Forest Sites Research Articles

Camera trapping of forest mammals in Bükk Mountain, Hungary

AbstractThe link between large- and middle-sized mammals in forest habitat is understudied in Central Europe; meanwhile these animals could have important effects on their habitats. In our study, we analysed camera trapping data obtained from May 2015 to September 2021 on 29 different sites in a temperate forest at the Bükk Mountain, Hungary. We investigated the temporal activity of ungulates (red deer, roe deer, wild boar) and predators (red fox and grey wolf), together with their response to human disturbance. We calculated temporal overlap value (Δ4) and occurrence dynamics with multi-state modelling (msm). The results suggest that human activity was higher at daytime, while the mammals were more active at night. Multi-state modelling (msm) grouped animals and humans separately. Ungulates chose nighttime, when predators were also active, while they avoided daytime and human disturbance. Grey wolf were mostly co-occurred with its main food source, the red deer. Red fox overlapped the most with roe deer, suggesting that fox prey upon deer fawns. We found that human disturbance has a significant impact on the activity of forest mammals, whereas the expected avoidance of predators by ungulates does not appear to be evident. To better understand the effect of prey–predator behavioural responses in the presence of human disturbance, more field studies are needed in the region.

How Habitat Simplification Shapes the Morphological Characteristics of Ant Assemblages (Hymenoptera: Formicidae) in Different Biogeographical Contexts

Human-driven changes in land cover and use can significantly impact species ants community structures, often leading to a decline in taxonomic diversity or species homogenization. Ant morphology, used as a proxy for ecological function, offers a valuable framework for understanding the effects of anthropogenic disturbances on ant diversity. This study explored the morphological diversity of ant assemblages in agricultural ecosystems and secondary forests in Italy and the Brazilian Amazon, analyzing how these communities are structured and adapted to different environments. The research aims to understand the ecological interactions and the role of ants in maintaining biodiversity in these contexts. The study was conducted in the Ticino River Natural Park, Italy, and the Paragominas mosaic in Pará, Brazil. The ants were sampled using epigean pitfall traps at 15 agricultural and 13 forest sites. In the secondary forests, the species richness was significantly higher in both countries compared to agricultural areas. In general, the Community Weighted Mean (CWM) of the selected traits (head length, head width, interocular distance, mandible length, eye width, Weber’s length, and tibia length) of Brazilian ants was higher than those of Italian. However, the CWM of agricultural areas of the two countries was more similar. We noticed the convex hull (i.e., the volume of an assemblage in the morphological space) of Brazilian secondary forests was still larger than Italian secondary forests when both assemblages have the same number of species. Morphological homogenization was more pronounced in agricultural settings, whereas secondary forests showed more variability, highlighting the role of environmental filtering in shaping ant communities across land use types.

Differences in foraging phenology dampen the impact of an invasive slug on ant-mediated seed dispersal of understory forest plants

Seed-dispersal mutualisms are important ecosystem functions that, if disrupted, influence plant fitness and community structure. Anthropogenic stressors such as invasive species and climate change may independently or synergistically influence animal-mediated seed dispersal. Aphaenogaster sp. ants are the primary dispersers of myrmecochorous plants that produce diaspores or seeds with lipid-rich appendages (elaiosomes) that make them attractive to ants in eastern North American forest understories. An invasive slug, Arion sp., damages diaspores by consuming elaiosomes, rendering seeds unattractive to ants. Here, in one forest site, we examine if slugs negatively affect seed dispersal by assessing interactions between seed-dispersing ants and invasive slugs on four species of myrmecochores that release diaspores at different times. We performed an exclusion experiment, excluding slugs and ants to diaspores on depots, when diaspores of four myrmecochore species were released from fruits. We also conducted a similar experiment presenting diaspores of all species at one time in the field and slug preference trials in the lab to determine if particular myrmecochore species are vulnerable to the invasive slug. We found that slugs did not reduce dispersal by ants despite slugs damaging diaspores. This was because peak ant and slug activity differed, with slugs damaging most diaspores of early-dehiscing Sanguinaria canadensis, and ants dispersing most diaspores of later-dehiscing Trillium grandiflorum. When diaspores were presented at the same time, ants and slugs preferred the same species, T. grandiflorum. While we did not find overlap in the phenology of ant and slug interactions in this study, phenological interactions are likely context-dependent. Thus, high-preference species may be vulnerable to invasive slugs if interacting species overlap in different contexts, including under climate change.

Assessment and correction of representational bias in phytoliths from modern soil in the Dongting Lake Basin, China

Understanding how well topsoil phytoliths represent their aboveground plant communities, and then correcting for any representational bias, is the basis for the accurate phytolith-based reconstruction of past vegetation. We evaluated the representational bias in topsoil phytoliths at 39 sampling sites in forest, shrub, and herb communities in the Dongting Lake Basin, China. We compared the types, concentrations, and percentages of topsoil phytoliths and corresponding plant community phytoliths within the same plant community and quantified the relationships. We observed significant representational biases. Combined with the representation indices of phytoliths, we quantitatively defined the vegetation representativeness of different phytolith types in the topsoil samples. We defined four categories of representation: Associated types, Over-represented types, Under-represented types, and “Special” types. We observed differences in the vegetation representativeness of different topsoil phytolith types, and the same phytolith type also showed significant differences in vegetation representativeness between different plant communities. Additionally, using the preservation index (R-value), we corrected the representational bias of topsoil phytoliths between the different plant communities. After validation, we found that the corrected topsoil phytoliths more accurately represented quantitative changes in the aboveground plant communities. Therefore, the preservation index (R value) is an effective means of correcting the representational bias of topsoil phytoliths, and it can provide the basis for more accurate phytolith-based reconstructions of past vegetation.

Butterfly community dynamics in a monoculture‐dominated agricultural landscape

Abstract Understanding biodiversity dynamics in agricultural landscapes is essential for promoting sustainable land use and conserving wildlife. We examined butterfly communities in a monoculture‐dominated landscape, comparing remnant grassland sites surrounded by agricultural land (AGR), grasslands (GR), and forests (FOR). Data were collected from 30 sites across these three categories. We used non‐metric multidimensional scaling (NMDS) to assess community composition, rank abundance curves for community structure, and Hill numbers for alpha diversity. Generalised additive models (GAMs) identified key drivers of rare species richness and the abundance of the most common species, Coenonympha pamphilus. Results showed a few dominant species, with most having low abundances. Species richness was similar across all site categories, but differences in evenness and species dominance highlighted variations in community structure. GR and FOR sites had higher numbers of both rare and abundant species, indicating a more balanced distribution compared to AGR sites. NMDS revealed significant differences in composition, especially between FOR and AGR. The GAM results showed that the combination of agricultural land and forest cover enhances rare species richness, while agricultural cover alone had a negative impact. Even for the most common species C. pamphilus, high agricultural cover negatively impacts its population but shifts positively when combined with greater vegetation height in adjacent grasslands. These findings highlight the critical role of forest habitats within monoculture‐dominated landscapes in enhancing butterfly community diversity and stability. The adaptability of butterfly species to agricultural landscapes is limited to a small number of species and only up to a certain extent.

A Mathematical Model for Estimating Carbon Storage Dynamics of Forest Communities

Using the JABOWA single-tree growth model, a program was designed to estimate carbon storage dynamics in the aboveground biomass of a mixed forest community. The developed model incorporates the parameters of tree species that are common to the forests of Central Russia: pedunculate oak (Quercus robur L.), silver birch (Betula pendula Roth), common aspen (Populus tremula L.), small-leaved lime (Tilia cordata Mill.), Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), and fir (Abies Mill.). A differential equation for tree diameter at breast height (D) was solved. The results were compared with the forest inventory data. The amount of carbon stored in the aboveground biomass of trees was calculated following the methodology suggested by the Intergovernmental Panel on Climate Change. The dynamics of tree volume were analyzed. An analytical formula was proposed to describe the dependence of tree volume and stored carbon on tree age. The differences in the rates of tree volume growth and carbon accumulation were identified among the species studied. The analytical and numerical results on stored carbon and tree age showed a good agreement for a test plot with the known species composition and tree count, which is located within the forest part of the carbon polygon of Kazan Federal University. The formula offers an accurate estimation and prediction of carbon storage dynamics in mixed forest communities with trees varying in age and, hence, is a valuable tool for managing forestry activities. However, when predicting tree biomass growth and carbon storage dynamics, one should also consider forest site quality classes reflecting the actual growth conditions of trees. Developing a mathematical model based on forest site quality classes as a key variable would help increase the reliability of biomass growth and carbon storage predictions for forest communities. Notably, the obtained model applies to actual forest communities with known species composition and fails to account for natural regeneration. To incorporate this parameter, spatial diffusion models that describe forest regeneration in non-forest areas should be utilized.

Methane and carbon dioxide evasion from a mosaic of Amazon lakes, river channels, and inundated forests

Seasonally inundated forests are the largest type of wetland in the Amazon basin. Here we provide new data from inundated forests, a lake, and river channels during high water in the forested Anavilhanas archipelago (Negro River, Brazil). Evasion pathways of CH4 in flooded forests include tree trunks, diffusion from the water, and ebullition. Within flooded forest sites, diffusive CH4 fluxes were lowest (mean, 6.2 µmol m-2 h-1), ebullitive fluxes averaged 50 µmol m-2 h-1, and fluxes from the trees had the highest fluxes when expressed per inundated surface area (83 µmol m-2 h-1). The lake and river channels usually had higher CH4 and CO2 fluxes than inundated forests. Overall, mean CH4 fluxes from inundated forests in our study were lower than fluxes measured in nutrient-rich inundated forests. Our results contribute to understanding the heterogeneity of C fluxes from inundated forests. Water levels, currents and extent of inundated habitats contribute to variability in gas fluxes. Outgassing rates are expected to become more variable with projected periods of especially high and low water levels as the climate changes.

Assessment of the heartwood contribution to carbon accumulation in Pinus sylvestris L. trees under different forest site conditions

BackgroundThe heartwood (HW) proportion in the trunk of mature trees is an important characteristic not only for wood quality but also for assessing the role of forests in carbon sequestration. We have for the first time studied the proportion of HW in the trunk and the distribution of carbon and extractives in sapwood (SW) and HW of 70–80 year old Pinus sylvestris L. trees under different growing conditions in the pine forests of North-West Russia. MethodWe have examined the influence of conditions and tree position in stand (dominant, intermediate and suppressed trees) in the ecological series: blueberry pine forest (Blu) – lingonberry pine forest (Lin) – lichen pine forest (Lic). We have analyzed the influence of climate conditions in the biogeographical series of Lin: the middle taiga subzone – the northern taiga subzone – the transition area of the northern taiga subzone and tundra. ResultsWe found that the carbon concentration in HW was 1.6%–3.4% higher than in SW, and the difference depended on growing conditions. Carbon concentration in HW increased with a decrease in stand productivity (Blu-Lin-Lic). In medium-productive stands, the carbon concentration in SW was higher in intermediate and supressed trees compared to dominant trees. In the series from south to north, carbon concentration in HW increased by up to 2%, while in SW, it rose by 2.7%–3.8%. ConclusionsOur results once again emphasized the need for an empirical assessment of the accurate carbon content in aboveground wood biomass, including various forest growing conditions, to better understand the role of boreal forests in carbon storage.

Evaluating forest aboveground biomass estimation model using simulated ALS point cloud from an individual-based forest model and 3D radiative transfer model across continents

Area-based approach (ABA) has been widely employed for estimating forest aboveground biomass (AGB) using airborne laser scanning (ALS) data. However, its scalability is limited due to challenges in model generalization across different forest types and regions. The selection of sensitive variables from ALS data is crucial for constructing robust forest AGB estimation models, yet this selection varies significantly among forest types and regions. Traditionally, assessing the influence of variable selection is hindered by the lack of accurate reference forest AGB values. Computer simulation-based method provides a perspective for exploring these challenges. This study employs an individual-based forest growth process model, FORMIND, coupled with a 3D radiative transfer model (RTM), LESS, to evaluate the transferability of ABA-based forest AGB estimation models and the generalization of ALS-derived variables. We used six virtual 3D forest scenes and two real-world forest sites, representing a range of global forest types, along with their simulated ALS data, to develop a forest AGB estimation model using the random forest algorithm, which allowed us to analyze the importance of various variables. We assessed model transferability through cross-comparison. Additionally, we validated the model using field plots and ALS data collected from two distinct regions. The results showed that the canopy surface area and volume extracted using the α-shape algorithm and parameters fitted from the Weibull distribution are vital variables when using ALS for forest AGB estimation across forest types and regions. Incorporating these variables into the model significantly improves the accuracy of forest AGB estimation. The optimized model achieved a R2 of 0.945, a RMSE of 34.22 t/ha, and a MAE of 20.53 t/ha. Our study not only deepens the understanding of the relationship between forest vertical structural metrics and AGB but also highlights the potential of computer simulation as a tool for refining the estimation of forest structural parameters.

Antibacterial activity of the biogenic volatile organic compounds from three species of bamboo.

Plant biogenic volatile organic compounds (BVOCs) possess ecological functions in antimicrobial benefits and air purification. The objectives of the study were to determine the differences in antimicrobial capacity of bamboo forests at different sampling sites. Three common bamboo species-Phyllostachys edulis, Bambusa emeiensis, and Phyllostachys violascens-were selected to determinate the antimicrobial activity of bamboo forests as well as under ex vivo conditions. Natural sedimentation method was used to determine the microbe counts in bamboo forests, and the microbe counts in grassland in the same area was measured as control treatment. The results showed that except for the P. violascens in Ya'an, the airborne microbial content of the sampling sites in bamboo forests was significantly lower relative to that of grassland in the same area, and inhibition rate reached 74.14% in the P. violascens forest in Dujiangyan. P. edulis forest and P. violascens forest in Ya'an had significantly lower inhibition rates than the other sampling sites, and there was no significant difference in the inhibition rates among the rest of the bamboo forest. The bacterial inhibition rate of bamboo leaves under ex vivo conditions varied with bamboo species and bacterial strains, with higher antibacterial activity against Gram-negative bacteria overall. Escherichia coli was sensitive to B. emeiensis leaves, while Staphylococcus aureus and Bacillus subtilis were sensitive to P. violascens leaves. Moreover, Candida albicans, S. cremoris, and Shigella Castellani were sensitive to P. edulis leaves. An analysis of the BVOCs composition from P. edulis collected in Changning by SPME-GC/MS revealed that the relative content of ocimene was obviously higher than other components. This study showed that P. edulis BVOCs have strong inhibitory ability to the tested microorganisms, and its main constituent, ocimene, has health benefit. P. edulis has the potential to become a forest recreation bamboo species.

Rhizosphere as a hotspot for microbial necromass deposition into the soil carbon pool

Abstract Microbial leftovers, known as necromass, are key players in storing carbon in the soil around plant roots (i.e. rhizosphere), a zone characterized by high‐efficiency microbial anabolism. Yet, the extent and mechanisms through which the rhizosphere contributes to soil organic carbon (SOC) via microbial necromass, especially under changing environments remain unclear. We aimed to evaluate the contributions of microbial necromass to SOC and influencing factors from the rhizosphere perspective. We collected the rhizosphere and bulk soil from 39 alpine coniferous forest sites on the eastern Tibetan Plateau to assess the extent of microbial necromass contribution to SOC in the rhizosphere from a dynamic perspective by calculating the ratio of increased amino sugars (AS) to increased SOC in the rhizosphere relative to that in bulk soil (RAS/SOC). We also collected climate data and determined nutrient concentrations and microbial physiological traits in rhizosphere soil to elucidate the factors affecting RAS/SOC. The results showed that across all sampling sites, the average concentrations of SOC‐normalized AS in the rhizosphere were significantly higher than those in the bulk soil. Furthermore, the average RAS/SOC was greater than 1, indicating a faster microbial necromass accumulation than SOC accumulation in the rhizosphere. These results implied that the rhizosphere sustains a greater capacity for microbial necromass contribution to the SOC pool than the bulk soil does. Soil nutrient availability was the primary factor affecting RAS/SOC, and precipitation indirectly affected microbial anabolism and RAS/SOC by changing soil nutrient status. Additionally, with increasing rhizosphere soil nutrient availability, microbial carbon‐use efficiency and growth rate increased but the biomass‐specific enzyme activity declined, indicating that microorganisms tended to exhibit high‐yield strategies with increasing soil nutrient availability. Synthesis. Our findings underpin the vital effect of microbial necromass in SOC accumulation from the rhizosphere perspective and offer valuable insights into mechanisms underlying microbial C metabolic processes in rhizosphere SOC accumulation under changing environments.

Learning extreme vegetation response to climate drivers with recurrent neural networks

Abstract. The spectral signatures of vegetation are indicative of ecosystem states and health. Spectral indices used to monitor vegetation are characterized by long-term trends, seasonal fluctuations, and responses to weather anomalies. This study investigates the potential of neural networks in learning and predicting vegetation response, including extreme behavior from meteorological data. While machine learning methods, particularly neural networks, have significantly advanced in modeling nonlinear dynamics, it has become standard practice to approach the problem using recurrent architectures capable of capturing nonlinear effects and accommodating both long- and short-term memory. We compare four recurrent-based learning models, which differ in their training and architecture for predicting spectral indices at different forest sites in Europe: (1) recurrent neural networks (RNNs), (2) long short-term memory networks (LSTMs), (3) gated recurrent unit networks (GRUs), and (4) echo state networks (ESNs). While our results show minimal quantitative differences in their performances, ESNs exhibit slightly superior results across various metrics. Overall, we show that recurrent network architectures prove generally suitable for vegetation state prediction yet exhibit limitations under extreme conditions. This study highlights the potential of recurrent network architectures for vegetation state prediction, emphasizing the need for further research to address limitations in modeling extreme conditions within ecosystem dynamics.

Traction Assistance of a Forwarder in Flat Terrain

Traction assistance of forest machines via traction aid winches has gained widespread application in steep-terrain forest operations as it can mitigate soil disturbance by reducing wheel or track slip of the assisted machine. Since slip affects machine operations in flat terrain as well, especially on fine-grained and moist soils, the effectiveness of traction assistance under such conditions was evaluated. At a forest site, a forwarder with a total mass of 28.6 t was driven over two plots in 15 passes. The machine travelled unassisted over one plot, while on the second plot traction assistance was manually adjusted to keep slip close to 0%. Wheel slip and winch tractive force were recorded during each pass, and rut depth was measured after each pass. Soil density was measured pre-impact and at three times after different traffic increments. Although the mean wheel slip was low even during unassisted travel, traction assistance was found to cause a significant reduction. While both a decrease in rut depth and soil compaction were observed with traction assistance, only the latter was significant after three machine passes. A potential influence of inhomogeneous soil reinforcement due to roots suggests repeating the experiment on a more homogenous soil.

Disentangling direct and indirect effects of forest structure on biodiversity: Bottom‐up and top‐down effects between forestry, bats and their insect prey

Abstract Timber‐oriented forest management profoundly alters forest structure and composition, with complex effects on associated biodiversity. However, while species' responses to forest management and resulting structural characteristics have been the subject of numerous studies, direct and indirect effects that cascade through trophic levels are rarely disentangled. As insectivorous bats are particularly sensitive to changes in forest structure, that shape their available flight space, we investigated how forest structure, composition and management also indirectly modify their habitats, for example, by affecting important insect prey groups. We used structural equation models (SEMs) to test bat responses to forest composition, structure (forest heterogeneity, old‐growth attributes) and management intensity, quantifying direct and indirect prey‐mediated effects. For that, three bat guilds—short‐ (SRE), mid‐ (MRE) and long‐range echolocating (LRE) bats—and their prey insects (moths and ground beetles) were analysed from 64 sites in the Black Forest, Germany. We found guild‐specific effects on bats: While the structural heterogeneity of forests directly influenced the activity of bat guilds, the main influence of forest management, composition and structure was mediated through their prey‐groups. SRE activity responded to moths and LRE activity was associated with ground beetles, with positive effects of the insect groups' abundance, but negative effects of the same group's species richness. In addition, the SEM approach revealed a negative top‐down relationship between MRE activities and moths, suggesting predation or avoidance behaviour of moths. While forest management directly or indirectly increased prey insect abundance, it negatively affected the availability of roosting structures for bats. Synthesis and applications. The results highlight the indirect and positive effects of forest management on bats and support the important role of bats in insect regulation within continuous cover forests. Although forest management created small gaps that improved foraging habitats for most bats, it compromised the roosting functionality for bats. The ‘close‐to‐nature forestry’ currently prevalent in Europe mainly promotes continuous‐cover forests in mid‐successional stages. Expanding the forest management portfolio towards open and old‐growth forests would increase roosting opportunities and provide complementary foraging habitats for different bat species, while promoting high biodiversity in managed forest landscapes.

Quartz grain surface features and mineralogy of sediments in the Sundarbans Forest site, Bangladesh: Constraints on the depositional environment and provenance

An investigation on medium to coarse-grained quartz grains (QG) recovered from a ~ 100-m drilled core section of the Sundarbans Forest site in the southwestern Bangladesh was carried out to infer the source and depositional environment. Thirty-six microtextures were identified from 200 QG using a scanning electron microscopy (SEM). The QG surface features are categorized into mechanical (number of features n = 25), chemical (n = 5), and combined mechanical and chemical (n = 6), which provide invaluable insights on the transport mechanism, provenance, and depositional environment. Microtextures of mechanical origin include parallel striations, straight steps, crescentic percussion marks, conchoidal fractures, arcuate steps, fresh polished surfaces, V-shaped marks, broken edges, abrasion fatigue, and bulbous and meandering edges, which are more common in QG and ascribed to high-energy eolian and fluvial transports. The abundant chemical features such as crystalline overgrowth, silica globules, scaling, silica pellicle, and silica flower are omnipresent on QG surfaces, demonstrating a subaqueous diagenetic environment. Fracture plates/planes, high relief, elongated depressions, adhering particles, chatter marks, and oriented etch pits are common in the QG, suggesting a subaqueous nearshore marine environment. There is a high abundance of quartz (Si), feldspar (Na and K), titanite (Ti), and zircon (Zr) in the core sediments, indicating their derivation from felsic source rocks.

MOSQUITO SPECIES DISTRIBUTION IN TIRES IN RURAL AND URBAN LANDSCAPES ACROSS NORTHERN KENTUCKY.

Discarded vehicle tires can be found in habitats spanning a human land-use gradient from rural to urban and create an ideal artificial container habitat for mosquito larval development. The purpose of this study was to examine mosquito species composition in discarded vehicle tires in rural and urban habitats. Discarded tires were placed at 6 rural and 6 urban forested sites and sampled weekly for juvenile mosquitoes. Adult traps were also placed at these sites and were sampled weekly. There was no significant difference between the total number of juvenile mosquitoes collected from tires in urban sites compared to rural sites, but significantly more Aedes triseriatus and Ae. albopictus juveniles were found in urban sites compared to rural sites. This study also found that significantly more adult mosquitoes were collected in urban sites compared to rural, but there were no significant differences found between sites when comparing individual species. The results of this study suggest discarded vehicle tires are important mosquito larval habitats across human-land-use gradients and that Ae. triseriatus may be more common in urban areas than previously thought.

Characterization and prediction of hydraulic properties of traffic-compacted forest soils based on soil information and traffic treatments

Key messageThe hydraulic properties of compacted and rutted soils were evaluated through in-situ infiltration experiments and predicted based on soil texture class and traffic treatments. A significant decrease in saturated soil water content and soil hydraulic conductivity at saturation was observed. The resulting soil hydraulic parameters, when integrated into a soil water transfer model, effectively simulated water dynamics in these impacted forest soils, providing a crucial first step toward developing decision support tools for real-time trafficability. This approach can assist forest managers in minimizing the extent of soil compaction.ContextTo overcome trafficability issues of forest soils induced by heavy logging machinery, planning support tools are needed to determine suitable soil moisture conditions for traffic.AimsThis study aimed to identify the soil properties that differ significantly between undisturbed and compacted soils and to provide several estimation tools to predict the hydraulic properties of compacted soils beneath the skid trails.MethodsFour hundred seventeen water infiltration tests were conducted on 19 forest sites, mostly in North-eastern France, and analysed with the BEST method to estimate the hydraulic properties of the skid trails and undisturbed soils. The hydraulic properties of the skid trails were predicted thanks to linear mixed effect models using a bulk treatment effect, a site effect, or a skid trail degradation score. The predicted hydraulic properties were tested using a water flow model to assess their relevance regarding the prediction of water dynamics in skid trails.ResultsThe compaction effect was only significant for the logarithm of the hydraulic conductivity at saturation (log10(Ksat)) and the soil water content at saturation (θsat). For the skid trails, θsat was reduced by - 0.02 and − 0.11 m3m−3 in the 0 − 10 cm and 15 − 25 cm layers respectively, compared to undisturbed topsoil (0 − 10 cm). log10(Ksat) was reduced by − 0.38 and − 0.85 for skid trails in the 0 − 10 and 15 − 25 cm soil layers respectively, compared to undisturbed topsoil. The use of a pedotransfer function, in replacement of water infiltration tests, and their combination with the same correction coefficients proved to efficiently simulate the difference in water dynamics between skid trails and undisturbed forest soils.ConclusionEstimation of soil hydraulic properties based on in situ water infiltration experiments proved efficient to simulate water dynamics in compacted and rutted forest soils. Yet, further studies are needed to identify the most adapted pedotransfer function to forest soils and to test the generalisation of our findings in different conditions, especially deeply rutted soils (rut depths > 12 cm).

The functions and factors governing fungal communities and diversity in agricultural waters: insights into the ecosystem services aquatic mycobiota provide.

Fungi are essential to the aquatic food web, nutrient cycling, energy flow, and ecosystem regulation. Fungal community structures in water can be influenced by adjacent terrestrial environments, which drive and control some ecosystem services they provide. However, the roles of freshwater fungal communities remain underexplored compared to bacterial communities in this context. We assessed the impact of anthropological and environmental factors on freshwater mycobiota in an agriculturally dominated water basin in eastern Ontario, Canada. We undertook bi-weekly surface water sampling from 2016 to 2021 and conducted fungal internal transcribed spacer 2 (ITS2) metabarcoding on the samples, complemented by ancillary data, including water physicochemical properties, upstream land use, hydrology, and weather conditions. Our study yielded 6,571 OTUs from 503 water samples, spanning 15 fungal phyla, dominated by Ascomycota, Basidiomycota, and Chytridiomycota. Agricultural land use was associated with decreased mycobiota alpha diversity and distinct fungal communities were observed at agricultural drainage ditch and mixed-land use sites compared to a forested site that had minimal anthropogenic activities in catchment. Notably, river discharge emerged as a predominant influencer of both community diversity and composition, likely amplified by precipitation-induced erosion and drainage from adjacent terrestrial environments. Water physicochemical properties, including stream fungicide levels, explained a small proportion of the variation in mycobiota communities, underscoring the significance of unmeasured factors, alongside stochastic community assembly processes. Nevertheless, stream mycobiota demonstrated functional resilience for critical ecological processes under different environmental conditions. Altogether, these results highlight the complex interplay of factors influencing the freshwater mycobiota, which is essential for elevated understanding of the ecosystem services these fungi provide.

Within-Site Variations in Soil Physicochemical Properties Explained the Spatiality and Cohabitation of Arbuscular Mycorrhizal Fungi in the Roots of Cryptomeria Japonica

Arbuscular mycorrhizal fungi (AMF) live in a community in the roots of host plants. Still, the patterns and factors that drive their spatiality and cohabitation remain uncovered, particularly that of trees in planted forests, which we aimed to clarify in Cryptomeria japonica, a major plantation tree in Japan. We analyzed 65 paired root and soil samples of Cryptomeria japonica trees collected from 11 microsite (MS) plots at two environmentally different forest sites in central Japan and measured soil pH, total phosphorus (TP), C, N, and the carbon-to-nitrogen ratio. Root AMF communities were recovered using Illumina’s next-generation amplicon sequencing targeting the small subunit of ribosomal DNA. We detected more than 500 AMF OTUs at each site but only three belonging to Dominikia, Rhizophagus, and Sclerocystis were dominant in the roots of C. japonica, detected each at an average relative abundance higher than 20%. Two showed negatively correlated spatial distributions and different associations with soil pH. Similarly, the physicochemical properties at MSs significantly determined the AMF assemblages in the roots of C. japonica. Dominikia, Rhizophagus, and Sclerocystis coexist in the roots of C. japonica where soil physicochemical properties, particularly pH, determine their spatial dynamic, turnovers, and cohabitation patterns. These findings highlight the importance of simultaneous colonization of plants by multiple AMF.

Understanding the ecological versatility of Tetracladium species in temperate forest soils.

Although Tetracladium species have traditionally been studied as aquatic saprotrophs, the growing number of metagenomic and metabarcoding reports detecting them in soil environments raises important questions about their ecological adaptability and versatility. We investigated the factors associated with the relative abundance, diversity and ecological dynamics of Tetracladium in temperate forest soils. Through amplicon sequencing of soil samples collected from 54 stands in six forest sites across the eastern United States, we identified 29 distinct Amplicon Sequence Variants (ASVs) representing Tetracladium, with large differences in relative abundance and small changes in ASV community composition among sites. Tetracladium richness was positively related to soil pH, soil temperature, total sulphur and silt content, and negatively related to plant litter quality, such as the lignin-to-nitrogen ratio and the lignocellulose index. Co-occurrence network analysis indicated negative relationships between Tetracladium and other abundant fungal groups, including ectomycorrhizal and arbuscular mycorrhizal fungi. Collectively, our findings highlight the ecological significance of Tetracladium in temperate forest soils and emphasize the importance of site-specific factors and microbial interactions in shaping their distribution patterns and ecological dynamics.