Leaf Litter Decomposition Research Articles

Non-native palm affects arthropod communities and litter decomposition in an ongoing biome shift

The emergence of novel ecosystems, characterized by shifts in species composition and interactions, abiotic conditions and altered ecosystem functioning, is a major and inevitable challenge to contemporary ecosystem management. This study examines the ecological implications of Trachycarpus fortunei, a non-native evergreen palm, currently involved in a biome shift from deciduous temperate forest to evergreen laurophyllous forest in the Southern European Alps. Specifically, we investigated the effects of T. fortunei encroachment in peri-urban forests on flying and ground-dwelling arthropod communities as well as on leaf-litter decomposition. We found that the presence of T. fortunei altered arthropod community composition, mostly by reducing the number of herbivore species. This effect was likely driven by the lower quality of palm leaves as a food source compared to deciduous, dicotyledonous tree leaves and by a lower plant richness in the herb and shrub layer. Furthermore, we observed higher rates of leaf-litter decomposition associated with increasing abundance of young palm trees, which was not explained by predictors commonly associated with litter decomposition (i.e., detritivore abundance, litter depth and air temperature). Hence, the slow decay of palm leaves appears to be counterbalanced by the favourable conditions for litter decomposition within dense palm stands. Overall, our findings indicate that high densities of the non-native palm species (T. fortunei) impacts herbivore arthropod communities in the Southern European Alps, providing first evidence of possible effects on ecosystem functioning of this ongoing biome shift. These outcomes are integral components of the broader process of laurophyllisation in the study region, a phenomenon linked to climate warming and land use change, encompassing both native and non-native species.

Tree species selection for optimizing soil carbon storage: Insights from litter decomposition and bacterial community analysis in coastal ecosystems

Coastal wetland ecosystems are critical sinks for atmospheric carbon dioxide, playing a vital role in global carbon cycling and climate regulation. The decomposition of leaf litter plays a crucial role in the formation and stability of soil organic carbon (SOC) in these environments. This study investigated the impact of leaf litter decomposition from five tree species (Populus deltoids, Ligustrum lucidum, Taxodium 'Zhongshanshan', Hibiscus hamabo, and Nerium oleander) on SOC dynamics, humus composition, and soil bacterial community structure in a tidal flat. Litterbags were used to monitor the mass loss and changes in litter chemical composition over 270 days. The results revealed significant differences in decomposition rates among the tree species, with Nerium oleander exhibiting the fastest decomposition and Populus deltoids the slowest. Surprisingly, initial litter chemistry did not correlate with decomposition rates; however, changes in lignin and hemicellulose content during decomposition were significantly related to mass loss. Despite its rapid decomposition, Nerium oleander litter resulted in the highest accumulation of SOC, total humus, and humin compared to the other species, challenging the conventional view that slower decomposition leads to greater SOC storage. The soil microbial community structure was significantly influenced by SOC, humus, and litter components, with distinct microbial assemblages associated with each tree species. A random forest model identified key bacterial taxa, predominantly Proteobacteria, as important predictors of SOC content, highlighting the role of bacterial diversity in regulating SOC dynamics. These findings underscore the importance of considering litter quality, decomposition dynamics, and bacterial community composition in strategies aimed at enhancing soil carbon sequestration. This study suggests that selecting tree species with rapidly decomposing litter, such as Nerium oleander, in coastal plantations can be an effective management tool for optimizing soil carbon storage, offering valuable insights for mitigating climate change impacts.

Microplastics and silver nanoparticles compromise detrital food chains in streams through effects on microbial decomposers and invertebrate detritivores.

Abundance of microplastics (MPs) in freshwater ecosystems has become an emerging concern due to their persistence, toxicity and potential interactions with other contaminants. Silver nanoparticles (Ag-NPs), which share common sources with MPs (e.g., personal care products), are also a subject of concern. Thus, the high probability of co-occurrence of both contaminants raises additional apprehensions. This study assessed, for the first time, the impacts of MPs and Ag-NPs, alone or in mixtures, on stream detritus food webs. Physiological and ecological responses of aquatic fungal communities, invertebrate shredders (Allogamus sp.) and collectors (Chironomus riparius) were examined. Additionally, antioxidant enzymatic responses of microbes and shredders were analyzed to unravel the mechanisms of toxicity; also, neuronal stress responses of Allogamus sp. were assessed based on the activities of cholinesterases. Organisms were exposed to environmentally realistic concentrations of polyethylene MPs, extracted from a personal care product (0.1, 0.5 and 10 mg L-1), for 7 days, in the absence or presence of Ag-NPs (0.1 mg L-1 and 1 mg L-1). The exposure to both contaminants reduced the growth rates of all tested organisms. MPs, Ag-NPs, and their mixtures led to a decrease in leaf litter decomposition by fungi and shredders. The availability of fine particulate organic matter, released by the shredders, increased when exposed to these contaminants. The negative effects of these contaminants were further strengthened by the responses of antioxidant enzymes that revealed high level of oxidative stress in both fungi and Allogamus sp. Moreover, the activities of cholinesterases showed that Allogamus sp. were under neuronal stress upon exposure to both contaminants. The impacts in mixtures were stronger than those of individual contaminants suggesting interactive effects. Overall, our study showed adverse effects of MPs and Ag-NPs across trophic levels and indicated that they may compromise key processes, such as organic matter decomposition in streams.

Vertical profile measurements for ammonia in a Japanese deciduous forest using denuder sampling technique: ammonia emissions near the forest floor

Ammonia (NH3) has received considerable attention as a major reduced nitrogen. However, accurate estimates of the deposition amount are difficult due to its complex behavior characterized by bidirectional exchange between the atmosphere and the surface. We observed the vertical profile of NH3 concentration in a deciduous forest in Japan for 1 year to further advance the studies on NH3 bidirectional exchange in Asia, especially focusing on the process near the forest floor. The observation period lasted from September 29, 2020, to September 28, 2021, including leafy and leafless periods. Using the denuder sampling technique, we measured NH3 concentration in the forest at three heights (above the forest canopy, 30 m, and near the forest floor, 2 m and 0.2 m). NH3 concentrations tended to be highest at the top of the canopy (30 m). Focusing on the concentration near the forest floor, the concentrations at 0.2 m were frequently higher than those at 2 m regardless of the leafy and leafless period, thus suggesting NH3 emissions from the forest floor. NH3 concentration near the forest floor showed strong positive correlations with air temperature during the leafy period. The NH3 emissions from the forest floor during the leafy period were possibly due to the decomposition of leaf litter with increased air temperature. The decrease in leaf area index might induced the increase in NH3 concentration and emission. NH3 emission during the leafless period was also possibly dependent on the state of the deposition surface, apart from air temperature, relative humidity, and leaf area index.Graphical

Patterns of decomposition and functional traits for flower and leaf litter in tropical woody species.

The variation within and across species has afterlife effects on carbon and nutrient cycling through the alteration of litter decomposability. However, the focus on leaves may not reflect a whole-plant economic spectrum of strategies. Here, we assessed the patterns and predictors of flower and leaf-litter decomposition at the intra- (i.e., flowers and leaves of the same species) and inter-specific (i.e., flowers and leaves from different species) levels for 29 tropical woody species in northeast Brazil. We evaluated nine functional litter traits, including structural and chemical traits. Flower litter decomposed, on average, three times faster than leaf litter (11.9% and 39.4% mass remaining, respectively) and exhibited higher water-holding capacity (WHC), leaching (LEA), and N, P, and K content. Otherwise, leaf litter showed higher density (DEN) and Ca, Mg, and Na content. The average relative differences in decomposition rate and functional traits between flower and leaf litter did not differ at both intra- and inter-specific levels. The predictors of decomposition were mostly similar, explaining 39% and 37% of flower and leaf litter, respectively. Leaching, P, Ca, Mg, and Na predict both flower and leaf-litter decomposition. However, WHC exclusively predicted flower-litter decomposition, and DEN, N, and K exclusively predicted leaf-litter decomposition. The observed differences in decomposition rate and functional traits between flower and leaf litter indicate that the afterlife effects differ between these plant organs and leverage the role of flower litter and its secondary consequences to nutrient and carbon cycling on ecosystems.

Salt Pulse Effects on Leaf Litter Decomposition in a Manipulated Stream: The Importance of the Conditioning Status

ABSTRACTAnthropogenic salinization constitutes a still understudied growing global threat impacting the biodiversity and the functioning of stream ecosystems. In this study, we evaluated the consequences of salt pulses in a manipulated mountain stream (central Portugal) with a salinized and a reference reach, assessing microbial decomposition of conditioned and nonconditioned chestnut (Castanea sativa) leaves, immediately after a period of NaCl exposure (daily short‐term pulses for 7 days; salinization period) and 4 days after salt contamination cessation (recovery period). Conditioned leaves consistently presented higher mass loss, fungal biomass, and respiration rates than nonconditioned leaves. Leaf conditioning status modulated the deleterious effects of salinization, being more pervasive on the decomposition process of conditioned leaves. The depressing effect on mass loss and associated parameters promoted by daily pulses of salt on these leaves was extended after the cessation of salt contamination. This suggests salt legacy effects on already established microbial communities promoted by structural changes and/or mycelial physiological adjustments. In opposition, no effects of salinization were observed in nonconditioned leaves in either period. This may result from a potentially higher salt tolerance of the pioneer species that may also take advantage of the low basal salt concentration between salt pulses and/or of further incorporation of fungal species provided from upstream. Such continuous fungal imprint may result in redundant dissimilar (salinization period) or similar (recovery period) fungal decomposing communities able to determine balanced mass loss between sides in each period. Globally, results point to the importance of considering leaf litter quality and salt exposure timing in relation to leaf litter pulses when evaluating the consequences and delineating protection measures for streams facing discrete salt contamination.

Exotic mangrove Laguncularia racemosa litter input accelerates nutrient cycling in mangrove ecosystems.

Exotic plant litter presents different chemical and physical properties relative to native plant litter and alters ecosystem processes and functions that may facilitate exotic plant dispersal. However, these effects are largely unknown, especially within wetland ecosystems. This study examines whether introducing litter from theexotic mangrove Laguncularia racemosa could result in (1) accelerated community litter decomposition rates and increased nutrient cycling rates and (2)microbial community structure changes in the invaded areas. A single decomposition experiment using litterbags was conducted to examine the short-term effects of L. racemosa litter in the native mangrove forest ecosystem. The soil nutrients and microbial communities of Rhizophora stylosa, L. racemosa, and mixed forests were also compared to explore the long-term cumulative effects of L. racemosa litter in native ecosystems. The results indicated that L. racemosa has lower-quality leaf litter than R. stylosa and a significantly faster decomposition rate. This may result from changes in the soil microbial community structure caused by L. racemosa leaf litter input, which favors the decomposition of its own litter. Both the short-term and cumulative effect experiments demonstrated that L. racemosa leaf litter significantly increased the relative abundance of microbes related to litter decomposition, such as Proteobacteria and Bdellovibrionota, and enhanced the alpha diversity of soil fungi, thus creating a microbial environment conducive to L. racemosa leaf litter decomposition. Moreover, the accumulation of soil nutrients was lower under L. racemosa than under R. stylosa over several years. This may be related to the more rapid growth of L. racemosa, which causes soil nutrient absorption and storage within the plant tissues, thereby reducing the soil nutrient content. Inputting exotic mangrove L. racemosa leaf litter reduced the soil blue carbon content, potentially adversely affecting global climate change. L. racemosa may employ a unique strategy to lower soil nutrient levels in native mangroves based on its low-quality leaf litter, thereby weakening the competitive ability of native plants that are intolerant to low-nutrient conditions and enhancing its own competitive advantage to further spread into these areas. In summary, the input of exotic L. racemosa leaf litter accelerates nutrient cycling in local mangroves.

The Addition of an Invasive Plant Alters the Home-Field Advantage of Native Leaf Litter Decomposition

The Addition of an Invasive Plant Alters the Home-Field Advantage of Native Leaf Litter Decomposition

Nitrogen Deposition Reduces the Rate of Leaf Litter Decomposition: A Global Study

The litter decomposition of plant leaves is a vital process in carbon (C) and nitrogen (N) cycling in global terrestrial ecosystems. However, previous assessments of the key determinants of the N deposition effects of litter decomposition have been more controversial. In this meta-analysis, we compared the overall effects of N addition on the litter decomposition rates, litter nutrient content (C and N), and litter constituent (lignin and cellulose) residual rates using a log response ratio approach. Our results showed that exogenous N addition increased the N content and inhibited lignin degradation in litter. N deposition decreased the leaf litter decomposition rate by increasing the lignin and N residues and decreasing the litter C content and soil pH. The analysis also concluded that the initial litter C/N ratio, lignin content, and soil pH were main factors in mediating the effect of N deposition on litter decomposition rate. Overall, the results of this study indicate that N deposition can slow decomposition rates by inhibiting N release and lignin degradation of litter. Notably, these results emphasize that the effect of N deposition on litter decomposition mainly depends on the endogenous quality of the litter and soil pH in the decomposition environment.

Variability in the home-field advantage of litter decomposition mediates alterations in soil CO2 and CH4 fluxes: A transplantation experiment study

The decomposition of litter is susceptible to the influence of climate change and soil conditions, which can subsequently impact the release of carbon dioxide (CO2) from forest soils and the absorption of methane (CH4). Ecological theory proposes the existence of a home-field advantage (HFA) in litter decomposition, suggesting that the decomposition rate of litter (such as fallen leaves, twigs, and roots) may be faster in their native habitat than in foreign environments. Therefore, we selected litter from Pinus tabuliformis (PT) and Quercus acutissima Carruth (QC) in the field and conducted a 439-day litter transplant experiment to test the magnitude and direction of the HFA of these two litter types in three forest stands. During this experiment, we monitored the changes in soil CO2 and CH4 fluxes associated with the decomposition of PT and QC leaf litter in their native and foreign sites. Furthermore, we measured various soil physical, chemical, and biological indicators. The results indicated that the decomposition rate of QC leaf litter was faster in its native habitat, demonstrating a clear HFA effect. Conversely, the decomposition of PT leaf litter was observed to be more rapid in away soil, suggesting a pronounced home-field disadvantage (HFD). The study found that PT leaf litter exhibited greater CO2 release when decomposing in away soil, demonstrating 43 % and 32 % increases compared to bare soil, respectively. Conversely, QC leaf litter was observed to release more CO2 in its home soil. Additionally, the bare soils of the PT and QC home sites were found to absorb more CH4 compared to leaf litter coverage, with increases of 37.8 % and 31.2 %, respectively. The partial least squares model indicated that the litter attributes had a significant direct effect on soil temperature and enzyme activity. Soil temperature and enzyme activity further directly influenced the soil CO2 and CH4 fluxes. The results of our study indicate that the HFA of litter is dependent on litter type, and that litter transplantation can impact soil greenhouse gas exchange. This research provides a theoretical foundation for forest management and conservation strategies, as well as valuable data for global carbon neutrality efforts.

Response of stream habitat and microbiomes to spruce budworm defoliation: New considerations for outbreak management.

Defoliation by eastern spruce budworm is one of the most important natural disturbances in Canadian boreal and hemi-boreal forests with annual area affected surpassing that of fire and harvest combined, and its impacts are projected to increase in frequency, severity, and range under future climate scenarios. Deciding on an active management strategy to control outbreaks and minimize broader economic, ecological, and social impacts is becoming increasingly important. These strategies differ in the degree to which defoliation is suppressed, but little is known about the downstream consequences of defoliation and, thus, the implications of management. Given the disproportionate role of headwater streams and their microbiomes on net riverine productivity across forested landscapes, we investigated the effects of defoliation by spruce budworm on headwater stream habitat and microbiome structure and function to inform management decisions. We experimentally manipulated a gradient of defoliation among 12 watersheds during a spruce budworm outbreak in the Gaspésie Peninsula, Québec, Canada. From May through October of 2019-2021, stream habitat (flow rates, dissolved organic matter [DOM], water chemistry, and nutrients), algal biomass, and water temperatures were assessed. Bacterial and fungal biofilm communities were examined by incubating six leaf packs for five weeks (mid-August to late September) in one stream reach per watershed. Microbiome community structure was determined using metabarcoding of 16S and ITS rRNA genes, and community functions were examined using extracellular enzyme assays, leaf litter decomposition rates, and taxonomic functional assignments. We found that cumulative defoliation was correlated with increased streamflow rates and temperatures, and more aromatic DOM (measured as specific ultraviolet absorbance at 254 nm), but was not correlated to nutrient concentrations. Cumulative defoliation was also associated with altered microbial community composition, an increase in carbohydrate biosynthesis, and a reduction in aromatic compound degradation, suggesting that microbes are shifting to the preferential use of simple carbohydrates rather than more complex aromatic compounds. These results demonstrate that high levels of defoliation can affect headwater stream microbiomes to the point of altering stream ecosystem productivity and carbon cycling potential, highlighting the importance of incorporating broader ecological processes into spruce budworm management decisions.

Agricultural Runoff Effects on Leaf Litter Decomposition: A Comparative Study in Natural and Constructed Deltaic Mediterranean Wetlands

Wetlands, widely distributed and hotspots of biodiversity, play a crucial role in global biogeochemical cycles and human well-being. However, despite their ecological importance, wetlands worldwide are under threat due to widespread conversion into agricultural fields, leading to changes in hydrology, increased salinity, and more frequent eutrophication. In response to these challenges, constructed wetlands are created to treat agricultural wastewater and mitigate eutrophication. This study aims to assess the effect of natural vs. constructed wetlands on ecosystem functioning (organic matter decomposition of the dominant vegetation: Phragmites australis and Typha angustifolia). We conducted this study in the Ebro River Delta (NE Spain), which represents a deltaic wetland affected by agricultural land-use changes, examining two constructed and two natural wetlands. Our findings indicate that the influence of agricultural runoff on the decomposition process was similar in both types of wetlands, suggesting that freshwater agricultural runoff has a consistent effect on ecosystem functioning, regardless of its origin, natural vs. constructed. Differences in macroinvertebrate communities associated with leaf litter were likely due to specific conductivity but did not impact decomposition rates. The estimated time required to decompose 95% of the T. angustifolia litter produced annually in the studied wetlands ranged from 288 to 856 days. In constructed wetland, this decomposition time exceeded one year, contributing to soil formation and carbon sequestration in wetland ecosystems. Our study suggests that the utilization of constructed wetlands for treating agricultural runoff can aid in mitigating the impacts of agricultural land use in these areas.

The impact of anthropogenic pressures on microbial diversity and river multifunctionality relationships on a global scale

Conserving biodiversity is crucial for maintaining essential ecosystem functions, as indicated by the positive relationships between biodiversity and ecosystem functioning. However, the impacts of declining biodiversity on ecosystem functions in response to mounting human pressures remain uncertain. This uncertainty arises from the complexity of trade-offs among human activities, climate change, river properties, and biodiversity, which have not been comprehensively addressed collectively. Here, we provide evidence that river biodiversity was significantly and positively associated with multifunctionality and contributed to key ecosystem functions such as microbially driven water purification, leaf litter decomposition and pathogen control. However, human pressure led to abrupt changes in microbial diversity and river multifunctionality relationships at a human pressure value of 0.5. In approximately 30 % (N = 58) of countries globally, the ratio of area above this threshold exceeded the global average (∼11 %), especially in Europe. Results show that human pressure affected ecosystem functions through direct effects and interactive effects. We provide more direct evidence that the nonadditive effects triggered by prevailing human pressure impact the multifunctionality of rivers globally. Under high levels of human stress, the beneficial effects of biodiversity on nutrient cycling, carbon storage, gross primary productivity, leaf litter decomposition, and pathogen control tend to diminish. Our findings highlight that considering interactions between human pressure and local abiotic and biotic factors is key for understanding the fate of river ecosystems under climate change and increasing human pressure.

What makes decomposition faster under conspecific trees? The factors controlling the magnitude of home‐field advantage

The ‘home‐field advantage (HFA)' for decomposition means that leaf litter decomposes faster on soils under the conspecific species (i.e. the home field) than on soils under different species (i.e. ‘away'). Many previous studies have demonstrated the HFA, but the underlying mechanisms remain unclear. We conducted a reciprocal litter‐decomposition experiment using two species with different leaf traits: Abies mariesii, an evergreen conifer, and Fagus crenata, a deciduous broad‐leaved tree. Dominance of these species shifts along an elevation gradient with a transition zone where both species coexist. In mixed forests of the transition zone along the elevation gradient, we explored how the magnitude of HFA between these two species was influenced by temperature, soil properties, or leaf litter traits which could directly affect the decomposition rate. The magnitude of HFA observed between the two species varied widely from −3.89 to 28.3%. Our modeling showed that the magnitude of HFA increased with decreasing soil pH and leaf litter N, i.e. in more acidic soil and for less decomposable litter. Soil pH affected leaf litter decomposition in the home plots of each species, whereas leaf litter N did not. The magnitude of the HFA increased as the difference in soil pH between the F. crenata and A. mariesii plots at the same elevation became greater, but decreased as the difference in soil C became greater. Thus, the response of leaf litter decomposition to environmental changes might vary not only through direct effects of vegetation traits but also through indirect effects of the HFA. This highlights the importance of considering HFA for accurately predicting the response of local carbon and nutrient cycles to climate change, particularly in communities where a replacement of dominant species by others is expected due to climate change.

Colonization & Decomposition Pattern of Water Borne Conidial Fungi in Freshwater Stream of Central Himalaya

In the freshwater streams the leaf litter substrate is colonized by early fungal colonizer and helps in decomposition of leaf litter and makes the substrate more suitable for the recruitment of late successional species. The study was carried out at Central Himalayan stream (Vinayak) to examine the colonization and decomposition pattern of Water Borne Conidial Fungi as all the streams are naturally subjected to great spatial and temporal variability, which is likely to affect the distribution and activity of organism in aquatic ecosystem. In this study nylon-mesh bags technique was used for the period of twelve months, using Angiospermic and Gymnospermic leaves as leaf litter substrate. Decomposition (weight loss) of different substrates in different months of submergence was analyzed statistically and was found that species number significantly affect the weight loss of tested leaf litter. KEY WORDS: Water Borne Conidial Fungi, Fresh Water Streams, Colonization, Decomposition.

How do soil fauna mediate leaf litter decomposition in north temperate forest ecosystems?

We investigated how soil fauna impact leaf litter decomposition in north temperate forests using litter bags with different mesh sizes (5 mm, 0.5 mm, and 0.01 mm) to exclude specific fauna by size. The experimental design included two regions (warmer, cooler) in New York State, two forest types (coniferous, deciduous), and litter bags with four tree species (yellow birch, sugar maple, red oak, red pine) that varied in litter resource quality. Excluding most soil fauna with 0.01-mm mesh decreased mass loss from litter bags by 8.8 % overall; by 19 % in the relatively warmer region; by 12 % in coniferous forest stands; and by 18 % for high-quality yellow birch litter but not for high-quality sugar maple litter or low-quality red oak and red pine litters. Mass loss rates were predicted by initial nitrogen concentrations and by initial ratios of carbon / nitrogen and lignin / nitrogen of the leaf litter; these relationships were stronger for litter bags that excluded soil fauna. Fauna extracted from the leaf litter residue were predominantly Acari (mites) and Collembola (springtails). Soil fauna mediated the extent that biochemical fractions (nitrogen, hemicellulose, cellulose, lignin) were lost from decomposing litter but in idiosyncratic ways. Not only are soil fauna impacts on leaf litter decomposition widespread, but, as shown here, they can be idiosyncratic when evaluated with several litter species that differ in resource quality, placed in different forest types, and across a climate gradient. Future analyses of soil fauna impacts on leaf litter decomposition should combine litter-, site-, and climate-related variability to improve understanding and enable prediction.

Effects of nanoplastic exposure routes on leaf decomposition in streams

Polystyrene nanoparticles (PS NPs) released from plastic products have been demonstrated to pose a threat to leaf litter decomposition in streams. Given the multitrophic systems of species interactions, the effects of PS NPs through different exposure routes on ecosystem functioning remain unclear. Especially dietary exposure, a frequently overlooked pathway leading to toxicity, deserves more attention. A microcosm experiment was conducted in this study to assess the effects of waterborne and dietary exposure to PS NPs on the litter-based food chain involving leaves, microbial decomposers, and detritivores (river snails). Compared to waterborne contamination, dietary contamination resulted in lower microbial enzyme activities and a significantly higher decrease in the lipid content of leaves. For river snails, their antioxidant activity was significantly increased by 20.21%–69.93%, and their leaf consumption rate was significantly reduced by 16.60% through the dietary route due to the lower lipid content of leaves. Besides, the significantly decreased nutritional quality of river snails would negatively influence their palatability to predators. The findings of this study indicate that dietary exposure to PS NPs significantly impacts microbial and detritivore activities, thus affecting their functions in the detritus food chain as well as nutrient cycling.

Unraveling the Role of Bacteria in Nitrogen Cycling: Insights from Leaf Litter Decomposition in the Knyszyn Forest

Unraveling the Role of Bacteria in Nitrogen Cycling: Insights from Leaf Litter Decomposition in the Knyszyn Forest

Salamander loss alters montane stream ecosystem functioning and structure through top‐down effects

AbstractAmphibians are among the most endangered taxa worldwide, but little is known about how their disappearance can alter the functioning and structure of freshwater ecosystems, where they live as larval stages. This is particularly true for urodeles, which often are key predators in these ecosystems. The fire salamander (Salamandra salamandra) is a common predator in European fresh waters, but the species is declining due to habitat loss and the infection by fungal pathogens. We studied the consequences of fire salamander loss from three montane streams, by comparing two key ecosystem processes (periphyton accrual and leaf litter decomposition) and the structure of three communities (periphytic algae, aquatic hyphomycetes and invertebrates) using stream enclosures with and without salamander larvae. Salamander loss did not cause changes in invertebrate abundance or community structure, except for one stream where abundance increased in the absence of salamander larvae. However, salamander loss led to lower periphyton accrual, changes in algal community structure and slower leaf litter decomposition, with no associated changes in fungal communities or microbial decomposition. The changes observed may have been caused by release of salamander predatory pressure on invertebrates, which could have promoted their grazing on periphyton, in contrast to their preference for leaf shredding in the presence of salamander. Our study demonstrates an important role of salamander larvae in montane streams through top‐down control of lower trophic levels and thus in regulating key stream ecosystem processes. Our results highlight the need for improving protection measures for amphibians to prevent these alterations on ecosystem structure and function.

Magnesium addition increases microbial metabolic efficiency during decomposition of Patagonian leaf litter

Magnesium addition increases microbial metabolic efficiency during decomposition of Patagonian leaf litter