Augustine Ovie Edegbene

Freshwater systems, including urban streams and groundwater, are increasingly affected by climate change through altered precipitation, rising temperatures, droughts, floods, and changing water demand. This narrative review synthesizes evidence on how these pressures modify groundwater–stream connectivity and the resulting ecological, conservation, and sustainability implications in urban environments. The literature shows that groundwater supports baseflow, thermal buffering, hyporheic exchange, and habitat persistence, but that urbanization can simultaneously reduce natural recharge and create new anthropogenic recharge pathways. Studies of urban streams document flashier hydrographs and ecological degradation under conventional urbanization, whereas infiltration-focused low-impact development has been shown in some catchments to increase baseflow and reduce seasonal variability. Climate change adds further pressure: global modelling projects substantial warming of shallow groundwater by 2100, while long-term stream studies show taxon-specific community responses to warming and extreme events. Major knowledge gaps include limited long-term paired groundwater–stream observations, scale mismatches among hydrology, ecology, and governance, and underrepresentation of arid, semi-arid, tropical, and Global South cities. Addressing these gaps requires coupled hydrological–ecological research, functional indicators, and context-specific nature-based and hybrid management strategies that maintain or restore groundwater–stream connectivity as a component of urban freshwater resilience.

Rising temperatures further compound these challenges (Zhang et al., 2024). Elevated air temperatures increase stream water temperatures, reducing dissolved oxygen concentrations and creating stressful conditions for temperature-sensitive aquatic organisms (Johnson et al., 2024;Lyu et al., 2026). Warmer waters also promote the proliferation of harmful algal blooms, which impair ecosystem functioning, reduce water quality, and pose risks to both human and ecological health (Sousa et al., 2025;Lu et al., 2026). In many Mediterranean, semi-arid, tropical and subtropical regions, prolonged droughts and increased evapotranspiration have contributed to declining stream flows and reduced water availability, further threatening the ecological integrity of urban waterways.Climate change is also altering streamflow regimes by affecting the timing, magnitude, and variability of water flows (Zhang et al., 2025). Such changes disrupt habitat availability, species migration, reproductive cycles, and ecosystem resilience, potentially leading to biodiversity loss and shifts in community taxonomic and functional structure (Feio et al., 2015;Tonkin, 2021). As urbanization continues to expand, particularly across countries of the global south[EE1][DDO2], an increasing number of streams are being incorporated into urban catchments, intensifying their exposure to both climatic and anthropogenic pressures.Despite the growing awareness of climate change impacts on freshwater systems, research specifically examining how climatic shifts can change reshapes urban stream ecosystems remains fragmented. This Research Topic "Effects of climate change on urban streams in the Anthropocene: how ready are we to tackle this looming danger?" soughteeks to advance the understanding of the complex interactions between climate change and urban stream dynamics globally. We invited , contributionswhile highlighting innovative approaches tofor hydrological modelling, monitoring, adaptation, restoration, and sustainable management. Addressing these challenges is critical for safeguarding urban freshwater ecosystems and enhancing their resilience in an increasingly uncertain climatic future. In addressing the challenges posed by climate change, one of the articles published in this Research Topic, proposed a novel quantitative approach to assessing integrating the resistance, resilience and stability of a river ecosystem and its driving factors (Yue et al.). The Han River Basin in China was selected by the authors as it has for its distinctive climate characteristics and evidence of significant anthropogenic impact. Thise river basin has been reported to be subjected to urbanization, dam construction, variations in precipitation, and internal factors which include Total Phosphorus (TP) and Electrical Conductivity (EC) ( (Li et al., 2008). Other river systems in China have also been reported to experience varied degrees of anthropogenic pressure, such as urbanization and dam construction, in China, e.g., Yellow River (Ma et al., 2025). The Han River study proposed a novel and comprehensive method for evaluating the resilience, resistance and stability of river ecosystems based on variations in the diversity of zoobenthos, zooplankton, and phytoplankton. This study revealed that resilience in the lower reaches of the river decreased by 35.75% compared to the upstream reaches. of the river. They also noted that u Urbanization had the most significant negative impact on the ecosystem stability, followed by change in climatic conditions, represented by precipitation, river velocity and discharge which together enhance water exchange and diffusion of organic pollutants such as nitrogen and phosphorus (Liu et al., 2024b), and influence levels of DO, nutrients and conductivity (Liu Y. et al., 2024c). Therefore, increased precipitation negatively impacts the diversity of aquatic organisms, and reduces ecosystem stability. precipitation and dam construction, while environmental variables such as TP, DO, and EC affected the ecosystem stability. In mitigating the impacts caused by these changes in the environment, they proposed a novel and comprehensive method based on the diversity of zoobenthos, zooplankton, and phytoplankton, which will help in evaluating the resilience and resistance of river ecosystems. Overall, their the findings of this study highlighted the need for targeted conservation strategies to mitigate human-induced disturbances and which can help enhance river ecosystem stability. Watershed management and ecological restoration support systems were recommended for sustainable river conservation.Aside from the impact of urbanization and dam construction outlined by Yue et al., hHydraulic investigations of the impacts of projected climate change and land cover changes on flooding events in the Pinacanauan de Ilagan River a river in Isabela, Philippines wereas explored by Yumol and Santos. Using projected rainfall patterns to project future climate conditions, estimates of two different land cover levels were used to represent changes in development of highly built-up areas and the influence of landcover versus climate change on a flood depths model. Their results revealed that flood depths increased to as high as 12.83% between 2015-2020 while increased precipitation as a representation of future climate generated has flood depths of 19.79% which signifyies that climate has greater more negative impacts on river flooding compared tothan land cover change. Theseir findings highlighted the need for strategic planning of future developments to reduce the potential effects on flood risk along the Ilagan River. This study can also provide insights for local decision-makers on the potential impacts of climate change on flood risk management. Finally, the authors recommended that modelled flood parameters can be incorporated in the planning, design, and site selection of future evacuation facilities to improve disaster risk...

In Nigeria, pollution of freshwater ecosystems by anthropogenic activities is a matter of urgent concern as it threatens the productivity and sustainability of the ecosystems. Freshwater ecosystems...

Lassa fever remains a major public health threat in West Africa, yet the household and behavioural determinants of prior Lassa virus exposure are not sufficiently understood. This study examined environmental, behavioural, and demographic factors associated with Lassa virus IgG seropositivity among residents of selected states in North-Central Nigeria. Analysis was carried out on baseline data from 958 participants enrolled in the first phase of an ongoing longitudinal cohort study, which collected information on rodent exposure, house integrity, food safety practices, and household composition. Formative indices were constructed and standardised, and logistic regression models with 1000-iteration bootstrap estimation were used to identify predictors of IgG positivity. Seroprevalence of Lassa virus IgG was 19%, while IgM positivity was 1.15%. Rodent activity around and within homes was widespread, with more than 86% of participants reporting rodent presence. Logistic regression analysis showed that rodent exposure (standardised coefficient 0.20, 95% CI 0.02–0.43) and participant age (0.20, 95% CI 0.05–0.35) were significant predictors of IgG seropositivity. Household size demonstrated a strong inverse association (−0.41, 95% CI −0.68 to −0.20). House integrity and food safety formative indices exhibited weak and non-significant effects. Model performance was acceptable (AUC 0.63; Brier score 0.148), and variance inflation factor values confirmed negligible multicollinearity. These findings emphasised the continuing role of rodent exposure and demographic factors in Lassa virus transmission risk. This implies that there is a need to strengthen community-level rodent control and household-based prevention strategies, which can help to reduce exposure.

Lassa fever (LF), a severe hemorrhagic disease endemic to West Africa, is primarily transmitted by rodents of the genus Mastomys, particularly Mastomys natalensis, which serve as the main reservoirs of Lassa virus (LASV). There have been reports of high prevalence of LF in Nigeria, and outbreaks tend to be recurrent yet geographically restricted, implying that additional ecological or epidemiological factors influence the distribution of the disease beyond the mere presence of M. natalensis. However, national-scale data on LASV prevalence in rodent populations remain scarce. To address this gap, a targeted small mammal survey was conducted over a four-month period (May to August 2024) in Otukpo Local Government Area (LGA) of Benue State, north-central Nigeria. Rodents and other small mammals were trapped across three purposively selected wards identified as high-risk areas based on prior reports of occurrence of such small mammals in the areas and the informal settlements in which the selected wards were located in in Otukpo LGA. Analysis of the samples revealed no statistically significant variation in LASV prevalence among the study sites, indicating a relatively uniform, low-level exposure risk across the LGA and region. However, a marginally significant difference in LASV detection between plasma and serum samples suggests that sample type and storage conditions may influence serological sensitivity. These findings highlight the importance of refining diagnostic protocols, broadening surveillance to include additional rodent hosts, and integrating ecological data with public health strategies to improve early warning systems and strengthen Lassa fever control efforts.

Freshwater ecosystems across Africa are increasingly threatened by anthropogenic pressures, including land-use changes, pollution, hydrological alterations, and climate variability. While traditional taxonomic approaches for biomonitoring these ecosystems remain valuable, they often fall short in detecting ecological processes and stressor-specific responses. In contrast, trait-based approaches (TBAs) provide a function-oriented perspective on ecosystem integrity by linking organismal traits to environmental gradients. This review synthesizes the current state of TBAs in African freshwater ecosystems assessments, highlighting their limited but growing application across the continent. We identify key challenges hindering wider implementation, such as the scarcity of trait databases tailored to African taxa, inconsistent taxonomic resolution, limited institutional capacity, and gaps in ecological traits knowledge. Despite these limitations, TBAs offer strong potential to improve diagnostic precision, enable ecological comparisons across regions, and support resilience assessment in data-limited contexts. We suggest future avenues to advance standardized trait frameworks, regional trait banks, and coordinated monitoring schemes in line with global biodiversity objectives and sustainable freshwater ecosystems management in Africa.

Lassa fever (LF), a severe hemorrhagic disease endemic to West Africa, is primarily transmitted by rodents of the genus Mastomys, particularly Mastomys natalensis, which serve as the main reservoirs of Lassa virus (LASV). There have been reports of high preva-lence of LF in Nigeria, and outbreaks tend to be recurrent yet geographically restricted, implying that additional ecological or epidemiological factors influence the distribution of the disease beyond the mere presence of M. natalensis. However, national-scale data on LASV prevalence in rodent populations remain scarce. To address this gap, a targeted small mammals survey was conducted over a four-month period (May to August 2024) in Otukpo Local Government Area (LGA) of Benue State, north-central Nigeria. Rodents and other small mammals were trapped across three purposively selected wards identified as high-risk areas based on prior reports of occurrence of such small mammals in the areas as well the informal settlements in which the selected wards in Otukpo LGA. Analysis of the samples revealed no statistically significant variation in LASV prevalence among the study sites, indicating a relatively uniform, low-level exposure risk across the LGA and region. However, a marginally significant difference in LASV detection between plasma and serum samples suggests that sample type and storage conditions may influence se-rological sensitivity. These findings highlight the importance of refining diagnostic pro-tocols, broadening surveillance to include additional rodent hosts, and integrating eco-logical data with public health strategies to improve early warning systems and strengthen Lassa fever control efforts.