Search Results (124)

This study evaluates the multi-year taxonomic diversity and functional structure of beetle assemblages (Coleoptera) within Sub Arini Park, a historic urban green space in Sibiu, Romania. Following a preliminary baseline and methodological calibration phase in 2023, systematic monitoring was conducted during the 2024 and 2025 seasonal cycles utilizing standardized pitfall trapping across diverse park zones. We explicitly tested two hypotheses: (H1) that long-standing historic park management preserves a resilient and functional insect community structure, and (H2) that local spatial heterogeneity and microhabitat variations significantly drive species distribution. A total of 14,843 individuals belonging to 39 species were analyzed. While total abundance exhibited a slight decrease from 2024 (N = 7112) to 2025 (N = 6551), true diversity metrics (Hill numbers) revealed a significant increase in raw species richness (q = 0) from 30 to 39 species, alongside an enhanced equity of frequent species (Shannon diversity, q = 1, increased from 4.26 to 5.12). Functional guild analysis and multivariate PCA demonstrated a highly structured biocenotic distribution; specialist and hygrophilous species (e.g., Carabus variolosus Fabricius, 1787) were strictly constrained to high-humidity riparian corridors, whereas thermophilous generalists dominated open lawns under high anthropogenic stress. Our spatial analysis identified critical degradation within these heavily managed zones, specifically driven by intensive mowing, soil compaction, and organic debris removal. These findings confirm both hypotheses, revealing that the park operates as a heterogeneous mosaic of ecological refugia rather than a uniform habitat block. Crucially, this study provides a concrete, quantitative basis—derived from empirical thresholds of species richness, abundance shifts, and mapped microhabitat preferences—for implementing nature-based management strategies (such as establishing buffer zones with reduced mowing frequencies, limiting trampling, and retaining coarse woody debris) aimed at mitigating urban biodiversity loss and maintaining vital biological pest control services in Central–Eastern Europe. Full article

The expansion of Moso bamboo (Phyllostachys edulis) significantly alters the spatial configuration of surrounding trees, leading to dynamic shifts in the spatial distribution of coarse woody debris (CWD). Investigating the spatial patterns of CWD during bamboo expansion can reveal the dynamic mechanisms of forest communities in this process, thereby providing scientific insights for forest management and conservation. In this study, conducted within the Yangjifeng Biodiversity Monitoring Large Plot, all trees with a diameter at breast height (DBH) ≥ 1 cm within the plots were tagged and important variables were measured, including DBH, tree height, and spatial attributes. Coarse woody debris (CWD) with a DBH ≥ 10 cm was also measured, including DBH, diameters at both ends, length, and spatial attributes. Based on the importance values of tree species in each 20 m × 20 m plot—where an importance value comprehensively measured a species’ relative abundance, frequency, and dominance in the community—the sample plots were divided into three continuous sample transects: evergreen broad-leaved forest (EBF), bamboo–broadleaf mixed forest (BMF), and Phyllostachys edulis forest (PEF). Ripley’s ‘g’-function was employed to analyze the spatial patterns and associations of CWD across these three forest types. A random sampling approach was used to collect CWD samples for the measurement and calculation of carbon storage. Three key findings emerged. (1) With the expansion of Moso bamboo, the biomass and carbon storage of standing dead trees both decrease. The biomass is highest in EBF, followed by BMF and PEF. However, carbon storage is greatest in BMF and lowest in PEF. (2) With the expansion of Moso bamboo, the distribution of CWD became increasingly uniform in PEF; analysis of the overall spatial pattern of CWD indicated that with increasing spatial scale, CWD changed from an aggregated to a random distribution across all three forest types, with a pattern scale of approximately 10 m. In EBF, the CWD of Moso bamboo exhibited a random distribution at all spatial scales. Additionally, CWD across different diameter classes, decay stages, and types changed from aggregated to random distributions as the spatial scale increased, with a reduction in aggregation intensity correlated with larger diameter classes. (3) Finally, we found an almost exclusively negative spatial association between living trees and CWD across all scales, and this negative correlation may be attributed to the absence of new tree growth following tree mortality. Collectively, our findings demonstrate that during Moso bamboo expansion, the spatial distribution of CWD changes from aggregated to random, while maintaining a significantly negative spatial association with living trees. This reveals the dynamic changes in the spatial patterns of CWD during community development, thereby providing a scientific basis for the forest management of subtropical evergreen broadleaf forests and bamboo management and control. Full article

Availability of phosphorus (P) is thought to limit bole growth in wet tropical forests, raising concern that removing P through repeated logging in P-limited stands may be unsustainable. Motivated by a study in Indonesia, we analyzed Olsen extractable and total soil P in the upper 10 cm in paired samples we collected under vs. near decaying boles of two contrasting species in a wet tropical forest in Puerto Rico. Guarea guidonia had higher wood and leaf P concentrations than Dacryodes excelsa. G. guidonia colonized valleys with higher soil P concentrations than ridge sites dominated by D. excelsa. We used two age cohorts of trees > 30 cm diameter, felled by hurricanes Hugo in 1989 (11 years old) and Georges in 1998 (1.5 years old), but soil P did not differ with age. Soil Olsen P concentrations were significantly higher under versus away from boles of both species. Paradoxically, augmentation of soil P was greater under boles of D. excelsa than G. guidonia despite having lower wood P. Soil % C and Olsen P were strongly positively correlated in D. excelsa but not in G. guidonia, suggesting that regulation of soil P-availability differs between ridges and valleys. Both soil C and P may be critical for maintaining soil fertility on ridges in a wet tropical forest. Our results are discussed in the context of prior experiments at our site, including two where bole growth increased with wood addition and/or decreased after removal of woody debris. These studies in Puerto Rico, together with others elsewhere, suggest that reduced forest productivity could potentially result from repeated logging of forest stands on ridges with low P-availability in humid tropical areas since decaying wood could directly and indirectly maintain P-availability in sites with low soil P-availability. We suggest several hypotheses on P-cycling in montane humid tropical forests that need further research to elucidate mechanisms controlling soil P-availability and identify sites where repeated logging is likely to be unsustainable. Full article

This review examines how forest microrefugia (fine-scale thermal and moisture shelters formed by canopy complexity, deadwood, topography, and snow) protect small mammals from climate extremes in European forests. It synthesizes evidence on the physiological and behavioral sensitivity of rodents and shrews to near-ground abiotic environmental conditions and highlights methods for measuring and modeling microclimatic factors using LiDAR and sensor networks. These findings are integrated into a framework that links structural retention, coarse woody debris, and canopy heterogeneity to microclimate resilience. Despite global advances in microclimate research and the development of new research methods and equipment, empirical data from European forests remain scarce, particularly regarding operative temperature, humidity, and vapor pressure deficit near the ground and within subnivean habitats. By bridging the fields of microclimate physics, small mammal ecology, and silvicultural design, the review identifies the mechanisms and metrics recommended to sustain functional refugia. The synthesis identifies knowledge gaps, standardizes microclimate metrics, and outlines required forest management practices, revitalizing research and inspiring new approaches to small mammal ecology. Full article

Old-growth forests are rare in Europe, yet they play a critical role in biodiversity and carbon storage. This study examines the structural dynamics of the Janj old-growth forest in the Dinaric Alps using repeated field measurements from 2011 and 2021 at 39 systematically arranged 12 m radius plots. All trees (DBH ≥ 7.5 cm), regeneration (10 cm height to 7.5 cm DBH), and coarse woody debris (CWD) were assessed. Results revealed that total basal area declined by 3.5 m² ha⁻¹ over the decade, primarily driven by significant reductions in stem density for silver fir (p = 0.001) and Norway spruce (p = 0.001). In contrast, European beech maintained a stable basal area throughout the study period. Moreover, silver fir exhibited a significant increase in mean diameter (p = 0.032) and a pronounced rise in regeneration individuals (t = 3.257, p = 0.002). These findings underscore a gradual compositional shift towards European beech dominance, with conifers facing higher mortality in larger diameter classes. The substantial volume of CWD (463 m³ ha⁻¹) highlights advanced decay dynamics consistent with mature forest conditions. This study emphasizes the value of repeated measurements to capture subtle yet important successional changes in primeval forests, which is essential for conservation planning and sustainable forest management. Full article

Deadwood is a vital component of forest ecosystems, significantly contributing to biodiversity and carbon storage. Accurate mapping of deadwood is essential for ecological monitoring and sustainable forest management. This study introduces a method for downed deadwood mapping using a convolutional neural network (CNN) applied to very high-resolution UAV RGB imagery. The research was conducted in Hainich National Park, central Germany, aiming to enhance the precision of coarse woody debris (CWD) delineation in a dense and structurally diverse temperate deciduous forest. Key objectives included testing the deep learning (DL) model’s performance at area, length, and object levels and benchmarking its accuracy against a traditional object-based image analysis (OBIA) method. Deadwood volume was calculated from the mapping results. By implementing a U-Net architecture with a ResNet-34 backbone and utilizing data augmentation techniques, the model achieved very high classification performance (F1-scores between 73% and 96%). It provided precise delineation of individual CWD objects from the underlying ground, representing detailed stem forms. High precision values highlight the reliability of the mapping results, while lower recall values indicate that some CWD objects, especially smaller branches, were missed. The DL approach achieved higher accuracy values across all testing methods compared to the OBIA method. The study also addresses the challenges posed by spectral ambiguities in decomposed deadwood and recommends future research directions for enhancing model generalization across diverse forest types and acquisition conditions. Full article

Pyrogenic carbon (PyC) is generated from the incomplete combustion of biomass and fossil fuels. Pyrogenic carbon is highly stable and is often referred to as a missing carbon sink. It plays a crucial role in global carbon cycling and climate change research. We analyzed the storage of PyC and uncharred biological organic carbon (BOC) within woody debris (WD) and the charcoal layer, as well as the properties of PyC, across four forest types in the cold temperate coniferous forest of the Greater Khingan Mountains. Pyrogenic carbon in WD appears as charred, blackened material, while PyC in the charcoal layer was extracted through chemical oxidation using HF/HCl treatment. Our methodology included particle size separation through dry sieving, followed by the analysis of four size fractions (>2 mm, 2–1 mm, 1–0.5 mm and <0.5 mm) for elemental composition, and the chemical composition was analyzed using DRIFT. With respect to WD, PyC storage ranged from 0.040 to 0.179 Mg·ha⁻¹, whereas BOC storage ranged from 3.1 to 16.8 Mg·ha⁻¹. In the charcoal layer, PyC storage ranged from 7.9 to 44.3 Mg·ha⁻¹, and BOC storage ranged from 3.8 to 11.6 Mg·ha⁻¹. Pyrogenic carbon storage in the charcoal layer dominated (>99%) on the above-ground in each forest type. The DRIFT analysis confirmed that the coarse fraction (>2 mm) contain more polymeric aromatic structures, and most likely indicated the presence of benzene carboxylic compounds (1710 cm⁻¹), which may originate from the charred plant material. Our research aims to enhance the understanding of the retention effects of recalcitrant carbon in WD and charcoal layer of cold temperate coniferous forest, thereby providing new insights into the impact of fire disturbances on carbon cycling within forest ecosystems. Full article

As global forest areas decline and face increased risk from extreme events, optimizing forest types for long-term stability becomes crucial. However, empirical evidence for the effects of mixing methods on carbon and nitrogen dynamics in forest ecosystems remains limited. This study investigates five forest types in Southern China: the Tsuga longibracteata W.C.Cheng pure forests, the Tsuga longibracteata–hardwood mixed forests, the Tsuga longibracteata–Phyllostachys edulis (Carr.) J.Houz. mixed forests, the Tsuga longibracteata–Rhododendron simiarum Hance mixed forests, and the Tsuga longibracteata–hardwood–Rhododendron simiarum mixed forests (the tree species are all dominant community species). We examined one monoculture and four mixed forests, categorized into pure tree forests and tree–shrub mixed forests, and categorized by tree species richness levels of 1, 2, and 3. We measured carbon (C) and nitrogen (N) content, along with the C:N, of coarse woody debris (CWD) at various decay stages and in the adjacent topsoil (0–10 cm) to analyze decomposition rates and their effects on soil nutrients. Our results indicate that the C content and density of CWD differed significantly among forest types (p < 0.001). The Tsuga longibracteata–Phyllostachys edulis mixed forest exhibited the highest C and N content in CWD, but the lowest in adjacent topsoil, alongside the fastest decomposition rate. Soil C content and the C:N ratio showed highly significant differences among forest types (p < 0.001), and N content showed a significant difference (p < 0.05). Optimal outcomes occurred at a species richness level of 2, as excessive or insufficient species richness can diminish decomposition rates. The ecological benefits of tree–shrub mixed forests surpassed pure tree forests. Overall, these findings suggest that mixed forests do not always provide greater ecological advantages than pure forests, and that improper mixing can deplete soil. Full article

Coarse woody debris (CWD) is an essential component in forest ecosystems, playing a significant role in enhancing biodiversity, soil formation, and nutrient cycling through decomposition processes. CWD also contributes to greenhouse gas fluxes, particularly through CO₂ emissions. This study investigated the physical and chemical properties of CWD and the CO₂ effluxes from CWD of different decay classes. For this study, a range of CWD—from recently dead to highly decomposed wood—of native tree species such as silver birch (Betula pendula Roth), black alder (Alnus glutinosa (L.) Gaertn.), and Norway spruce (Picea abies (L.) H. Karst.) in hemiboreal forests were investigated. The findings showed that CWD properties significantly differed among tree species and CWD decay classes. Significant variations in wood density and total nitrogen (N) were observed in the early stages of CWD decay, with the highest values found for the deciduous tree species. The concentration of organic carbon (C) increased throughout the decomposition. The lowest CO₂ efflux from CWD was found for spruce CWD from all decay classes and it was the highest for black alder and silver birch, especially for the 3rd and 4th decay classes. CO₂ efflux was mainly influenced by the degree of decomposition, which was represented by the CWD decay class, followed by wood density and C content. Full article

This paper presents the diversification of fluvial sediments caused by the occurrence of coarse woody debris (CWD), boulder steps (BSs), and mixed structures (MSs), understood as a combination of CWD and BSs in a stream channel in a small forested catchment in the Polish Carpathians. This research is crucial for understanding the role of this kind of threshold present in a stream channel in shaping fluvial sediment characteristics in small forested mountain catchments. Our hypothesis is that the threshold type in a stream channel determines fluvial sediment diversification. This was verified in field research, including identification of the channel’s morphodynamic structure and the morphometric characteristics of CWD, BSs, and MSs as well as the collection of fluvial sediments upstream and downstream of them. In order to preserve research objectivity, tests were performed during comparable flow conditions in the summer (EX1) and autumn (EX2) periods. The statistical analysis showed that the type of threshold significantly affects the processing, size, and shape diversification of mineral material. This diversity is particularly noticeable in fluvial sediments within CWD and MSs, which retain material of more diverse sizes and shapes. Full article

Coarse woody debris (CWD) has historically been extensively utilized in Korea, with significant accumulation occurring mainly after the establishment of protected areas. This study, conducted in Odaesan National Park (designated in 1975), investigated the distribution and characteristics of CWD across five forest types with permanent plots. It also examined the effects of human and natural disturbances on CWD dynamics and evaluated its role in carbon storage. CWD mass varied significantly, ranging from 0.7 Mg ha⁻¹ in Pinus-Quercus (PQ) forests to 31.9 Mg ha⁻¹ in Broadleaved–Abies (BA) forests. The impacts of disturbances shifted markedly before and after the park’s designation; prior to this, human activities such as logging substantially affected BA, PQ, and Prunus-Salix (PS) forests, while Quercus-Tilia (QT) forests were primarily impacted by wildfires. After designation, natural disturbances became the primary contributors to CWD accumulation, with a major windstorm in BA forests adding 12.09 Mg ha⁻¹ of CWD (37.8% of the total). Late-successional forests exhibited higher CWD mass, advanced decay stages, and greater diversity, as well as elevated CWD-to-carbon storage ratios, highlighting their role as crucial carbon reservoirs. In light of climate change, these findings emphasize the need for forest management practices that enhance CWD’s contributions to biodiversity conservation and carbon storage. Full article

The investigation into the spatial distribution of living woody (LWD) and coarse woody debris (CWD) within forests represents a fundamental methodology for probing the inherent mechanisms governing coexistence and mortality within forest ecosystems. Here, a complete spatial randomness (CSR) null model was employed to scrutinize the spatial pattern, while canonical correspondence analysis (CCA) and the Torus-translation test (TTT) were utilized to elucidate the distribution patterns of LWD and CWD within warm-temperate deciduous broadleaf secondary forests in Dongling Mountains plot, northern China. The results reveal that both LWD and CWD exhibit an aggregated distribution as the predominant pattern in the Dongling Mountains plot, with the proportion and intensity of aggregation diminishing as spatial scale increases. Specifically, the aggregation intensity g_0–10 demonstrates a significant negative correlation with abundance and maximum diameter at breast height (DBH). Notably, the g_0–10 of LWD manifests a stronger correlation with the maximum DBH, whereas the g_0–10 of CWD exhibits a greater association with the mortality rate. CCA outcomes suggest that elevation, convexity, and aspect significantly impact LWD distribution, whereas CWD distribution shows substantial negative correlations with elevation, convexity, slope, and aspect. TTT findings indicate that ecosystems characterized by a substantial presence of LWD also display a notable prevalence of CWD. Additionally, the majority of species exhibit no habitat preference, displaying neutral habitat connections and low ecological niche differentiation within the sampled plot. Full article

The forests of the boreal biome, which perform an important climate-regulating function, are the most susceptible to forest fires. An important task is to obtain quantitative estimates of carbon (C) losses of forest ecosystems under different fire damage scenarios, as well as the possibility of such estimates based on remote sensing data. Our study provides comprehensive field data on C stocks in pools of plant phytomass and necromass, forest litter, and ground cover for a vast area of boreal forests in the Russian Far East. We studied forests of the larch formation that have been affected by fires of varying intensity. The severity of the fires was assessed based on differenced Normalized Burn Ratio (dNBR). The variation in C pools depending on the strength of the fire is shown. We did not find a relationship of C stocks with the dNBR in the forests in the south of the study area that might have caused the rapid change of species during post-fire recovery. In the northern part of the area, there is a trend of a decrease in plant phytomass with an increase in dNBR (R² = 0.78). The proportion of dead standing wood share in the total C stock increases with increasing fire severity (R² = 0.63). The maximum and average C stocks in the litter were 10.6 and 3.9 t C ha⁻¹, respectively; coarse woody debris contained 8.7 and 2.0 t C ha⁻¹; carbon stocks in living ground cover were 1.2 on average and reached 4.7 t C ha⁻¹. Our study shows that dNBR can serve as a good predictor of the C stock of phytomass after a fire in the northern part of the Far East region, which opens up opportunities for approximate quantitative remote estimates of C losses. Full article

The deadwood contributes to an increase in soil heterogeneity due to the changing the microrelief (by the formation of windthrow-soil complexes), as well as changes in physical and chemical characteristics of decaying wood directly during xylolysis. We hypothesized that fallen logs as an element of microrelief influence the species composition and cover structure of vascular plants. We studied the influence of Picea abies (L.) Karst fallen logs of moderate and advanced decay stages on the horizontal distribution and heterogeneity of vascular plant cover in different microsite types (small boreal grass type, blueberry type, small boreal grass-blueberry type, herbs, and blueberry type) in old-growth middle taiga spruce forest in the Kivach State Nature Reserve (Republic of Karelia, Russia). The fallen deadwood acts as a factor of heterogeneity, causing reversible changes in the homogeneity of the original plant cover. The decaying logs influence the horizontal distribution of small herbs by changing the occurrence and density of shoots of Oxalis acetosella L., Maianthemum bifolium (L.) F.W. Schmidt, Vaccinium myrtillus L., and Vaccinium vitis-idaea L., as well as the occurrence of Luzula pilosa (L.) Willd. and Calamagrostis arundinacea (L.) Roth. Its impact on the heterogeneity parameters can be traced up to 20 cm from the log. The differences in vascular plant cover between fallen logs and the surrounding forest floor depend on the soil conditions of the microsite. The heterogeneity of conditions created by the logs smoothed out with increasing decay class, resulting in decreasing differences in the heterogeneity parameters of vascular plant cover between deadwood and forest floor. The changes in the homogeneity of the initial vascular plant cover by deadwood and the gradual smoothing of heterogeneity between the logs and the forest floor in rich and poor conditions have different, mainly opposite, trends. Finally, the structure of the vegetation cover reaches a state that is typical of particular growth conditions beyond deadwood. Full article

We investigated the relationship between benthic macroinvertebrate community attributes (richness, abundance, biodiversity, and climate-specific and resistance forms) and the physical characteristics of distinct mesohabitats (hydromorphological unit types) discretized into fast (e.g., riffles or rapids) and slow (e.g., pools or glides) flow types in four Mediterranean rivers of Spain. Key attributes of hydromorphological units, including length, width, depth, shade, substrate composition, embeddedness, abundance of aquatic vegetation, and density of woody debris, were considered. Through a comprehensive suite of multivariate analyses, we unraveled taxonomic and habitat distinctions among rivers and hydromorphological unit types, with a notable influence of spatial proximity (greater similarity within the same river basin). In slow hydromorphological units, aquatic vegetation, depth, and abundance of coarse substrate emerged as pivotal factors shaping macroinvertebrate assemblages, whereas in fast-flowing units, vegetation, substrate embeddedness, and density of woody debris were the most important. Contrary to the remaining community attributes, the studied resistance forms (absent, eggs, cocoons, and cells against desiccation and diapause) exhibited uniformity across rivers despite observed variations in macroinvertebrate communities, underscoring regional functional analogies in biological and ecological mechanisms within the investigated Mediterranean river basins. This study contributes valuable insights for anticipating the repercussions of ongoing climate change, particularly in regions where fast-flowing hydromorphological units are more susceptible to depletion during drought periods. Full article