Variation In Litter Decomposition Research Articles

Taking sides? Aspect has limited influence on soil environment or litter decomposition in pan-European study of roadside verges

In addition to well-known effects on species ecophysiology, phenology, and distributions, climate change is widely predicted to impact essential ecosystem services such as decomposition and nutrient cycling. While temperature and soil moisture are thought to influence litter decomposition, elucidating consistent soil process responses to observed or predicted shifts in climate have proven difficult to evidence. Here we investigated how aspect (i.e., north-south orientation), a natural model for variation in soil temperature, influenced soil physico-chemical conditions and decomposition of two standardised litter types (Green tea and Rooibos teabags) in Pole-facing (PF) and Equator-facing (EF) roadside verges spanning a 3000 km and 27° latitudinal gradient across Europe. Despite average daily temperatures being 1.5 - 3.0 °C warmer on EF than PF slopes, there were only minor region-specific differences in initial soil physico-chemical conditions and short-term variation in litter decomposition (i.e., litter mass loss was higher in EF-verges for the first month of deployment only) associated with aspect. We conclude that previously observed differences in soil environments and the decomposition process associated with slope orientation, is largely litter or environment specific, although medium-term soil-decomposition in semi-natural grassland ecosystems may also be insensitive to the magnitude of temperature variation within the range predicted by the IPCC SSP1–2.6 emissions scenario. Nonetheless, consistent average and extreme temperature differences between adjacent PF- and EF-aspects along roadside verges provides a model system to explore exactly how resilient the soil environment and the micro-organisms responsible for decomposition, are to temperature variation.

Influence of rhizosphere activity on litter decomposition in subtropical forest: implications of estimating soil organic matter contributions to soil respiration

AbstractLitter decomposition plays an important role in the carbon cycle and is affected by many factors in forest ecosystems. This study aimed to quantify the rhizosphere priming effect on litter decomposition in subtropical forest southwestern China. A litter decomposition experiment including control and trenching treatments was conducted using the litter bag method, and the litter decomposition rate was calculated by litter dry mass loss. Trenching did not change soil temperature, but increased the soil water content by 14.5%. In this study, the interaction of soil temperature and soil water content controlled the litter decomposition rate, and explained 87.4 and 85.5% of the variation in litter decomposition in the control and trenching treatments, respectively. Considering changes in soil environmental factors due to trenching, the litter decomposition rates were corrected by regression models. After correction, the litter decomposition rates of the control and trenching treatments were 32.47 ± 3.15 and 25.71 ± 2.72% year–1, respectively, in the 2-year period. Rhizosphere activity significantly primed litter decomposition by 26.3%. Our study suggested a priming effect of rhizosphere activity on litter decomposition in the subtropical forest. Combining previous interaction effect results, we estimated the contributions of total soil organic matter (SOM) decomposition, total litter decomposition, and root respiration to soil respiration in the subtropical forest, and our new method of estimating the components of soil respiration provided basic theory for SOM decomposition research.

Decreased community litter decomposition associated with nitrogen-induced convergence in leaf traits in an alpine meadow

Anthropogenic activities introduce nitrogen (N) into terrestrial ecosystems, inducing changes in quantity and quality of plants. However, little is known about how do nitrogen (N)-mediated such changes alter functional diversity of green leaf traits? How does N-mediated changes in leaf quality contribute to the rate of litter decomposition at intra- or inter-species level? How can such N-mediated changes in quantity and quality be scaled up to explain and predict community-level litter decomposition? A common garden litter decomposition was conducted in an alpine meadow on the Tibetan Plateau, where six litter species and litter mixtures from the communities that had experienced eight-year N addition treatment, were subjected to decomposition for 641 days, with three harvests. For litter mixtures, littles were selected randomly from aboveground shoots collected from 0.5 × 0.5 m2 quadrats. We found that N enrichment increased green leaf and litter N concentrations, and caused small and idiosyncratic variations in phosphorus and carbon concentrations. Plasticity in leaf nutrient concentrations induced little variation in litter decomposition in the six species. Meanwhile, N enrichment induced a reduction in leaf trait diversity and community-level litter decomposition. Correspondingly, positive relationship between decomposition rate (k) and leaf trait diversity were observed. N enrichment reduced dissimilarity of leaf traits, which could relate a reduction of litter decomposition at community level. By integrating intra- and interspecific trait variation with the abundances of coexisting species, these findings can help predict ecosystem function with N enrichment.

Nitrogen addition drives convergence of leaf litter decomposition rates between Flaveria bidentis and native plant

Evidence is growing that invasive species can change decomposition rates and associated nutrient cycling within an ecosystem by changing the quality of the litter entering a system. However, the relative contribution of their distinct litter types to carbon turnover is less understood, especially in the context of enhanced N deposition. The objective of this study was to investigate the whole-plant responses of an invasive plant Flaveria bidentis in litter decay to simulated N eutrophication. A 1-year study was conducted to assess if N enhancement influenced decomposition and nutrient dynamics of litters from foliage, fine roots and twigs of F. bidentis compared to co-occurring native species Setaria viridis. N fertilization significantly decreased the decomposition rate of the foliage of the invasive F. bidentis by more than 25% relative to the water control, but had relatively minor effects on decomposition of its twigs and fine root litter or leaf litter from the native species. Collectively, decomposition rates of foliar litters of the invasive and native species become convergent over time in the presence of N addition. Moreover, net N loss was predominately influenced by litter species, followed by the litter type, while N addition had little effect on net N loss. Our study showed that the variation in litter decomposition was much greater between litter types of the invasive F. bidentis than between different plant species under the N addition and that the litter of invasive species with higher inherent decomposability did not always decompose more rapidly than the litter of native species in response to predicted N deposition enhancement.

Home‐field advantages of litter decomposition increase with increasing N deposition rates: a litter and soil perspective

Summary 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 under long‐term N deposition. We collected soil and two types of litter (monospecific and mixed species litter) from five replicate plots from a long‐term N deposition field experiment with seven N addition treatments (0, 2, 5, 10, 15, 20, 50 g N m−2 year−1). We examined the effects of N addition on litter quality and soil characteristics. We then carried out a three‐pronged microcosm decomposition experiment with (i) litter from different N addition treatments decomposed on a standard field soil; (ii) standard litter decomposed on soils from the different N addition treatments; and (iii) litter decomposed on soil from the same N addition treatment plot. Decomposition of litter on standard soil was influenced strongly by the N addition treatment, but did not consistently decrease or increase with increasing N addition rates. Instead, decomposition of standard litter on soils collected from different N addition treatments decreased with increasing rates of N addition. Decomposition of litter on soil collected from the same plot increased with increasing N addition rates. Soil characteristics explained more of the variation in litter decomposition than litter characteristics. There was a clear HFA effect for litter decomposition, both from a litter and from a soil perspective. HFA effects increased when the dissimilarity in litter quality (N content and C : N ratio) increase among the different N addition treatments and the soil effect was strongest at high N addition rates. N addition influenced litter decomposition by changing both litter and soil characteristics. Importantly, N addition decreased the capability of soils to decompose litter and it increased the HFA effect indicating that soils decomposed local litter better than other litter, due to specialization in soil communities. Nitrogen deposition is an important threat to ecosystems worldwide and our study emphasizes that ecosystem functions such as decomposition can be greatly influenced by these global changes. A lay summary is available for this article.

Controls on Litter Decomposition of Emergent Macrophyte in Dongting Lake Wetlands

Both litter composition and site environment are important factors influencing litter decomposition, but their relative roles in driving spatial variation in litter decomposition among wetlands remain unclear. The responses of mass loss and nutrient dynamics to site environment and litter source were investigated in Carex brevicuspis leaves from the Dongting Lake wetlands, China, using reciprocal transplants of litterbags. Litters originating from lower elevation (24–25 m; flooded for 180–200 days every year) and higher elevation (27–28 m; flooded for 60–90 days every year) sites were incubated simultaneously at lower and higher sites at three locations for 1 year. The remaining litter mass, N, P, and lignin contents were analyzed during decomposition. Initial N and P contents were richer in litters from lower sites than those from higher ones. The decomposition rate was higher for the litters originating from lower sites (0.0030 day−1) than those from higher ones (0.0025 day−1) and higher at lower sites (0.0031 day−1) than at higher sites (0.0024 day−1). Litters from lower sites displayed greater N and P mineralization than those from higher sites, whereas only P dynamics were affected by site elevation. The variation in litter decomposition rate among the different litter source groups was twice that among the different site elevation groups. These data indicate that, in wetlands ecosystems, litter composition plays a more important role in the speed of litter decomposition than site environment (here represented by site elevation).

Temperature and substrate chemistry as major drivers of interregional variability of leaf microbial decomposition and cellulolytic activity in headwater streams.

Abiotic factors, substrate chemistry and decomposers community composition are primary drivers of leaf litter decomposition. In soil, much of the variation in litter decomposition is explained by climate and substrate chemistry, but with a significant contribution of the specialisation of decomposer communities to degrade specific substrates (home-field advantage, HFA). In streams, however, HFA effects on litter decomposition have not been explicitly tested. We evaluated responses of microbial decomposition and β-glucosidase activity to abiotic factors, substrate and decomposer assemblages, using a reciprocal litter transplant experiment: 'ecosystem type' (mountain vs lowland streams) × 'litter chemistry' (alder vs reed). Temperature, pH and ionic concentration were higher in lowland streams. Decomposition for both species was faster in lowland streams. Decomposition of reed was more accelerated in lowland compared with mountain streams than that of alder, suggesting higher temperature sensitivity of decomposition in reed. Q10 (5°C-15°C) values of β-glucosidase activity were over 2. The alkaline pH and high ionic concentration of lowland streams depleted enzyme activity. We found similar relationships of decomposition or enzyme activity with abiotic factors for both species, suggesting limited support to the HFA hypothesis. Overall, our results suggest a prime role of temperature interacting with substrate chemistry on litter decomposition.

Litter stoichiometric traits of plant species of high‐latitude ecosystems show high responsiveness to global change without causing strong variation in litter decomposition

• High-latitude ecosystems are important carbon accumulators, mainly as a result of low decomposition rates of litter and soil organic matter. We investigated whether global change impacts on litter decomposition rates are constrained by litter stoichiometry. • Thereto, we investigated the interspecific natural variation in litter stoichiometric traits (LSTs) in high-latitude ecosystems, and compared it with climate change-induced LST variation measured in the Meeting of Litters (MOL) experiment. This experiment includes leaf litters originating from 33 circumpolar and high-altitude global change experiments. Two-year decomposition rates of litters from these experiments were measured earlier in two common litter beds in sub-Arctic Sweden. • Response ratios of LSTs in plants of high-latitude ecosystems in the global change treatments showed a three-fold variation, and this was in the same range as the natural variation among species. However, response ratios of decomposition were about an order of magnitude lower than those of litter carbon/nitrogen ratios. • This implies that litter stoichiometry does not constrain the response of plant litter decomposition to global change. We suggest that responsiveness is rather constrained by the less responsive traits of the Plant Economics Spectrum of litter decomposability, such as lignin and dry matter content and specific leaf area.

凋落物分解主场效应及其土壤生物驱动

凋落物分解主场效应是指凋落物具有在其生长的栖息地比在别的生境分解更快的特征,土壤生物的特化作用被认为是主场效应的产生机理。主场效应是除基质质量和物理化学环境外控制凋落物分解的重要因子,可影响模拟精度的8%。凋落物分解主场效应驱动机制的深入研究对促进分解模型中纳入生物因子,提高区域尺度模拟精度具有重要作用。虽然时间和基质质量可导致主场效应强度变化,但不能全面解释主场效应强度差异特别是负效应的产生。通过分析凋落物分解过程中土壤生物的作用机理,指出凋落物分解主场效应的土壤生物驱动可能包括土壤微生物的调节性适应,土壤动物的后期插入以及物理化学环境的间接影响。为深入了解主场效应土壤生物驱动机制,更好地模拟凋落物分解过程,提出延长凋落物分解交互移置实验时间,拓展实验空间,结合室内模拟分析和构建分解模型等方法与途径。;Decomposition has been studied for decades due to its significance in understanding nutrient cycling and carbon sequestration processes. The current study identified the three interacting factors that control decomposion: the physicochemical environment, litter quality, and decomposer organisms. Exsiting biogeochemical models that that are derived by local cliamte and little quality parameters can explain about 70% of the variation in litter decomposition. However, the role of soil organisms has been largely ignored in these models that assume the functions of soil organisms are mainly controlled by temperature, moisture and litter quality. Recent studies suggest that leaf litters tend to decompose more rapidly in the habitat from which it was derived (i.e. home) than in other habitats (i.e. new home away from its origion), this phenomena has been termed as the home-field advantage (<em>HFA </em>) in litter decomposition.<br> In contrast to plant growth, leaf litter-soil feedbacks are expected to consistently cause positive feedback at a home habitat resulting in faster litter decay. This is because 1) leaf litter from different plant species often varies considerably in structure and chemical composition; and 2) leaf litter inputs are a major source of nutrients and energy for soil biota that access decomposed litter. Thus, competition among soil biota for accessing nutrients may create a selective pressure for organisms that are efficient at breaking down litter derived locally resulting in <em>HFA</em>.. Unique soil biota developed in the litter derived from the orgional ecosystem has been regarded as the reason for this phenomenon. quantifying <em>HFA</em> is more complex than a simply comparison between the decomposition rates for a litter type at its home site and an away site, because differences in environmental contitions between the sites could also influence decomposition. The method originally developed for evaluating home-site effects in sports allows the <em>HFA</em> to be calculated for each of the litters separately in fully reciprocal transplants experiment of three or more litter species. <br> Existing literature suggests there is a large amount of variation in <em>HFA</em> among reciprocal transplants between different tree species. Differences in litter traits could explain some of these variations, but it is apparent that other factors influence the relationship given the initially large <em>HFA</em> observed in field and laboratory experiments, as well as periods of home-field disadvantage. Thus we need a better understanding of the drivers of <em>HFA</em> and how soil biota are involved in order to address this potential problem in how we model decomposition. Based on the review about the rules of soil organisms on litter decompositon, three mechanisms are considered to reveal the soil biological drive of <em>HFA</em>: soil microorganism adjustability has a weakening effect on the <em>HFA</em>, soil animals' late entry can lead to different <em>HFA</em> intensity, including a disadvantage of home decomposition, environmental climatic conditions have indirect effects on <em>HFA</em>, especially under soil water stress.Integrating these using an ecosystem approach helps to elucidate the effects of soil organism on the <em>HFA</em> of litter decomposition, and interpret the causes of different intensity, especially negative effect of <em>HFA</em>. In order to clearly understand the effects of soil organisms on <em>HFA</em>, long term reciprocal litter transplant experiments, including in-situ and laboratory, should be established across a large geographic and climatic gradient. Based on the effects of soil organisms on <em>HFA</em>, mathematical models of litter decomposition should incorporate with biological factors. This is especially important for global ecosystems that are used for understaing climate change effects on carbon and nutrient cycles.

Litter decomposition and nitrogen mineralization from an annual to a monthly model

The forest litter decomposition model (FLDM) described in this paper provides an important basis for assessing the impacts of forest management on seasonal stream water quality and export of dissolved organic carbon (DOC). By definition, models with annual time steps are unable to capture seasonal, within-year variation. In order to simulate seasonal variation in litter decomposition and DOC production and export, we have modified an existing annual FLDM to account for monthly dynamics of decomposition and residual mass in experimental litterbags placed in 21 different forests across Canada. The original annual FLDM was formulated with three main litter pools (fast, slow, and very slow decomposing litter) to address the fact that forest litter is naturally composed of a mixture of organic compounds that decompose at different rates. The annual FLDM was shown to provide better simulations than more complex models like CENTURY and SOMM. The revised monthly model retains the original structure of the annual FLDM, but separates litter decomposition from nitrogen (N) mineralization. In the model, monthly soil temperature, soil moisture, and mean January soil temperature are shown to be the most important controlling variables of within-year variation in decomposition. Use of the three variables in a process-based definition of litter decomposition is a significant departure from the empirical definition in the annual model. The revised model is shown to give similar calculations of residual mass and N concentration as the annual model ( r 2 = 0.91, 0.78), despite producing very different timeseries of decomposition over six years. It is shown from a modelling perspective that (i) forest litter decomposition is independent of N mineralization, whereas N mineralization is dependent on litter decomposition, and (ii) mean January soil temperature defines litter decomposition in the summer because of winter-temperatures’ role in modifying forest-floor microorganism community composition and functioning in the following summer.

Leaf litter decomposition differs among genotypes in a local Betula pendula population

Ecosystem processes, such as plant litter decomposition, are known to be partly genetically determined, but the magnitude of genetic variation within local populations is still poorly known. We used micropropagated field-grown saplings of 19 Betula pendula genotypes, representing genetic variation in a natural birch population, to examine (1) whether genotype can explain variation in leaf litter decomposition within a local plant population, and (2) whether genotypic variation in litter decomposition is associated with genotypic variation in other plant attributes. We found that a local B. pendula population can have substantial genotypic variation in leaf litter mass loss at the early stages of the decomposition process and that this variation can be associated with genotypic variation in herbivore resistance and leaf concentrations of soluble proteins and total nitrogen (N). Our results are among the first to show that fundamental ecosystem processes can be significantly affected by truly intraspecific genetic variation of a plant species.

Species control variation in litter decomposition in a pine forest exposed to elevated CO2

AbstractNet primary production and the flux of dry matter and nutrients from vegetation to soils has increased following four years of exposure to elevated CO2 in a southern pine forest in NC, USA. This has increased the demand for nutrients to support enhanced rates of NPP and altered the conditions for litter decomposition on the forest floor. We quantified the chemistry and decomposition dynamics of leaf litter produced by five of the most abundant tree species in this ecosystem during the third and fourth growing seasons under elevated CO2. The objectives of this study were to determine (i) if there were systemic or species‐specific changes in leaf litter chemistry associated with a sustained enhancement of plant growth under elevated CO2; and (ii) whether the process of litter decomposition was altered by increased inputs of energy and nutrients to the forest floor in the plots under elevated CO2. Leaf litter chemistry, including various C fractions and N concentration, was virtually unchanged by elevated CO2. With few exceptions, plant litter produced under elevated CO2 lost mass or N at the same relative rate as that produced under ambient CO2. The relationship between initial litter chemistry and decomposition was not altered by elevated CO2. The greater forest floor mass and nutrient content in the plots under elevated CO2 had no consistent or long‐term effect on litter decomposition. Thus, we found no evidence that plant and microbial processes under elevated CO2 resulted in systemic changes in mass loss or N dynamics during decomposition. In contrast to the limited effects of elevated CO2 on litter chemistry and decomposition, there were large differences among species in initial litter chemistry, mass loss and N dynamics during decomposition. If the species composition of this forest community is altered by elevated CO2, the indirect effect of a change in species composition will exert greater control over the long‐term rate of nutrient cycling than the direct effect of elevated CO2 on litter chemistry and decomposition dynamics alone.