Search Results (192)

Managed freshwater replenishment is a significant restoration method in the Yellow River Delta. However, their impacts on plankton communities, which are key bioindicators of aquatic ecosystem health and sensitive to the changes in the environment, remain poorly quantified. In this study, we conducted plankton surveys across wetlands subjected to freshwater restoration durations ranging from 5 to 22 years. We assessed shifts in phytoplankton and zooplankton community structure, biomass, diversity, and their relationships with environmental drivers. Results revealed distinct temporal dynamics: phytoplankton biomass and diversity followed a “U-shaped” trajectory (initial decline followed by recovery), while zooplankton biomass decreased but diversity increased with restoration duration. Canonical Correspondence Analysis (CCA) and Partial Least Squares Path Modeling (PLS-PM) identified salinity (Cl⁻, SO₄²⁻) and dissolved nitrate (NO₃⁻) as primary environmental controls for both groups. Cyanobacteria dominated phytoplankton biomass initially but declined with restoration age, while rotifers replaced copepods as the dominant zooplankton taxon over time. These findings demonstrate that freshwater restoration restructures plankton communities through salinity-mediated physiological constraints and altered nutrient availability, with implications for ecosystem function and adaptive management in anthropogenically influenced deltas. Full article

The Adiabatic Sonic Evaporation and Crystallization (ASEC) technology was developed as a disruptive zero-liquid discharge system to treat contaminated mining effluents. This study evaluates its ecotoxicological efficacy using Lemna minor, a freshwater macrophyte, as a sensitive bioindicator. Acute growth inhibition tests were conducted using OECD Guideline 221. Lemna minor was exposed for 7 days to untreated and treated effluents from the Tharsis mine and the Tinto River in southern Spain. The results revealed 100% inhibition of frond growth and biomass in untreated samples (pH < 2.6), indicating acute toxicity. In contrast, effluents treated with ASEC showed growth and biomass accumulation statistically indistinguishable from the control, confirming the system’s efficiency in reducing toxicity and restoring water quality. These findings support the environmental viability of ASEC technology for mine and port effluent treatment. Full article

It is well established that effective management and restoration of freshwater ecosystems is often limited by the availability of reusable data. Although numerous public, private, and nonprofit organizations collect data from freshwater ecosystems, much of what is collected remains inaccessible or unusable by Rights holders and end users (including researchers, practitioners, community members, and decision-makers). In Canada, the federal government plans to improve freshwater data sharing practices through the newly formed Canada Water Agency, which is currently drafting a National Freshwater Data Strategy. Our study aimed to support these efforts by synthesizing insights from the technology sector, where data management and sharing practices are more mature. We interviewed 12 experts from the technology sector, asking them for advice on how to improve data sharing practices in the freshwater science sector. Using a Reflexive Thematic Analysis of participants’ responses to semi-structured interview questions, we identified nine broad recommendations. Recommendations centred on motivating open data sharing, promoting data reuse through data licences, training and skill building, and developing standards and digital solutions that enable data discovery, accessibility, interoperability, and reuse. These recommendations can support the numerous initiatives that are working to improve access to high-quality freshwater data and help address the pressing crisis of global freshwater ecosystem degradation. Full article

Cyanobacterial blooms and aquatic vegetation dynamics are critical indicators of freshwater ecosystem health, increasingly shaped by climate change, nutrient enrichment, and ecological restoration efforts. Here, we present an automated monitoring system optimized for small- and medium-sized lakes. This system integrates phenology-based algorithms with Sentinel-2 MSI imagery, leveraging the AI Earth (AIE) platform developed by Alibaba DAMO Academy. Applied to monitor 12 ecologically sensitive lakes and reservoirs in Jiangsu Province, China, the system enables multi-year tracking of spatiotemporal changes from 2019 to 2024. A clear north-south gradient in cyanobacterial bloom intensity was observed, with southern lakes exhibiting higher bloom levels. Although bloom intensity decreased in lakes such as Changdang, Yangcheng, and Dianshan, Ge Lake displayed fluctuating patterns. In contrast, ecological restoration efforts in Cheng and Yuandang Lakes led to substantial increases in bloom intensity in 2024, with affected areas reaching 33.16% and 33.11%, respectively. Although bloom intensity remained low in northern lakes, increases were recorded in Hongze, Gaoyou, and Luoma Lakes after 2023, particularly in Hongze Lake, where bloom coverage surged to 3.29% in 2024. Aquatic vegetation dynamics displayed contrasting trends. In southern lakes—particularly Cheng, Dianshan, Yuandang, and Changdang Lakes—vegetation coverage significantly increased, with Changdang Lake reaching 44.56% in 2024. In contrast, northern lakes, including Gaoyou, Luoma, and Hongze, experienced a long-term decline in vegetation coverage. By 2024, compared to 2019, coverage in Gaoyou, Luoma, and Hongze Lakes decreased by 11.28%, 16.02%, and 47.32%, respectively. These declines are likely linked to increased grazing pressure following fishing bans, which may have disrupted vegetation dynamics and reduced their ability to suppress cyanobacterial blooms. These findings provide quantitative evidence supporting adaptive lake restoration strategies and underscore the effectiveness of satellite-based phenological monitoring in assessing freshwater ecosystem health. Full article

As human activities increasingly encroach on ecologically sensitive lake zones, China’s lake-ring urban agglomerations struggle to balance the intensifying human footprint (HF) and declining habitat quality (EQ). Addressing the spatiotemporal interactions between HF and EQ is essential for achieving human–environment coordination. This study examined five major freshwater lake-ring urban agglomerations in China during the period from 2000 to 2020 and developed an HF–EQ assessment framework. First, the coupling coordination degree (CCD) model quantified the spatiotemporal coupling between HF and EQ. Second, GeoDetector identified how HF and EQ interact to influence CCD. Finally, the four-quadrant static model and CCD change rate index formed a dual-dimensional management framework. The results indicate that the spatiotemporal evolution patterns of HF and EQ are highly complementary, exhibiting a significant coupling interaction. High-CCD zones expanded from lakeside urban areas and transport corridors, while low-CCD zones remained in remote, forested areas. HF factors such as GDP, land use intensity, and nighttime lights dominated CCD dynamics, while EQ-related factors showed increasing interaction effects. Five human–environment coordination zones were identified based on the static and dynamic characteristics of HF and EQ. Synergy efficiency zones had the highest coordination with diverse land use. Ecological conservation potential zones were found in low-disturbance hilly regions. Synergy restoration zones were concentrated in croplands and urban–rural fringe areas. Imbalance regulation zones were in forest areas under development pressure. Conflict alert zones were concentrated in urban cores, transport corridors, and lakeshore belts. These findings offer insights for global human–environment coordination in lake regions. Full article

The deterioration of European freshwater ecosystems, driven by habitat fragmentation and connectivity loss, seriously threatens biodiversity and ecosystem integrity. While restoration efforts often focus on reconnecting river networks, ecological assessments tend to overlook the broader concept of connectivity. This study highlights the need to incorporate ecological quality into connectivity assessments, ensuring more effective restoration that is aligned with European Union (EU) conservation policies. Using the dendritic connectivity index for potamodromous (DCIp) species, we analysed seven connectivity scenarios, integrating natural and artificial barriers to assess both structural connectivity and quality-weighted connectivity. These scenarios included: (1) structural connectivity considering only natural barriers (S_NB) and (2) all barriers (S_AB); (3) quality-weighted connectivity considering natural barriers (W_NB), and (4) all barriers (W_AB); three enhanced scenarios considering all barriers with (5) improved quality (W_AB_IQ), (6) improved probability of connectivity (W_AB_IC), and (7) improved quality and probability of connectivity (W_AB_IQC). Connectivity values varied across scenarios, with the natural baseline (S_NB) showing the highest connectivity values (mean = 0.98). When the natural baseline was weighted by the GES probability (W_NB), connectivity values dropped considerably (mean = 0.30). Incorporating all barriers (W_AB) further reduced the connectivity values (mean = 0.26). The improved scenario W_AB_IQC showed notable connectivity improvements (mean = 0.40). This study underscores the importance of integrating ecological quality into river connectivity assessments. It demonstrates that restoring habitat quality alongside connectivity restoration can substantially enhance river ecosystems. Prioritising restoration in high-quality areas maximises ecological and social benefits, supports sustainable river management, improves connectivity, and promotes biodiversity conservation. 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

Freshwater fishes are one of the most threatened animal taxa in North America. In Canada, roughly 30% of the occurring species are currently listed and under protection, including redhorses. This review covers Moxostoma spp. ecology, biology, conservation efforts, and highlights challenges to galvanize actions and outcomes through research. The threats to their survival are strongly associated to increasing anthropogenic pressures, superimposed by climate change effects. In Canada, recovery plans for the copper and the black redhorse, and a management plan for the river redhorse, are operational. The recovery strategy for the copper redhorse relies on stocking campaigns of 0⁺ juveniles, which was exclusively based on artificial breeding of captured wild broodstock. A conservation aquaculture program that includes genetic diversity and adaptation considerations was recently initiated, and the areas of refinement identified are the following: broodstock and early-life rearing protocols and environmental and physical enrichment protocols to improve juveniles’ post-release fitness. Research through the prism of conservation physiology is proposed in the identification welfare and health bioindicators and adaptability/response to climatic change. Concurrently, aquatic ecosystem protection/restoration, control of invasive species, eDNA detection/telemetry tracking, and post-release monitoring efforts should also be reinforced. Full article

Conservation of ecologically important freshwater mussels is high on the international agenda, but there is only limited knowledge about the status of rare unionid species in arid and semi-arid areas which are particularly vulnerable. One such example concerns Anodonta vescoiana which was recognized as one of the few endemic species of unionid mussels from Iraq and was restricted to the marshes of southern Mesopotamia and its connected river systems. The last confirmed report of A. vescoiana was in 2009 from the Al-Ezz River. We conducted extensive field surveys during the years 2021 and 2022 at approximately 20 freshwater sites, but we failed to observe any live or dead specimens, suggesting a probable extirpation or severe decline. In contrast, we documented the invasive Sinanodonta woodiana at numerous sites across the Tigris–Euphrates basin including the Al-Ezz River. This documentation of S. woodiana indicates successful establishment of the species and colonization of freshwater systems modified by anthropogenic practices, which include alterations of hydrological dynamics and ecological conditions. Here, we compile existing evidence of the global ecological impacts and development of S. woodiana invasion, while also highlighting Iraq as an important example of the displacement of native unionid mussel species by invasive alien unionids. We assessed the factors that contributed to the disappearance of A. vescoiana in Iraq including biological competition (with S. woodiana), salinity stress, habitat fragmentation, and pollution. The time window to act and prevent the further decline of rare unionid species in Iraq, as well as other arid and semi-arid areas which face similar threats, is short. Urgent actions include systematic monitoring to identify remnant populations, implementing biosecurity policies (for fisheries or habitats), and restoration (of habitats) to secure the long-term persistence of remaining unionid diversity. Full article

Long-term sedimentation patterns influence the ecological succession of shallow lakes. However, human-induced impacts can disrupt these processes, leading to prolonged hysteresis. Using historical sedimentation data, we simulated the future terrestrialization of Lake Izunuma-Uchinuma, a Ramsar-listed wetland in Japan. The results indicated that ecotone recovery would take over 150 years, highlighting the strong legacy effects of shoreline vegetation loss. To accelerate restoration, we implemented an integrated approach that combined water-level management with sediment stabilization structures, including fences and coconut mat rolls. Over three years, these interventions successfully restored shoreline sediment accumulation, facilitated the re-establishment of Zizania latifolia (from 328 m² to 1537 m² in Ecotone 1), and improved water quality and waterbird use. Waterbird abundance significantly increased (p < 0.05) in the treated zones, and sediment exposure led to a reduction in COD release, indicating improved substrate conditions. Our results suggest that proactive ecotone restoration strategies, including hydrological regulation and sediment management, are essential in lakes where natural recovery is hindered by long-term sedimentation deficits and water-level changes. This study highlights the importance of integrating these measures to mitigate hysteresis and enhance ecosystem resilience in degraded shallow lakes. Full article

Nigeria is currently grappling with an acute freshwater crisis, characterized by a stark contradiction where abundant water resources coexist with a widespread lack of access to safe and reliable water. This study examines the complex interplay of factors driving this crisis. It highlights how climate change and the degradation of critical infrastructure and water management systems have significantly reduced the resilience of freshwater systems. This study draws on survey data to assess public perceptions of water scarcity and its causes, revealing a public consensus on the impacts and challenges of freshwater scarcity. This finding points to the pervasive nature of water insecurity in the surveyed population and suggests that reliable access to freshwater remains elusive for many. The findings emphasize the need for integrated, climate-resilient policies that include ecosystem restoration, infrastructure modernization, pollution control, and inclusive, community-based governance frameworks. Addressing these multifaceted challenges is essential not only for improving freshwater access but also for advancing public health, reducing conflict, and fostering sustainable development. This research contributes to the growing body of knowledge on water security in the Global South and outlines pathways for transformative water governance in Nigeria. Full article

Freshwater mussels play a vital ecological role in aquatic ecosystems, serving as effective natural filters that enhance water quality by removing suspended particles and excess nutrients, thereby preventing eutrophication. Their filtration activity supports overall ecosystem stability and promotes biodiversity by providing habitat structure for various aquatic species. Additionally, mussels are valuable bioindicators of environmental health, reflecting water quality changes and accumulating pollutants, including pharmaceuticals and heavy metals, which can offer insights into pollution trends. Freshwater mussels offer considerable economic potential through sustainable aquaculture, particularly in pearl production and jewelry applications, while also contributing nutritionally in controlled and culturally appropriate contexts. Despite these benefits, freshwater mussels face significant threats, including habitat destruction, pollution, invasive species, and overexploitation. These pressures have resulted in drastic population declines and extinctions across various species. Effective conservation and management strategies are essential to protect freshwater mussels, focusing on habitat protection and restoration, ongoing research, and stakeholder engagement to ensure the sustainability of these crucial organisms. This review highlights the multifaceted ecological and economic values of freshwater mussels, the challenges they face, and the importance of comprehensive conservation efforts to maintain their populations and the health of aquatic ecosystems. Full article

Eurasian otters, as apex predators in freshwater ecosystems, are crucial to maintaining nutrient cycling and habitat stability. Although Eurasian otters prefer unaltered natural habitats, their adaptive and opportunistic behavior allows them to occupy suboptimal environments, including urbanized areas. As urbanization increases, the pressure on apex carnivores like the Eurasian otter will continue to grow. To date, urban stream restoration plans have not used the Eurasian otter as a keystone species, but given their influence across the trophic levels, Eurasian otter-focused restoration plans could enhance otter populations and overall biodiversity in urban areas. Here, we lay out six principles designed as a template for enhancing urban habitats for Eurasian otters as well as biodiversity. The principles (enhancing habitat structure complexity, restoring natural riparian vegetation and habitats, safeguarding water quality, providing native prey species, reducing otter mortality, and promoting positive public perception) are essential for urban ecosystem regeneration focused on Eurasian otters. Although there have been no urban restoration projects specifically tailored toward Eurasian otters, initiatives based on similar principles have been effective in promoting biodiversity and otter presence. Overall, an urban habitat restoration plan focused on Eurasian otters will not just increase otter presence but biodiversity across all trophic levels. Full article

Sea level rise is an escalating threat to saltmarsh ecosystems as increased inundation can lead to decreased biomass, lowered productivity, and plant death. Another potential stressor is elevated nitrogen often brought into coastal regions via freshwater diversions. Nitrogen has a controversial impact on belowground biomass, potentially affecting saltmarsh stability. In this study, we examined the effects of inundation and nitrogen on common saltmarsh plants (Spartina alterniflora and Spartina patens) placed within two marsh organs (a collection of PVC pipes at different levels, the varied elevation levels expose the plants to different inundation amounts) located in the Pascagoula River, Mississippi, USA, with six rows and eight replicates in each row. We randomly fertilized four replicates in each row with 25 g/m² of NH4⁺-N every two-three weeks during the growing season in 2021 and 2022. We concurrently collected vegetative traits such as plant height and leaf count to better understand strategies saltmarshes utilize to maximize survival or growth. We harvested half of the vegetation in Year 1 and the remaining in Year 2 to evaluate the impact of inundation and nitrogen on above- and belowground biomass at different temporal scales. We developed Bayesian models that show inundation had a largely positive impact on S. alterniflora and a mostly negative impact S. patens, suggesting that S. alterniflora will adapt better to increasing inundation than S. patens. Additionally, fertilized plants from both species had higher aboveground biomass than non-fertilized plants for both years, with nitrogen addition only showing impact on belowground biomass in the long term. Our results highlight the importance of long-term study to facilitate more-informed restoration and conservation efforts in coastal wetlands while accounting for climate change and sea level rise. Full article

Lake Taihu, China’s third-largest freshwater lake, faces severe eutrophication challenges and therefore requires innovative ecological restoration strategies. This study systematically evaluates the ecological effects of aquatic vegetation restoration in Baimao Bay through comprehensive analysis of macrobenthic communities and environmental parameters, demonstrating significant water quality improvements including a 42.9% decrease in total phosphorus, a 69.4% decline in chl-a concentration, a 34.8% reduction in ammonium nitrogen, and a 81.2% increase in water transparency. Multivariate analysis revealed a fundamental ecological driver shift where post-restoration pH and transparency replaced nutrients as dominant factors, reducing total nitrogen/total phosphorus influence by 40–60%, while filter-feeding species (predominantly bivalves and gastropods) became the dominant macrobenthic biomass group (72.4%) with pollution-tolerant oligochaetes decreasing by 69.1% in abundance, alongside distinct spatial heterogeneity showing pH-regulated lakeshore communities (8.37 to 8.45), transparency-governed shallow-water communities (H′ = 1.35), and a residual nutrient-influenced deep-water area, with a shallow-water area (<2.5 m) unexpectedly exhibiting 3.2 times higher biomass (222.51 g/m²) than deep waters, highlighting vegetation-mediated habitat optimization. These findings advance restoration ecology theory by elucidating ecosystem transition mechanisms from nutrient-driven to light-regulated systems while providing a replicable technical framework for global shallow eutrophic lake restoration, establishing quantitative benchmarks including target transparency (>64 cm) and chlorophyll-a levels (<10 μg/L) for effective eutrophication reversal. Full article