fungal communities using 454-pyrosequencing, quantified the proportion of root length colonised by AM fungi using microscopy, and estimated AM fungal biomass using a lipid biomarker. AM fungal community composition was altered by litter removal but not litter addition. Root colonisation was substantially greater in the superficial organic layer compared with the mineral soil. Overall colonisation was lower in the litter removal treatment, which lacked an organic layer. There was no effect of litter manipulation on the concentration of the AM fungal lipid biomarker in the mineral soil. We hypothesise that reductions in organic matter brought about by litter removal may lead to AM fungi obtaining nutrients from recalcitrant organic or mineral sources in the soil, besides increasing fungal competition for progressively limited resources.

  11. Composition of riparian litter input regulates organic matter decomposition: Implications for headwater stream functioning in a managed forest landscape.

    Science.gov (United States)

    Lidman, Johan; Jonsson, Micael; Burrows, Ryan M; Bundschuh, Mirco; Sponseller, Ryan A

    2017-02-01

    Although the importance of stream condition for leaf litter decomposition has been extensively studied, little is known about how processing rates change in response to altered riparian vegetation community composition. We investigated patterns of plant litter input and decomposition across 20 boreal headwater streams that varied in proportions of riparian deciduous and coniferous trees. We measured a suite of in-stream physical and chemical characteristics, as well as the amount and type of litter inputs from riparian vegetation, and related these to decomposition rates of native (alder, birch, and spruce) and introduced (lodgepole pine) litter species incubated in coarse- and fine-mesh bags. Total litter inputs ranged more than fivefold among sites and increased with the proportion of deciduous vegetation in the riparian zone. In line with differences in initial litter quality, mean decomposition rate was highest for alder, followed by birch, spruce, and lodgepole pine (12, 55, and 68% lower rates, respectively). Further, these rates were greater in coarse-mesh bags that allow colonization by macroinvertebrates. Variance in decomposition rate among sites for different species was best explained by different sets of environmental conditions, but litter-input composition (i.e., quality) was overall highly important. On average, native litter decomposed faster in sites with higher-quality litter input and (with the exception of spruce) higher concentrations of dissolved nutrients and open canopies. By contrast, lodgepole pine decomposed more rapidly in sites receiving lower-quality litter inputs. Birch litter decomposition rate in coarse-mesh bags was best predicted by the same environmental variables as in fine-mesh bags, with additional positive influences of macroinvertebrate species richness. Hence, to facilitate energy turnover in boreal headwaters, forest management with focus on conifer production should aim at increasing the presence of native deciduous

  12. FOREST LITTER DECOMPOSITION AS AFFECTED BY EUCALYPTUS STAND AGE AND TOPOGRAPHY IN SOUTH-EASTERN BRAZIL1

    Directory of Open Access Journals (Sweden)

    Alba Lucia Araujo Skorupa

    2015-12-01

    Full Text Available Forest litter decomposition is a major process in returning nutrients to soils and thus promoting wood productivity in the humid tropic. This study aimed to assess decomposition of eucalypt litter in the Rio Doce region, Brazil. Leaf litter was sampled under clonal eucalypt stands aged 2, 4 and 6 years on hillslopes and footslopes. Soil and soil+litter samples were incubated at two levels of soil moisture, temperature and fertilization. C-CO2 emissions from soil measured during 106 days were higher at 32 °C than at 23°C, mainly for the 2-yr-old stand on footslope. When leaf litter was added on soils, C-CO2 emissions were eight times higher, mainly on footslopes, with no effect of stand age. Leaf decomposition in situ, assessed with a litterbag experiment showed a mean weight loss of at least 50% during 365 days, reaching 74% for 2 yr-old stands on footslopes. In comparison with data from the native forest and the literature, no apparent restrictions were found in eucalypt litter decomposition. Differences between in vitro and in situ results, and between eucalypt and native forest, were most likely related to the response of diverse decomposer communities and to substrate quality.

  13. Uso del microhábitat por hembras grávidas de la rana de hojarasca Craugastor loki en la selva alta perennifolia de Los Tuxtlas, Veracruz, México Microhabitat use by the leaf litter frog Craugastor loki gravid females in the tropical rainforest at Los Tuxtlas, Veracruz, Mexico

    Directory of Open Access Journals (Sweden)

    José Nicolás Urbina-Cardona

    2009-08-01

    Full Text Available Craugastor loki es la especie de anfibio más abundante en la selva alta perennifolia de Los Tuxtlas, registrándose 1 251 individuos (58% adultos durante un año de muestreo a lo largo de gran variedad de microhábitats en 6 fragmentos de selva. A pesar de que C. loki se considera una especie tolerante a la modificación del hábitat, el 71% de las hembras grávidas se encontraron en las áreas mejor conservadas. Hubo un mayor registro de hembras grávidas en el fragmento de selva continuo (473 ha, prefiriendo hábitats con una distancia mayor a 50 m del borde y suelos con cobertura y espesor de hojarasca altas, cobertura herbácea alta, humedad relativa alta, pero independientes de la distancia a los cuerpos de agua. En el presente estudio se demuestra que las hembras grávidas, un eslabón crítico para el mantenimiento de la especie, son vulnerables a la perdida de hábitat y efectos de borde. Un cambio en las zonas conservadas pudiera afectar la abundancia y estructura poblacional de C. loki, generando a futuro una peligrosa disrupción en la cadena trófica y en la estructura de las comunidades de la selva.Craugastor loki is the dominant amphibian in the Los Tuxtlas tropical rainforest. We recorded 1 251 individuals (58% adults in a sampling year within a great variety of microhabitats in 6 forest fragments. Although C. loki is considered tolerant to habitat disturbance, 71% of all gravid females were found in most highly conserved sites. Gravid females were mostly found in the largest forest fragment with continuous rainforest (473 ha, preferring habitats with distances to the edge over 50 m, soils with high leaf litter cover and depth, high understory density, high relative humidity but independent of the distance to water bodies. Gravid females, a critical element to maintain the species, are very vulnerable to habitat loss and edge effects. A change in conserved habitats may affect C. loki abundance and population structure

  14. Variation in litter decomposition-temperature relationships between coniferous and broadleaf forests in Huangshan Mountain,China

    Institute of Scientific and Technical Information of China (English)

    HE Xing-bing; SONG Fu-qiang; ZHANG Peng; LIN Yong-hui; TIAN Xing-jun; REN Li-li; CHEN Cheng; LI Xiao-na; Tan Hai-xia

    2007-01-01

    A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, China. Results showed that at 20℃ mass loss of leaf litter driven by microbial decomposers was higher in broadleaf forest than that in coniferous forest, whereas the difference in mass loss of leaf litter was not significant at 30℃. The temperature increase did not affect the mass loss of leaf litter for coniferous forest treatment, but significantly reduced the decomposition rate for broadleaf forest treatment. The functional decomposers of microorganism in broadleaf forest produced a higher lignin decomposition rate at 20℃, compared to that in coniferous forest, but the difference in lignin decomposition was not found between two forest types at 30℃. Improved temperature increased the lignin decomposition for both broadleaf and coniferous forest. Additionally, the functional group of microorganism from broadleaf forest showed marginally higher carbohydrate loss than that from coniferous forest at both temperatures. Temperature increase reduced the carbohydrate decomposition for broadleaf forest, while only a little reduce was found for coniferous forest. Remarkable differences occurred in responses between most enzymes (Phenoloxidase, peroxidase, β-glucosidase and endocellulase) and decomposition rate of leaf litter to forest type and temperature, although there exist strong relationships between measured enzyme activities and decomposition rate in most cases. The reason is that more than one enzyme contribute to the mass loss of leaf litter and organic chemical components. In conclusion, at a community scale the coniferous and broadleaf forests differed in their temperature-decomposition relationships.

  15. Climate change triggers effects of fungal pathogens and insect herbivores on litter decomposition

    Science.gov (United States)

    Butenschoen, Olaf; Scheu, Stefan

    2014-10-01

    Increasing infestation by insect herbivores and pathogenic fungi in response to climate change will inevitably impact the amount and quality of leaf litter inputs into the soil. However, little is known on the interactive effect of infestation severity and climate change on litter decomposition, and no such study has been published for deciduous forests in Central Europe. We assessed changes in initial chemical quality of beech (Fagus sylvatica L.) and maple litter (Acer platanoides L.) in response to infestation by the gall midge Mikiola fagi Hart. and the pathogenic fungus Sawadaea tulasnei Fuckel, respectively, and investigated interactive effects of infestation severity, changes in temperature and soil moisture on carbon mineralization in a short-term laboratory study. We found that infestation by the gall midge M. fagi and the pathogenic fungus S. tulasnei significantly changed the chemical quality of beech and maple litter. Changes in element concentrations were generally positive and more pronounced, and if negative less pronounced for maple than beech litter most likely due to high quality fungal tissue remaining on litter after abscission. More importantly, alterations in litter chemical quality did not translate to distinct patterns of carbon mineralization at ambient conditions, but even low amounts of infested litter accelerated carbon mineralization at moderately increased soil moisture and in particular at higher temperature. Our results indicate that insect herbivores and fungal pathogens can markedly alter initial litter chemical quality, but that afterlife effects on carbon mineralization depend on soil moisture and temperature, suggesting that increased infestation severity under projected climate change potentially increases soil carbon release in deciduous forests in Central Europe.

  16. Litter dominates surface fluxes of carbonyl sulfide in a Californian oak woodland

    Science.gov (United States)

    Sun, Wu; Maseyk, Kadmiel; Lett, Céline; Seibt, Ulli

    2016-02-01

    Carbonyl sulfide (COS) is a promising tracer for partitioning terrestrial photosynthesis and respiration from net carbon fluxes, based on its daytime co-uptake alongside CO2 through leaf stomata. Because ecosystem COS fluxes are the sum of plant and soil fluxes, using COS as a photosynthesis tracer requires accurate knowledge of soil COS fluxes. At an oak woodland in Southern California, we monitored below-canopy surface (soil + litter) COS and CO2 fluxes for 40 days using chambers and laser spectroscopy. We also measured litter fluxes separately and used a depth-resolved diffusion-reaction model to quantify the role of litter uptake in surface COS fluxes. Soil and litter were primarily COS sinks, and mean surface COS uptake was small (˜1 pmol m-2 s-1). After rainfall, uptake rates were higher (6-8 pmol m-2 s-1), and litter contributed a significant fraction (up to 90%) to surface fluxes. We observed rapid concurrent increases in COS uptake and CO2 efflux following the onset of rain. The patterns were similar to the Birch effect widely documented for soils; however, both COS and CO2 flux increases originated mainly in the litter. The synchronous COS-CO2 litter Birch effect indicates that it results from a rapid increase in litter microbial activity after rainfall. We expect that the drying-rewetting cycles typical for mediterranean and other semiarid ecosystems create a pronounced seasonality in surface COS fluxes. Our results highlight that litter uptake is an important component of surface COS exchange that needs to be taken into account in ecosystem COS budgets and model simulations.

  17. INTERACTION EFFECT OF TREE LEAF LITTER, MANURE AND

    African Journals Online (AJOL)

    INORGANIC FERTILIZER ON THE PERFORMANCE OF MAIZE IN ... experiment was conducted over two seasons to evaluate the effects of 5 that1 of different organic inputs ... growth was overcome by the application of Compound D fertilizer.

  18. Contrasting patterns of litterfall seasonality and seasonal changes in litter decomposability in a tropical rainforest region

    Directory of Open Access Journals (Sweden)

    S. A. Parsons

    2014-06-01

    Full Text Available The seasonality of litter inputs in forests has important implications for understanding ecosystem processes and biogeochemical cycles. We quantified the drivers of seasonality in litterfall and leaf decomposability, using plots throughout the Australian wet tropical region. Litter fell mostly in the summer (wet, warm months in the region, but other peaks occurred throughout the year. Litterfall seasonality was modelled well with the level of deciduousness of the site (plots with more deciduous species had lower seasonality than evergreen plots, temperature (higher seasonality in the uplands, disturbance (lower seasonality with more early secondary species and soil fertility (higher seasonality with higher N : P/P limitation (SL total litterfall model 1 = deciduousness + soil N : P + early secondary sp: r2 = 0.63, n = 30 plots; model 2 = temperature + early secondary sp. + soil N : P: r2 = 0.54, n = 30; SL leaf = temperature + early secondary sp. + rainfall seasonality: r2 = 0.39, n = 30. Leaf litter decomposability was lower in the dry season than in the wet season, driven by higher phenolic concentrations in the dry, with the difference exacerbated particularly by lower dry season moisture. Our results are contrary to the global trend for tropical rainforests; in that seasonality of litterfall inputs were generally higher in wetter, cooler, evergreen forests, compared to generally drier, warmer, semi-deciduous sites that had more uniform monthly inputs. We consider this due to more diverse litter shedding patterns in semi-deciduous and raingreen rainforest sites, and an important consideration for ecosystem modellers. Seasonal changes in litter quality are likely to have impacts on decomposition and biogeochemical cycles in these forests due to the litter that falls in the dry being more recalcitrant to decay.

  19. 46 CFR 108.709 - Litter.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Litter. 108.709 Section 108.709 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.709 Litter. Each unit must have a litter that is— (a) Stowed in a location that...

  20. Influence of packaging design on littering behavior

    NARCIS (Netherlands)

    Wever, R.

    2006-01-01

    Litter is an environmental and social problem that is closely related to packaging. Many attempts have been made to reduce litter. So far these attempts have mainly focused on influencing littering behavior either through general campaigns or through manipulating the environment. The latter might be

  1. Influence of packaging design on littering behavior

    NARCIS (Netherlands)

    Wever, R.

    2006-01-01

    Litter is an environmental and social problem that is closely related to packaging. Many attempts have been made to reduce litter. So far these attempts have mainly focused on influencing littering behavior either through general campaigns or through manipulating the environment. The latter might be

  2. Litter chemistry and chemical diversity drive ecosystem processes in forest ponds.

    Science.gov (United States)

    Stoler, Aaron B; Burke, David J; Relyea, Rick A

    2016-07-01

    Research suggests that a positive relationship exists between diversity and ecological function, yet the multi-trophic effects of biodiversity remain poorly understood. The resource complementarity hypothesis suggests that increasing the trait diversity of resources provides a more complete diet for consumers, elevating consumer feeding rates. Whereas previous tests of this mechanism have measured trait diversity as the variation of single traits or the richness of functional groups, we employed a multivariate trait index to manipulate the chemical diversity of temperate tree litter species in outdoor pond mesocosms. We inoculated outdoor mesocosms with diverse and multi-trophic communities of microbial and macro-consumer species that rely on leaf litter for energy and nutrients. Litter was provided at three levels of chemical trait diversity, a constant level of species richness, and an equal representation of all litter species. Over three months, we measured more than 65 responses, and assessed the effects of litter chemical diversity and chemical trait means (i.e., community-weighted means). We found that litter chemical diversity positively correlated with decomposition rate of leaf litter, but had no effect on biomass or density of producers and consumers. However, the pond communities often responded to chemical trait means, particularly those related to nutrients, structure, and defense. Our results suggest that resource complementarity does have some effect on the release of energy and nutrients from decomposing substrates in forest ponds, but does not have multi-trophic effects. Our results further suggest that loss of tree biodiversity could affect forest ecosystem functionality, and particularly the processes occurring in and around ponds and wetlands. © 2016 by the Ecological Society of America.

  3. Litter dynamics in two Sierran mixed conifer forests. I. Litterfall and decomposition rates

    Science.gov (United States)

    Stohlgren, Thomas J.

    1988-01-01

    Litterfall was measured for 4 years and leaf litter decomposition rates were studied for 3.6 years in two mixed conifer forest (giant sequoia-fir and fir-pine) in the southern Sierra Nevada of California. The giant sequoia-fir forest (GS site) was dominated by giant sequoia (Sequoiadendron giganteum (Lindl.) Buchh.), white fir (Abies concolor Lindl. & Gord.), and sugar pine (Pinus lambertiana Dougl.). The fir-pine forest (FP site) was dominated by white fir, sugar pine, and incense cedar (Calocedrus decurrens (Torr.) Florin). Litterfall, including large woody debris -1•year-1 compared with 4355 kg•ha-1•year-1 at the FP site (3.4:1). In the GS site, leaf litter decomposition after 3.6 years was slowest for giant sequoia (28.2% mass loss), followed by sugar pine (34.3%) and white fie (45.1%). In the FP site, mass loss was slowest for sugar pine (40.0%), followed by white fir (45.1%), while incense cedar showed the greatest mass loss (56.9%) after 3.6 years. High litterfall rates of large woody debris (i.e., 2.5-15.2 cm diameter) and slow rates of leaf litter decomposition in the giant sequoia-fir forest type may result in higher litter accumulation rates than in the fir-pine type. Leaf litter times to 95% decay for the GS and FP sites were 30 and 27 years, respectively, if the initial 0.7-year period (a short period of rapid mass decay) was ignored in the calculation. A mass balance approach for total litterfall (<15.2 cm diameter) decomposition yielded lower decay constants than did the litterbag study and therefore longer times to 95% decay (57 years for the GS site and 62 years for the FP site).

  4. Climate change effects on macrofaunal litter decomposition: the interplay of temperature, body masses and stoichiometry.

    Science.gov (United States)

    Ott, David; Rall, Björn C; Brose, Ulrich

    2012-11-05

    Macrofauna invertebrates of forest floors provide important functions in the decomposition process of soil organic matter, which is affected by the nutrient stoichiometry of the leaf litter. Climate change effects on forest ecosystems include warming and decreasing litter quality (e.g. higher C : nutrient ratios) induced by higher atmospheric CO(2) concentrations. While litter-bag experiments unravelled separate effects, a mechanistic understanding of how interactions between temperature and litter stoichiometry are driving decomposition rates is lacking. In a laboratory experiment, we filled this void by quantifying decomposer consumption rates analogous to predator-prey functional responses that include the mechanistic parameters handling time and attack rate. Systematically, we varied the body masses of isopods, the environmental temperature and the resource between poor (hornbeam) and good quality (ash). We found that attack rates increased and handling times decreased (i) with body masses and (ii) temperature. Interestingly, these relationships interacted with litter quality: small isopods possibly avoided the poorer resource, whereas large isopods exhibited increased, compensatory feeding of the poorer resource, which may be explained by their higher metabolic demands. The combination of metabolic theory and ecological stoichiometry provided critically important mechanistic insights into how warming and varying litter quality may modify macrofaunal decomposition rates.

  5. The effect of latitudinal gradient on the species diversity of Chinese litter-dwelling thrips

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2014-06-01

    Full Text Available To understand the global distribution patterns of litter-dwelling thrips, a total 150 leaf litter samples were collected from 6 natural reserves located in three climatic regions, temperate, subtropical and tropical. The results showed the relative abundance of Thysanoptera was over 3.0% in 4 natural reserves from subtropical and tropical zone, and reached 5.9% in one tropical reserve, only less than Acarina and Collembola. In contrast it was only 0.3% in the warm temperate natural reserves, and no thrips were collected in a mid temperate reserve. The order on the average species numbers per plot of litter thrips was tropic > subtropics > temperate (n=25, p<0.05. Mean density of litter thrips per plots in the tropics and subtropics was significantly higher than that in the temperate region (n=25, p<0.05, but the average density was not significantly different between tropical and subtropical zones (n=25, p>0.05. The diversity of litter thrips in the tropics and subtropics was much higher than that in the temperate area based on comparsions of Shannon-Wiener diversity index (H΄, Pielou eveness index (J, and Simpson dominance index (D. All of these results indicated that litter-dwelling thrips lived mainly in tropical and subtropical regions; meanwhile, species number and relative abundance increased with decreasing latitude.

  6. 不同比例凋落物的分解动态变化研究%Study on the Dynamics Changes of Litter Decomposition in Different Proportions

    Institute of Scientific and Technical Information of China (English)

    陈志锋

    2016-01-01

    Toanalyze the influence of diversity of litter leaf on different decomposition stages and rates ,weadopted the method of mixing different proportions of litter into the nylon bag for field decomposition experiment .The results showed that :in different decomposition stages ,pure litter decomposition rate of Cunninghamia lanceolatewas low , suggesting that the composition of single litter leaf might not be conducive to the decomposition of litter leaf .On the other side ,for the litter leaf decomposition rate ,the rate of pure Cunninghamia lanceolate litter in the initial stage of decomposition was poor ,and with the increase of the decomposition time ,decomposition rate of Cunninghamia lance‐olate and Masson pine litter leaf was poor .%为分析凋落叶多样性对凋落物不同分解阶段分解量及分解速率的影响,采用将不同混合比例的凋落物装入分解尼龙网袋的方法,进行了野外分解实验,结果表明:在不同分解阶段,纯杉木凋落叶的分解量均较低,这表明单一凋落叶组成可能不利于凋落叶的分解。同时,从凋落叶的分解速率来看,纯杉木凋落叶在分解初期的分解速率较差,随着分解时间的增加,杉木+马尾松凋落叶的分解速率则较差。

  7. The abiotic litter decomposition in the drylands

    Science.gov (United States)

    Lee, H.; Throop, H.; Rahn, T. A.

    2009-12-01

    The decomposition of litter is an important ecosystem function that controls carbon and nutrient cycling, which is well understood from the relationship between temperature and moisture. However, the decomposition in the arid and semiarid environments (hereafter drylands) is relatively poorly predicted due to several abiotic factors such as the effect of ultraviolet radiation and physical mixing of fallen litter with soil. The relative magnitude of these abiotic factors to ecosystem scale litter decomposition is still in debate. Here, we examine the effect of two major abiotic factors in the drylands litter decomposition by conducting a controlled laboratory study using plant litter and soil collected from Sonoran and Chihuahuan desert areas. The first part of the experiment focused on the effect of soil-litter mixing. We established a complete block design of three levels of soil and litter mixing (no mixing, light soil-litter mixing, and complete soil-litter mixing) in combination with three levels of soil moisture (1%, 2%, and 6% volumetric water content) using 2g of two most dominant species litter, grass and mesquite, and 50g of air-dried soils in 500ml mason jar and incubated them under 25C. We measured CO2 fluxes from these soil-litter incubations and harvested the soil and litter at 0, 1, 2, 4, 8, and 16 weeks and analyzed them of carbon and nitrogen content as well as the actual mass loss in the litter. The second part of the experiment focused on the effect of ultraviolet radiation. We established short-term litter incubation on a quartz chamber and used different temperature, moisture, and minerals to find the mechanism of photodegradation of litter. We measured CO2 fluxes from the litter incubation under ultraviolet radiation and also measured 13CO2 from these emissions. We were able to detect changes in the rate of carbon mineralization as a result of our treatments in the first week of soil-litter mixing experiment. The carbon mineralization rate was

  8. Climate and litter quality differently modulate the effects of soil fauna on litter decomposition across biomes.

    Science.gov (United States)

    García-Palacios, Pablo; Maestre, Fernando T; Kattge, Jens; Wall, Diana H

    2013-08-01

    Climate and litter quality have been identified as major drivers of litter decomposition at large spatial scales. However, the role played by soil fauna remains largely unknown, despite its importance for litter fragmentation and microbial activity. We synthesised litterbag studies to quantify the effect sizes of soil fauna on litter decomposition rates at the global and biome scales, and to assess how climate, litter quality and soil fauna interact to determine such rates. Soil fauna consistently enhanced litter decomposition at both global and biome scales (average increment ~ 37%). [corrected]. However, climate and litter quality differently modulated the effects of soil fauna on decomposition rates between biomes, from climate-driven biomes to those where climate effects were mediated by changes in litter quality. Our results advocate for the inclusion of biome-specific soil fauna effects on litter decomposition as a mean to reduce the unexplained variation in large-scale decomposition models. © 2013 John Wiley & Sons Ltd/CNRS.

  9. Soil fauna and leaf species, but not species diversity, affect initial soil erosion in a subtropical forest plantation

    Science.gov (United States)

    Seitz, Steffen; Goebes, Philipp; Assmann, Thorsten; Schuldt, Andreas; Scholten, Thomas

    2017-04-01

    In subtropical parts of China, high rainfall intensities cause continuous soil losses and thereby provoke severe harms to ecosystems. In woodlands, it is not the tree canopy, but mostly an intact forest floor that provides protection from soil erosion. Although the protective role of leaf litter covers against soil losses is known for a long time, little research has been conducted on the processes involved. For instance, the role of different leaf species and leaf species diversity has been widely disregarded. Furthermore, the impact of soil meso- and macrofauna within the litter layer on soil losses remains unclear. To investigate how leaf litter species and diversity as well as soil meso- and macrofauna affect sediment discharge in a subtropical forest ecosystem, a field experiment was carried out in Xingangshan, Jiangxi Province, PR China (BEF China). A full-factorial random design with 96 micro-scale runoff plots and seven domestic leaf species in three diversity levels and a bare ground feature were established. Erosion was initiated with a rainfall simulator. This study confirms that leaf litter cover generally protects forest soils from water erosion (-82 % sediment discharge on leaf covered plots compared to bare plots) and this protection is gradually removed as the litter layer decomposes. Different leaf species showed variable impacts on sediment discharge and thus erosion control. This effect can be related to different leaf habitus, leaf decomposition rates and food preferences of litter decomposing meso- and macrofauna. In our experiment, runoff plots with leaf litter from Machilus thunbergii in monoculture showed the highest sediment discharge (68.0 g m-2), whereas plots with Cyclobalanopsis glauca in monoculture showed the smallest rates (7.9 g m-2). At the same time, neither leaf species diversity, nor functional diversity showed any significant influence, only a negative trend could be observed. Nevertheless, the protective effect of the leaf

  10. Mineralization and carbon turnover in subarctic heath soil as affected by warming and additional litter

    DEFF Research Database (Denmark)

    Rinnan, Riikka; Michelsen, Anders; Baath, Erland

    2007-01-01

    Arctic soil carbon (C) stocks are threatened by the rapidly advancing global warming. In addition to temperature, increasing amounts of leaf litter fall following from the expansion of deciduous shrubs and trees in northern ecosystems may alter biogeochemical cycling of C and nutrients. Our aim...... was to assess how factorial warming and litter addition in a long-term field experiment on a subarctic heath affect resource limitation of soil microbial communities (measured by thymidine and leucine incorporation techniques), net growing-season mineralization of nitrogen (N) and phosphorus (P), and carbon...... the field incubation. The added litter did not affect the carbon content, but it was a source of nutrients to the soil, and it also tended to increase bacterial growth rate and net mineralization of P. The inorganic N pool decreased during the field incubation of soil cores, especially in the separate...

  11. Enhanced summer warming reduces fungal decomposer diversity and litter mass loss more strongly in dry than in wet tundra.

    Science.gov (United States)

    Christiansen, Casper T; Haugwitz, Merian S; Priemé, Anders; Nielsen, Cecilie S; Elberling, Bo; Michelsen, Anders; Grogan, Paul; Blok, Daan

    2017-01-01

    Many Arctic regions are currently experiencing substantial summer and winter climate changes. Litter decomposition is a fundamental component of ecosystem carbon and nutrient cycles, with fungi being among the primary decomposers. To assess the impacts of seasonal climatic changes on litter fungal communities and their functioning, Betula glandulosa leaf litter was surface-incubated in two adjacent low Arctic sites with contrasting soil moisture regimes: dry shrub heath and wet sedge tundra at Disko Island, Greenland. At both sites, we investigated the impacts of factorial combinations of enhanced summer warming (using open-top chambers; OTCs) and deepened snow (using snow fences) on surface litter mass loss, chemistry and fungal decomposer communities after approximately 1 year. Enhanced summer warming significantly restricted litter mass loss by 32% in the dry and 17% in the wet site. Litter moisture content was significantly reduced by summer warming in the dry, but not in the wet site. Likewise, fungal total abundance and diversity were reduced by OTC warming at the dry site, while comparatively modest warming effects were observed in the wet site. These results suggest that increased evapotranspiration in the OTC plots lowered litter moisture content to the point where fungal decomposition activities became inhibited. In contrast, snow addition enhanced fungal abundance in both sites but did not significantly affect litter mass loss rates. Across sites, control plots only shared 15% of their fungal phylotypes, suggesting strong local controls on fungal decomposer community composition. Nevertheless, fungal community functioning (litter decomposition) was negatively affected by warming in both sites. We conclude that although buried soil organic matter decomposition is widely expected to increase with future summer warming, surface litter decay and nutrient turnover rates in both xeric and relatively moist tundra are likely to be significantly restricted by

  12. High-frequency fire alters C : N : P stoichiometry in forest litter.

    Science.gov (United States)

    Toberman, Hannah; Chen, Chengrong; Lewis, Tom; Elser, James J

    2014-07-01

    Fire is a major driver of ecosystem change and can disproportionately affect the cycling of different nutrients. Thus, a stoichiometric approach to investigate the relationships between nutrient availability and microbial resource use during decomposition is likely to provide insight into the effects of fire on ecosystem functioning. We conducted a field litter bag experiment to investigate the long-term impact of repeated fire on the stoichiometry of leaf litter C, N and P pools, and nutrient-acquiring enzyme activities during decomposition in a wet sclerophyll eucalypt forest in Queensland, Australia. Fire frequency treatments have been maintained since 1972, including burning every 2 years (2yrB), burning every 4 years (4 yrB) and no burning (NB). C : N ratios in freshly fallen litter were 29-42% higher and C : P ratios were 6-25% lower for 2 yrB than NB during decomposition, with correspondingly lower 2yrB N : P ratios (27-32) than for NB (34-49). Trends in litter soluble and microbial N : P ratios were similar to the overall litter N : P ratios across fire treatments. Consistent with these, the ratio of activities for N-acquiring to P-acquiring enzymes in litter was higher for 2 yrB than NB, whereas 4 yrB was generally intermediate between 2 yrB and NB. Decomposition rates of freshly fallen litter were significantly lower for 2 yrB (72 ± 2% mass remaining at the end of experiment) than for 4 yrB (59 ± 3%) and NB (62 ± 3%), a difference that may be related to effects of N limitation, lower moisture content, and/or litter C quality. Results for older mixed-age litter were similar to those for freshly fallen litter although treatment differences were less pronounced. Overall, these findings show that frequent fire (2 yrB) decoupled N and P cycling, as manifested in litter C : N : P stoichiometry and in microbial biomass N : P ratio and enzymatic activities. Furthermore, these data indicate that fire induced a transient shift to N-limited ecosystem conditions

  13. Species identities, not functional groups, explain the effects of earthworms on litter carbon-derived soil respiration

    Science.gov (United States)

    Soil respiration is frequently measured as a surrogate for biological activities and is important in soil carbon cycling. The heterotrophic component of soil respiration is primarily driven by microbial decomposition of leaf litter and soil organic matter, and is partially controlled by resource ava...

  14. Effects of litter addition and warming on soil carbon, nutrient pools and microbial communities in a subarctic heath ecosystem

    DEFF Research Database (Denmark)

    Rinnan, Riikka; Michelsen, Anders; Jonasson, Sven Evert

    2008-01-01

    Climatic warming leads to the expansion of deciduous shrubs and trees in the Arctic. This leads to higher leaf litter inputs, which together with warming may alter the rate of carbon and nutrient cycling in the arctic ecosystems. We assessed effects of factorial warming and additional litter...... on the soil ecosystem of a subarctic heath in a 7-year-long field experiment. Fine root biomass, dissolved organic carbon (DOC) and total C concentration increased in response to warming, which probably was a result of the increased vegetation cover. Litter addition increased the concentration of inorganic P...... in the uppermost 5 cm soil, while decreasing the pool of total P per unit area of the organic profile and having no significant effects on N concentrations or pools. Microbial biomass C and N were unaffected by the treatments, while the microbial biomass P increased significantly with litter addition. Soil...

  15. Association between litterers' profile and littering behavior: A chi-square approach

    Science.gov (United States)

    Asmui, Mas'udah; Zaki, Suhanom Mohd; Wahid, Sharifah Norhuda Syed; Mokhtar, Noorsuraya Mohd; Harith, Siti Suhaila

    2017-05-01

    Littering is not a novelty, yet a prolonged issue. The solutions have been discussed for a long time; however this issue still remains unresolved. Littering is commonly associated with littering behavior and awareness. The littering behavior is normally influenced by the litter profile such as gender, family income, education level and age. Jengka Street market, which is located in Pahang, is popularly known as a trade market. It offers diversities of wet and dry goods and is awaited by local residents and tourists. This study analyzes association between litterers' profile and littering behavior. Littering behavior is measured based on factors of trash bin facilities, awareness campaign and public littering behavior. 114 respondents were involved in this study with 62 (54.39%) are female aged more than 18 years old and majority of these female respondents are diploma holders. In addition, 78.95% of the respondents have family income below than RM3,000.00 per month. Based on the data analysis, it was found that first-time visitors littered higher than frequent visitors, lack of providing trash bin facilities contributes to positive littering behavior and there is a significant association between litterers' age and littering behavior by using chi-square approach.

  16. Litter input decreased the response of soil organic matter decomposition to warming in two subtropical forest soils

    Science.gov (United States)

    Wang, Qingkui; He, Tongxin; Liu, Jing

    2016-09-01

    Interaction effect of temperature and litter input on SOM decomposition is poor understood, restricting accurate prediction of the dynamics and stocks of soil organic carbon under global warming. To address this knowledge gap, we conducted an incubation experiment by adding 13C labeled leaf-litter into a coniferous forest (CF) soil and a broadleaved forest (BF) soil. In this experiment, response of the temperature sensitivity (Q10) of SOM decomposition to the increase in litter input was investigated. The temperature dependences of priming effect (PE) and soil microbial community were analyzed. The Q10 for CF soil significantly decreased from 2.41 in no-litter treatment to 2.05 in litter-added treatment and for BF soil from 2.14 to 1.82, suggesting that litter addition decreases the Q10. PE in the CF soil was 24.9% at 20 °C and 6.2% at 30 °C, and in the BF soil the PE was 8.8% at 20 °C and ‑7.0% at 30 °C, suggesting that PE decreases with increasing temperature. Relative PE was positively related to the concentrations of Gram-negative bacterial and fungal PLFAs. This study moves a step forward in understanding warming effect on forest carbon cycling by highlighting interaction effect of litter input and warming on soil carbon cycling.

  17. Litter input decreased the response of soil organic matter decomposition to warming in two subtropical forest soils

    Science.gov (United States)

    Wang, Qingkui; He, Tongxin; Liu, Jing

    2016-01-01

    Interaction effect of temperature and litter input on SOM decomposition is poor understood, restricting accurate prediction of the dynamics and stocks of soil organic carbon under global warming. To address this knowledge gap, we conducted an incubation experiment by adding 13C labeled leaf-litter into a coniferous forest (CF) soil and a broadleaved forest (BF) soil. In this experiment, response of the temperature sensitivity (Q10) of SOM decomposition to the increase in litter input was investigated. The temperature dependences of priming effect (PE) and soil microbial community were analyzed. The Q10 for CF soil significantly decreased from 2.41 in no-litter treatment to 2.05 in litter-added treatment and for BF soil from 2.14 to 1.82, suggesting that litter addition decreases the Q10. PE in the CF soil was 24.9% at 20 °C and 6.2% at 30 °C, and in the BF soil the PE was 8.8% at 20 °C and −7.0% at 30 °C, suggesting that PE decreases with increasing temperature. Relative PE was positively related to the concentrations of Gram-negative bacterial and fungal PLFAs. This study moves a step forward in understanding warming effect on forest carbon cycling by highlighting interaction effect of litter input and warming on soil carbon cycling. PMID:27644258

  18. Resource stoichiometry and availability modulate species richness and biomass of tropical litter macro-invertebrates.

    Science.gov (United States)

    Jochum, Malte; Barnes, Andrew D; Weigelt, Patrick; Ott, David; Rembold, Katja; Farajallah, Achmad; Brose, Ulrich

    2017-09-01

    High biodiversity and biomass of soil communities are crucial for litter decomposition in terrestrial ecosystems such as tropical forests. However, the leaf litter that these communities consume is of particularly poor quality as indicated by elemental stoichiometry. The impact of resource quantity, quality and other habitat parameters on species richness and biomass of consumer communities is often studied in isolation, although much can be learned from simultaneously studying both community characteristics. Using a dataset of 780 macro-invertebrate consumer species across 32 sites in tropical lowland rain forest and agricultural systems on Sumatra, Indonesia, we investigated the effects of basal resource stoichiometry (C:X ratios of N, P, K, Ca, Mg, Na, S in local leaf litter), litter mass (basal resource quantity and habitat space), plant species richness (surrogate for litter habitat heterogeneity), and soil pH (acidity) on consumer species richness and biomass across different consumer groups (i.e. 3 feeding guilds and 10 selected taxonomic groups). In order to distinguish the most important predictors of consumer species richness and biomass, we applied a standardised model averaging approach investigating the effects of basal resource stoichiometry, litter mass, plant species richness and soil pH on both consumer community characteristics. This standardised approach enabled us to identify differences and similarities in the magnitude and importance of such effects on consumer species richness and biomass. Across consumer groups, we found litter mass to be the most important predictor of both species richness and biomass. Resource stoichiometry had a more pronounced impact on consumer species richness than on their biomass. As expected, taxonomic groups differed in which resource and habitat parameters (basal resource stoichiometry, litter mass, plant species richness and pH) were most important for modulating their community characteristics. The importance

  19. LITTER DEVOLUTION AND DECOMPOSITION IN CERRADÃO AND MATA MESOFÍTICA AREAS IN ECOLOGICAL STATION OF PIRAPITINGA – MG

    Directory of Open Access Journals (Sweden)

    Rômulo Guimarães Giácomo

    2012-12-01

    Full Text Available http://dx.doi.org/10.5902/198050987549This study aimed to quantify the litter and nutrients amount and to estimate the decomposition rate in areas of mesophytic forest and ‘Cerradão’ in the Ecological Station of Pirapitinga. To evaluate litter and nutrients devolution 10 conic litter traps were randomly distributed in an area 0.1 ha in each area of study, with monthly evaluations. The litter decomposition in the areas of study was evaluated by using litter bags. The total production of litter was 2.50 and 2.92 Mg ha-1 yr-1 for mesophytic forest and ‘Cerradão’ areas, respectively. The nutrients devolution importance order was nitrogen> potassium> phosphorus. The mesophytic forest showed more homogeneous distribution of litter fall over the year and higher values of total annual litter and nutrients, the highest values were observed at the dry season. The half-life decomposition of leaf litter was equivalent between areas, about 161 days in the mesophytic forest area and 173 in ‘Cerradão’ area.

  20. Production and decomposition of forest litter fall on the Apalachicola River flood plain, Florida: Chapter B, Apalachicola River quality assessment

    Science.gov (United States)

    Elder, John F.; Cairns, Duncan J.

    1982-01-01

    Measurements of litter fall (leaves and other particulate organic material) and leaf decomposition were made on the bottom-land hardwood swamp of the Apalachicola River flood plain in 1979-80. Litter fall was collected monthly from nets located in 16 study plots. The plots represented five forest types in the swamp and levee areas of the Apalachicola River flood plain. Forty-three species of trees, vines, and other plants contributed to the total litter fall, but more than 90 percent of the leaf material originated from 12 species. Nonleaf material made up 42 percent of the total litter fall. Average litter fall was determined to be 800 grams per square meter per year, resulting in an annual deposition of 3.6 ? 105 metric tons of organic material in the 454-square-kilometer flood plain. The levee communities have less tree biomass but greater tree diversity than do swamp communities. The levee vegetation, containing less tree biomass, produces slightly more litter fall per unit of ground surface area than does the swamp vegetation. The swamps are dominated by three genera: tupelo (Nyssa), cypress (Taxodium) and ash (Fraxinus). These genera account for more than 50 percent of the total leaf fall in the flood plain, but they are the least productive, on a weight-perbiomass basis, of any of the 12 major leaf producers. Decomposition rates of leaves from five common floodplain tree species were measured using a standard leaf-bag technique. Leaf decomposition was highly species dependent. Tupelo (Nyssa spp.) and sweetgum (Liquidambar styraciflua) leaves decomposed completely in 6 months when flooded by river water. Leaves of baldcypress (Taxodium distichum) and diamond-leaf oak (Quercus laurifolia) were much more resistant. Water hickory (Carya aquatica) leaves showed intermediate decomposition rates. Decomposition of all species was greatly reduced in dry environments. Carbon and biomass loss rates from the leaves were nearly linear over a 6-month period, but nitrogen

  1. A Greener Arctic: Vascular Plant Litter Input in Subarctic Peat Bogs Changes Soil Invertebrate Diets and Decomposition Patterns

    Science.gov (United States)

    Krab, E. J.; Berg, M. P.; Aerts, R.; van Logtestijn, R. S. P.; Cornelissen, H. H. C.

    2014-12-01

    Climate-change-induced trends towards shrub dominance in subarctic, moss-dominated peatlands will most likely have large effects on soil carbon (C) dynamics through an input of more easily decomposable litter. The mechanisms by which this increase in vascular litter input interacts with the abundance and diet-choice of the decomposer community to alter C-processing have, however, not yet been unraveled. We used a novel 13C tracer approach to link invertebrate species composition (Collembola), abundance and species-specific feeding behavior to C-processing of vascular and peat moss litters. We incubated different litter mixtures, 100% Sphagnum moss litter, 100% Betula leaf litter, and a 50/50 mixture of both, in mesocosms for 406 days. We revealed the transfer of C from the litters to the soil invertebrate species by 13C labeling of each of the litter types and assessed 13C signatures of the invertebrates Collembola species composition differed significantly between Sphagnum and Betula litter. Within the 'single type litter' mesocosms, Collembola species showed different 13C signatures, implying species-specific differences in diet choice. Surprisingly, the species composition and Collembola abundance changed relatively little as a consequence of Betula input to a Sphagnum based system. Their diet choice, however, changed drastically; species-specific differences in diet choice disappeared and approximately 67% of the food ingested by all Collembola originated from Betula litter. Furthermore, litter decomposition patterns corresponded to these findings; mass loss of Betula increased from 16.1% to 26.2% when decomposing in combination with Sphagnum, while Sphagnum decomposed even slower in combination with Betula litter (1.9%) than alone (4.7%). This study is the first to empirically show that collective diet shifts of the peatland decomposer community from mosses towards vascular plant litter may drive altered decomposition patterns. In addition, we showed that

  2. Cigarette litter: smokers' attitudes and behaviors.

    Science.gov (United States)

    Rath, Jessica M; Rubenstein, Rebecca A; Curry, Laurel E; Shank, Sarah E; Cartwright, Julia C

    2012-06-01

    Cigarette butts are consistently the most collected items in litter clean-up efforts, which are a costly burden to local economies. In addition, tobacco waste may be detrimental to our natural environment. The tobacco industry has conducted or funded numerous studies on smokers' littering knowledge and behavior, however, non-industry sponsored research is rare. We sought to examine whether demographics and smokers' knowledge and beliefs toward cigarette waste as litter predicts littering behavior. Smokers aged 18 and older (n = 1,000) were interviewed about their knowledge and beliefs towards cigarette waste as litter. Respondents were members of the Research Now panel, an online panel of over three million respondents in the United States. Multivariate logistic regressions were conducted to determine factors significantly predictive of ever having littered cigarette butts or having littered cigarette butts within the past month (p-value littered cigarette butts at least once in their life, by disposing of them on the ground or throwing them out of a car window. Over half (55.7%) reported disposing of cigarette butts on the ground, in a sewer/gutter, or down a drain in the past month. Those who did not consider cigarette butts to be litter were over three and half times as likely to report having ever littered cigarette butts (OR = 3.68, 95%CI = 2.04, 6.66) and four times as likely to have littered cigarette butts in the past month (OR = 4.00, 95%CI = 2.53, 6.32). Males were significantly more likely to have littered cigarette butts in the past month compared to females (OR = 1.49, 95%CI = 1.14, 1.94). Holding the belief that cigarette butts are not litter was the only belief in this study that predicted ever or past-month littering of cigarette waste. Messages in anti-cigarette-litter campaigns should emphasize that cigarette butts are not just litter but are toxic waste and are harmful when disposed of improperly.

  3. Cigarette Litter: Smokers’ Attitudes and Behaviors

    Directory of Open Access Journals (Sweden)

    Julia C. Cartwright

    2012-06-01

    Full Text Available Cigarette butts are consistently the most collected items in litter clean-up efforts, which are a costly burden to local economies. In addition, tobacco waste may be detrimental to our natural environment. The tobacco industry has conducted or funded numerous studies on smokers’ littering knowledge and behavior, however, non-industry sponsored research is rare. We sought to examine whether demographics and smokers’ knowledge and beliefs toward cigarette waste as litter predicts littering behavior. Smokers aged 18 and older (n = 1,000 were interviewed about their knowledge and beliefs towards cigarette waste as litter. Respondents were members of the Research Now panel, an online panel of over three million respondents in the United States. Multivariate logistic regressions were conducted to determine factors significantly predictive of ever having littered cigarette butts or having littered cigarette butts within the past month (p-value < 0.05. The majority (74.1% of smokers reported having littered cigarette butts at least once in their life, by disposing of them on the ground or throwing them out of a car window. Over half (55.7% reported disposing of cigarette butts on the ground, in a sewer/gutter, or down a drain in the past month. Those who did not consider cigarette butts to be litter were over three and half times as likely to report having ever littered cigarette butts (OR = 3.68, 95%CI = 2.04, 6.66 and four times as likely to have littered cigarette butts in the past month (OR = 4.00, 95%CI = 2.53, 6.32. Males were significantly more likely to have littered cigarette butts in the past month compared to females (OR = 1.49, 95%CI = 1.14, 1.94. Holding the belief that cigarette butts are not litter was the only belief in this study that predicted ever or past-month littering of cigarette waste. Messages in anti-cigarette-litter campaigns should emphasize that cigarette butts are not just litter but are toxic

  4. Litter dominates surface fluxes of carbonyl sulfide in a Californian oak woodland

    OpenAIRE

    Sun, Wu; Maseyk, Kadmiel; Lett, Céline; Seibt, Ulli

    2016-01-01

    Carbonyl sulfide (COS) is a promising tracer for partitioning terrestrial photosynthesis and respiration from net carbon fluxes, based on its daytime co-uptake alongside CO2 through leaf stomata. Because ecosystem COS fluxes are the sum of plant and soil fluxes, using COS as a photosynthesis tracer requires accurate knowledge of soil COS fluxes. At an oak woodland in Southern California, we monitored below-canopy surface (soil + litter) COS and CO2 fluxes for 40 days using chambers and laser ...

  5. Effect of leaf type and pesticide exposure on abundance of bacterial taxa in mosquito larval habitats.

    Directory of Open Access Journals (Sweden)

    Ephantus J Muturi

    Full Text Available Lentic freshwater systems including those inhabited by aquatic stages of mosquitoes derive most of their carbon inputs from terrestrial organic matter mainly leaf litter. The leaf litter is colonized by microbial communities that provide the resource base for mosquito larvae. While the microbial biomass associated with different leaf species in container aquatic habitats is well documented, the taxonomic composition of these microbes and their response to common environmental stressors is poorly understood. We used indoor aquatic microcosms to determine the abundances of major taxonomic groups of bacteria in leaf litters from seven plant species and their responses to low concentrations of four pesticides with different modes of action on the target organisms; permethrin, malathion, atrazine and glyphosate. We tested the hypotheses that leaf species support different quantities of major taxonomic groups of bacteria and that exposure to pesticides at environmentally relevant concentrations alters bacterial abundance and community structure in mosquito larval habitats. We found support for both hypotheses suggesting that leaf litter identity and chemical contamination may alter the quality and quantity of mosquito food base (microbial communities in larval habitats. The effect of pesticides on microbial communities varied significantly among leaf types, suggesting that the impact of pesticides on natural microbial communities may be highly complex and difficult to predict. Collectively, these findings demonstrate the potential for detritus composition within mosquito larval habitats and exposure to pesticides to influence the quality of mosquito larval habitats.

  6. Litter composition effects on decomposition across the litter-soil interface

    Science.gov (United States)

    Background/Question/Methods Many studies have investigated the influence of plant litter species composition on decomposition dynamics, but given the variety of communities and environments around the world, a variety of consequences of litter-mixing have been reported. Litter ...

  7. McDonald's Litter Hunt: A Community Litter Control System for Youth.

    Science.gov (United States)

    McNees, M. Patrick; And Others

    1979-01-01

    Describes a community litter control program. Special adhesive stickers were randomly placed on existing litter throughout a community and youth were rewarded with special prizes for participating in the program. Litter was reduced 32 percent across the city. (Author/MA)

  8. Population Dynamics of the Rubber Plantation Litter Beetle Luprops tristis, in Relation to Annual Cycle of Foliage Phenology of Its Host, the Para Rubber Tree, Hevea brasiliensis

    Science.gov (United States)

    Sabu, Thomas K.; Vinod, K.V.

    2009-01-01

    The population dynamics of the rubber plantation litter beetle, Luprops tristis Fabricius 1801 (Coleoptera: Tenebrionidae) was assessed in relation to the phenology of leaf shedding and defoliation pattern of para rubber trees, Hevea brasiliensis Müll. Arg (Malpighiales: Euphorbiaceae), during a two year study period. The abundance of adults, larvae and pupae per 1m2 of litter sample was recorded. Post dormancy beetles appeared in leaf litter following annual leaf shedding, whereas larvae, pupae and teneral adults were present after leaf flush. No stages were recorded from plantations following the summer rains until the annual litter fall in the next season. Parental adults peaked at the time of leaf sprouting and tender leaf fall. Larvae and teneral adults peaked at the time of premature fall of green leaves and flowers. Teneral adults of six age classes were recorded and all entered dormancy irrespective of the feeding time available to each age class. Females outnumbered males in the parent generation, while the sex ratio of new generation adults was not biased towards either sex. The phenological stages of rubber trees included leaf fall in late December and early January, leaf sprouting and new leaf production in January and flowering in February. All feeding stages of L. tristis peaked in abundance when premature leaves are most abundant in the leaf litter. Prediction of the timing of appearance of various developmental stages of L. tristis in plantations, invasion into buildings and intensity of population build up in rubber belts is possible by tracking the phenology of leaf fall in rubber plantations, time of return of post dormancy adults and the onset of summer rainfall. Perfect synchrony was recorded between the field return of parental adults with annual leaf shedding, the oviposition phase of parental adults with tender leaf fall at the time of leaf sprouting, and larval and teneral adult stages with premature fall of leaves. Premature leaf

  9. Nutrient and Litter Patterns in Three Subalpine Coniferous Forests of Western Sichuan, China

    Institute of Scientific and Technical Information of China (English)

    LIN Bo; LIU Qing; WU Yan; HE Hai

    2006-01-01

    Investigations were conducted to quantify litterfall, and litter and nutrient accumulation in forest floor, and to acquire information on litter decomposition and nitrogen and phosphorus-release patterns in three different subalpine coniferous forests, a plantation (Pl), a secondary forest (SF), and a primitive forest (PF), in western Sichuan, China. The litter trap method was used to evaluate litterfall with the litterbag method being utilized for litterdecomposition. Seasonal patterns of litterfall were similar in the three forests, with two peaks occurring in September-November and March-May. The plantation revealed an annual litterfall of 4.38 × 103 kg ha-1, which was similar to those of SF and PF, but Pl had a lower mass loss rate and a higher C/N ratio. The C/N ratio may be a sound predictor for the decomposition differences. N concentrations of leaf litter in both the secondary forest and primitive forest increased first and then decreased, and the percentages of their final/initial values were 108.9% and 99.9%, respectively. P concentration in the three forests increased by the end of the study. The results of litterfall and decomposition indicated that in the plantation the potential to provide nutrients for soil organic matter was similar to those of SF and PF; however, its slower decomposition rate could result in a somewhat transient accumulation of litter in the forest floor.

  10. Low Nitrogen Retention in Soil and Litter under Conditions without Plants in a Subtropical Pine Plantation

    Directory of Open Access Journals (Sweden)

    Yanmei Xiong

    2015-07-01

    Full Text Available Soil acts as a major sink for added nitrogen (N in forests, but it remains unclear about the capacity of soil to immobilize N under conditions without plant roots and whether added N interacts with ecosystem N to affect N retention. We added 15NH415NO3 to in situ soil columns (with leaching and leaf litter (without leaching of two tree species in a subtropical Pinus elliottii plantation. Soil and litter were collected three or eight months after N addition to measure concentrations of indigenous and exogenous N. About 70% of exogenous N was retained in soil three months after N addition, of which 65.9% were in inorganic forms. Eight months after N addition, 16.0% of exogenous N was retained in soil and 9.8%–13.6% was immobilized in litter. N addition increased the mineral release and nitrification of soil indigenous N. Loss of litter indigenous N was also increased by N addition. Our results suggest that N deposition on lands with low root activities or low soil carbon (C contents may lead to increased N output due to low N immobilization. Moreover, the effects of added N on ecosystem indigenous N may decrease the capacity of soil and litter in N retention.

  11. Some Sensitivity Studies of Chemical Transport Simulated in Models of the Soil-Plant-Litter System

    Energy Technology Data Exchange (ETDEWEB)

    Begovich, C.L.

    2002-10-28

    Fifteen parameters in a set of five coupled models describing carbon, water, and chemical dynamics in the soil-plant-litter system were varied in a sensitivity analysis of model response. Results are presented for chemical distribution in the components of soil, plants, and litter along with selected responses of biomass, internal chemical transport (xylem and phloem pathways), and chemical uptake. Response and sensitivity coefficients are presented for up to 102 model outputs in an appendix. Two soil properties (chemical distribution coefficient and chemical solubility) and three plant properties (leaf chemical permeability, cuticle thickness, and root chemical conductivity) had the greatest influence on chemical transport in the soil-plant-litter system under the conditions examined. Pollutant gas uptake (SO{sub 2}) increased with change in plant properties that increased plant growth. Heavy metal dynamics in litter responded to plant properties (phloem resistance, respiration characteristics) which induced changes in the chemical cycling to the litter system. Some of the SO{sub 2} and heavy metal responses were not expected but became apparent through the modeling analysis.

  12. Some sensitivity studies of chemical transport simulated in models of the soil-plant-litter system

    Energy Technology Data Exchange (ETDEWEB)

    Begovich, C.L.; Luxmoore, R.J.

    1979-09-01

    Fifteen parameters in a set of five coupled models describing carbon, water, and chemical dynamics in the soil-plant-litter system were varied in a sensitivity analysis of model response. Results are presented for chemical distribution in the components of soil, plants, and litter along with selected responses of biomass, internal chemical transport (xylem and phloem pathways), and chemical uptake. Response and sensitivity coefficients are presented for up to 102 model outputs in an appendix. Two soil properties (chemical distribution coefficient and chemical solubility) and three plant properties (leaf chemical permeability, cuticle thickness, and root chemical conductivity) had the greatest influence on chemical transport in the soil-plant-litter system under the conditions examined. Pollutant gas uptake (SO/sub 2/) increased with change in plant properties that increased plant growth. Heavy metal dynamics in litter responded to plant properties (phloem resistance, respiration characteristics) which induced changes in the chemical cycling to the litter system. Some of the SO/sub 2/ and heavy metal responses were not expected but became apparent through the modeling analysis.

  13. Broiler house litter sampling: the final frontier

    Science.gov (United States)

    Today, the sustainability of broiler operations reaches beyond the need for litter nutrient management plans that came to the forefront of the industry’s attention in the last fifteen years. Thorough characterization of litter within houses provides the basis for emission models to benefit growers,...

  14. Characteristics of fresh leaf litter-derived dissolved organic matter and its capacity to enhance the apparent water solubility of phenanthrene%森林新近凋落叶溶出DOM的性质及其对菲增溶作用的影响

    Institute of Scientific and Technical Information of China (English)

    雷秋霜; 杨秀虹; 方志文; 王诗忠; 赵云; 仇荣亮

    2014-01-01

    logKDOC and specific UV absorption values at 254 nm and 280 nm (SUV-A280, SUV-A254), and between logKDOC and the relative contents of SS and SP, while significant negative correlations (p<0.01) were found between logKDOC and the values of A240/A420 and A254/A400. This implies that leaf litter-derived DOM with more aromatic structures, higher molecular weight and higher proportions of SS and SP, tends to hold a greater capacity to enhance phenanthrene solubility.

  15. Evaluation of leaf removal as a means to reduce nutrient concentrations and loads in urban stormwater.

    Science.gov (United States)

    Selbig, William R

    2016-11-15

    While the sources of nutrients to urban stormwater are many, the primary contributor is often organic detritus, especially in areas with dense overhead tree canopy. One way to remove organic detritus before it becomes entrained in runoff is to implement a city-wide leaf collection and street cleaning program. Improving our knowledge of the potential reduction of nutrients to stormwater through removal of leaves and other organic detritus on streets could help tailor more targeted municipal leaf collection programs. This study characterized an upper ideal limit in reductions of total and dissolved forms of phosphorus and nitrogen in stormwater through implementation of a municipal leaf collection and street cleaning program in Madison, WI, USA. Additional measures were taken to remove leaf litter from street surfaces prior to precipitation events. Loads of total and dissolved phosphorus were reduced by 84 and 83% (premoval program. Without leaf removal, 56% of the annual total phosphorus yield (winter excluded) was due to leaf litter in the fall compared to 16% with leaf removal. Despite significant reductions in load, total nitrogen showed only minor changes in fall yields without and with leaf removal at 19 and 16%, respectively. The majority of nutrient concentrations were in the dissolved fraction making source control through leaf removal one of the few treatment options available to environmental managers when reducing the amount of dissolved nutrients in stormwater runoff. Subsequently, the efficiency, frequency, and timing of leaf removal and street cleaning are the primary factors to consider when developing a leaf management program.

  16. Effects of Nitrogen Addition on Litter Decomposition and CO2 Release: Considering Changes in Litter Quantity.

    Science.gov (United States)

    Li, Hui-Chao; Hu, Ya-Lin; Mao, Rong; Zhao, Qiong; Zeng, De-Hui

    2015-01-01

    This study aims to evaluate the impacts of changes in litter quantity under simulated N deposition on litter decomposition, CO2 release, and soil C loss potential in a larch plantation in Northeast China. We conducted a laboratory incubation experiment using soil and litter collected from control and N addition (100 kg ha-1 year-1 for 10 years) plots. Different quantities of litter (0, 1, 2 and 4 g) were placed on 150 g soils collected from the same plots and incubated in microcosms for 270 days. We found that increased litter input strongly stimulated litter decomposition rate and CO2 release in both control and N fertilization microcosms, though reduced soil microbial biomass C (MBC) and dissolved inorganic N (DIN) concentration. Carbon input (C loss from litter decomposition) and carbon output (the cumulative C loss due to respiration) elevated with increasing litter input in both control and N fertilization microcosms. However, soil C loss potentials (C output-C input) reduced by 62% in control microcosms and 111% in N fertilization microcosms when litter addition increased from 1 g to 4 g, respectively. Our results indicated that increased litter input had a potential to suppress soil organic C loss especially for N addition plots.

  17. Imidacloprid in leaves from systemically treated trees may inhibit litter breakdown by non-target invertebrates.

    Science.gov (United States)

    Kreutzweiser, David P; Thompson, Dean G; Scarr, Taylor A

    2009-05-01

    Imidacloprid is a systemic insecticide that is used in trees to control several invasive, wood-boring insect pests in North America. Applications to deciduous trees result in foliar concentrations of imidacloprid that could pose a risk of harm to non-target decomposer invertebrates when autumn-shed leaves fall to forest floors or adjacent water bodies. Selection experiments were conducted in aquatic and terrestrial microcosms to test the hypothesis that non-target, leaf-shredding invertebrates can detect and avoid leaves from imidacloprid-treated trees thereby circumventing effects on leaf litter decomposition. There was no significant preferential feeding on non-contaminated leaves in selection microcosms indicating that the invertebrates could not detect and avoid imidacloprid-containing leaves. Mass loss and area consumed of both imidacloprid-containing and natural leaves in selection microcosms were significantly less than in control microcosms, indicating a sub-lethal feeding inhibition effect from consumption of leaf material at realistic field concentrations of 18-30microg/g fresh weight. Our results indicate that imidacloprid at realistic concentrations in leaves can inhibit leaf litter breakdown through adverse sub-lethal effects on decomposer invertebrates.

  18. The Litter Problem. Environmental Education Supplementary Instructional Guide, Elementary Level.

    Science.gov (United States)

    Hawaii State Dept. of Education, Honolulu. Office of Instructional Services.

    Presented is a guide for helping elementary school students become aware of the litter problem, acquire litter control skills, and develop an anti-litter ethic. The manual contains a hierarchy of learning objectives, a pretest/posttest instrument, background information on litter, and 12 lessons designed to promote attainment of the learning…

  19. The Litter Problem. Environmental Education Supplementary Instructional Guide, Secondary Level.

    Science.gov (United States)

    Hawaii State Dept. of Education, Honolulu. Office of Instructional Services.

    Presented is a guide for helping secondary school students investigate the litter problem, acquire litter control skills, and develop an anti-litter ethic. The manual contains a hierarchy of learning objectives, a pretest/posttest, background information on litter, and activities keyed to the learning objectives. Each lesson includes brief…

  20. An Approach to Litter Generation and Littering Practices in a Mexico City Neighborhood

    Directory of Open Access Journals (Sweden)

    Cecilia E. Muñoz-Cadena

    2012-08-01

    Full Text Available Urban litter is generated by human societies everywhere. Some litter is recyclable waste. In this study, the acronym RMSW is used to refer to recyclable municipal solid waste generated in streets. Public attitude towards RMSW generation, generators’ perceptions, and quantification of RMSW in streets were examined in a Mexico City neighborhood, where litter presence causes major environmental problems affecting the population year after year. Interviews with neighborhood residents and item counts were carried out from 2010 to 2011. In all, 58% of interviewees reported generating RMSW at variable frequencies while 42% said they did not generate this kind of waste. Laziness, lack of vigilance by municipal authorities, no litter bins in streets, and imitation were the main causes identified by interviewees as reasons for littering. Potential litter generators may be of any age, educational level or income. Interviewees’ perception of RMSW generation was compared with item counts in the neighborhood studied.

  1. Litter quality mediated nitrogen effect on plant litter decomposition regardless of soil fauna presence.

    Science.gov (United States)

    Zhang, Weidong; Chao, Lin; Yang, Qingpeng; Wang, Qingkui; Fang, Yunting; Wang, Silong

    2016-10-01

    Nitrogen addition has been shown to affect plant litter decomposition in terrestrial ecosystems. The way that nitrogen deposition impacts the relationship between plant litter decomposition and altered soil nitrogen availability is unclear, however. This study examined 18 co-occurring litter types in a subtropical forest in China in terms of their decomposition (1 yr of exposure in the field) with nitrogen addition treatment (0, 0.4, 1.6, and 4.0 mol·N·m(-2) ·yr(-1) ) and soil fauna exclusion (litter bags with 0.1 and 2 cm mesh size). Results showed that the plant litter decomposition rate is significantly reduced because of nitrogen addition; the strength of the nitrogen addition effect is closely related to the nitrogen addition levels. Plant litters with diverse quality responded to nitrogen addition differently. When soil fauna was present, the nitrogen addition effect on medium-quality or high-quality plant litter decomposition rate was -26% ± 5% and -29% ± 4%, respectively; these values are significantly higher than that of low-quality plant litter decomposition. The pattern is similar when soil fauna is absent. In general, the plant litter decomposition rate is decreased by soil fauna exclusion; an average inhibition of -17% ± 1.5% was exhibited across nitrogen addition treatment and litter quality groups. However, this effect is weakly related to nitrogen addition treatment and plant litter quality. We conclude that the variations in plant litter quality, nitrogen deposition, and soil fauna are important factors of decomposition and nutrient cycling in a subtropical forest ecosystem.

  2. [Litter decomposition and nutrient release in Acacia mangium plantations established on degraded soils of Colombia].

    Science.gov (United States)

    Castellanos-Barliza, Jeiner; León Peláez, Juan Diego

    2011-03-01

    Several factors control the decomposition in terrestrial ecosystems such as humidity, temperature, quality of litter and microbial activity. We investigated the effects of rainfall and soil plowing prior to the establishment of Acacia mangium plantations, using the litterbag technique, during a six month period, in forests plantations in Bajo Cauca region, Colombia. The annual decomposition constants (k) of simple exponential model, oscillated between 1.24 and 1.80, meanwhile k1 y k2 decomposition constants of double exponential model were 0.88-1.81 and 0.58-7.01. At the end of the study, the mean residual dry matter (RDM) was 47% of the initial value for the three sites. We found a slow N, Ca and Mg release pattern from the A. mangium leaf litter, meanwhile, phosphorus (P) showed a dominant immobilization phase, suggesting its low availability in soils. Chemical leaf litter quality parameters (e.g. N and P concentrations, C/N, N/P ratios and phenols content) showed an important influence on decomposition rates. The results of this study indicated that rainfall plays an important role on the decomposition process, but not soil plowing.

  3. Home-field advantages of litter decomposition increase with increasing N deposition rates: a litter and soil perspective

    NARCIS (Netherlands)

    Li, Y.; Li, Q.; Yang, J.; Xiaotao, L.; Liang, W.; Han, X.; Bezemer, T.M.

    2017-01-01

    1.Differences in litter quality and in soil microbial community composition can influence the litter decomposition and “home-field advantage” (HFA). However, our knowledge about the relative role of litter and soil characteristics on litter decomposition and HFA effects is still limited, especially

  4. Effects of litter manipulation on litter decomposition in a successional gradients of tropical forests in southern China

    DEFF Research Database (Denmark)

    Chen, Hao; Gurmesa, Geshere A.; Liu, Lei;

    2014-01-01

    Global changes such as increasing CO2, rising temperature, and land-use change are likely to drive shifts in litter inputs to forest floors, but the effects of such changes on litter decomposition remain largely unknown. We initiated a litter manipulation experiment to test the response of litter...

  5. Can't See the Wood for the Litter: Evaluation of Litter Behavior Modification in a Forest

    Science.gov (United States)

    Lindemann-Matthies, Petra; Bonigk, Isabel; Benkowitz, Dorothee

    2012-01-01

    This study investigated elementary school children's (n = 171) litter behavior during guided forest tours following two different treatments. Four classes received a verbal appeal not to litter in the forest, while another four classes received both a verbal appeal and a demonstration of the desired litter behavior (picking up litter, putting it…

  6. Can't See the Wood for the Litter: Evaluation of Litter Behavior Modification in a Forest

    Science.gov (United States)

    Lindemann-Matthies, Petra; Bonigk, Isabel; Benkowitz, Dorothee

    2012-01-01

    This study investigated elementary school children's (n = 171) litter behavior during guided forest tours following two different treatments. Four classes received a verbal appeal not to litter in the forest, while another four classes received both a verbal appeal and a demonstration of the desired litter behavior (picking up litter, putting it…

  7. No Litter Will Make a Better Place.

    Science.gov (United States)

    Rodgers, Amy

    1987-01-01

    Describes a community anti-litter campaign developed by second grades, involving letter writing, dramatics, photography, and the creation of posters and a videotape. Identifies skills from the Kentucky Essential Skills list that were taught by the project. (SV)

  8. Arst on patsiendi poolel / Galina Litter

    Index Scriptorium Estoniae

    Litter, Galina, 1956-

    2006-01-01

    Naistearst Galina Litter seadusest, mis lubab alaealistel ilma vanema nõusolekuta aborti teha. Vastus artiklile : Varro Vooglaid. Vanemate vastutus - kas reaalne või paljasõnaline? // Õpetajate Leht (2006) 13. okt., lk. 1, 7

  9. Arst on patsiendi poolel / Galina Litter

    Index Scriptorium Estoniae

    Litter, Galina, 1956-

    2006-01-01

    Naistearst Galina Litter seadusest, mis lubab alaealistel ilma vanema nõusolekuta aborti teha. Vastus artiklile : Varro Vooglaid. Vanemate vastutus - kas reaalne või paljasõnaline? // Õpetajate Leht (2006) 13. okt., lk. 1, 7

  10. Linear loss of litter over time, 2015

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This table contains data on dry mass remaining in a subset of Salicornia pacifica and Deschampsia cespitosa litter bags removed over a series of time points spanning...

  11. Arbuscular mycorrhiza enhance the rate of litter decomposition while inhibiting soil microbial community development.

    Science.gov (United States)

    Gui, Heng; Hyde, Kevin; Xu, Jianchu; Mortimer, Peter

    2017-02-08

    Although there is a growing amount of evidence that arbuscular mycorrhizal fungi (AMF) influence the decomposition process, the extent of their involvement remains unclear. Therefore, given this knowledge gap, our aim was to test how AMF influence the soil decomposer communities. Dual compartment microcosms, where AMF (Glomus mosseae) were either allowed access (AM+) to or excluded (AM-) from forest soil compartments containing litterbags (leaf litter from Calophyllum polyanthum) were used. The experiment ran for six months, with destructive harvests at 0, 90, 120, 150, and 180 days. For each harvest we measured AMF colonization, soil nutrients, litter mass loss, and microbial biomass (using phospholipid fatty acid analysis (PLFA)). AMF significantly enhanced litter decomposition in the first 5 months, whilst delaying the development of total microbial biomass (represented by total PLFA) from T150 to T180. A significant decline in soil available N was observed through the course of the experiment for both treatments. This study shows that AMF have the capacity to interact with soil microbial communities and inhibit the development of fungal and bacterial groups in the soil at the later stage of the litter decomposition (180 days), whilst enhancing the rates of decomposition.

  12. Arbuscular mycorrhiza enhance the rate of litter decomposition while inhibiting soil microbial community development

    Science.gov (United States)

    Gui, Heng; Hyde, Kevin; Xu, Jianchu; Mortimer, Peter

    2017-01-01

    Although there is a growing amount of evidence that arbuscular mycorrhizal fungi (AMF) influence the decomposition process, the extent of their involvement remains unclear. Therefore, given this knowledge gap, our aim was to test how AMF influence the soil decomposer communities. Dual compartment microcosms, where AMF (Glomus mosseae) were either allowed access (AM+) to or excluded (AM−) from forest soil compartments containing litterbags (leaf litter from Calophyllum polyanthum) were used. The experiment ran for six months, with destructive harvests at 0, 90, 120, 150, and 180 days. For each harvest we measured AMF colonization, soil nutrients, litter mass loss, and microbial biomass (using phospholipid fatty acid analysis (PLFA)). AMF significantly enhanced litter decomposition in the first 5 months, whilst delaying the development of total microbial biomass (represented by total PLFA) from T150 to T180. A significant decline in soil available N was observed through the course of the experiment for both treatments. This study shows that AMF have the capacity to interact with soil microbial communities and inhibit the development of fungal and bacterial groups in the soil at the later stage of the litter decomposition (180 days), whilst enhancing the rates of decomposition. PMID:28176855

  13. Water addition, evaporation and water holding capacity of poultry litter.

    Science.gov (United States)

    Dunlop, Mark W; Blackall, Patrick J; Stuetz, Richard M

    2015-12-15

    Litter moisture content has been related to ammonia, dust and odour emissions as well as bird health and welfare. Improved understanding of the water holding properties of poultry litter as well as water additions to litter and evaporation from litter will contribute to improved litter moisture management during the meat chicken grow-out. The purpose of this paper is to demonstrate how management and environmental conditions over the course of a grow-out affect the volume of water A) applied to litter, B) able to be stored in litter, and C) evaporated from litter on a daily basis. The same unit of measurement has been used to enable direct comparison-litres of water per square metre of poultry shed floor area, L/m(2), assuming a litter depth of 5cm. An equation was developed to estimate the amount of water added to litter from bird excretion and drinking spillage, which are sources of regular water application to the litter. Using this equation showed that water applied to litter from these sources changes over the course of a grow-out, and can be as much as 3.2L/m(2)/day. Over a 56day grow-out, the total quantity of water added to the litter was estimated to be 104L/m(2). Litter porosity, water holding capacity and water evaporation rates from litter were measured experimentally. Litter porosity decreased and water holding capacity increased over the course of a grow-out due to manure addition. Water evaporation rates at 25°C and 50% relative humidity ranged from 0.5 to 10L/m(2)/day. Evaporation rates increased with litter moisture content and air speed. Maintaining dry litter at the peak of a grow-out is likely to be challenging because evaporation rates from dry litter may be insufficient to remove the quantity of water added to the litter on a daily basis.

  14. EFFECTS OF SOIL FAUNA ON LITTER DECOMPOSITION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Forest litter is the physical makeup part of forest ecosystem. The rate of decomposition of forest litter is low in temperate and cool temperate zones. There is important significance to search and utilize the function of soil animals, in order to probe the material circulation and energy flow in forest ecosystem. We selected three kinds of mesh bag with different mesh size, in which, large pore mesh bag is large enough to permit the activities of all kinds of soil animals, medium mesh bag is designed to exclude the function of soil macrofauna, while small mesh bag is small enough to exclude the effects of any kind of soil animals as far as possible. The decomposition time is three years. The studying results show that: the decomposing speed of the bags with big meshes, under functions of all kinds of soil animals, faster than the bags with medium meshes, under functions of medium and small soil animals, as well as the bags with small meshes that excluding all possibility of functions of soil animals; in the process of decomposition of litter, relationship of the litter lost weight with number of soil animals is not obvious clearly; the degree of functions of soil animals to soft litter higher than hard litter; according to the analysis of diversity index, no regular changes will happen to the diversity of soil animals as the time of decomposing samples lengthen.

  15. Leaf Litterfall and Decomposition of Polylepis reticulata in the Treeline of the Ecuadorian Andes

    Directory of Open Access Journals (Sweden)

    Juan Pinos

    2017-02-01

    Full Text Available Leaf litterfall contributes significantly to carbon fluxes in forests. A crucial open question for the sustainability of mountain forests is how climate change will affect this and other carbon fluxes (eg photosynthesis and respiration. Leaf litterfall and decomposition of Polylepis reticulata, an endemic species of the Andes, were analyzed during a period of 1 year at 6 experimental plots located in the Andean páramo between 3700 and 3900 m above sea level in Cajas National Park, Ecuador. Litterfall was collected in each plot using 5 randomly distributed traps. Every trap had a 40-cm diameter (0.125 m2 and was suspended 0.8 to 1.0 m above the ground. The decomposition rate of the leaf litter was analyzed using litter bags. Eighteen bags with approximately 20 g of dry litter were placed in the litter layer in each experimental plot and collected 30, 60, 90, 150, 210, 300, and 365 days after they were installed. The mean annual litterfall recorded was 3.77 Mg ha−1, representing 51% of the leaf biomass present in the canopy, so the leaf life span of P. reticulata in Cajas National Park is 1.98 years. Litterfall occurred all year, with no significant seasonal pattern. The mean decomposition rate (k obtained for this study period was 0.38 year−1. This study contributes to the information gap on litterfall and decomposition in natural forests located at the highest elevations in the world.

  16. Litterfall and Leaf Area Index in the CONECOFOR Permanent Monitoring Plots

    Directory of Open Access Journals (Sweden)

    Andrea CUTINI

    2002-09-01

    Full Text Available Forest canopies are more sensitive and react more promptly to abiotic and biotic disturbances than other stand structural components. Monitoring crown and canopy characteristics is therefore a crucial issue for intensive and continuous monitoring programs of forest ecosystem status. These observations formed the basis for the measurement of annual litter production and leaf area index (LAI in the Italian permanent monitoring plots (CONECOFOR program established within the EC-UN/ECE program "Intensive Monitoring (Level II of Forest Ecosystems". Preliminary results after three years of observation are presented. The low value of within plot mean relative standard deviation (20.8 ± 1.9% of litter production, which in any case never exceeded 30%, accounted for the good sampling error and accuracy of the chosen method, which seems to be accurate enough to detect changes in litter production through the years. The higher inconsistency of the amount of woody and fruits fractions over the years demonstrated the greater reliability of leaf fraction or, on the other hand, of LAI compared to total litter. Mean values of annual leaf-litter and total litter production and LAI were rather high in comparison with data reported in literature for similar stands, and reflected both a medium-high productivity and a juvenile phase in the development of the selected stands on average. Focusing on changes in litter production through the years, statistical analysis on a sub-sample of plots showed the existence of significant differences both in leaf litter and total litter production. These findings seem to attribute to the "year" factor a driving role in determining changes in litter production and LAI. Temporal intermittence in data collection, together with the shortness of the monitoring period, make it difficult to speculate or arrive at definitive conclusions on changes in litter production due to time-dependent factors. The importance of having a complete

  17. DNA barcoding survey of Trichoderma diversity in soil and litter of the Colombian lowland Amazonian rainforest reveals Trichoderma strigosellum sp. nov. and other species

    NARCIS (Netherlands)

    Lopez-Quintero, C.A.; Atanasova, L.; Franco-Molano, A.E.; Gams, W.; Komon-Zelazowska, M.; Theelen, B.; Muller, W.H.; Boekhout, T.; Druzhinina, I.

    2013-01-01

    The diversity of Trichoderma (Hypocreales, Ascomycota) colonizing leaf litter as well as the rhizosphere of Garcinia macrophylla (Clusiaceae) was investigated in primary and secondary rain forests in Colombian Amazonia. DNA barcoding of 107 strains based on the internal transcribed spacers 1 and 2 (

  18. DNA barcoding survey of Trichoderma diversity in soil and litter of the Colombian lowland Amazonian rainforest reveals Trichoderma strigosellum sp. nov. and other species

    NARCIS (Netherlands)

    Lopez-Quintero, C.A.; Atanasova, L.; Franco-Molano, A.E.; Gams, W.; Komon-Zelazowska, M.; Theelen, B.; Muller, W.H.; Boekhout, T.; Druzhinina, I.

    2013-01-01

    The diversity of Trichoderma (Hypocreales, Ascomycota) colonizing leaf litter as well as the rhizosphere of Garcinia macrophylla (Clusiaceae) was investigated in primary and secondary rain forests in Colombian Amazonia. DNA barcoding of 107 strains based on the internal transcribed spacers 1 and 2

  19. A canopy trimming experiment in Puerto Rico: The response of litter decomposition and nutrient release to canopy opening and debris deposition in a subtropical wet forest

    Science.gov (United States)

    G. Gonzalez; D.J. Lodge; B.A. Richardson; M.J. Richardson

    2014-01-01

    In this study, we used a replicated factorial design to separate the individual and interacting effects of two main components of a severe hurricane – canopy opening and green debris deposition on leaf litter decay in the tabonuco forest in the Luquillo Mountains of Puerto Rico. We quantify changes in percent mass remaining (PMR), the concentration and absolute amounts...

  20. The role of microbial communities in phosphorus cycling during litter decomposition in a tropical forest

    Science.gov (United States)

    Lloret Sevilla, E.; Brodie, E.; Bouskill, N.; Hao, Z.

    2016-12-01

    Phosphorus is an essential nutrient with a reduced availability in tropical forests. In these ecosystems, P is recycled highly efficiently through resorption and mineralization and P immobilization in the microbial biomass prevents its loss through occlusion in the soil mineral fraction. To improve models of ecosystem response to global change, further studies of the above and belowground plant and microbial traits related to P availability and uptake, are required. In tropical forests, high temperature and rainfall lead to some of the highest rates of litter decomposition on earth. Litter decomposition is a complex process mediated by a range of trophic groups: meso and microfauna initiate litter turnover through litter fragmentation facilitating colonization by fungi, and bacteria mediate the mineralization of organic matter and release of nutrients. To determine the important functional traits of these players in the efficient cycling of P in soils with low P availability, we are performing a leaf litter decomposition experiment in a humid tropical forest in Puerto Rico. Nylon litterbags with three mesh sizes (2mm, 20 μm and 0.45 μm) containing litter with different chemistry (tabonuco and palm) will be deployed on soil surface and sampled 6 times throughout 12 months. The use of different mesh sizes will allow us to identify the leading roles in litter turnover by physical allowance and/or exclusion of the decomposers. The 2 mm bags allow meso and microfauna, roots, fungi and bacteria. 20 μm bags will exclude fauna and roots and 0.45 μm only allow some bacteria. We hypothesize that fungi will dominate over bacteria in earlier stages of the decomposition with a higher production of extracellular hydrolytic enzymes. On the other hand, bacterial biomass is expected to increase with time. Qualitative changes in both fungal and bacterial communities along the decomposition process are also expected leading to changes in enzyme activity. We also postulate an

  1. Intraspecific growth and functional leaf trait responses to natural soil resource gradients for conifer species with contrasting leaf habit.

    Science.gov (United States)

    Walters, Michael B; Gerlach, John P

    2013-03-01

    Interspecific relationships among species mean leaf traits, performance and species resource/climate distributions help provide the foundation for a predictive, functionally based plant ecology. Intraspecific responses of leaf traits and performance to resource gradients and how these vary among species may be equally important but have received less attention. Here, we examine relationships between proxies of soil resource availability, leaf traits and growth (height at 25 years, SI25) for winter deciduous Larix decidua Mill. and evergreen Pinus resinosa Ait. trees distributed over soil resource gradients in the Great Lakes region of North America. We predicted that (i) leaf trait responses to soil resources within species will be similar to reported distributions of mean leaf traits over soil resource gradients among species; (ii) soil resource-related variation in leaf traits can help explain SI25; and (iii) SI25 will be greater for Larix than Pinus at higher soil resources and greater for Pinus than Larix at lower soil resources and this pattern will be associated with species differences in leaf trait responses to soil resources. Among the measured leaf traits (live N, Mg, Ca, K, P, and Mn, litter N, N resorption, carbon isotope discrimination, specific leaf area, lifespan), soil resources only impacted live and litter N for both species and K for Pinus. In turn, only the leaf traits responsive to soil resources affected SI25 in the expected manner. Larix had greater SI25 than Pinus across soil resource gradients and both species had similar growth and leaf trait sensitivities to resources. In summary: (i) several leaf traits reported to be associated with performance and edaphic distributions across species were, within species, unresponsive to nitrogen and water availability and unrelated to growth; (ii) leaf N showed high plasticity to soil resources and this plasticity was functionally relevant to growth over its entire range of response; (iii) large

  2. LITTER AND MACRONUTRIENT DEPOSITION IN A STAND OF BLACK WATTLE (Acacia mearnsii De Wild. IN THE STATE OF RIO GRANDE DO SUL, BRAZIL

    Directory of Open Access Journals (Sweden)

    Márcio Viera

    2010-08-01

    Full Text Available This study evaluated litter and macronutrient deposition in a six year-old black wattle (Acacia mearnsii De Wild. stand, in Butia-RS. Five plots (18mx24m of litter were systematically allocated, each one with four trap collectors of 1 m2. The litter intercepted was collected monthly between January 2002 and December 2003. After collection, litter was divided into leaves, flowers, fruits and caterpillar (Adeloneivaia subangulata feces, oven dried, weighed, milled and analyzed for N, P, K, Ca and Mg contents. The average annual litter deposition reached 4.32 Mg ha-1, and was composed of 75.5, 11.1, 11.2 and 2.2% of leaves, flowers, fruits and feces, respectively. Litter deposition was more concentrated in the spring. The higher deposition of nutrients was through the leaf fraction, which contributed annually with a great amount of litter biomass, although not showing the highest nutrient concentrations. The supply of total amount of macronutrients to the soil was of 74.8 of N, 26.8 of K, 23.1 of Ca, 7.9 of Mg and 2.4 of P (kg ha-1.

  3. Microbiological Safety of Chicken Litter or Chicken Litter-Based Organic Fertilizers: A Review

    Directory of Open Access Journals (Sweden)

    Zhao Chen

    2014-01-01

    Full Text Available Chicken litter or chicken litter-based organic fertilizers are usually recycled into the soil to improve the structure and fertility of agricultural land. As an important source of nutrients for crop production, chicken litter may also contain a variety of human pathogens that can threaten humans who consume the contaminated food or water. Composting can inactivate pathogens while creating a soil amendment beneficial for application to arable agricultural land. Some foodborne pathogens may have the potential to survive for long periods of time in raw chicken litter or its composted products after land application, and a small population of pathogenic cells may even regrow to high levels when the conditions are favorable for growth. Thermal processing is a good choice for inactivating pathogens in chicken litter or chicken litter-based organic fertilizers prior to land application. However, some populations may become acclimatized to a hostile environment during build-up or composting and develop heat resistance through cross-protection during subsequent high temperature treatment. Therefore, this paper reviews currently available information on the microbiological safety of chicken litter or chicken litter-based organic fertilizers, and discusses about further research on developing novel and effective disinfection techniques, including physical, chemical, and biological treatments, as an alternative to current methods.

  4. Watching eyes on potential litter can reduce littering: evidence from two field experiments.

    Science.gov (United States)

    Bateson, Melissa; Robinson, Rebecca; Abayomi-Cole, Tim; Greenlees, Josh; O'Connor, Abby; Nettle, Daniel

    2015-01-01

    Littering constitutes a major societal problem, and any simple intervention that reduces its prevalence would be widely beneficial. In previous research, we have found that displaying images of watching eyes in the environment makes people less likely to litter. Here, we investigate whether the watching eyes images can be transferred onto the potential items of litter themselves. In two field experiments on a university campus, we created an opportunity to litter by attaching leaflets that either did or did not feature an image of watching eyes to parked bicycles. In both experiments, the watching eyes leaflets were substantially less likely to be littered than control leaflets (odds ratios 0.22-0.32). We also found that people were less likely to litter when there other people in the immediate vicinity than when there were not (odds ratios 0.04-0.25) and, in one experiment but not the other, that eye leaflets only reduced littering when there no other people in the immediate vicinity. We suggest that designing cues of observation into packaging could be a simple but fruitful strategy for reducing littering.

  5. Watching eyes on potential litter can reduce littering: evidence from two field experiments

    Directory of Open Access Journals (Sweden)

    Melissa Bateson

    2015-12-01

    Full Text Available Littering constitutes a major societal problem, and any simple intervention that reduces its prevalence would be widely beneficial. In previous research, we have found that displaying images of watching eyes in the environment makes people less likely to litter. Here, we investigate whether the watching eyes images can be transferred onto the potential items of litter themselves. In two field experiments on a university campus, we created an opportunity to litter by attaching leaflets that either did or did not feature an image of watching eyes to parked bicycles. In both experiments, the watching eyes leaflets were substantially less likely to be littered than control leaflets (odds ratios 0.22–0.32. We also found that people were less likely to litter when there other people in the immediate vicinity than when there were not (odds ratios 0.04–0.25 and, in one experiment but not the other, that eye leaflets only reduced littering when there no other people in the immediate vicinity. We suggest that designing cues of observation into packaging could be a simple but fruitful strategy for reducing littering.

  6. Litter NSV; marine litter monitoring by northern fulmars (a pilot study)

    NARCIS (Netherlands)

    Franeker, van J.A.; Meijboom, A.

    2002-01-01

    The northern fulmar is a seabird known to consume litter such as plastic. The Dutch government has asked for an investigation of the possibility to use stomach contents of beach-washed fulmars as a monitoring tool for the abundance of marine litter inthe North Sea. Such monitoring is of importance

  7. Lignin degradation during plant litter photodegradation

    Science.gov (United States)

    Lin, Y.; King, J. Y.

    2014-12-01

    Lignin is the second most abundant compound, after cellulose, synthesized by plants. Numerous studies have demonstrated that initial lignin concentration is negatively correlated with litter decomposition rate under both laboratory and field conditions. Thus lignin is commonly considered to be a "recalcitrant" compound during litter decomposition. However, lignin can also serve as a radiation-absorbing compound during photodegradation, the process through which solar radiation breaks down organic matter. Here, we synthesize recent studies concerning lignin degradation during litter photodegradation and report results from our study on how photodegradation changes lignin chemistry at a molecular scale. Recent field studies have found that litter with high initial lignin concentration does not necessarily exhibit high mass loss during photodegradation. A meta-analysis (King et al. 2012) even found a weak negative correlation between initial lignin concentration and photodegradation rate. Contradicting results have been reported with regard to the change in lignin concentration during photodegradation. Some studies have found significant loss of lignin during photodegradation, while others have not. In most studies, loss of lignin only accounts for a small proportion of the overall mass loss. Using NMR spectroscopy, we found significant loss of lignin structural units containing beta-aryl ether linkages during photodegradation of a common grass litter, Bromus diandrus, even though conventional forage fiber analysis did not reveal changes in lignin concentration. Both our NMR and fiber analyses supported the idea that photodegradation induced loss of hemicellulose, which was mainly responsible for the litter mass loss during photodegradation. Our results suggest that photodegradation induces degradation, but not necessarily complete breakdown, of lignin structures and consequently exposes hemicellulose and cellulose to microbial decomposition. We conclude that lignin

  8. Morphology and composition of beach-cast Posidonia oceanica litter on beaches with different exposures

    Science.gov (United States)

    Simeone, Simone; De Falco, Giovanni

    2012-05-01

    Posidonia oceanica seagrass litter is commonly found along sandy shores in the Mediterranean region, forming structures called banquettes, which are often removed in order to allow the beach to be used for tourism. This paper evaluates the relationship between the morphology and composition of banquettes and beach exposure to dominant waves. A Real Time Kinematic Differential Global Positioning System was used to evaluate the variability of banquettes and beach morphology over a period of 1 year. Banquette samples, collected at two different levels of the beach profile (i.e. foreshore and backshore), were used to evaluate the contribution of leaves, rhizomes and sediments to the total weight. Banquettes showed a higher volume, thickness and cross-shore length on exposed beaches, whereas narrower litter deposits were found on the sheltered beach. On exposed beaches, banquettes were deposited in beach zones characterized by changes in elevation. These changes in elevation were mainly due to the deposition and erosion of sediments and secondly to the deposition and or erosion of leaf litter. On sheltered beaches, the variability in beach morphology was low and was restricted to areas where the banquettes were located. The leaf/sediment ratio changed along the cross-shore profile. On the backshore, banquettes were a mixture of sediments and leaves, whereas leaves were the main component on the foreshore, independently of the beach exposure. The processes which control the morphodynamics in the swash zone could explain the variability of banquette composition along the cross-shore profile. Finally, this study highlighted that Posidonia oceanica seagrass litter plays an important role in the geomorphology of the beachface and its removal can have a harmful impact on the beaches.

  9. Cedar leaf oil poisoning

    Science.gov (United States)

    Cedar leaf oil is made from some types of cedar trees. Cedar leaf oil poisoning occurs when someone swallows this substance. ... The substance in cedar leaf oil that can be harmful is thujone (a hydrocarbon).

  10. Biological nitrogen fixation and nutrient release from litter of the guachapele leguminous tree under pure and mixed plantation with eucalyptus.

    OpenAIRE

    Fabiano de Carvalho Balieiro; Bruno José Rodrigues Alves; Marcos Gervásio Pereira; Sérgio Miana de Faria; Avílio Antônio Franco; Campello,Eduardo F.C.

    2008-01-01

    Pseudosamanea guachapele (guachapele), a nitrogen fixing leguminous tree, is an alternative for mixed forest plantations in the tropics. As little information is available for guachapele (Mimosoideae) in mixed plantation with eucalyptus considering the Brazilian edaphoclimatic conditions, an experiment was carried out to evaluate the contribution of biological nitrogen fixation to guachapele and leaf litter decomposition rates and nutrient release of eucalyptus and guachapele residues (pure a...

  11. Litter production, soil organic matter dynamics and microbial activity in two coeval forest stands on Mount Vesuvius

    Science.gov (United States)

    de Marco, Anna; Esposito, Fabrizio; Giordano, Maria; Vittozzi, Paola; Virzo de Santo, Amalia

    2010-05-01

    Forest ecosystems in different climatic zones may accumulate different amounts of soil organic matter (SOM) with different chemical-physical properties. C inputs to SOM are related to net primary production, however C accumulation in the soil largely depends on the balance between net primary production and decomposition. On the other side rates of SOM decomposition are the major control over the supply of mineral nutrients to vegetation and thus over primary production. This study was performed in two coeval (36 years old), adjacent forest stands, a Corsican pine (Pinus nigra Arn.) and a Black locust (Robinia pseudoacacia L.) forest (Atrio del Cavallo, 40° 49'N, 14° 26'E; 810 a.s.l.). The two forests were implanted in 1970 on piroclastic material of the last eruption of Mount Vesuvius (1944). We assessed the quantity and the quality of SOM in a vertical gradient in the continuum of the litter layer, humus layer and mineral soil for the whole soil profile. Moreover we estimated litter production and decomposition, litter and mineral soil (0-5cm) respiration as well as microbial biomass and total and active fungal biomass. Litter fall (measured throughout the years 2006-2008) was higher in the Corsican pine than in the Black locust stand (5234 vs. 2396 g/m2/y). Black locust leaf litter and Corsican pine needle litter reached respectively 60 % and 50% of initial mass after 600 days in situ decomposition. Consistently with the lower litter input and the higher decomposition of black locust, the amount of organic C in the organic soil layers (litter + humus), was significantly higher in the Corsican pine as compared to the Black locust stand (2702 vs. 1636 g/m2). In contrast, in the mineral layers (0-15 cm) the amount of soil organic C was slightly higher in Black locust than in Corsican pine stand (136 vs. 116 g/m2). Litter quality, decomposition dynamics, and SOM quality and activity may help to understand the reason for the uneven distribution of organic carbon

  12. Ammonia emissions from deciduous forest after leaf fall

    DEFF Research Database (Denmark)

    Hansen, Kristina; Sørensen, Lise Lotte; Hertel, Ole

    2013-01-01

    leaf fall, the magnitude and temporal structure of the measured NH3 emission fluxes could be adequately reproduced with the bi-directional resistance model; it suggested the forest ground layer (soil and litter) to be the main contributing component to the NH3 emissions. The modelled concentration from...... anthropogenic NH3 sources. This suggests that an accurate description of ammonia fluxes over forest ecosystems requires a dynamic description of atmospheric and vegetation processes....

  13. Schima superba as a fuelbreak: Litter combustibility of three tree species with five water content levels using a cone calorimeter

    Institute of Scientific and Technical Information of China (English)

    Guomo ZHOU; Yufeng ZHOU; Shuquan YU; Shangbin BAI; Fengzhu LU

    2009-01-01

    To determine the suitability of Schima superba Gardn. et Champ as a fuelbreak, we compared and analyzed the flammability characteristics of tree litter from three trees commonly grown in south China, i.e., Pinus massoniana Lamb., Cunninghamia lanceolata (Lamb.) Hook., and S. superba, using a cone calorimeter at five different water content levels. Water content levels of 10%, 15%, 20%, 25% and 30% for the litter were manually produced with a new technique of adding water to dry litter. The cone calorimeter utilized a radiant heat intensity for leaf litter of 20 kW/m2 (510 C) and for twig litter of 30 kW/m2 (608 C). Results show that fixing the water content level by adding water with a pipette was an acceptable technique. For S. superba, compared to P. massoniana and C. lanceolata, 1) the heat release rate (HRR) was slower and lower; 2) the total heat released (THR) from the material was lower and started later in the burning process; and 3) except for the 10% water content, pkHRR/TTI was less. These results show that overall, S. superba was the best of the three species to be used as a fuelbreak in south China.

  14. Seasonal changes in the communities of microorganisms and algae in the litters of tree plantations in the steppe zone

    Science.gov (United States)

    Maltsev, Ye. I.; Didovich, S. V.; Maltseva, I. A.

    2017-08-01

    Specific structural and dynamic parameters of communities from various ecological and trophic groups of microorganisms and algae in the litter of artificial tree stands were studied using the example of the Staro-Berdyansky Forest in the steppe zone of Ukraine. The composition of the communities was shown to vary by seasons and depend on the forest-forming woody species. In spring, in all the litters, the maximal number of actinomycetes and aminotrophs was recorded; in the leaf litter, the number of phosphate-mobilizing organisms was also the largest. In summer, the development of cellulolytic organisms, ammonifiers, and nitrogen-fixers was intensified; in autumn, the number of micromycetes and oligotrophic organisms decreased. The composition of dominants, the species richness of algae and their abundance also varied by seasons. Representatives of the Chlorophyta division predominated. The highest species richness of algae was characteristic of the spring litter samples, and their number, for the spring and autumn ones. The positive correlation was established between the numbers of micromycetes and oligotrophs, micromycetes and algae. The negative correlation was found between the numbers of micromycetes and actinomycetes, cellulose-decompose bacteria and algae in the litters.

  15. Leaf Collection Posting Log

    Data.gov (United States)

    Montgomery County of Maryland — This dataset contains leaf collection dates for area and subarea where leaf collection service is provided by Montgomery County Department of Transportation. Update...

  16. Crayfish impact desert river ecosystem function and litter-dwelling invertebrate communities through association with novel detrital resources.

    Directory of Open Access Journals (Sweden)

    Eric K Moody

    Full Text Available Shifts in plant species distributions due to global change are increasing the availability of novel resources in a variety of ecosystems worldwide. In semiarid riparian areas, hydric pioneer tree species are being replaced by drought-tolerant plant species as water availability decreases. Additionally, introduced omnivorous crayfish, which feed upon primary producers, allochthonous detritus, and benthic invertebrates, can impact communities at multiple levels through both direct and indirect effects mediated by drought-tolerant plants. We tested the impact of both virile crayfish (Orconectes virilis and litter type on benthic invertebrates and the effect of crayfish on detrital resources across a gradient of riparian vegetation drought-tolerance using field cages with leaf litter bags in the San Pedro River in Southeastern Arizona. Virile crayfish increased breakdown rate of novel drought-tolerant saltcedar (Tamarix ramosissima, but did not impact breakdown of drought-tolerant seepwillow (Baccharis salicifolia or hydric Fremont cottonwood (Populus fremontii and Gooding's willow (Salix goodingii. Effects on invertebrate diversity were observed at the litter bag scale, but no effects were found at the cage scale. Crayfish decreased alpha diversity of colonizing macroinvertebrates, but did not affect beta diversity. In contrast, the drought-tolerant litter treatment decreased beta diversity relative to hydric litter. As drought-tolerant species become more abundant in riparian zones, their litter will become a larger component of the organic matter budget of desert streams which may serve to homogenize the litter-dwelling community and support elevated populations of virile crayfish. Through impacts at multiple trophic levels, crayfish have a significant effect on desert stream ecosystems.

  17. Earthworm effects on the incorporation of litter C and N into soil organic matter in a sugar maple forest.

    Science.gov (United States)

    Fahey, Timothy J; Yavitt, Joseph B; Sherman, Ruth E; Maerz, John C; Groffman, Peter M; Fisk, Melany C; Bohlen, Patrick J

    2013-07-01

    To examine the mechanisms of earthworm effects on forest soil C and N, we double-labeled leaf litter with 13C and 15N, applied it to sugar maple forest plots with and without earthworms, and traced isotopes into soil pools. The experimental design included forest plots with different earthworm community composition (dominated by Lumbricus terrestris or L. rubellus). Soil carbon pools were 37% lower in earthworm-invaded plots largely because of the elimination of the forest floor horizons, and mineral soil C:N was lower in earthworm plots despite the mixing of high C:N organic matter into soil by earthworms. Litter disappearance over the first winter-spring was highest in the L. terrestris (T) plots, but during the warm season, rapid loss of litter was observed in both L. rubellus (R) and T plots. After two years, 22.0% +/- 5.4% of 13C released from litter was recovered in soil with no significant differences among plots. Total recovery of added 13C (decaying litter plus soil) was much higher in no-worm (NW) plots (61-68%) than in R and T plots (20-29%) as much of the litter remained in the former whereas it had disappeared in the latter. Much higher percentage recovery of 15N than 13C was observed, with significantly lower values for T than R and NW plots. Higher overwinter earthworm activity in T plots contributed to lower soil N recovery. In earthworm-invaded plots isotope enrichment was highest in macroaggregates and microaggregates whereas in NW plots silt plus clay fractions were most enriched. The net effect of litter mixing and priming of recalcitrant soil organic matter (SOM), stabilization of SOM in soil aggregates, and alteration of the soil microbial community by earthworm activity results in loss of SOM and lowering of the C:N ratio. We suggest that earthworm stoichiometry plays a fundamental role in regulating C and N dynamics of forest SOM.

  18. Influence of plastic slatted floors compared with pine shaving litter on Pekin Duck condition during the summer months.

    Science.gov (United States)

    Fraley, S M; Fraley, G S; Karcher, D M; Makagon, M M; Lilburn, M S

    2013-07-01

    The management and well-being of commercial Pekin ducks has been studied in the European Union where straw is the predominant litter source. In the United States, however, the most prevalent litter is wood shavings, with a recent trend toward using plastic slatted flooring. A previous study in the United States evaluated the relationship between flooring type (litter, slats) and duck condition during winter months and found very few differences between the 2 in terms of overall duck condition. The purpose of the current study was to reevaluate the 2 flooring systems during the summer months to determine if seasonal differences would interact with flooring type to have an impact on duck condition. Eighteen commercial barns that produce Pekin ducks for Maple Leaf Farms Inc. (Leesburg, IN), located in northern Indiana and southern Wisconsin (n = 9 litter; n = 9 raised slatted floor), were used for this study. Twenty ducks were randomly selected from 5 predetermined areas within each house (n = 100 total) and scored for eye condition, nostril and feather cleanliness, and feather and foot pad quality at 7, 21, and 32 d of age. Environmental data, including carbon monoxide, ammonia, RH, and temperature, were also obtained at each collection day. The only statistical differences in body condition occurred at 7 d; there were more ducks with clear eyes and eye rings on the litter flooring, whereas average nostril scores were better on the plastic slatted floors. Live weight, weight gain per day, flock mortality, and condemnations at the plant were collected, and the only statistical difference was a higher gain per day for ducks reared on slatted floors compared with litter (P < 0.05). There were no differences between flooring systems in the environmental parameters measured within the barns. In summary, there were very few differences between the litter and slatted flooring systems, indicating that there may not be clear advantages for one particular flooring system over

  19. Agroforestry systems, nutrients in litter and microbial activity in soils cultivated with coffee at high altitude

    Directory of Open Access Journals (Sweden)

    Krystal de Alcantara Notaro

    2014-04-01

    Full Text Available Agroforestry systems are an alternative option for sustainable production management. These systems contain trees that absorb nutrients from deeper layers of the soil and leaf litter that help improve the soil quality of the rough terrain in high altitude areas, which are areas extremely susceptible to environmental degradation. The aim of this study was to characterize the stock and nutrients in litter, soil activity and the population of microorganisms in coffee (Coffea arabica L. plantations under high altitude agroforestry systems in the semi-arid region of the state of Pernambuco, Brazil. Samples were collected from the surface litter together with soil samples taken at two depths (0-10 and 10-20 cm from areas each subject to one of the following four treatments: agroforestry system (AS, native forest (NF, biodynamic system (BS and coffee control (CT.The coffee plantation had been abandoned for nearly 15 years and, although there had been no management or harvesting, still contained productive coffee plants. The accumulation of litter and mean nutrient content of the litter, the soil nutrient content, microbial biomass carbon, total carbon, total nitrogen, C/N ratio, basal respiration, microbial quotient, metabolic quotient and microbial populations (total bacteria, fluorescent bacteria group, total fungi and Trichoderma spp. were all analyzed. The systems thatwere exposed to human intervention (A and BS differed in their chemical attributes and contained higher levels of nutrients when compared to NF and CT. BS for coffee production at high altitude can be used as a sustainable alternative in the high altitude zones of the semi-arid region in Brazil, which is an area that is highly susceptible to environmental degradation.

  20. Photodegradation of roxarsone in poultry litter leachates.

    Science.gov (United States)

    Bednar, A J; Garbarino, J R; Ferrer, I; Rutherford, D W; Wershaw, R L; Ranville, J F; Wildeman, T R

    2003-01-20

    Arsenic compounds have been used extensively in agriculture in the US for applications ranging from cotton herbicides to animal feed supplements. Roxarsone (3-nitro-4-hydroxyphenylarsonic acid), in particular, is used widely in poultry production to control coccidial intestinal parasites. It is excreted unchanged in the manure and introduced into the environment when litter is applied to farmland as fertilizer. Although the toxicity of roxarsone is less than that of inorganic arsenic, roxarsone can degrade, biotically and abiotically, to produce more toxic inorganic forms of arsenic, such as arsenite and arsenate. Experiments were conducted on aqueous litter leachates to test the stability of roxarsone under different conditions. Laboratory experiments have shown that arsenite can be cleaved photolytically from the roxarsone moiety at pH 4-8 and that the degradation rate increases with increasing pH. Furthermore, the rate of photodegradation increases with nitrate and natural organic matter concentration, reactants that are commonly found in poultry-litter-water leachates. Additional photochemical reactions rapidly oxidize the cleaved arsenite to arsenate. The formation of arsenate is not entirely undesirable, because it is less mobile in soil systems and less toxic than arsenite. A possible mechanism for the degradation of roxarsone in poultry litter leachates is proposed. The results suggest that poultry litter storage and field application practices could affect the degradation of roxarsone and subsequent mobilization of inorganic arsenic species.

  1. Natural zeolites in diet or litter of broilers.

    Science.gov (United States)

    Schneider, A F; Almeida, D S De; Yuri, F M; Zimmermann, O F; Gerber, M W; Gewehr, C E

    2016-04-01

    This study aims to analyse the influence of adding natural zeolites (clinoptilolite) to the diet or litter of broilers and their effects on growth performance, carcass yield and litter quality. Three consecutive flocks of broilers were raised on the same sawdust litter, from d 1 to d 42 of age, and distributed in three treatments (control with no added zeolites, addition of 5 g/kg zeolite to diet and addition of 100 g/kg zeolites to litter). The addition of zeolites to the diet or litter did not affect growth performance or carcass yield. The addition of zeolites to the diet did not influence moisture content of the litter, ammonia volatilisation was reduced only in the first flock and pH of litter was reduced in the second and third flock. However, the addition of zeolites to the litter reduced moisture content, litter pH and ammonia volatilisation in all flocks analysed. The addition of 5 g/kg zeolite to the diet in three consecutive flocks was not effective in maintaining litter quality, whereas the addition of 100 g/kg natural zeolites to sawdust litter reduced litter moisture and ammonia volatilisation in three consecutive flocks raised on the same litter.

  2. Impacts of multiple stressors on ecosystem function: Leaf decomposition in constructed urban wetlands.

    Science.gov (United States)

    Mackintosh, Teresa J; Davis, Jenny A; Thompson, Ross M

    2016-01-01

    The impact of stormwater on stream biota is well documented, but less is known about the impacts on ecosystem processes, such as the breakdown of organic matter. This study sought to establish whether the degree of urbanisation affected rates of leaf-litter breakdown within constructed wetlands. A litter bag method was used to ascertain rate of decomposition along a gradient of urbanisation (total imperviousness, TI), in constructed wetlands in western and south-eastern Melbourne. A significant positive relationship between TI and breakdown rate was found in the south-eastern wetlands. The significant reduction in rate of invertebrate-mediated breakdown with increasing concentration of certain metals was consistent with other studies. However, overall there was an increase in rate of breakdown. Studies have shown that the effects of heavy metals can be negated if nutrient levels are high. Our results suggest that other parameters besides exposure to contaminants are likely to affect leaf litter breakdown.

  3. Heritabilities and genetic and phenotypic correlations of litter uniformity and litter size in Large White sows

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tian; ZHAO Ke-bin; WANG Li-xian; WANG Li-gang; SHI Hui-bi; YAN Hua; ZHANG Long-chao; LIU Xin; PU Lei; LIANG Jing; ZHANG Yue-bo

    2016-01-01

    Litter uniformity, which is usualy represented by within-litter weight coefifcient of variation at birth (CVB), could inlfuence litter performance of sows and the proiftability of pig enterprises. The objective of this study was to characterize CVB and its effect on other reproductive traits in Large White sows. Genetic parameters and genetic correlation of the reproductive traits, including CVB, within-litter weight coefifcient of variation at three weeks (CVT), total number born (TNB), number born alive (NBA), number born dead (NBD), gestation length (GL), piglet mortality at birth (M0), piglet mortality at three weeks (M3), total litter weight at birth (TLW0), and total litter weight at three weeks (TLW3) were estimated for 2032 Large White litters. The effects of parity and classiifed litter size on CVB, CVT, TNB, NBA, NBD, GL, M0, M3, TLW0, and TLW3 were also estimated. The heritabilities of these reproductive traits ranged from 0.06 to 0.17, with the lowest heritability for CVB and the highest heritability for TLW0. Phenotypic and genetic correlations between these reproductive traits were low to highly positive and negative (ranging from −0.03 to 0.93, and −0.53 to 0.93, respectively). The genetic correlations between TNB and CVB, and between M0 and CVB were 0.32 and 0.29, respectively. In addition, CVB was signiifcantly inlfuenced by parity and litter size class (P<0.05). Al the results suggest that piglet uniformity should be maintained in pig production practices and pig breeding programs.

  4. Power generation from poultry litter biomass

    Energy Technology Data Exchange (ETDEWEB)

    Giaier, T.A.; Morrow, R.S. [Detroit Stoker Co., Detroit (United States)

    1999-07-01

    The following paper presents the experiences of power plants utilizing poultry litter as a boiler fuel. The combustion of poultry litter provides an innovative solution to problems such as ground water run-off contamination while producing electric power with this renewable fuel. The ash from the combustion process can be utilized for resale as a fertilizer, thereby helping to provide a closed-loop environmental cycle. As with all biomass fuels, the power generated results in a net reduction in CO{sub 2} emissions and thus contributes to the solution of current greenhouse gas problems. (author)

  5. Characterization of Forest Structure and an Assessment of Litter ...

    African Journals Online (AJOL)

    Nafiisah

    Kristensen et al., 2008). ... the mangrove litter is not just restricted to the coastal line, but extends beyond it ... Litter dynamics in mangroves involve measurements of components such as .... The lagoon at Bambous Virieux is approximately 5 km large.