Small rivers are among the most vulnerable components of river networks. They remain among the least studied in hydrological and hydrobiological contexts. These rivers serve as the uppermost elements of extensive landscape systems and are predominantly influenced by the detrimental effects of anthropogenic activities. In the city of Ridder, located in East Kazakhstan, industrial sites associated with mining enterprises are present, along with tailings, sludge, and ore and overburden dumps. The proximity of these pollution sources to rivers results in the accumulation and deposition of contaminants, particularly heavy metals, leading to ecological degradation of aquatic ecosystems. This study evaluates the bioaccumulation processes of heavy metals and toxic elements in the dominant fish species (Carassius carassius, Phoxinus phoxinus, Perca fluviatilis) within the hydrographic network (rivers Filippovka, Tikhaya, Zhuravlikha, Ulba) of the industrial city of Ridder during 2023–2024. Laboratory analyses were conducted using ICP-MS and ICP-AES techniques. The findings revealed elevated concentrations of Cd, Pb, and Mn on a wet-weight basis, with Mn levels exceeding WHO standards by up to 20 times. Accumulation coefficients for pollutants in the “water -fish” system were also calculated. The results of this research provide valuable insights into the efficiency of bioaccumulation processes in the ichthyofauna of small rivers affected by industrial pollution. This assessment is crucial for the ongoing monitoring of these processes and their potential ecological and human exposure risks.
This study aimed to address a critical knowledge gap in understanding how bioclimatic variables shape the global distribution of bee populations, which are increasingly threatened by climate change. By identifying the climatic factors that most strongly influence bee distributions across diverse geographic regions, the research provides a foundation for predicting future range shifts and developing effective conservation strategies for these essential pollinators. I compiled a reliable, standardized dataset containing more than 18.3 million bee occurrence records from multiple databases. Following extensive data cleaning, the analysis focused on 3,643 bee species with at least 20 occurrence records each, resulting in a final dataset of 389,097 occurrence points. Bioclimatic predictors were obtained from the WorldClim database, and a stepwise variable-selection procedure was used to retain ecologically relevant variables while removing highly correlated predictors. Species distributions were modeled using MaxEnt, which was also used to assess the relative importance of individual bioclimatic variables. The results showed that Precipitation Seasonality (Bio15) was the most influential predictor, representing the primary driver for 32.12
The composition of seed bank in the former topsoil was examined 45 years after the 1977–1978 eruptions of Mount Usu in northern Japan. This study investigated the fate of the seed bank, which had been measured at 10-year intervals. 200 former topsoil samples, 1–2 m below tephra, were collected by a 100 cm3 soil tin in 2023. Seed bank composition was analyzed through greenhouse germination (GM) of 100 samples and by a centrifuged floatation method (FM) for the remainders. Eight species were detected, with six species identified by FM and five by GM. The seed density was 500 ± 81/m2 (mean ± se) by FM and 300 ± 73/m2 by GM. All identified species were perennial herbs. Nonnative species accounted for 90
With a view to creating a biodiversity baseline to monitor a rewilding effort, I estimated the community structure of birdlife in subtropical South-East Queensland, Australia. Community structure was derived from patterns of temporal species co-occurrence and principles from network theory. In summary, 88 avian species were identified at Hiddenvale Research Station on 10 dates spanning 3 seasons in 2019. Rarefaction-extrapolation and Chao2 coverage estimation indicates comprehensive (94
Mountain ecosystems exhibit strong environmental heterogeneity, yet biodiversity assessments often focus on observed species richness and neglect dark diversity, the unrealized species pool of ecological communities. We examined patterns of observed richness, dark diversity, potential species pool, and community completeness across elevational gradients (2200–3800 m) on north- and south-facing slopes at two Himalayan sites: Daksum–Sinthan Top and Drang–Kongdoori. Across vegetation zones (closed canopy forest, treeline ecotone, and alpine meadow), observed richness generally increased from lower to higher zones, whereas dark diversity remained consistently lower than observed richness but contributed substantially to the total potential species pool. The potential species pool was highest in the treeline and alpine zones, particularly on north-facing slopes. The observed richness and dark diversity exhibited strong nonlinear patterns along the elevation gradients that varied by site and aspect. Dark diversity tended to increase at higher elevations, especially on south-facing slopes, suggesting stronger environmental filtering or recruitment limitation under harsher conditions. In contrast, the potential species pool remained relatively stable or increased only moderately with elevation, indicating that regional species availability does not fully constrain local diversity patterns. Spatially explicit generalized additive models explained substantial variation in dark diversity (R2 ≈ 0.69) and community completeness (R2 ≈ 0.47), with significant aspect-dependent and site-specific elevational effects. South-facing slopes showed reduced dark diversity but higher community completeness at Daksum–Sinthan Top, whereas this relationship was weaker at Drang–Kongdoori. Overall, our findings highlight strong nonlinear and aspect-dependent elevational controls on unrealized diversity and community saturation in Himalayan mountain ecosystems.
Urbanization has increasingly altered suburban ecosystems, which act as transitional zones between rural and urban landscapes. These areas face rapid habitat modification, leading to biodiversity declines, yet the ecological responses of human-modified suburban environments remain understudied. While the impacts on rural and urban biodiversity are well studied, little is known about how human-modified suburban ecosystems respond, particularly for sensitive fauna. Butterflies, being highly responsive to habitat and climatic changes, are effective indicators of ecosystem health. Therefore, this study investigated biodiversity variation in four selected suburban ecosystems in the Katana Municipal Area, Gampaha District, Sri Lanka using butterfly species composition and distribution. Butterfly surveys were conducted using a standardized plot sampling method at each site, with observations made during three daily intervals (10:00–10:30 am, 12:00–12:30 pm, and 2:00–2:30 pm) over eleven sampling days between October 2019, and April, 2020. A total of 51 species representing five families; Papilionidae, Pieridae, Nymphalidae, Lycaenidae, and Hesperiidae were recorded. Family-level dominance varied by habitat: Pieridae prevailed in both home gardens, Nymphalidae in the coconut estate, and Hesperiidae in the paddy field. Diurnal patterns revealed peak activity of Pieridae and Nymphalidae during most time intervals, except in the paddy field, where Hesperiidae remained dominant throughout all three-time intervals. The large home garden exhibited the highest diversity, with a Shannon–Wiener index (H′) of 2.95 and Simpson’s index (D) of 0.94. Pielou’s evenness (J = 0.88) was highest in both the large home garden and paddy field, while species richness peaked in the coconut estate (32 species). The findings of this research indicate that butterflies tend to favor large home garden habitats over agricultural mono-cultivated sites, as home gardens offer more favorable conditions for their survival, providing feeding grounds, courtship, and mating sites for butterflies. Thus, it is important to implement conservation strategies and raise awareness among the public to promote urban home gardening, thereby contributing to the conservation of declining butterfly populations.
Subterranean ecosystems are key yet understudied components of tropical biodiversity, particularly in iron-rich landscapes where the mesovoid shallow substratum (MSS) forms an interface between surface and deep subterranean environments. Despite its relevance, the temporal dynamics and underlying processes structuring MSS communities remain poorly understood. We investigated how seasonality and climatic variables influence the temporal dynamics of invertebrate communities inhabiting MSS environments in Iron Formations of southeastern Brazil (Iron Quadrangle and Southern Espinhaço Range). We conducted monthly sampling over 12 months across three localities and assessed variation in species richness, abundance, and composition for edaphic and subterranean-specialized fauna. Temporal change in β-diversity was partitioned into colonization-extinction components, and the effects of climatic variables were assessed using AIC-based model selection. We recorded 66,609 individuals and 802 morphospecies, with edaphic assemblages dominating richness and abundance. Seasonal effects were limited and spatially heterogeneous, influencing edaphic fauna in only one locality, while subterranean-specialized communities remained temporally stable. Temporal β-diversity was primarily driven by colonization rather than extinction, particularly in edaphic assemblages, leading to increased community differentiation over time. In contrast, subterranean-specialized fauna exhibited low temporal variability and high persistence. Climatic variables showed weak explanatory power, although precipitation had a positive effect on edaphic richness. Our study indicates that MSS invertebrate communities in Iron Formation landscapes exhibit high temporal stability and limited responses to seasonal climatic variation. While edaphic assemblages showed localized temporal changes, subterranean-specialized fauna remained stable through time. These findings highlight the importance of MSS habitats for maintaining subterranean biodiversity in Iron Formation landscapes.
Small to medium-sized tropical rivers in India face severe anthropogenic stress, yet remain understudied in terms of aquatic biodiversity and habitat condition. The Kana Damodar River, a tropical river in eastern India, exemplifies this problem, being increasingly impacted by sewage, industrial effluents, and seasonal water scarcity that threaten its aquatic biodiversity. This study aimed to assess the spatio-seasonal variations in fish assemblages in the Kana Damodar River and explore how hydro-environmental variables influence species composition and diversity. Monthly fish and water samples were collected from four sampling stations (S1, S2, S3, and S4) along the longitudinal fluvial gradient of the river over a two-year period (July 2020 to June 2022). Fish assemblage composition, richness, and diversity indices were analysed, and multivariate approaches (NMDS, ANOSIM, RDA) were applied to link fish communities with environmental variables. A total of 36 fish species from 18 families were identified, with fish assemblages dominated by the order Cypriniformes and the family Cyprinidae. The presence of both exotic and threatened native species in the Kana Damodar River raises significant conservation concerns. Notable variations in species richness and abundance were observed across sites, with S4 exhibiting the highest species richness and S3 the lowest. Seasonally, fish diversity and abundance declined markedly during the pre-monsoon period, when reduced river discharge led to habitat contraction and deterioration of water quality. This low-flow phase functioned as a seasonal ecological bottleneck, intensifying anthropogenic stressors and selectively favouring pollution-tolerant species, thereby compromising fish assemblages across most sampling sites. Diversity indices revealed significant spatial variations (p < 0.05). Non-metric multidimensional scaling (NMDS) indicated distinct fish assemblages at different sites and seasons, with significant dissimilarities confirmed by analysis of similarity (ANOSIM) (p < 0.05). Redundancy Analysis (RDA) emphasized the importance of dissolved oxygen (DO), biochemical oxygen demand (BOD), turbidity (TUR), and water temperature (WT) in shaping fish assemblages in the studied river. This study indicates that degraded water quality and seasonal low-flow conditions influence the fish assemblage structure in the Kana Damodar River. The findings of this study emphasize the urgent need for conservation efforts, including habitat restoration and pollution control, to protect this ecologically fragile river system from further degradation.
Although caves are generally considered more environmentally stable than surface ecosystems, their biological communities do not invariably exhibit temporal constancy. The influence of seasonality on species richness and community composition in subterranean systems remains poorly understood, particularly in Neotropical regions. Changes in rainfall, temperature, humidity, and epigean productivity may alter cave microhabitat conditions, potentially affecting the abundance, composition, richness, and niche occupancy of terrestrial invertebrates. To test this hypothesis, we investigated Brejões I Cave, a large cave system located in the Brazilian semi-arid region. Twenty-four fixed sectors were surveyed during wet and dry periods, with concurrent measurements of microclimatic conditions, habitat structure, and resource availability. Seasonal changes in terrestrial invertebrate community composition were quantified using the Temporal Beta-diversity Index (TBI), while species’ niche dynamics were assessed using the Outlying Mean Index (OMI) and Within Outlying Mean Index (WitOMI). Contrary to expectations, no significant seasonal differences were detected in species turnover, richness, or abundance, indicating seasonal stability in community structure. Although only a small subset of species responded to environmental gradients, WitOMI analyses revealed seasonal shifts in subniche breadth, mainly characterized by niche contractions during the dry season and occasional expansions in some taxa. These patterns were associated with reductions in temperature and humidity. Overall, our results indicate that climatic fluctuations can influence species-level niche dynamics without altering overall community structure in large, environmentally buffered cave systems.
Although invasive tree species pose a significant threat to biodiversity, their impact on soil micro- and mesofauna has not been sufficiently investigated yet. We investigated the influence of black locust Robinia pseudoacacia L., a naturalised exotic non-native species with invasive potential on soil Nematodes. Using a paired-vice approach, we analysed how nematode communities (diversity, genus richness, trophic and functional composition, structure), differ in pure black locust stands compared with those in native neighbouring native oak (Quercus robur) forest. The nematodes made up incredible communities in this study, both in abundance of individuals as well as taxa number, when a total of 107 nematode genera were recorded (102 genera in black locust and 105 genera in oak forests). Contrary to our expectation however, the structure of nematode communities in oak and in black locust stands did not differ in terms of total nematode abundance, genus richness, biomass, functional and trophic composition as well as alpha diversity. Nevertheless analyses of beta diversity revealed distinct differences in nematode community composition suggesting that the taxonomic composition of nematode assemblages differed between forest types. Bacterivorous nematodes prevailed, followed by plant parasites, omnivores, fungivores and predators in both invasive black locust and native oak forests without statistical differences (p > 0.05), except plant parasitic nematodes. Both Maturity indices (MI, MI2–5), Enrichment, Structure and Channel index did not show significant responses to black locust, except for the plant parasitic index (PPI), which was found to be higher in R. pseudoacacia forests. The analysis of nematode metabolic footprints showed that black locust increased the herbivore footprint but did not significantly influence enrichment, structure, composite, bacterivore, omnivore, predator and fungivore footprints. In conclusion, invasive black locust and native oak formed similar communities of soil nematodes and likewise regulated the soil food web mainly via a top-down effect.
Understanding the drivers of species richness in temperate montane ecosystems is essential for testing biodiversity theories and initiating conservation, yet seasonally constrained temperate montane ecosystems remain underrepresented in climate–diversity studies. We tested three climate-based hypotheses, productivity, water–energy dynamics (WED), and seasonally modified WED, using multi-taxon data collected along an elevational gradient in a Central European mountain system. Species richness of eight major taxonomic groups was related to (i) net primary productivity (NPP), (ii) annual precipitation and potential evapotranspiration (PET) as proxies of WED, and (iii) interactions between precipitation and length of the growing season (LGS) to account for seasonal limitation. Model performance was evaluated using Akaike’s Information Criterion and deviance explained. The productivity model showed weak and taxon-specific support and was rarely the best-performing model. In contrast, WED provided the best fit for four taxonomic groups. Vascular plants and vertebrates exhibited unimodal relationships with PET, whereas bryophyte and lichen richness increased with precipitation but declined with PET. The seasonal modification of WED, defined as interaction between precipitation and LGS, best explained richness patterns for insects, arachnids and overall biodiversity, indicating that seasonal constraints strongly mediate climate–diversity relationships in temperate montane ecosystems. Overall, our results demonstrate that biodiversity patterns in temperate mountain regions are driven primarily by interactions between water availability, atmospheric energy, and growing-season length rather than productivity alone. The pronounced variation in responses among taxonomic groups suggests that conservation strategies should explicitly include differences in ecological responses, rather than focusing on a single generalised approach in seasonally constrained temperate montane ecosystems.
The Moroccan sardine stock is keystone species in Morocco’s Atlantic waters, supporting one of the nation’s most economically important fisheries. However, concerns overexploitation and limited stock assessment have hindered sustainable management. This study assessed the status of the central and southern Moroccan sardine stocks from 1995 to 2021 using three complementary data-limited models (CMSY, SPiCT, and LBSPR). Results revealed marked spatial variability and widespread overexploitation, particularly in the southern stock, where biomass remained below 0.3BMSY and fishing mortality exceeded FMSY by more than fivefold. The central stock exhibited a less critical but still vulnerable condition, with biomass fluctuating around 0.5BMSY and fishing mortality near the sustainability threshold. The LBSPR model indicated severe growth overfishing across both regions, with sardines being harvested before reaching maturity (Lc < L50) and a chronically low spawning potential ratio (SPR < 0.3). While CMSY and SPiCT produced comparable estimates of maximum sustainable yield ( 500–730 kt), they diverged in biological reference points due to structural assumptions, with CMSY provided more stable and precautionary results, whereas SPiCT was more sensitive to data limitations but captured temporal dynamics. The findings underscore the urgent need for management measure such as size-selective fishing practices, reduced fishing effort, and precautionary harvest controls to ensure the sustainability of these ecologically and economically critical fisheries. This study demonstrates the interest of ensemble modelling approaches in data-limited contexts and provides a foundation for evidence-based fisheries management in Morocco.
Airborne environmental DNA (eDNAir) metabarcoding has recently emerged as a promising approach for monitoring terrestrial plant communities from atmospheric samples. However, its application remains limited, and key methodological uncertainties still constrain its ecological interpretation. In this study, eDNAir metabarcoding was applied for the first time in Türkiye to assess terrestrial plant diversity. We employed a multilocus framework using the chloroplast trnL (P6-loop) and nuclear ITS2 markers. Taxonomic assignment of ITS2 sequences was performed using three reference databases: NCBI, ITS2, and a locally generated Sanger reference library, whereas trnL sequences were assigned using the NCBI database only. This design allowed us to evaluate how marker choice and reference database completeness influence taxonomic resolution diversity estimates, and the interpretation of plant community composition. The multilocus approach revealed that marker and database selection strongly shape detected diversity patterns. Our results reveal a temporally structured airborne plant community in Central Anatolia, dominated by major flowering plant families including Asteraceae, Poaceae, Fabaceae, Rosaceae, and Salicaceae, reflecting seasonal vegetation dynamics and flowering phenology. The trnL (P6-loop) marker effectively captured broad community composition and significant temporal differentiation among sampling months (PERMANOVA R² = 0.52, p = 0.008), highlighting its suitability for ecosystem-level monitoring. In contrast, ITS2 combined with a locally curated Sanger reference database improved taxonomic resolution, particularly within species-rich groups such as Asteraceae, enabling finer-scale ecological interpretation. Overall, our results suggest that eDNAir metabarcoding can be a promising, non-invasive complement to traditional plant monitoring, provided that marker selection, reference-database curation and spatial replication are carefully considered. Integrating multilocus strategies with curated regional reference databases improves taxonomic resolution and supports more reliable interpretation of plant community patterns, offering a methodological framework for future eDNAir studies in Türkiye and comparable temperate regions.
Existing approaches for assessing the impacts of climate change on plant–pollinator systems generally fall into two categories. The first relies on species distribution models (SDMs) to generate habitat suitability maps for individual species, which are subsequently projected under future climate scenarios. While useful, this approach evaluates plants and pollinators independently and does not explicitly account for their ecological interactions. The second approach focuses on constructing plant–pollinator interaction networks and simulating the consequences of species loss, either randomly or through the targeted removal of generalist or specialist species, to evaluate network vulnerability. However, this method lacks ecological realism because it does not incorporate actual changes in species distributions driven by climate change. To bridge these approaches, we present an integrative framework that combines species distribution modeling with network analysis. Specifically, we first generated continuous climate suitability maps for plants and pollinators under current and future (2070) climate conditions using SDMs. We then developed a Python-based tool to identify potential spatial co-occurrence between interacting species by overlaying their continuous suitability surfaces and constructing geographically explicit interaction matrices. Applied to a Chilean dataset comprising 187 plant species and 171 pollinator species, our framework indicated that approximately 75
Interspecific synchrony (i.e. synchrony among species pairs) influences community synchrony (i.e. synchrony among all species) and thereby the temporal variability of the entire community and ecosystem functioning. Yet, the mechanisms driving synchrony remain difficult to identify. Recent studies suggest that both the timescale and the functional similarity, determined by functional traits, influence interspecific synchrony, but both have rarely been considered together. Furthermore, plankton population dynamics differ among seasonal phases representing contrasting environmental conditions, but interspecific synchrony across phases remain understudied. Thus, we analysed 20 years of phytoplankton dynamics in Lake Constance and explored (i) how community and interspecific synchrony vary across timescales; (ii) the functional similarity-interspecific synchrony relationships across timescales; and (iii) how interspecific synchrony and its relationship with functional similarity depend on seasonal phases. Community and interspecific synchrony varied across timescales: they were notably highest at the annual scale and lowest at longer scales. Furthermore, we found positive functional similarity-interspecific synchrony relationships depending on the timescale and the seasonal phase. Functional similarity explained up to 20
Colombia’s long-lasting internal conflict has profoundly shaped the country’s socio-ecological system, imposing relational patterns that persist beyond the 2016 peace agreement. Whether post-conflict policies can effectively achieve socially and environmentally desirable outcomes, or whether conflict-related constraints may instead generate unintended consequences, remains an open question. This study conceptualizes the Colombian socio-ecological system as a parsimonious set of key social and ecological variables embedded within a conflict-related framework. Interactions among these variables as reconstructed using elicitation-based information and literature, are represented using a signed digraph. Loop analysis combined with numerical simulations is applied to assess system responses to policy interventions, including subsidized credit for capital-intensive activities and measures aimed at enhancing smallholder competitiveness and market access. Results show that persistent conflict-related mechanisms generate counterintuitive interactions between social and ecological components, with unexpected interdependencies between licit and illicit activities that undermine policy effectiveness. Synergies among desirable objectives emerge only under limited conditions.
