Search Results (48)

This study provides the first comprehensive characterization of benthic macrofaunal communities in the Loukkos estuary, highlighting their spatial and seasonal variability and the environmental factors shaping their structure. A total of 47 species were identified across 12 site–season combinations, dominated by molluscs (47%), polychaetes (23%), and crustaceans (21%). Species richness varied considerably along the estuarine gradient, ranging from fewer than five species in the upstream sector to up to 30 species downstream. Overall, higher diversity was observed in the downstream areas and during the dry season. Macrofaunal density also exhibited substantial variability, ranging from 95 ind.m⁻² to 14,852 ind.m⁻², with a mean density of 2535 ± 4058 ind.m⁻². Multivariate analyses identified four distinct benthic assemblages structured primarily by spatial factors (ANOSIM R = 0.86, p = 0.002), with negligible seasonal effect (R = −0.03, p = 0.6). Assemblages ranged from marine-influenced communities at the estuary mouth dominated by Cerastoderma edule, through rich and diverse seagrass-associated communities in the lower estuary dominated by Bittium reticulatum, and moderately enriched mid-estuary communities characterized by Scrobicularia plana and Hediste diversicolor, to species-poor upstream communities dominated by the tolerant species H. diversicolor. Canonical analysis showed that salinity and vegetation explain nearly 40% of the variation in benthic assemblages, highlighting the key role of Zostera seagrass beds as structuring habitats. Moreover, upstream anthropogenic pressures alter environmental conditions, reducing benthic diversity and favoring tolerant species. Full article

Rivers in tropical semi-arid regions face increasing anthropogenic pressures yet remain critically understudied despite their global importance. This study evaluated the aquatic macroinvertebrate community structure in the Ranchería River, Colombia, across three land use conditions: conserved zones (CZs), urban/agricultural zones (UAZs), and mining influence zones (MZs). Ten sampling stations were established, and macroinvertebrate communities were assessed alongside physical, chemical, and hydromorphological variables during the dry season (January–March 2021). A total of 9288 individuals from 84 genera across 16 orders were collected. Generalized Linear Models revealed significant differences among zones for 67 genera (79.8%), indicating strong community responses to land use gradients. Conserved zones exhibited the highest diversity according to the Hill numbers and were dominated by sensitive taxa, including Simulium, Smicridea, and Leptohyphes. Urban/agricultural zones showed the lowest richness (35 genera) and were characterized by disturbance-tolerant species, particularly Melanoides. Mining zones displayed intermediate diversity but exhibited severe habitat alterations. A redundancy analysis with variance partitioning revealed that land use types constituted the primary driver of community structure (a 24.1% pure effect), exceeding the physical and chemical variables (19.5%) and land cover characteristics (19.2%). The integrated model explained 63.5% of the total compositional variation, demonstrating that landscape-scale anthropogenic disturbances exert a greater influence on aquatic communities than local environmental conditions alone. Different anthropogenic activities create distinct environmental filters affecting macroinvertebrate assemblages, emphasizing the importance of land use planning for maintaining aquatic ecosystem integrity in semi-arid watersheds. Full article

Amid declining fish diversity and human pressures in freshwater ecosystems, robust basin-scale assessments are vital for effective fisheries management. This study collated nearly four decades of fishery yields from the Pearl and Yangtze Rivers to identify conservation priorities in the Pearl River Basin. It introduced a novel cumulative effect indicator based on zeta diversity—a biodiversity pattern metric—integrated with cumulative effects analysis for management decision-making. The research employed a multi-site generalized dissimilarity model to examine the non-linear relationships between fish species composition (ζ_n) and human pressures, environmental factors, and geospatial variations across elevation gradients. The cumulative effect indicator, reflecting responses to anthropogenic stress when assessing ζ₂ (related to β diversity), helped evaluate basins for conservation or restoration needs based on their unique or homogenized biotic communities. The results suggest that ζ diversity in low-elevation sub-basins has a stronger filtering effect on ζ by human pressures than in mid- to high-elevation sub-basins, where community aggregation is more random. The impact varied with diversity aspects (nestedness vs. turnover) and zeta order. A negative correlation between cumulative effects and community uniqueness validated the novel cumulative effect indicator’s effectiveness for guiding restoration in the Pearl River Delta, potential fishing bans, and karst conservation. This approach offers a theoretical basis for prioritizing areas for freshwater fish diversity conservation and fishing restrictions in the Pearl River Basin. Full article

This study assessed the water quality and ecological integrity of the Columbe River micro-watershed in the Ecuadorian Andes through a multidimensional approach incorporating biotic, physicochemical, and structural indices. Indices such as the Andean Biotic Index (ABI), Biological Monitoring Working Party index adapted for Colombian conditions (BMWP-Col), Fluvial Habitat Index (IHF), Riparian Quality Index adapted for Andean conditions (QBR-And), and Water Quality Index (WQI) characterized environmental quality gradients and evaluated the impact of human activities across 11 monitoring sites. Hierarchical cluster analysis classified sampling sites into three groups: less polluted (LP), moderately polluted (MP), and highly polluted (HP). HP sites showed elevated levels of biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), electrical conductivity (EC), and turbidity, alongside low biotic and structural scores, indicating advanced ecological degradation. Conversely, LP sites demonstrated greater ecological integrity, despite elevated BOD₅ and COD levels across the watershed, suggesting widespread diffuse contamination. The findings identify anthropogenic activities such as livestock, agriculture, and domestic discharges as major pressures on water quality and macroinvertebrate biodiversity. Significant correlations between physicochemical parameters—including BOD₅ and EC—and declining biotic indices underscore the link between chemical water degradation and ecological fragmentation. In this context, this study highlights the critical need for comprehensive management and restoration strategies to combat pollution, safeguard relatively pristine areas, and rehabilitate the ecological integrity and connectivity of high-altitude Andean aquatic ecosystems under anthropogenic pressure. Full article

In the context of global climate change and intensified anthropogenic pressures, the coordinated development of a social-ecological system (SES) faces unprecedented challenges, necessitating an enhanced understanding of complex system interactions to achieve SES sustainability. This study quantified water resource–water environment–social economy resilience (WR-WE-SEr) and four ecosystem services (ESs)—water yield (WY), habitat quality (HQ), soil retention (SR), and carbon storage (CS)—in Northwest China from 2010 to 2020. Intersystem interactions were analyzed using resilience theory, the InVEST model, and the coupling coordination degree (CCD) model. The key findings include the following: (1) Spatiotemporal evolution patterns (RQ1): WR-WE-SEr exhibited sustained growth with significant regional disparities (Qinghai > Xinjiang > Gansu > Shaanxi > Ningxia), predominantly driven by resistance-dominated dynamics. ESs showed spatial heterogeneity: WY was concentrated in humid areas but declined temporally, while HQ and CS aligned with vegetation/land cover. All ESs followed a “V”-shaped trajectory of initial decline and recovery, with localized fluctuations but regional stability. (2) Coordinated coupling relationships (RQ2): The CCD between WR-WE-SEr and ESs maintained temporal stability but mirrored ESs’ spatial patterns, characterized by a southeast–northwest diminishing gradient. Coordination hierarchy (CS > HQ > WY > SR) and regional performance (Shaanxi > Ningxia > Qinghai > Gansu > Xinjiang) revealed synergies between system resilience and ES provisioning capacity. Transitional coordination (dissonance to coordination) at the integrated ES level highlighted gradual optimization of human–nature interactions. These findings underscore the need for multidimensional strategies to enhance WR-WE-SE-ES synergies in Northwest China. Full article

Soil represents a fundamental yet delicate ecosystem susceptible to threats and alterations that can significantly impact its biota, especially in urban areas. Soil microarthropods may serve as bioindicators of soil quality. The aim of this study was to provide a comprehensive investigation of the response of soil microarthropod communities to anthropogenic pressures and to assess the biological quality of the soil in urban Rome (Italy). Microarthropods were extracted from soil samples collected at 16 sites, representing four distinct land-use types (disturbed unmanaged green spaces, disturbed managed green spaces, urban forests, and natural forests as reference) along a disturbance gradient. The basic soil properties and landscape characteristics were measured at each sampling site. Values of community diversity (calculated as Hill’s numbers based on biological forms reflecting specialization to the edaphic life), total microarthropod density, and soil biological quality indices based on microarthropod biological forms (QBS-ar and its variation QBS-ab, which also considers group abundances), were calculated for each sampling site and compared among land-use types. Land-use types varied in soil chemo-physical characteristics, with soils of managed and unmanaged green spaces being more alkaline, sodic, and compacted, and with lower organic matter, carbon, and nitrogen levels compared to urban and natural forests. Microarthropod diversity decreased from semi-natural or natural forests to highly disturbed urban sites. QBS-ar and QBS-ab values significantly differed among almost all land-use types, with managed urban green spaces exhibiting lower values than the unmanaged ones. No significant differences were observed between urban and natural forests. Soil pH, soil compaction, cation exchange capacity, C/N ratio, and vegetation cover appeared to be the most significant factors influencing the diversity and composition of microarthropod biological forms, as well as the QBS-ar and QBS-ab indices. Although with the limit of using biological forms instead of species, our investigation reaffirmed the valuable role of large, forested patches within cities for soil conservation and the preservation of their microarthropod communities. The potential of green spaces as suitable habitats for soil microarthropods should be carefully considered in urban management plans. Full article

Mangrove ecosystems are globally significant for their biodiversity and ecosystem services but face persistent threats from invasive species and anthropogenic disturbances. This study investigates the interactions between Cyperus rotundus, a widespread invasive weed, and fungal communities in the mangrove-adjacent wetlands of Isla Santay, Ecuador. Using metagenomic sequencing of the ITS region, we analyzed fungal diversity in samples from an anthropogenically pressured area and a non-impacted site. Results revealed significant differences in microbial assemblages: the rhizosphere sample from the disturbed area exhibited lower fungal richness and was dominated by Magnaporthaceae (9%) and Aureobasidium melanogenum (5%), both associated with stress-tolerant traits. In contrast, the rhizosphere sample from the non-impacted site showed higher species diversity, with Cladosporium dominicanum (62%) and Talaromyces (11%) as dominant endophytic taxa. Principal Coordinates Analysis (PCoA) and co-occurrence networks highlighted distinct fungal partitioning between the two sample tissues, indicating that C. rotundus mediates microbial composition in response to environmental gradients. These findings underscore the role of microbial communities in the plant’s invasive success and suggest that leveraging beneficial fungi could enhance ecosystem resilience and support wetland restoration. By integrating molecular approaches with ecological insights, this work contributes to a deeper understanding of microbial dynamics in coastal wetlands and informs targeted management strategies to preserve mangrove habitats. Full article

Grassland ecosystems provide a range of services in semi-arid and arid regions. However, they have significantly declined due to overgrazing and desertification. In the current study, we employed Landsat time series data (TM, OLI, OLI-2) spanning from 1990 to 2024, combined with vegetation indices such as NDVI and SAVI, along with NDWI and digital elevation models (DEMs), to analyze land cover dynamics in the Ugii Lake watershed area, Mongolia. By integrating multisource remote sensing data into the advanced XGBoost (extreme gradient boosting) machine learning algorithm, we achieved high classification accuracy, with overall accuracies exceeding 94% and Kappa coefficients greater than 0.92. The results revealed a decline in montane grasslands (−6.2%) and an increase in other grassland types, suggesting ecosystem redistribution influenced by climatic and anthropogenic factors. Cropland exhibited resilience, recovering from a significant decline in the 1990s to moderate growth by 2024. Our findings highlight the stability of barren land and underscore pressures from ecological degradation and human activities. This study provides up-to-date statistical data to support decision-making in the conservation and sustainable management of grassland ecosystems in Mongolia under changing climatic conditions. Full article

Background: the widespread use of antibiotics in human and veterinary medicine has contributed to the global challenge of antimicrobial resistance, posing significant environmental and public health risks. Objectives: this study aimed to examine the microbiome and resistome dynamics across a salinity gradient, analyzing water and sediment samples from the Baltic Sea coast and the Curonian Lagoon between 2017 and 2023. Methods: the composition of the water and sediment bacterial community was determined by Full-Length Amplicon Metagenomics Sequencing, while ARG detection and quantification were performed using the SmartChipTM Real-Time PCR system. Results: the observed differences in bacterial community composition between the Baltic Sea coast and the Curonian Lagoon were driven by variations in salinity and chlorophyll a (chl a) concentration. The genera associated with infectious potential were observed in higher abundances in sediment than in water samples. Over 300 genes encoding antibiotic resistance (ARGs), such as aminoglycosides, beta-lactams, and multidrug resistance genes, were identified. Of particular interest were those ARGs that have previously been detected in pathogens and those currently classified as a potential future threat. Furthermore, our findings reveal a higher abundance and a distinct profile of ARGs in sediment samples from the lagoon compared to water. Conclusions: these results suggest that transitional waters such as lagoons may serve as reservoirs for ARGs, and might be influenced by anthropogenic pressures and natural processes such as salinity fluctuation and nutrient cycling. Full article

The present study investigates territorial disparities in selected socioeconomic forces and environmental factors underlying soil degradation that may lead to early desertification processes in a dry Mediterranean region exposed to increasing human pressure. To verify if spatial disparities in land resources have increased over time, a standard approach based on the Environmentally Sensitive Area Index (ESAI) was adopted to evaluate sixty years of territorial transformations in Latium, Central Italy, a region prone to intense processes of land resource depletion. The ESAI provides a standard, holistic assessment of soil degradation based on the estimation of four different ‘resource qualities’ (climate, soil, vegetation, and land use) and their change over sufficiently long time windows; in this study, the procedure was run at three reference years (1960, 1990, and 2020). The observed divergence in soil degradation levels between coastal and inland districts arose during the study period, with a consequent reduction in the local-scale variability of the ESAI. Such differential processes observed along the elevation gradient in Central Italy are likely due to anthropogenic factors affecting land use and leveraging crop intensification in flat districts and farmland abandonment in steep areas. New findings to be achieved in the context of human impacts on land resource depletion are regarded as an original contribution to the study of early desertification processes in advanced economies. Full article

The presence of anthropogenic compounds, including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), was studied in three salt marshes within the Tagus estuary, Portugal, along an anthropogenic pressure gradient. Results revealed differences in OCPs and PCBs among the marshes, with differing concentration levels. Specifically, one marsh, with surrounding agricultural activity, showed the highest OCP concentrations, while another, with a historical industrial past, exhibited elevated PCB levels. In contrast, a third marsh, part of a natural reserve, displayed comparatively lower concentrations of both substances. Sediment concentrations, likely influenced by agricultural practices, were found to be comparable to or higher than those observed in other Portuguese estuaries. The halophyte Spartina maritima was found to absorb OCPs, particularly in its aboveground tissues, suggesting bioaccumulation within the plant. Additionally, PCB levels appeared to be influenced by industrial history, with one marsh displaying notably higher concentrations. In conclusion, the persistence of organochlorine compounds in the salt marsh ecosystems notwithstanding the regulatory prohibitions implemented in the 1990s highlights the need for continuous monitoring and study of such sites and the necessity of remediation practices, which are imperative to mitigate ecological and health risks in these polluted salt marshes. Full article

Riverine floodplains are recognized as centers of biodiversity, but due to intense anthropogenic pressures, many active floodplains have disappeared during the last century. This research focuses on the long-term changes in phytoplankton diversity in the floodplain lake situated in the Kopački Rit (Croatia), one of the largest conserved floodplains in the Middle Danube. The recent dataset from 2003 to 2016 and historical data from the 1970s and 1980s indicate high phytoplankton diversity, summarising 680 taxa for nearly half a century. The variability of species richness is driven by specific in-lake variables, particularly water temperature, water depth, total nitrogen, pH, and transparency, determined by a redundancy analysis of the current data. The high phytoplankton diversity levels are sustained regardless of intense pressures on the lake environment, including exposure to strong anthropogenic pollution in the past and extreme hydrological events, both droughts and floods, which have increasingly affected this part of the Danube in the last decades. The conserved hydrological connection between various biotopes along the river–floodplain gradient seems crucial in maintaining high phytoplankton diversity. Accordingly, conserving natural flooding is mandatory to maintain high biodiversity in complex and dynamic river–floodplain systems. Full article

Phytoplankton is a polyphyletic group of organisms that responds rapidly to environmental conditions and provides a reliable response to changes, making it a good ecological indicator for water quality monitoring. However, a gradient is almost essential for a reliable relationship between pressure and impact. In a low-gradient environment, ingenuity is required to outsmart the limitations of the commonly used linear relationship. Here, we examine changes in biomass and functional biodiversity by analysing larger data sets (2013–2022) in six ecologically diverse, natural, deep Croatian karst lakes with low nutrient gradients using nonlinear correlation coefficients and multivariate analyses in 209 samples. We found that phytoplankton biomass was most strongly influenced by nutrients, salinity and alkalinity, while light availability and total nitrogen strongly influenced phytoplankton functional biodiversity. An additional analysis of the TN:TP ratio revealed that the oligotrophic Lake Vransko is nitrogen-limited, and lakes Kozjak and Prošće are phosphorus-limited. This further clarified the relationship of phytoplankton to nutrients despite the low gradient. The complex analysis in this study provides a new perspective for predicting changes in the structure and succession of phytoplankton in deep karst lakes for successful management under apparent anthropogenic pressure and climate change. Full article

Groundwater, essential for supplying drinking water to half of the global population and supporting nearly half of all irrigation needs, faces significant contamination risks. These risks pose serious threats to human health and ecosystem integrity, driven by increasing pressures from both concentrated and diffuse pollution sources, as well as from growing exploitation. The presented research was conducted with the dual objectives of identifying sources of nitrate contamination (up to 128.1 mg/L) in an oxic groundwater source (Perkićevo, Serbia) and proposing an optimal extraction regimen to ensure a sufficient supply of potable water. Correlations between chemical elements’ concentrations and principal component analysis (PCA) indicated a significant relationship between anthropogenic impact indicators (NO₃⁻, Na⁺, B, Cl⁻, SO₄²⁻, KMnO₄ consumption, and electroconductivity), unambiguously showing that groundwater quality was primarily impacted by untreated sewage inflow and confirming nitrate’s tracer behavior in oxic environments. The spatial distribution of selected parameter concentration gradients highlighted the expansion and distribution of the contamination front. A numerical groundwater flow model (Vistas 4 and Modflow) was applied to determine the groundwater flow direction and the quantity of groundwater originating from different parts of the investigated area. Through four simulated groundwater extraction scenarios, Scenario 2, with an average extraction rate of 80 L/s from 12 wells, and Scenario 3, with an average extraction rate of 75 L/s and 4 additional wells, were identified as the most optimal, providing a sufficient quantity of adequately sanitary water. Full article

Coastal marine areas are threatened by different forms of pollution, among which potentially toxic elements (PTEs) represent a primary hazard. In this study, 16 Mediterranean macroalgae colonizing the upper eulittoral and infralittoral zones were studied for their PTE accumulation capabilities in order to identify possible biomonitors that could replace the use of Posidonia oceanica, a protected species. To achieve this objective, macronutrients (Ca, K, Mg, P, S), micronutrients (Cr, Cu, Fe, Mn, Na, Ni, Si, V, Zn) and non-essential elements (Cd, Pb) were analyzed in the thalli of different algal species, the leaves of P. oceanica and in sediments collected from six sampling sites along the Cilento coast (Campania, Italy), all characterized by different anthropogenic pressures. For sediments, a sequential extraction of PTEs to evaluate their bioavailability profile was also carried out together with the analysis of mineralogical composition, particle size distribution, pH and organic matter content. Macrophytes, belonging to different divisions (six Rhodophyta, four Chlorophyta, six Heterokontophyta, one Embryophyta), are characterized by different PTE concentrations, with a few ones being characterized by an even accumulation response toward the different PTEs. One of these, the brown alga Dictyota spiralis, is able to accumulate PTEs in concentrations similar to P. oceanica and provides more accurate concentration gradients, highlighting clear pollution scenarios that were overlooked using P. oceanica only. Therefore, D. spiralis is a useful PTE biomonitor of coastal marine ecosystems and a suitable replacement for P. oceanica, also featuring the possibility of being employed in active biomonitoring applications. Full article