Leaf Litter Decomposition Research Articles

Effects of Naphthalene Application on Soil Fungal Community Structure in a Poplar Plantation in Northern Jiangsu, China

The soil food web is essential for the functioning of terrestrial ecosystems. The application of naphthalene is a commonly employed experimental treatment for expelling soil fauna to examine faunal effects on litter decomposition processes, for which is it assumed that naphthalene has negligible effects on soil microbial communities. An experiment was conducted to examine the potential soil-fauna-repellent effect of naphthalene application (100 g/m2/month, TR) on a soil fungal community during litter decomposition. The results showed that TR greatly suppressed the abundance and taxonomic richness of soil fauna by 83.7 ± 14.2% and 48.1 ± 17.2%, respectively, and reduced the rates of poplar leaf litter decomposition compared to the control (CK, without naphthalene treatment). Among the fungal communities, the abundance of Thelephorales in the TR soil was suppressed, while the abundance of Capnodiales was stimulated, although TR did not significantly alter the carbon and nitrogen content in the soil microbial biomass nor the diversity of soil fungal communities and the most abundant fungal phylum. Thus, both the suppressed soil arthropod abundance and altered soil fungal community might contribute to the observed slowdown in litter decomposition. These results suggest that naphthalene, as a soil fauna repellent, can alter the abundance of specific taxa in a soil fungal community, thereby impeding the effort to elucidate the contribution of soil fauna to ecosystem functioning (e.g., with respect to litter decomposition).

Leaf Species-Dependent Fungicide Effects on the Function and Abundance of Associated Microbial Communities

Microbially-mediated leaf litter decomposition is a critical ecosystem function in running waters within forested areas, which can be affected by fungicides. However, fungicide effects on leaf litter decomposition have been investigated almost exclusively with black alder leaves, a leaf species with traits favourable to consumers (i.e., low recalcitrance and high nutrient content). At the same time, little is known about fungicide effects on microbial colonisation and decomposition of other leaf species with less favourable traits. In this 21 day lasting study, we explore the effects of increasing fungicide sum concentrations (0–3000 µg/L) on microbial colonisation and decomposition of three leaf species (black alder, Norway maple and European beech) differing in terms of recalcitrance and nutrient content. Leaf litter decomposition rate, leaf-associated fungal biomass and bacterial density were quantified to observe potential effects at the functional level. Beech, as the species with the least favourable leaf traits, showed a substantially lower decomposition rate (50%) in absence of fungicides than alder and maple. In the presence of high fungicide concentrations (300–3000 µg/L), beech showed a concentration-related decrease not only in microbial leaf litter decomposition but also fungal biomass. This suggests that favourable traits of leaf litter (as for alder and maple) enable leaf-associated microorganisms to acquire leaf-bound energy more easily to withstand potential effects induced by fungicide exposure. Our results indicate the need to deepen our understanding on how leaf species’ traits interact with the impact of chemical stressors on the leaf decomposition activity of microbial communities.

Dual Isotopes Tracing Carbon and Nitrogen Dynamics during Leguminous and Non-Leguminous Litter Decomposition under Controlled Precipitation

Plant litter decomposition figures importantly in the cycling of C and N pools in terrestrial ecosystems. We investigated how C and N fluxes changed during the decomposition of leguminous and non-leguminous leaf litters, and how these processes responded to different precipitation regimes. We used the dual-isotope tracing method to investigate differences in leaf and soil C and N, along with δ13C and δ15N, in the soil of the Loess Plateau in China. The δ15N and δ13C values were 3604‰ and 56‰ for Robinia pseudoacacia (Leguminosae) and 8115‰ and 452‰ for Populus tomentosa (Salicaceae) leaf litters. Through decomposition, δ13C decreased in all litters, and δ15N in the leguminous litter increased while it decreased in the non-leguminous litter. In the surface soil, the fraction of litter-derived N (14%) from the leguminous litter was significantly higher than that of the non-leguminous litter after 16 months. The C and N concentrations of both litters and soil always had a positive correlation during decomposition, and the responses of N to C changes in soil were reduced by the litter cover. Increased precipitation enhanced the litters’ C and N correlation. The 600 mm precipitation treatment most benefited litter C’s transformation to SOC, and drought conditions promoted the transformation of legume litter N to soil TN, but inhibited non-legume litter N. In the soil and both litters, C and N changes always had a positive correlation. After 16 months, the proportion of soil N from legumes was higher than that from non-legumes. Reduced precipitation could promote leguminous N in soil. Our results provide a scientific basis for accurately predicting the C and N cycles in terrestrial ecosystems.

Tracer or toxicant: Does stable isotope labeling affect central processes in aquatic food webs?

Stable isotope analysis (SIA) is an elementary technique in food web ecology, but its insights become increasingly ambiguous in complex systems. One approach to elevate the utility of SIA in such systems is the use of heavy isotope tracers (i.e., labeling). However, the fundamental assumption that the addition of such tracers does not affect in situ conditions has been challenged. This study tests if labeling is suitable for autotrophy-based and detritus-based aquatic food webs. For the former, the survival and reproduction of Daphnia magna fed with phytoplankton cultured at different levels of 15N addition were assessed. For the latter, the microbial decomposition of leaf litter was assessed at the same tracer levels. While no significant differences were observed, effect patterns were comparable to a previous study, supporting the isotopic redundancy hypothesis that postulates discrete quantum mechanical states at which the reaction speeds of metabolic processes are altered. Although physiology (reproduction) and activity (microbial decomposition) might not be altered to an ecologically significant level, labeling with heavy stable isotopes could potentially affect isotopic fractionation in biochemical processes and bias conclusions drawn from resulting SI ratios.

Mixed-Species Plantation of Pinus massoniana Lamb. and Quercus variabilis Bl. and High Soil Nutrient Increase Litter Decomposition Rate

Changes in land use and forest planting have led to substantial changes in soil fertility and leaf litter input. The effects of mixed planting on the leaf litter decomposition rate in contrasting soil nutrient conditions are poorly understood. To elucidate the effects of litter composition and soil fertility on litter decomposition, we conducted a field litterbag-decomposition experiment with single (Pinus massoniana Lamb. or Quercus variabilis Bl.) and mixed (P. massoniana and Q. variabilis) litter treatments on soils of three nutrient levels (high, medium, and low). During the 3-year decomposition, at each decomposition stage and soil nutrient level, the mass-loss rate (MLR) was higher in mixed-litter than in the two single-litter treatments, with the exception of Q. variabilis, which recorded a higher MLR at 724 d in medium and high soil substrates. Between the two single-litter treatments, the MLR of Q. variabilis litter was higher than that of the P. massoniana litter; the MLR of the component litter of P. massoniana and Q. variabilis was higher than that of the corresponding two single-litter treatments. The k values over the 3-year-experiment period increased with the soil nutrient level for all litter treatments, as did microbial biomass carbon and nitrogen content. These findings suggest that mixed planting and high level of soil nutrient can accelerate litter decomposition.

Leaf Litter Breakdown and Soil Microbes in Catalpa bungei Plantations in Response to Various Fertilization Regimes

Litter decomposition propels the geochemical cycle by returning nutrients to soil. Soil microbial communities play an important role during litter breakdown wherein various fertilization regimes are conducted. In this study, we carried out a five-year fertilization experiment in a young Catalpa bungei plantation in northern China. The fertilization strategies employed mainly included the integration of water and fertilizer (WF), hole fertilization (HF), and no fertilization (CK) as a control. We tracked the decomposition dynamics of leaf litter and identified the major microbial communities involved in litter breakdown for each fertilization regime. The results showed that fertilization increased the biomass and C content of leaf litter, and the C storage in the HF forest was higher than that in the WF forest. Fertilization significantly decreased leaf litter decomposition and nutrient release and prolonged the duration of breakdown. The breakdown of litter in the WF stand was slower than that in the HF stand, but the diversities of bacteria and fungi were higher in the WF soil. The community structures of bacteria and fungi in the WF soil showed obvious differences compared to those in the CK and HF soils. Fertilization strengthened competitive relationships but decreased cooperative interaction among microbes. The abundances of saprophytic fungi and decomposing bacteria in the WF soil were lower than those in the HF soil. The key flora, including Arthrobacter and Neocosmospora, regulated litter breakdown in the HF and WF forests. In addition, Arthrobacter, Filobasidium, and Coprinopsis were mainly involved in the decomposition process in the nonfertilized forests. Thus, studying the biomass and initial quality of litter treated with different fertilization measures and exploring the characteristics of nutrient release during litter decomposition are both of significant value with regard to deepening understanding of the effects of different fertilization methods on litter breakdown and their associated response mechanisms.

Contrasting the effects of microplastic types, concentrations and nutrient enrichment on freshwater communities and ecosystem functioning

Microplastics are now ubiquitous in freshwater environments. As most previous research has focused on species-specific effects of microplastics under controlled laboratory conditions, little is known about the impact of microplastics at higher levels of ecological organisation, such as freshwater communities and their associated ecosystem functions. To fill this knowledge gap, an outdoor experiment using 40 freshwater mesocosms, each 1.57 m3, was used to determine the effects of (i) microplastic type: traditional oil-based high-density polyethylene versus bio-based biodegradable polylactic acid, (ii) concentration of microplastic particles and (iii) nutrient enrichment. The two concentrations of microplastics used were equivalent to measured environmentally occurring concentrations and concentrations known to cause toxicological effects under laboratory conditions. Freshwater communities are also at increasing risk from nutrient enrichment, which can alter community composition in favour of competitively dominant taxa. The independent and interactive effects of these treatments on pelagic community structure (phytoplankton standing stock, taxonomic richness, and composition) and ecosystem functioning (periphyton productivity and leaf litter decomposition) were assessed. Taxonomic richness and community composition were not affected by exposure to the experimental treatments and there were no significant treatment effects on phytoplankton standing stock, periphyton productivity, total or microbial leaf litter decomposition. Overall, multiple microplastic exposures, crossed with nutrient addition had little impact on the structure and functioning of semi-natural freshwater ecosystems. These findings indicate that the negative impacts of microplastics predicted from species-specific studies may not be readily realised at the ecosystem scale.

Canopy Gaps Control Litter Decomposition and Nutrient Release in Subtropical Forests

The formation of a canopy gap results in changes to the microenvironment which, in turn, affect litter decomposition and nutrient release. However, the mechanisms underlying these effects in differently sized gaps and non-gaps remain poorly understood. To address this gap in knowledge, we selected three large gaps (above 150 m2), three medium gaps (50–100 m2), three small gaps (30–50 m2), and three non-gaps with basically the same site conditions. We then used the litter bag method to investigate leaf and branch litter decomposition over a year in a Castanopsis kawakamii natural forest with the aim of characterizing the litter mass remaining and the nutrient release in canopy gaps and non-gaps. Our results revealed that the remaining litter mass of leaf and branch litter was lower in medium gaps compared to other gaps, and leaf litter decomposed faster than branch litter. Environmental factors were identified as the primary drivers of total carbon and nitrogen release during litter decomposition. Gap size (canopy openness), taxonomic Margalef index, the Brillouin index of soil microbes, soil total nitrogen content, soil pH value, and average air temperature were identified as the main factors driving carbon and nitrogen release from branch litter. In the late decomposition stage, the taxonomic Pielou index, soil total potassium content, soil water content, and average relative air humidity were the main drivers of nutrient release from branch litter. The soil water content and average relative air humidity were also found to be the main factors affecting the nutrient release from leaf litter throughout the different stages of decomposition. Overall, our study highlights the impact of canopy gaps on microenvironmental variation, taxonomic community diversity, and soil microbial functional diversity and how these factors ultimately influence litter decomposition and nutrient release. Our findings provide an important foundation for further research into soil nutrient cycling in subtropical natural forests.

Heatwaves, elevated temperatures, and a pesticide cause interactive effects on multi-trophic levels of a freshwater ecosystem

Climate impacts of elevated temperatures and more severe and frequent weather extremes like heatwaves are globally becoming discernible on nature. While a mechanistic understanding is pivotal for ecosystem management, stressors like pesticides may interact with warming, leading to unpredictable effects on freshwater ecosystems. These multiple stressor studies are scarce and experimental designs often lack environmental realism. To investigate the multiple stressor effects, we conducted a microcosm experiment for 48 days comprising benthic macroinvertebrates, zooplankton, phytoplankton, macrophytes, and microbes. The fungicide carbendazim (100 μg/L) was investigated combined with temperature scenarios representing elevated temperatures (+4 °C) or heatwaves (+0 to +8 °C), both applied with similar energy input on a daily fluctuating ambient temperature (18 °C ± 1.5 °C), which served as control. Measurements showed the highest carbendazim dissipation in water under heatwaves followed by elevated and ambient temperatures. Average carbendazim concentrations were about 50% in water and 16% in sediment of the nominal concentration. In both heated cosms, zooplankton community dynamics revealed an unexpected shift from Rotifera to Cladocera and Copepoda nauplii, indicating variations in their thermal sensitivity, tolerance and resilience. Notably, warming and heatwaves shaped community responses similarly, suggesting heat intensity rather than distribution patterns determined the community structure. Heatwaves led to significant early and longer-lasting adverse effects that were exacerbated over time with Cladocera and Copepoda being most sensitive likely due to significant carbendazim interactions. Finally, a structural equation model demonstrated significant relationships between zooplankton and macrophytes and significantly negative carbendazim effects on zooplankton, whereas positive on macroinvertebrate abundances. The relationship between macroinvertebrate feeding and abundance was masked by significantly temperature-affected microbial leaf litter decomposition. Despite the thermal tolerance of zooplankton communities, our study highlights an increased pesticide threat under temperature extremes. More intense heatwaves are thus likely to cause significant alterations in community assemblages which will adversely affect ecosystem's processes and functions.

Soil arthropod communities associated with Berberis thunbergii invasion in a temperate deciduous forest harbour more detritivores

Abstract Barberry (Berberis thunbergii) is a widely established invasive shrub in temperate forests of the northeastern United States with the potential to alter soil arthropod communities through changes to soil nutrient cycling and acidity. We compared soil arthropod taxa and functional feeding groups between invaded and nearby control areas in a paired observational survey. Community ordination analysis suggested minimal differences between barberry and control samples. In contrast, pairwise differences revealed elevated densities of multiple taxa in barberry‐invaded soils. Among taxa that were able to be defined by functional feeding group and were collected at higher densities under barberry, all were detritivores. For example, barberry‐invaded soils harboured an average of 40% more Isopoda and more than twice as many Diplopoda per unit dry compared with control samples. Differences we observed between barberry and control samples despite the limited study spatiotemporal scope demonstrate the potential for invasions to restructure soil arthropod communities. Observed patterns potentially reflects elevated leaf litter decomposition rates associated with the invasion and results also highlight the need to integrate site‐specific environmental attributes when assessing the impact of invading plants on soil ecosystems.

Pathways of glyphosate effects on litter decomposition in grasslands

AbstractGrasslands store a third of global terrestrial carbon but are vulnerable to carbon loss due to inappropriate livestock grazing. Grasslands management can be improved with a mechanistic understanding of biogeochemical processes that determine carbon storage, such as plant litter decomposition.Herbicides, such as glyphosate, are used to improve the quantity and quality of the forage. In the Flooding Pampa, the most extensive cattle grazed natural grassland and one of the few remnants' temperate grasslands in South America—glyphosate is applied to promoteLolium multiflorum, a forage grass associated with a fungal endophyte nontoxic for cattle.We studied five mechanistic pathways in which the application of glyphosate can alter litter decomposition. We grouped them into single application pathways, through effects on living plants (1), leaf litter (2) and bare soil (3), and repeated annual application pathways, through legacies on ecosystem properties (4) and through the growth of an annual forage grass with a fungal endophyte (5). Single application pathways were tested in a greenhouse experiment using leaf litter ofL. multiflorumand of a native dominant grass. Repeated annual application pathways were tested through a field experiment with 3‐year annual glyphosate application using leaf and root litter ofL. multiflorumwith and without endophyte association.Glyphosate application on living plants produced leaf litter with 70% higher nitrogen content and 140% higher decomposition constant than naturally senesced litter. In contrast, glyphosate application on naturally senesced leaf litter reduced decomposition constant by 20%. Glyphosate application on the soil did not affect the decomposition of naturally senesced leaf litter but accelerated the decomposition of the glyphosate‐killed plants even more.Legacies of repeated annual application of glyphosate resulted in a notable reduction in plant cover (45%) and potential soil respiration (57%), with a consistent acceleration of leaf (53%) and root (18%) litter decomposition. Furthermore, endophytes inL. multiflorumplants reduced leaf litter decomposition by 22%. On the contrary, endophytes did not alter root litter decomposition.Glyphosate application on living plants and legacies of repeated application on the ecosystem stimulate litter decomposition, which can result in a net carbon loss from grasslands. In other ecosystems, the net result on decomposition would depend on the relative cover of vegetation, above‐ground litter and bare soil. This study highlights that glyphosate application should be considered when evaluating sustainable management to preserve and enhance soil carbon storage in grasslands.Read the freePlain Language Summaryfor this article on the Journal blog.

Temperature dependency of litter decomposition is not demonstrated under reciprocal transplantation of tussock leaves along an altitudinal gradient

Abstract Decomposition rates are an important component of carbon sequestration rates in soils, potentially mitigating future climate change. Here we aim to better understand decomposition's relationship with temperature in natural conditions. In snow‐tussock grassland dominated by Chionochloa rubra on Mount Tongariro, Tongariro National Park, New Zealand, we measured decomposition of Chionochloa leaf litter along an ≈ 700 m altitudinal gradient, as a space‐for‐temperature experiment, representing 4.2°C of warming. We examined decomposition rates in a full reciprocal translocation of litter bags between eight plots as both the origin of eight litter types and the eight destinations of plating out of litter bags, over 4 years using six replicates, and modelled their relationships to environmental variates. Litter decomposed progressively over time, but at the same rate along the altitudinal gradient. There was no home‐field advantage. In terms of litter quality, decomposition rates were related only to litter lignin, or fibre or litter N. Only decomposition at Year 4, and that only when organised by litter destination, showed a relationship to mean annual temperature jointly with soil C, and this was only weak and implausible. When studied across the full reciprocal transplant, there were no significant interactions between Origin and Destination data with or without Years. Therefore litter from each plot decomposed at the same rate as other plots' litter at all altitudes, allowing for small, often irregular differences in litter quality and micro‐environment. Despite the few modelled differences, decomposition rates show no plausible trends in our altitude‐for‐temperature substitution. We suggest this may be a universal finding, except perhaps under different moisture regimes. Thus, under projected climate warming scenarios, changes in temperature will not directly affect decomposition rates, and cannot influence C sequestration in nature. Read the free Plain Language Summary for this article on the Journal blog.

Effects of two-year nitrogen and phosphorus additions on nutrient release and enzyme activity during leaf litter decomposition in Larix principis-rupprechtii plantation

Effects of two-year nitrogen and phosphorus additions on nutrient release and enzyme activity during leaf litter decomposition in Larix principis-rupprechtii plantation

Loss of soil carbon and nitrogen indicates climate change-induced alterations in a temperate forest ecosystem

Climate warming is expected to influence terrestrial biogeochemical cycles by modifying the quality and quantity of plant litter input to soils. Although a growing number of studies recognize the importance of plant litter input in influencing the loss of soil organic matter (SOM) through a phenomenon called the priming effect (PE), the exact mechanisms behind PE are not well known. Importantly, most PE research is based on short term pot experiments in which fresh organic matter (FOM) input is represented by a single addition of compounds of unnaturally simple chemical composition. Furthermore, only a few studies exist in which the PE was explored in terms of organic C (SOC) and total N content in the soil. Here, we report results of a 3-year long litter manipulation study conducted under natural conditions in a broadleaved Korean pine forest in N-E China. We show that the extra supply (twice the normal input) of aboveground tree litter composing of conifer needles, leaves and small twigs was associated not only with slightly decreased SOC (by 5%) but especially that of soil total N (STN) (by 15%) content in the top soil (0–5 cm depth). In contrast, removal of litter resulted in an increased (ca. 15%) amount of both SOC and STN during the study when compared to control soils receiving natural litter input. Despite the enhanced leaf litter decomposition rate in the treatment receiving extra litter, the changes in SOC and STN were related neither to soil microbial biomass nor to community composition. The amount of N lost (40.0 g m−2) in the soil due to litter addition was ca. three times the amount of N added (12.3 g m−2) via the litter, while the amount of C lost (238 g m−2) was about one third of that added (940 g m−2), suggesting that soil N in our research site is more prone to the PE than soil C. As we did not manipulate belowground FOM input, our results suggest that input of aboveground litter rather than that by roots explained the PE in our study. Results of our long-term study conducted under natural conditions in undisturbed forest soils highlight the large potential of recalcitrant, aboveground litter to affect the PE, which should not go unnoticed when predicting the role of forest soils under conditions (such as climate warming) when these soils act as C sinks.

Elevated CO2 and nitrogen addition diminish the inhibitory effects of cadmium on leaf litter decomposition and nutrient release

Elevated CO2 and nitrogen addition diminish the inhibitory effects of cadmium on leaf litter decomposition and nutrient release

Microplastics and leaf litter decomposition dynamics: New insights from a lotic ecosystem (Northeastern Italy)

Microplastics represent one of the main environmental concerns of our time and their presence is well known in all freshwater ecosystems. However, there is still a lack of knowledge about the interference with some environmental dynamics, such as the leaf litter decomposition, which represents a key process in freshwater ecosystems. The work presented herein analyzed the leaf litter decomposition in a lotic ecosystem, in relation to water physicochemical parameters, macrobenthic invertebrate functional feeding guilds (FFG) and, as a novelty, the microplastics as additional factor. Physicochemical features were monitored every 15 days for one year. Phragmites australis decomposition rates were investigated during four seasons (summer, autumn, winter, and spring) using the leaf bag technique. Microplastic items were also collected within the leaf bags (used as retaining tool) and within macrobenthic invertebrate colonizers. Shredders were the most contaminated FFG in summer and autumn, while scrapers showed high microplastics levels in autumn and winter. Decomposition rates significantly differed among seasons (0.007 < k < 0.022) and water temperature was the main driver of the decomposition dynamics (relative importance = 70.3 %), positively affecting the decay rates, followed by pH (9.7 %), which showed a negative contribution. Microplastics showed a negative effect (3.1 %), with a relative importance similar and opposite to that observed for the shredders (3.9 %), which value was similar to those recorded for scarpers (2.7 %). This study represents a field investigation regarding the microplastic effects on the organic matter decomposition rates in freshwater environments carried out directly on field. Our results provide new insights about the microplastic interference on environmental dynamics and could represent a starting point for further studies.

Effect of Enzyme Activity Changes on Decomposition Characteristics of Leaf Litter Mixed Decomposition of Configurated Tree Species in Ecological Tea Garden

In the management of eco-tea gardens, the recycling of weathered leaves of the configured tree species plays an important role in the nutrients of the tea garden ecosystem. The in situ decomposition method was used to analyze the decomposition rate, elemental release, and enzymatic activity of different combinations of leaf litter in tea garden soil. The results showed that mixed decomposition accelerates the decomposition turnover period of Jiu’an ecological tea garden. The higher release rate of the litter improved the nutrient effectiveness in the ecological tea garden. The trends of CAT (catalase), AP (acid phosphatase), and PPO (polyphenol oxidase) activities were similar during the decomposition of different mixed leaf litters, while all other enzyme activities showed some differences. There were also some differences in the relationship between the enzyme activity and decomposition rate of leaf litter and the nutrient release rate related to the substrate mass content during the decomposition of leaf litter. Overall, the changes in the nutrient content of the leaf litter during decomposition promoted an increase in enzyme activity, which in turn promoted the release of leaf litter elements, shortened the turnover period of leaf litter decomposition, and accelerated the recycling of elements in the ecological tea garden.

Experimental Warming of Typically Acidic and Nutrient-Poor Boreal Soils Does Not Affect Leaf-Litter Decomposition of Temperate Deciduous Tree Species

Ongoing rapid climatic changes are expected to modify the structure, composition, and functioning of forest ecosystems. Studying the influence of such changes on biogeochemical processes is thus crucial for a fuller understanding of forest response to climate change. In a temperate forest of Quebec, Canada, we emulated climate change by warming the acidic, nutrient-poor, and dry soils of two mixedwoods by 3 to 4 °C using heating cables. Leaf-litter mass loss of the local red maple, sugar maple, large-tooth aspen, and American beech were monitored to assess the ability of these tree species to condition boreal soils in the context of their northward migration under climate change. We hypothesized that decomposition rates of all leaf-litter types would be decreased equally by warming due to a drying effect of the soil and its surface, which is detrimental to microbial biomass and activity. Our results suggest differences in decomposition rates between tree species as follows: sugar maple &gt; red maple ≥ American beech = large-tooth aspen. There was no indication of a slower turnover in these marginal soils compared to other studies conducted on typical hardwood soils. Moreover, no difference in litter mass loss was detected between treatments, likely due to a drying effect of the soil warming treatment. Results imply that climate change has a marginal influence on leaf-litter dynamics of temperate tree species on soils that are typical of the boreal forest. However, some variables that could play an important role on litter decomposition in the context of climate change were not measured (e.g., plant phenology, understory composition and density, microbes) and thus, uncertainties remain. The soil drying effect by warming also needs to be further documented and modeled. The study year was characterized by significant periods of water stress but was not considered an exceptional year in that regard. It would be relevant to test for leaf-litter dynamics during dry and wet summers and verify again our initial hypothesis of decreased leaf-litter decomposition rates due to soil warming/drying.

Carbon dioxide emission and its impacting factor from goldenrod (Solidago canadensis) and bulrush (Typha angustifolia) decomposition during the winter period

Leaf litter decomposition in solution is an important part of the carbon cycle. When leaf litter is deposited in water, the decomposition process takes place, releasing carbon dioxide into the atmosphere. In Hungary, the goldenrod and bulrush are spreading over increasing areas along lakes and rivers, including the shores of Lake Balaton. The primary role of the Kis-Balaton wetland is to retain inorganic nutrients, thereby improving the water quality of Lake Balaton. As the water movement in this area is not very intensive and the water retention time is long, carbon dioxide emissions of parts of decomposing plants can be higher in this area. We set up a microcosm experiment in a climate chamber to determine the carbon dioxide emissions from the decomposition of goldenrod and bulrush leaves and stems in winter when information about the process is limited. Due to short investigation time, the difference in the impact of temperatures on decomposition of the studied plants was restricted to leaves only. In the study, significant difference was obtained for the plant species and the plant parts. The carbon dioxide increments ranged from 46.7 (p<0.001) to 54.5% (p<0.001) in every plant treatment related to control one. Changes in water temperature are reflected in carbon dioxide release with a minor time delay. The results showed that the decomposition of plant parts in water during winter contributes to the increase of carbon dioxide emissions from shallow water bodies, such as the Kis-Balaton wetland.

Litterfall Production and Litter Decomposition Experiments: In Situ Datasets of Nutrient Fluxes in Two Bornean Lowland Rain Forests Associated with Acacia Invasion

It is increasingly recognized that invasion by alien plant species such as Acacia spp. can impact tropical forest ecosystems, although quantifications of nutrient fluxes for invaded lowland tropical rain forests in aseasonal climates remain understudied. This paper describes the methodology and presents data collected during a year-long study of litterfall production and leaf litter decomposition rates in two distinct tropical lowland forests in Borneo affected by Acacia invasion. The study is the first to present a comprehensive dataset on the impacts of invasive Acacia species on Bornean forests and can be further used for future research to assess the long-term impact of Acacia invasion in these forest ecosystems. Extensive studies of nutrient cycling processes in aseasonal tropical lowland rainforests occurring on different soil types remain limited. Therefore, this dataset improves understanding of nutrient cycling and ecosystem processes in tropical forests and can be utilized by the wider scientific community to examine ecosystem responses in tropical forests.