Leaf Litter Research Articles

Sourcing and long-range transport of particulate organic matter in river bedload: Río Bermejo, Argentina

Abstract. Fluvial transport of organic carbon from the terrestrial biosphere to the oceans is an important term in the global carbon cycle. Traditionally, the long-term burial flux of fluvial particulate organic carbon (POC) is estimated using river suspended sediment flux; however, organic carbon can also travel in river bedload as coarse particulate organic matter (POMBed). Estimates of fluvial POC export to the ocean are highly uncertain because few studies document POMbed sources, flux, and evolution during long-range fluvial transport from uplands to ocean basins. This knowledge gap limits our ability to determine the global terrestrial organic carbon burial flux. In this study we investigate the flux, sources, and transformations of POMBed during fluvial transport over a ∼1300 km long reach of the Río Bermejo, Argentina, which has no tributary inputs. To constrain sourcing of POMBed, we analyzed the composition and stable hydrogen and carbon isotope ratios (δ2H, δ13C) of plant wax biomarkers from POMBed at six locations along the Río Bermejo and compared this to samples of suspended sediment, soil, leaf litter, and floating organic debris (POMfloat) from both the lowland and headwater river system. Across all samples, we found no discernible differences in n-alkane average chain length or nC29 δ13C, indicting a common origin for all sampled POMBed. Leaf litter and POMfloat nC29 δ2H values decrease with elevation, making it a useful proxy for POMBed source elevation. Biomarker δ2H values suggest that POMBed is a mix of distally derived headwater and locally recruited floodplain sources at all sampling locations. These results indicate that POMBed can be preserved during transport through lowland rivers for hundreds of kilometers. However, the POMBed flux decreases with increasing transport distance, suggesting mechanical comminution of these coarse organic particles and progressive transfer into the suspended load. Our provisional estimates suggest that the carbon flux from POMBed comprises less than 1 % of the suspended load POC flux in the Río Bermejo. While this represents a small portion of the river POC flux, this coarse, high-density material likely has a higher probability of deposition and burial in sedimentary basins, potentially allowing it to be more effective in long-term CO2 drawdown relative to fine suspended particles. Because the rate and ratio of POMBed transport versus comminution likely vary across tectonic and climatic settings, additional research is needed to determine the importance of POMBed in the global carbon cycle.

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 influence of plant traits on soil microbial communities varies between arid and mesic grasslands

Abstract Background and aims Both soil properties and plant traits shape the diversity, composition and functions of plant-associated soil microbial communities. However, the relative influence of these factors is poorly understood, as are interactive effects between factors and the degree to which their influence varies among climate zones. Methods To address this gap, we compared the diversity and composition of soil microbial communities associated with co-occurring C3 and C4 grasses from arid and mesic environments, and plant traits influencing them. Results Climate emerged as the main determinant of plant traits and microbial community properties. Within each climatic region, above- and below-ground traits and soil properties differentially affected microbial community composition, and their relative influence varied among communities. In both mesic and arid environments aboveground traits related to quantity and quality of leaf litter (e.g., specific leaf area, leaf C content) and nutrient availability were the most influential variables for community composition. However, in arid regions, belowground traits (i.e., root tissue density and specific root area) significantly contributed to structure the eukaryotic community, supporting the role of roots as important driver of eukaryotic differentiation in constrained environments. Further, the presence of C4 plants in the arid region resulted in higher relative abundance of ciliate protists and higher recruitment of potentially beneficial microbial community members from green algae mediated by drought adaptation traits (e.g. decreased abundance of fine roots). Conclusions Overall, our study revealed a differential response of microbial communities to environmental conditions, suggesting that soil microbial community composition is influenced by trade-offs between host adaptive traits across distinct climatic regions.

Effects of riparian forest and annual variation in stream environmental conditions on leaf litter breakdown and invertebrate communities in highland grassland streams

Effects of riparian forest and annual variation in stream environmental conditions on leaf litter breakdown and invertebrate communities in highland grassland streams

Fire effects on plant communities in Ozark woodlands and glades

BackgroundDecades of fire suppression caused drastic changes to community structure and composition across ecosystems, including in Ozark woodlands in Missouri, USA. Reintroducing fire can restore ground flora by reducing midstory tree density, increasing ground layer light, and reducing leaf litter accumulation, but we lack a clear understanding of how these effects vary across time and space. We investigated the effects of repeated prescribed fire on ground flora species richness, floristic quality, abundance, community composition, and stand structure over 20 years in a landscape matrix of dry-mesic woodlands, dry woodlands, and glades using data collected from the Ozark National Scenic Riverways Fire Effects Monitoring program in the Current River Watershed in the Missouri Ozarks.ResultsWe found that fire plays a key role in driving community structure and dynamics across community types, although with varying levels of intensity. Herbaceous species richness, abundance, and floristic quality index increased across all community types, while mean coefficient of conservatism decreased. Abundance and floristic quality effects were stronger in drier sites. Community composition changed with successive burns, resulting in several indicator species for post burn treatments. The density of midstory trees declined across community types with repeated fire. The number of burns significantly affected overstory tree density overall, but overstory tree density only declined in dry woodlands and glades and not in dry-mesic woodlands.ConclusionsOur results suggest that landscape fire shapes plant community structure and dynamics. Specifically, these findings show that fire effects vary among community types and suggest that land managers should consider landscape heterogeneity in fire application for restoration. Separate community types imbedded in the same landscape may respond to fire differently. Understanding repeated fire effects over several decades across multiple community types is critical to informing fire-driven woodland restoration across landscape scales.

Changes in decomposition dynamics, soil community function and the growth of native seedlings under the leaf litter of two invasive plants

Changes in decomposition dynamics, soil community function and the growth of native seedlings under the leaf litter of two invasive plants

Variations in source-specific soil organic matter components across 32 forest sites in China

Forest soils store substantial amounts of carbon in various soil organic matter (SOM) components due to high plant litter inputs and active microbial turnover. However, the variations in plant- and microbial-derived SOM components in surface and subsurface forest soils across a wide geographic scale remain poorly understood. This study investigated the SOM components from aboveground and belowground plant inputs and fungal and bacterial necromass in surface (soil0–5 cm) and subsurface (soil5–10 cm) soils across 32 forest sites in China and analyzed their relationships with climate and edaphic factors. Compared to soil0–5 cm, soil5–10 cm exhibited lower soil organic carbon content and cutin biomarker concentration but higher concentrations of fungal necromass carbon and lignin phenols. Higher mean annual precipitation led to higher concentrations of cutin and suberin biomarkers in soil0–5 cm and soil5–10 cm, respectively. Higher soil organic carbon content was associated with lower plant-derived lignin biomarkers, higher lignin oxidation degrees, and increased microbial necromass-derived amino sugars across sites, highlighting the pivotal role of microbial necromass in SOM stabilization. Additionally, both fungal and bacterial necromass decreased with increasing mineral weathering across sites. These insights improve the understanding of environmental drivers of source-specific carbon storage in forest soils.Graphical

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.

Characterization of fungal microbiome structure in leaf litter compost through metagenomic profiling for harnessing the bio-organic fertilizer potential.

The online version contains supplementary material available at 10.1007/s13205-024-04028-0.

Drought effects on litter fraction and recovery in a subtropical forest

Litter input is a critical link between the circulation and flows of energy and matter in forest ecosystems. Drought events impact litter inputs, affecting forest ecosystems’ nutrient and energy cycles. To investigate the response of litter production to extreme drought, explore their recovery mechanism, and the difference between whole year, concurrent drought, non-drought period, rainy season, and dry season. We studied an extreme drought event in a subtropical evergreen broadleaved forest in the Ailao Mountain in 2009–2010. We used 10 years (2005–2014) of monthly litter production and climate data, including monthly average precipitation (MAP), soil water content (SWC), and monthly average temperature (MAT). The observation period was separated into pre-drought (2005–2008), during-drought (2009–2010), and post-drought (2011–2014) periods. We found that annual total litter production decreased by 12 % during the drought (p < 0. 05), similar to that in the drought period. Leaf litter production increased by 1 % during drought time, and other fraction decreased obviously. The contribution of water environmental factors to litter production was more evident after drought events. MAT, MAP, and SWC jointly affect litter input under extreme drought conditions, and the dominant factor is related to litter fraction and drought periods. Water environmental factors (MAP & SWC) contributed to litter input after drought events, while MAT mainly affected litter input during the non-drought and rainy seasons. Due to the growth and nutritional strategies of each fraction, the recovery time is branch < leaf < flower & fruit < moss < bark. The results further reveal litter production response to drought events and the importance of water factors in recovery.

Distributions of trace elements with Long-term grazing exclusion in a semi-arid grassland of Inner Mongolia.

Trace elements are the essential mineral nutrients in grassland, however, we still know little about the distributions of trace elements in grassland with long-term grazing exclusion. The contents, stocks, and proportions of iron (Fe), aluminum (Al), manganese (Mn), and boron (B) in green plant-litter-root-soil were evaluated by enclosing for 18, and 39 years inside the fence (F18 and F39) and grazing outside the fence (F0) in Inner Mongolia grassland. The results showed that F18 and F39 decreased the stocks of Fe, Al, and Mn in green plant and root compared to F0 (p < .05), while increased the stocks of them in litter (p < .05). The stock of Fe, Al, and Mn in green plant at F39 was 28.6%, 13.9%, and 39.2% higher than that at F18. The stocks of four trace elements in first layer litter at F39 were increased by 12.7%-52.2% compared to F18, whereas the stocks of them in third layer litter were decreased by 32.2%-42.5%. The F18 obviously increased the stocks of Fe and Mn in soil, especially B (p < .05). While the stocks of these trace elements in soil at F39 were 9.1%-28.0% lower than that at F18, especially B (p < .05). In conclusion, the trace elements were mainly shifted from green plant and root to soil and third layer litter with 18-year grazing exclusion. Compared to 18-year grazing exclusion, the trace elements were shifted from third layer litter and soil to root with 39-year grazing exclusion.

Seasonal Dynamics of Culturable Yeasts in Ornithogenically Influenced Soils in a Temperate Forest and Evaluation of Extracellular Enzyme Secretion in Tausonia pullulans at Different Temperatures.

The culturable yeast communities in temperate forest soils under the ornithogenic influence were studied in a seasonal dynamic. To investigate the intense ornithogenic influence, conventional and "live" feeders were used, which were attached to trees in the forest and constantly replenished throughout the year. It was found that the yeast abundance in the soil under strong ornithogenic influence reached the highest values in winter compared to the other seasons and amounted to 4.8 lg (cfu/g). This was almost an order of magnitude higher than the minimum value of yeast abundance in ornithogenic soils determined for summer. A total of 44 yeast species, 21 ascomycetes and 23 basidiomycetes, were detected in ornithogenic soil samples during the year. These included soil-related species (Barnettozyma californica, Cyberlindnera misumaiensis, Cutaneotrichosporon moniliiforme, Goffeauzyma gastrica, Holtermanniella festucosa, Leucosporidium creatinivorum, L. yakuticum, Naganishia adeliensis, N. albidosimilis, N. globosa, Tausonia pullulans, and Vanrija albida), eurybionts (yeast-like fungus Aureobasidium pullulans, Debaryomyces hansenii, and Rhodotorula mucilaginosa), inhabitants of plant substrates and litter (Cystofilobasidium capitatum, Cys. infirmominiatum, Cys. macerans, Filobasidium magnum, Hanseniaspora uvarum, Metschnikowia pulcherrima, and Rh. babjevae) as well as a group of pathogenic and opportunistic yeast species (Arxiozyma bovina, Candida albicans, C. parapsilosis, C. tropicalis, Clavispora lusitaniae, and Nakaseomyces glabratus). Under an ornithogenic influence, the diversity of soil yeasts was higher compared to the control, confirming the uneven distribution of yeasts in temperate forest soils and their dependence on natural hosts and vectors. Interestingly, the absolute dominant species in ornithogenic soils in winter (when the topsoil temperature was below zero) was the basidiomycetous psychrotolerant yeast T. pullulans. It is regularly observed in various soils in different geographical regions. Screening of the hydrolytic activity of 50 strains of this species at different temperatures (2, 4, 10, 15 and 20 °C) showed that the activity of esterases, lipases and proteases was significantly higher at the cultivation temperature. Ornithogenic soils could be a source for the relatively easy isolation of a large number of strains of the psychrotolerant yeast T. pullulans to test, study and optimize their potential for the production of cold-adapted enzymes for industry.

Wildfires Influence Mercury Transport, Methylation, and Bioaccumulation in Headwater Streams of the Pacific Northwest.

The increasing frequency and severity of wildfires are among the most visible impacts of climate change. However, the effects of wildfires on mercury (Hg) transformations and bioaccumulation in stream ecosystems are poorly understood. We sampled soils, water, sediment, in-stream leaf litter, periphyton, and aquatic invertebrates in 36 burned (one-year post fire) and 21 reference headwater streams across the northwestern U.S. to evaluate the effects of wildfire occurrence and severity on total Hg (THg) and methylmercury (MeHg) transport and bioaccumulation. Suspended particulate THg and MeHg concentrations were 89 and 178% greater in burned watersheds compared to unburned watersheds and increased with burn severity, likely associated with increased soil erosion. Concentrations of filter-passing THg were similar in burned and unburned watersheds, but filter-passing MeHg was 51% greater in burned watersheds, and suspended particles in burned watersheds were enriched in MeHg but not THg, suggesting higher MeHg production in burned watersheds. Among invertebrates, MeHg in grazers, filter-feeders, and collectors was 33, 48, and 251% greater in burned watersheds, respectively, but did not differ in shredders or predators. Thus, increasing wildfire frequency and severity may yield increased MeHg production, mobilization, and bioaccumulation in headwaters and increased transport of particulate THg and MeHg to downstream environments.

Overstory and fuel traits drive moisture dynamics of mesophytic and pyrophytic leaf litter and 10-h woody debris fuels in a mixed longleaf pine-hardwood woodland

BackgroundFollowing decades of fire exclusion, many open pine and oak forests across the central and eastern US are shifting to closed-canopy forests that are increasingly dominated by shade-tolerant, fire-sensitive species (i.e., mesophytes). As mesophytes encroach into historically pyrophytic landscapes, changes in crown traits and understory microclimate may interact with fine fuel traits to influence fuel moisture retention, and ultimately, fire behavior. To better understand potential interactions among overstory trees and underlying fine fuels that occur during mesophyte encroachment, we measured in situ drying rates of leaf litter and 10-h woody debris of three functional groups (pyrophytic pine, pyrophytic oak, and mesophytic oak) in gaps and beneath overstory trees of each functional group within a longleaf pine-mixed oak woodland along with crown (area, volume, cover), leaf litter (curling, thickness, specific leaf area, volume), and woody debris (density) traits of each functional group and understory microclimate (vapor pressure deficit (VPD)).ResultsWe found that leaf litter from pyrophytic and mesophytic oaks had higher initial moisture content than pyrophytic pines, but pyrophytic pine and pyrophytic oak leaf litter dried 1.5 times faster than that of mesophytic oaks, likely due to their greater leaf curl, thickness, and volume. Initial moisture content of mesophytic oak woody fuels was lower than that of pyrophytic pine and pyrophytic oak, potentially because of higher wood density, but there were no differences in fuel drying rates. Regardless of fuel functional type, leaf litter and woody fuels dried 1.5 times faster in gaps and underneath pyrophytic pine compared to mesophytic oaks, likely due to the more open conditions in these areas. Notably overstory functional group and time of the day interacted to influence VPD, with VPD increasing throughout the day for all groups, but more so for gaps and beneath pyrophytic pines than either oak functional group.ConclusionsThus, fuel and crown traits differentially impacted understory microclimate and leaf litter and 10-h woody debris drying rates, leading to slower drying of fuels of encroaching mesophytes compared to pyrophytic pines and oaks, which could lead to reduced forest flammability, and consequently, the continued encroachment of mesophytic species into fire-dependent pine and oak forests.

Secondary compounds increase litter removal by termites across 23 savanna grass species

Abstract Termites—one of the most abundant animal groups in tropical ecosystems—are vital in nutrient recycling, contributing significantly to maintaining ecosystem functioning. However, how selective they are in their litter food choice, and whether they prefer nutritious or less nutritious litter substrates, are still important unresolved questions. Here, we test the effect of litter traits on the removal of litter by fungus‐growing termites, a dominant group of macrodetritivores in the Serengeti‐Mara ecosystem. We used metal‐mesh litterbags to measure the mass loss of stem and leaf litter from 23 grass species after an incubation period of 61 days. Sheeting—soil deposits indicating termite presence—strongly increased with tannin and phenolic compounds, especially in leaf litter (R2 = 0.54), where highly aromatic species like Cymbopogon caesius and Bothriochloa insculpta exhibited the highest sheeting rates. Litterbags with sheeting displayed 66% higher mass loss on average compared to those without. Once termites had selected the substrate, mass loss increased consistently irrespective of litter traits. Quantifying the combined effects of sheeting frequency and differential mass loss, we found that fungus‐growing termites predominantly increased the mass loss of high‐nutrient litter. This was mainly due to additional mass loss in leaf litter, not stem litter, with tannin concentration being the primary predictor of enhanced overall decomposition by termites. This suggests termites ameliorate the otherwise adverse influence of plant secondary compounds on litter decomposition. Synthesis: Our results support the idea that fungus‐growing termites are generalists, as termites collected organic substrates with varying quality. The strong effect of phenolic compounds on sheeting rate implies that secondary compounds play an important role in termite substrate selection. The selective removal of substrates high in secondary compounds suggests fungus‐growing termites lift important constraints to microbial breakdown, potentially enhancing ecosystem‐level carbon and nutrient recycling rates. Termites play crucial roles in recycling organic matter across tropical biomes and our study highlights that the role of secondary compounds in their selection and detection in decomposition studies needs more attention

Fantastic Macrofungi in Poncokusumo District, Bromo Tengger Semeru National Park (TNBTS) Area and Their Habitat Characteristics

Bromo Tengger Semeru National Park (TNBTS) is a conservation area in East Java with an abundance of biodiversity, including macrofungi. This study aims to identify the macrofungal species existing in Poncokusumo district, TNBTS area, and their habitat characteristics for a further sustainable study of fungi. This study used a purposive sampling method by opportunistic exploration. Identification of macrofungi is conducted by morphological analysis and habitat characterization. The study identified 15 macrofungal species categorized as Ascomycota and Basidiomycota, that were distinct in their habitat characteristics. The 15 macrofungal species inhabited leaf litter, wood litter, soil, and bamboo.

Mechanisms of litter input changes on soil organic carbon dynamics: a microbial carbon use efficiency-based perspective

Plant litter is an important source of soil organic carbon (SOC) in terrestrial ecosystems, and the pattern of litter inputs is also influenced by global change and human activities. However, the current understanding of the impact of changes in litter inputs on SOC dynamics remains contentious, and the mechanisms by which changes in litter inputs affect SOC have rarely been investigated from the perspective of microbial carbon use efficiency (CUE). We conducted a 1-year experiment with litter treatments (no aboveground litter (NL), natural aboveground litter (CK), and double aboveground litter (DL)) in Robinia pseudoacacia plantation forest on the Loess Plateau. The objective was to assess how changes in litter input affect SOC accumulation in forest soils from the perspective of microbial CUE. Results showed that NL increased soil microbial C limitation by 77.11 % (0–10 cm) compared to CK, while it had a negligible effect on nitrogen and phosphorus limitation. In contrast, DL had no significant effect on soil microbial nutrient limitation. Furthermore, NL was found to significantly increase microbial CUE and decrease microbial metabolic quotient (QCO2), while the opposite was observed with DL. It is noteworthy that NL significantly contributed to an increase in SOC of 30.72 %, while DL had no significant effect on SOC. Correlation analysis showed that CUE was directly proportional to SOC and inversely proportional to QCO2. The partial least squares pathway model indicated that NL indirectly regulated the accumulation of SOC, mainly through two pathways: promoting microbial CUE increase and reducing QCO2. Overall, this study elucidates the mechanism and novel insights regarding SOC accumulation under changes in litter input from the perspective of microbial CUE. These findings are critical for further comprehension of soil carbon dynamics and the terrestrial C-cycle.

Collembola Diversity across Vegetation Types of a Neotropical Island in a River Delta

Springtails, vital for ecosystem assessment, are often overshadowed by taxonomy-focused research, which mostly neglects their ecology and distribution, particularly in the Neotropical Region. The objective of this study was to identify how environmental factors, especially vegetation types, affect the availability of food resources for epiedaphic Collembola and influence their diversity patterns in three vegetation types (riparian forest, mangrove, and restinga) in the Canárias Island, in Delta do Parnaíba Environmental Protection Area, Brazil (APADP). We collected samples along 200 m transects in each vegetation type during the dry and rainy seasons. After, specimens were sorted, counted and identified. Alpha (species richness, Shannon, Simpson, and Pielou indices) and beta diversity (Whittaker index) were analyzed, along with environmental factors’ influence through Redundancy Analysis (RDA). We sampled a total of 5346 specimens, belonging to three orders, eight families, 23 genera, 31 morphospecies, and one nominal species. Species abundance was positively influenced by soil moisture, plant richness, and leaf litter. The riparian forest sheltered a higher species richness and diversity, and its biotic and abiotic factors likely enhanced the food resource availability, including vegetal organic matter, fungi, and bacteria. These results provide the first taxonomic and ecological data on the Collembola fauna in the APADP.

Multi-kingdom characterization of living organisms by 13C CPMAS NMR spectroscopy reveals unique traits in bacteria, fungi, algae, and higher plants

Determining the chemical quality of soil organic matter and decomposing organisms is critical for predicting carbon fluxes in ecosystems. However, the classical C/N and lignin/N ratios have been criticized for their capability in predicting ecosystem function including litter decay rate, nitrogen mineralization and soil aggregation. Therefore, with our work we aim to complement information on the chemical properties of primary producers and decomposers based on 13C NMR. Overall, 108 unique 13C NMR spectra were collected from higher plant tissues including leaf litter, fine roots, woody debris, as well as a range of microbes i.e. bacteria, fungi, and marine algae. Results showed clear discrimination between organisms belonging to different kingdoms, but with limited variability within bacteria, fungi, and microalgae. In detail, bacteria were found to be distinct not only from plant tissues but also from fungi, characterized by a high proportion of alkyl and carbonyl C types and a rather low relative abundance of O Alkyl C and di-O Alkyl C types. Among the fungi, we found clear separation between yeasts, which are more similar to bacteria, and filamentous species, which are rich in O Alkyl and di-O Alkyl C types. Microalgae are characterized by a high content of aliphatic, carboxylic and methoxyl C fractions. In the spectra of terrestrial plants, the O Alkyl C region, associated with sugars and cellulose, is more abundant compared to algae and bacteria. In addition, the aromatic carbon signal, which is mainly associated with lignin, is much higher for higher plants than in microorganisms. As for plant tissues, woody tissues are clearly different from leaves and fine roots, with grasses, sedges, and ferns being well distinguished from forbs, coniferous and deciduous trees. In summary, our study contains the largest freely available 13C NMR spectral library of bacteria, fungi, algae, and higher plant tissues. However, the data from higher plants are sufficient to cover different functional types, which is not yet possible for bacteria and fungi.