Search Results (92)

Urban aquatic ecosystems are increasingly shaped by anthropogenic pressures that alter community structure and ecological functioning. This study investigates how the functional organization of zooplankton communities reflects ecosystem stability along an urbanization gradient in the Colentina River–Lake system (Romania). Zooplankton taxa were classified into trophic guilds and size-based functional groups, and functional diversity was quantified using the FEve, FDiv, FDis, and RaoQ indices, based on functional trait structure and distribution within communities. Ecosystem stability patterns were estimated through zooplankton community resilience (RSL) and resistance (RST), indices derived from Shannon diversity and Pielou evenness. Across the system, filter feeders dominated, and their density increased toward downstream, highly urbanized sectors. Also, small-sized organisms (SMC) were consistently prevalent, representing a zooplankton component commonly associated with stress tolerance and opportunism in disturbed aquatic environments. Functional diversity patterns showed low evenness but high divergence, suggesting that although few functional strategies dominate, communities maintain internal differentiation. While filter feeders remained dominant even in disturbed sectors, the uneven distribution of other groups, especially scrapers, may reflect greater sensitivity to anthropogenic conditions. These findings suggest that functional trait composition, in addition to diversity, plays an important role in shaping structural stability patterns. These findings indicate that functional trait composition, in addition to diversity, was associated with the observed stability patterns. The study reinforces the value of zooplankton as sensitive indicators of functional integrity in anthropogenically impacted freshwater systems and provides insights relevant for sustainable urban water management. Full article

Microplastic (MP) contamination is an emerging threat to aquatic ecosystems. However, species-specific bioaccumulation patterns across trophic guilds in tropical river ecosystems remain scarcely understood. This study assessed the occurrence, organ-level distribution, polymer composition, and ecological risk of MPs in 220 fish representing 12 species, spanning across multiple trophic guilds, sampled from four sites along a pollution gradient of the river Yamuna, India. MPs were detected in all examined species, confirming extensive distribution across the river ecosystem. A total 1678 MPs were recovered, with significantly higher abundance in fish from the highly urban Delhi stretch than in those from upstream regions (Kruskal–Wallis, H = 11.03, p = 0.011). The highest species-specific MP load was recorded in omnivorous Oreochromis niloticus from Sonia Vihar (436 MPs), whereas the carnivorous species Xenentodon cancila exhibited the lowest accumulation (37 MPs). Surface- and mid-water herbivores and omnivores accumulated more MPs than benthic carnivores and detritivores. Nonetheless, spatial pollution gradients exerted a stronger influence on MP accumulation, compared to trophic guilds. The gastrointestinal tract exhibited the highest MP abundance (751 MP particles), followed by gills (605) and muscle tissues (322), confirming ingestion as primary uptake route, and suggesting possible tissue translocation. Fibers dominated in the assemblage (77.8%), while transparent (44%) and blue (19.5%) were most abundant colors. ATR–FTIR analysis confirmed 10 diverse polymers, with polyethylene (≈24%) and polypropylene (≈21%) together accounting for nearly half of the identified particles. The Polymer Hazard Index analysis classified the recovered MP mix as Category IV (high ecological hazard). These findings identify the Delhi stretch of the Yamuna as a high MP contamination zone and highlight the combined influence of urban pollution and fish ecology on MP bioaccumulation. Full article

Urbanization can act as a powerful ecological filter, restructuring biodiversity through species loss, replacement, and altered resource pathways. While urban green spaces (UGS) are recognized as potential biodiversity refuges, the effectiveness and mechanisms for conserving insect diversity across the urban-to-natural gradient remain poorly understood. Here, we combine full-season Malaise trapping (April–November) with MinION-based DNA barcoding to test two predictions about how urbanization reshapes Diptera communities across five sites in Haidian District, Beijing, ranging from residential areas and urban parks to a nearby shallow mountain reserve (BWM). Based on 5528 barcoded individuals, we identified 686 putative species from 39 families. As predicted, β-diversity between urban and mountain sites was overwhelmingly driven by species turnover rather than nestedness, demonstrating that cities do not simply receive subsets of the surrounding fauna but actively reassemble communities. This filtering effect was, however, trophic-guild specific. Detritivores showed the highest replacement, consistent with a shift from natural to anthropogenic resource subsidies, while predators/parasitoids exhibited significant nested loss, aligning with their hypothesized sensitivity at higher trophic levels. Vegetation structure further clarified these patterns: vegetation density, not plant species richness, was the primary bottom-up driver for herbivore and predator/parasitoid diversity, whereas detritivores were decoupled from living plant biomass. These findings demonstrate that urban and near-natural habitats maintain distinct species pools via guild-specific assembly pathways, highlighting the need for guild-specific conservation strategies for urban biodiversity conservation. Extending beyond compositional analysis, we propose a temporal-abundance framework, classifying species by persistence and abundance, as a diagnostic tool for assessing ecological integrity and guiding conservation in urbanizing landscapes. Full article

Background: Soil degradation in intensive tea plantations necessitates sustainable management. Straw application (S) is a promising practice, yet its integrated effects on soil fungal communities in acidic tea soils require comprehensive evaluation. Methods: High-throughput sequencing based on the primers of fungal ITS1F-ITS2 was conducted on soils from tea plantations with/without straw application (S and CK, respectively). Analyses encompassed community structure, α- and β-diversity, differential taxa, co-occurrence networks, the main drivers by soil properties, and functional prediction. Results: The core fungal community structure except for Basidiomycota, and diversity remained stable under S. However, 17 ASVs responded as significant biomarkers, including fine-scale shifts within the genus Sebacina. S modified the complexity of the fungal co-occurrence network with enhancing its modularity and integration and increasing keystone connectors, while overall network cohesion was maintained. Soil available phosphorus (AP), soil organic matter (SOM) and nitrate nitrogen (NO₃⁻-N) were the dominant drivers of fungal amplicon sequence variants (ASVs), with water content (WC) the main driver of fungal keystones. Functionally, S selectively affects the richness of Symbiotrophs (including endophytes) without altering the relative abundance structure of major trophic guilds. Conclusions: S acts as a modulator, refining fungal network architecture and interactions within the resilience threshold of the community, offering a viable practice for sustainable tea soil management. Full article

Mixed plantations of Pinus sylvestris var. mongolica with native shrubs are widely established in semiarid sandy landscapes, yet soil microbial responses may differ among mixed-planting modes depending on the companion shrub species. We compared soil bacterial and fungal communities across three approximately 9-year-old mixed-planting modes in the Mu Us Sandy Land, where P. sylvestris var. mongolica was combined with Juniperus sabina (Ps–Js), Salix psammophila (Ps–Sp), or Corethrodendron fruticosum (Ps–Cf). Planting configuration was associated with shifts in soil physicochemical conditions. Bacterial α-diversity did not differ among modes, whereas fungal α-diversity was higher in Ps–Sp. Community composition diverged across modes for both domains, and LEfSe identified configuration-specific taxa. Null-model analyses showed that bacterial assembly was consistently dominated by stochastic components, whereas the relative contributions of fungal assembly processes varied among mixed-planting modes. Functional inference further suggested mode-associated differences in fungal trophic guild composition, with Ps–Cf showing significantly higher ectomycorrhizal abundance and Ps–Sp showing higher representation of saprotroph-associated guilds; by contrast, predicted bacterial functional profiles were broadly comparable among modes. Together, these results indicate that bacterial and fungal communities showed different response patterns among mixed-planting modes: bacterial communities showed compositional differentiation but little variation in α-diversity and consistently stochastic assembly, whereas fungal communities showed mode-related changes in α-diversity, the relative contributions of assembly processes, and trophic guild composition. These findings provide a microbial basis for considering shrub-species selection when designing P. sylvestris var. mongolica mixed plantations in semiarid sandy ecosystems. Full article

Although sedimentary zones in Lake Taihu differ in external inputs, hydrodynamic conditions, and sedimentary settings, the spatial differentiation of eukaryotic microbial communities and their assembly mechanisms remain insufficiently understood. This study analyzed sediment cores from four typical sedimentary zones of Lake Taihu: Dapu (DP), Gonghu (GH), the central lake area (HX), and Xuhu (XH). By integrating physicochemical measurements, 18S rRNA gene high-throughput sequencing, redundancy analysis, functional annotation, iCAMP, and co-occurrence network analysis, we characterized the composition, environmental associations, and assembly mechanisms of sedimentary eukaryotic microbial communities. The results showed that eukaryotic microbial communities in Lake Taihu sediments exhibited marked spatial heterogeneity, with dominant taxonomic groups including Chlorophyta, Intramacronucleata, and Diatomea. Alpha diversity was higher in the GH zone and lower in the HX zone, whereas beta diversity showed significant separation among lake zones. NH₄⁺-N, NO₃⁻-N, TN, TP, TOC, D50, MWC, and pH were associated with variation in community composition, but the main associated factors differed among zones. FunGuild annotation showed that annotated fungal functional groups exhibited distinct trophic distribution patterns across sedimentary zones. iCAMP analysis indicated that community assembly was generally dominated by stochastic processes, with dispersal limitation prevailing in the GH zone and ecological drift dominating in the DP, HX, and XH zones. Co-occurrence network analysis further revealed marked differentiation in potential biological associations among sedimentary zones. Overall, this study showed that nutrient conditions and sediment physical properties in different sedimentary environments of Lake Taihu jointly shaped the spatial patterns of eukaryotic microbial communities and their ecological associations, providing baseline information for understanding sedimentary ecological processes in eutrophic shallow lakes. Full article

The global expansion of tree plantations has led to extensive fragmentation of natural forests, posing significant challenges for biodiversity conservation. Understanding the diversity patterns and underlying mechanisms of ground-dwelling insects in these fragmented landscapes is critical to inform effective conservation strategies. To address this, we sampled ground-dwelling insects using pitfall traps across nine remnant natural forest fragments (“islands”) embedded within a tree plantation matrix in Guangxi, China. We examined insect family-level diversity and community composition in relation to fragment isolation (low vs. high) and size (large vs. small) and explored the mechanisms driving the observed patterns. Our results revealed no significant difference in ground-dwelling insect diversity between low-isolation and high-isolation fragments. However, diversity was significantly lower in smaller fragments compared to larger ones. This reduction was primarily driven by decreased seedling density within smaller fragments, directly reflecting the adverse effects of plantation-driven fragmentation on native seedling establishment. Furthermore, we observed noble shifts in community composition of ground-dwelling insects along both fragment isolation and size gradients. Highly isolated fragments exhibited a decline in phytophagous insects and omnivores (with detritivore-herbivore diets), but an increase in detritivores. Smaller fragments exhibited consistent declines across multiple insect taxa spanning various dietary guilds. The observed changes in ground-dwelling insect composition were driven by shifts in plant (especially seedling) community composition. Our findings reveal a clear cascading effect: plantation-driven fragmentation limits native plant regeneration, and these limitations subsequently propagate to higher trophic levels, profoundly impacting ground-dwelling insects. Effective restoration of plantation-fragmented landscapes requires strategies that both prioritize the preservation of large, continuous forest fragments and promote native seedling recruitment within existing fragments. Full article

Marine fungi are pivotal components of coastal ecosystems, facilitating essential biogeochemical cycling and trophic dynamics. However, the complex mechanisms governing their spatiotemporal community patterns in tropical–subtropical coasts remain largely unexplored. In this study, we characterized marine fungal diversity across a comprehensive seasonal cycle (spring (March), summer (June), autumn (August), and winter (December)) at 21 representative sites along the Leizhou Peninsula, China. These sites were strategically selected to encompass a broad range of dissolved inorganic nitrogen (DIN) gradients. Fungal community composition was characterized via high-throughput sequencing of the internal transcribed spacer 2 (ITS2) region, followed by functional guild profiling using the FUNGuild database. A total of 8777 amplicon sequence variants (ASVs) were identified, encompassing a broad taxonomic breadth of 10 phyla and 358 genera. Ascomycota, Basidiomycota, and Chytridiomycota emerged as the predominant phyla across all samples. Our results revealed significant spatiotemporal heterogeneities: seasonal succession fundamentally reshaped community composition, with DIN exerting its most pronounced influence during the winter. Furthermore, fungal functional structures exhibited distinctive clustering across regions defined by DIN enrichment levels. Co-occurrence network analysis revealed a highly modular and robust architecture, characterized by predominantly positive interactions and dense inter-taxon connectivity. These findings underscore the synergistic influence of temporal dynamics and DIN enrichment in shaping marine fungal community assembly and functional compositions. Our study provides critical baseline insights into the ecological resilience of coastal mycobiota in the South China Sea. Full article

We compared fish assemblage structure and total mercury (THg) bioaccumulation between a natural floodplain lake and a constructed irrigation canal in central Brazil. A total of 473 individuals representing 34 species were recorded, and dorsal muscle samples from 62 specimens representing shared species or species occupying comparable trophic positions were analyzed for THg (Curimatella immaculata, Hemiodus microlepis, Astyanax aff. bimaculatus, Triportheus albus, Geophagus sveni, Pimelodus blochii, Pygocentrus nattereri, Lycengraulis batesii, and Cichla kelberi). The floodplain lake exhibited higher species richness, diversity, and evenness, whereas the irrigation canal supported a simplified assemblage dominated by fewer species. Total Hg concentrations were significantly higher in the lake than in the irrigation canal; however, this pattern was observed only for the carnivorous guild (t = 5.384, p < 0.0001) and the detritivorous guild (t = 4.183, p = 0.0001). THg increased significantly with trophic level in both systems, from detritivores to carnivores (F₂,₄ = 15.127, p = 0.009), yielding comparable trophic magnification slopes (lake: 1.46, 95% CI: 1.11–1.81; canal: 1.36, 95% CI: 0.94–1.77). Despite lower diversity and THg concentrations in the irrigation canal, Hg transfer efficiency across trophic levels was conserved between systems. Full article

This study evaluates the ecological impact of Robinia pseudoacacia L. (black locust) invasion on native chestnut (Castanea sativa Mill.) groves on Mount Amiata (Central Italy), focusing on both plant and macrofungal community dynamics. Surveys were conducted over a three-year period (2022–2024) across 16 plots to assess shifts in taxonomic alpha diversity, species richness, and trophic guild structure. Our results demonstrate that while R. pseudoacacia stands exhibit a higher Shannon–Wiener index for plants, native chestnut groves host significantly greater species richness and higher taxonomic distinctiveness across both biological groups. A major shift in fungal functional structure was observed with chestnut-dominated plots characterized by a predominance of ectomycorrhizal species (58.3%), whereas invaded stands were heavily dominated by saprotrophic fungi (73.4%). Non-metric Multidimensional Scaling (NMDS) further confirmed a clear separation in community composition between the two forest types, indicating that R. pseudoacacia invasion leads to a homogenization of the forest biota and a potential decline in ecosystem health, as evidenced by the sharp reduction in mycorrhizal diversity. These findings highlight the importance of monitoring macrofungal communities as sensitive bioindicators of the ecological degradation caused by invasive woody species. Full article

Bats (Chiroptera) provide critical ecosystem services, including pest suppression, pollination, and seed dispersal. Understanding their dietary ecology is essential for conservation management yet has historically been constrained by methodological limitations. This review synthesizes advances in bat dietary analysis over the past several decades, from traditional morphological and stable isotope approaches to the revolutionary DNA metabarcoding techniques that now dominate the field. We systematically evaluate the strengths and limitations of each methodological approach and examine how molecular methods have transformed our understanding of bat trophic ecology. Research progress across major feeding guilds—insectivorous, frugivorous, nectarivorous, carnivorous, and sanguivorous bats—is examined, with emphasis on recent discoveries enabled by molecular techniques. We discuss ecological and conservation applications, including ecosystem service quantification, food web construction, and responses to environmental change. Finally, we identify priority directions for future research, including long-read sequencing technologies, multi-method integration, reference database expansion, and One Health applications. This synthesis provides guidance for researchers selecting appropriate analytical approaches and highlights the critical role of dietary studies in bat conservation amid accelerating global change. Full article

This study evaluated heavy metal accumulation in bird feathers across four contrasting environments in Jalisco, Mexico (urban, semi-urban, agricultural, and semi-natural). We analyzed 370 feather samples from 58 species spanning seven trophic guilds using XRF spectrometry. Fifteen metals were quantified, with zinc (Zn) showing the highest concentrations overall. Multivariate analyses identified trophic guild as the strongest predictor of metal variation, while spatial differences were present but less pronounced. CUAltos was the only site consistently distinct from the others, mainly due to lower concentrations of several metals. Despite quantitative differences among guilds, their proportional metal profiles were similar—dominated by Zn, Y, Mo, and Hf—suggesting broad regional exposure rather than guild-specific accumulation. Redundancy Analysis indicated that atmospheric pollutants (COV and PM10) were the main environmental drivers of spatial variation, especially in Guadalajara’s urban sites. Agricultural variables, including agave cover, showed minor and non-significant effects. Neither sex nor migratory status influenced metal loads, consistent with feathers reflecting exposure during feather growth at the molt site, while potentially also incorporating locally deposited external contaminants. Overall, this study demonstrates the effectiveness of feathers as a non-invasive biomonitoring tool and highlights air quality as a key determinant of regional heavy metal contamination. Full article

This study investigated the composition and temporal dynamics of wood-inhabiting fungal communities in four aging tree species in Lednice Castle Park (Czech Republic), located within the Lednice–Valtice Cultural Landscape, a UNESCO World Heritage Site. Forty wood cores were collected from 20 trees at two time points (2023 and 2024). The hosts included horse chestnut (Aesculus hippocastanum L.), copper beech (Fagus sylvatica ‘Atropunicea’ L.), oak (Quercus robur L.), and poplar (Populus alba L.), each exhibiting visual signs of decline. Fungal assemblages were profiled using ITS2 high-throughput amplicon sequencing. Ascomycota dominated across all hosts (72–89% of reads), while Basidiomycota contributed 8–24%, largely represented by Agaricomycetes in F. sylvatica. Alpha diversity varied significantly among hosts (Shannon: F_3,36 = 10.61, p = 0.001 in 2023; F_3,36 = 10.00, p = 0.001 in 2024). Temporal shifts were host-dependent: F. sylvatica exhibited the strongest year-to-year decline in richness (Chao1: −83%, p = 0.007) and increased beta dispersion, while A. hippocastanum and P. alba showed significant increases in diversity (+65% and +42%, respectively). Community composition was shaped by host species (PERMANOVA Bray–Curtis: p = 0.001) and shifted over time (Jaccard: p = 0.001), with F. sylvatica showing the highest temporal turnover. Functional guild analysis revealed consistent dominance of saprotrophs (29–41%) and mixed pathotroph–saprotroph guilds (23–36%) across hosts, indicating active degradation processes inside functional xylem. These results indicate that, within the studied system, the wood mycobiome of aging trees is host-dependent and temporally dynamic rather than static or functionally neutral. Short-term temporal turnover observed between sampling years may contribute to shifts in fungal community composition and succession within wood, with potential implications for tree decline processes in managed historical park landscapes. Full article

The aim of this study was to determine fungal diversity and composition in an area of high host diversity and identify the organisms involved in the appearance of symptoms in Pinus needles. Asymptomatic and symptomatic live needle samples were obtained from different Pinus spp. in an arboretum with confirmed presence of brown spot needle blight. The samples were analysed using high-throughput sequencing of fungal ITS2rDNA. Ascomycota dominated all samples, with Lophodermium as the most abundant genus, although it showed lower representation in symptomatic needles. Other genera with recognised pathogenic potential, including Lecanosticta, Pestalotiopsis, Cyclaneusma, Rhizosphaera, Neophysalospora, and Cenangium, were also detected, whereas the Dothistroma genus was absent despite its presence in the region. Alpha diversity was higher in asymptomatic needles, with a significant difference only for the Shannon index, while Bray–Curtis dissimilarity revealed significant shifts in community composition between needle types. Functional guilds were dominated by pathotroph–saprotroph trophic mode, and the functional guild ‘plant pathogen’ was the most abundant across samples. These findings identify fungal genera associated with symptomatic and asymptomatic needles and provide guidance for future targeted isolation and detailed morphological and molecular identification using more resolutive techniques, enabling a deeper understanding of pathogenic community presence and their potential synergistic interactions. Full article

The Yangtze River Estuary is one of the most productive estuarine ecosystems in the western Pacific, supporting diverse fish communities that sustain ecosystem functioning. This study investigated the seasonal patterns and community structure of intertidal fish assemblages to provide a baseline for future habitat assessments. Seasonal surveys conducted from May to December 2024 recorded 47 fish species belonging to 10 orders, 18 families, and 37 genera. Cyprinidae contributed the highest proportion of species (42.55%). Dominant species identified by the index of relative importance-including Cynoglossus gracilis, Coilia nasus, and Lateolabrax japonicus—characterized the seasonal assemblage structure. The assemblages were dominated by sedentary species (82.98%), and demersal fishes accounted for 48.94% of the species. Carnivorous taxa (57.45%) dominated the trophic guilds. Diversity indices indicated moderate diversity (H′: 1.797–2.441; C: 0.788–0.892; D: 1.724–4.770; J′: 0.6318–0.8642). Similarity analysis based on Jaccard’s index (Cj) showed the highest overlap between spring and summer (Cj = 0.5000) and the lowest between spring and winter (Cj = 0.1714); spring–autumn and summer–autumn were approximately 0.30, indicating moderate overlap. ABC curves yielded slightly negative W values in spring and summer and positive values in autumn and winter (W = −0.066 to 0.276), indicating moderately disturbed assemblages in spring–summer and less disturbed communities in autumn–winter. Overall, the study provides a seasonal baseline of intertidal fish assemblages in nearshore waters of the southern branch of the Yangtze River Estuary, which can provide useful ecological context for future assessments of nursery and feeding habitats of juvenile Chinese sturgeon (Acipenser sinensis). Full article