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Declines in pollinating invertebrates across intensively cultivated landscapes linked to reductions in flower‐rich habitats constitute a key threat to biodiversity conservation and the provision of ecosystem services. Over recent decades, many ponds in agricultural landscapes have become overgrown with woody vegetation, resulting in heavily shaded, flower‐poor pond basins and margins. Restoration of farmland ponds through removal of sediment and encroaching woody vegetation (canopy management) from pond margins greatly enhances freshwater biodiversity. Nevertheless, the consequences of pond management for pond‐margin plants and pollinating insects remain poorly understood. Here, we studied these effects for ponds in Norfolk, eastern England.We compared richness, abundance and composition of pollinating insects (hymenopterans and syrphids) and insect‐pollinated plant communities between open‐canopy pond systems subjected to either (i) long‐term regular management of woody vegetation or (ii) recent restoration by woody vegetation and sediment removal with those communities at (iii) ponds dominated by woody vegetation.Canopy management increased the richness and abundance of pollinators and insect‐pollinated plants. Pollinator richness and abundance was best explained by improvements in flower resources at open‐canopy ponds. Management most strongly influenced hymenopteran communities.Ponds represent important semi‐natural habitats for insect‐pollinated plant and pollinator communities in farmland. To enhance food resources, diversity and abundance of diurnal pollinators, conservation management at ponds should aim for mosaics of ponds at different successional stages with a high proportion of early successional open‐canopy ponds. Agricultural ponds are emerging as important habitats not only for aquatic biodiversity, but also for terrestrial species, thus warranting their prioritisation in future agri‐environment schemes. [ABSTRACT FROM AUTHOR]

The variability in water chemistry of samples taken on a monthly basis (October 1990-December 1991) from 31 shallow, artificial ponds in southeast England was examined. The survey revealed great within-yearvariation in the concentrations of nutrients. Total phosphorus (TP) concentrations displayed no overall marked seasonal pattern, althoughmany sites experienced summer peaks with a simultaneous increase in soluble reactive phosphorus (SRP) concentrations, indicating that sediment P release occurred. SRP and nitrate (NO3-N) concentrations displayed a marked seasonal pattern similar to that observed in deep, stratifying lakes, with 55% and 94% of the sites surveyed, respectively, experiencing a decline in concentrations in the spring, maintaining low levels throughout summer and the highest levels occurring in winter. Dissolved silica (SiO2-(Si) also displayed a marked seasonal distribution with a spring decline in concentrations associated with diatom growth, followed by an increase in the summer. The study demonstrated that intra-annual variability in nutrient concentrations is high and tends to be greatest in the most enriched waters. Thus, a high sampling frequency is required to provide representative annual mean data. Furthermore, annual means rather than winter-spring means provide more appropriate estimates of TP and SRP in these waters, owing to the importance of internal cycling of nutrients in summer. The findings are especially relevant to sampling strategy design and the averaging of seasonal water chemistry data for use in predictive models of lake trophic status. [ABSTRACT FROM AUTHOR]

Coastal lagoons are vital yet vulnerable marine ecosystems. This study analyzes a five-year dataset to evaluate changes in water quality and their impacts on biota in Pinqing Lagoon (PQL). Seasonal surveys conducted from 2019 to 2023 across 14 sites revealed significant variability in water and sediment quality parameters. During the wet summer season, water quality deteriorated significantly as nutrient levels peaked. In contrast, the dry winter season posed a high ecological risk from heavy metals (HMs), specifically Cu, Hg, and Cd, in sediments. Sediment core analysis indicates upward trends in HMs since the 1950s. Salinity and pH are the primary drivers shaping the benthic communities in transitional zones, while nutrients and HMs primarily affect organisms in the inner bay. Nutrient enrichment has exacerbated HM accumulation and ecological degradation, with tolerance to HMs emerging as a critical factor for benthic survival. This comprehensive assessment of PQL highlights the seasonal patterns of pollution in urban lagoons, providing valuable insights for future conservation efforts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Since the 1980s, fish farming (aquaculture) has been an important contributor to Scotland's economy, but there are concerns that nutrient-rich food waste and excreta from these farms are causing eutrophication. Water quality monitoring preceding the arrival and subsequent expansion of the industry is limited. Therefore, to better understand the impacts of in-lake fish farms on the quality of freshwater ecosystems, we examined the diatom records in sediment cores from seven freshwater lochs in Scotland over a timescale of c.100-200 years, spanning the period before and after installation of the fish cages at these sites. At three lochs (A, C, E) we observed marked diatom assemblage shifts indicative of eutrophication, coincident with arrival of the fish farms, at two lochs (B, G) there was evidence of enrichment over a longer timescale although with some further enrichment occurring with the advent of the fish farms, and at the other two lochs (D, F), diatom shifts were subtle and showed no sign of eutrophication. Thus, while marked ecological shifts are shown to occur with the arrival of fish farms in some sites, this is not always the case. The natural background conditions, the scale of operations, the siting of the fish cages in relation to location of inflows and outflows, the role of flushing rate and additional sources of nutrients are discussed as potential factors for the variable impacts observed across the seven lochs. Such factors should be considered when planning future installation and expansion of fish farms to ensure sustainable development of these resources. Our study provides an understanding of baseline conditions and long-term water quality trajectories in freshwater lakes with fish farms and demonstrates the value of paleolimnology in supporting management decisions with respect to fisheries., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Helen Bennion reports financial support was provided by Marine Harvest Limited. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Validating paleo total phosphorus (TP) inference methods over long time scales is essential for understanding historic changes in lake P supply and the processes leading up to the present-day global lake eutrophication crisis. Monitored lake water TP time series have enabled us to identify the drivers of eutrophication over recent decades. However, over longer time scales, the lack of reliable TP inference means our understanding of drivers is speculative. Validation of lake water TP reconstruction, therefore, remains the "ultimate aim" of eutrophication studies. Here, we present the first critical comparison of two fully independent paleo TP inference approaches: the well-established diatom method (DI-TP) and a recently developed sediment geochemical method (SI-TP). Using lake sediment records from a small eutrophic U.K. lake (Crose Mere), we find a statistically significant agreement between the two inferred TP records with greater than 60% shared variance. Both records show identical timings, with a 19th century acceleration in TP concentration and subsequent declines following a peak in 1930. This significant agreement establishes the validity of long-term paleo TP inference for the first time. With this, we can now test assumptions and paradigms that underpin understanding of catchment P sources and pathways over longer time scales.

Dramatic declines in diurnal pollinators have created great scientific interest in plant-pollinator relationships and associated pollination services. Existing literature, however, is generally focused on diurnal pollinating insect taxa, especially on Apidae (Hymenoptera) and Syrphidae (Diptera) pollinators, while nocturnal macro-moths that comprise extremely species-rich flower-visiting families have been largely neglected. Here, we report that in agricultural landscapes, macro-moths can provide unique, highly complex pollen transport links, making them vital components of overall wild plant-pollinator networks in agro-ecosystems. Pollen transport occurred more frequently on the moths' ventral thorax rather than on their mouthparts that have been traditionally targeted for pollen swabbing. Pollen transport loads suggest that nocturnal moths contribute key pollination services for several wild plant families in agricultural landscapes, in addition to providing functional resilience to diurnal networks. Severe declines in richness and abundance of settling moth populations highlight the urgent need to include them in future management and conservation strategies within agricultural landscapes.

A three-tiered, hierarchical, risk-based prioritisation system was developed to assess the number of standing waters in Great Britain (GB) at risk from eutrophication. The scheme is based on four properties: importance, hazard, sensitivity to enrichment and sensitivity to recovery. Lake size, conservation status and legislative requirements were used to assess importance. The anthropogenic total phosphorus (P) load estimated from land cover, livestock and population data was used as a measure of the eutrophication hazard. Lakes with a retention time >3 days were considered to be sensitive to enrichment. The Wederburn depth (an estimate of the average summer thermocline depth) was used to predict the potential response of a lake to nutrient reduction. Lakes which were mainly stratified or fully stratified during the summer were expected to respond quickly to remediation. An initial Tier 1 risk assessment was made for all standing waters in GB (approximately 14,300 with surface area greater than 1 ha), using the four parameters derived from nationally available, GIS-based data sources held in the GB Lakes Inventory. Of the 2362 important lakes in GB, the system identified 1736 with low hazard but under potential threat because of their high sensitivity to enrichment. The system assessed that the ecology of 212 was likely to be damaged by eutrophication owing to high hazard and high sensitivity but with relatively poor chance of recovery following remediation. A further 332 lakes were considered to be damaged but were likely to respond to rehabilitation. In summary, the risk-based prioritisation system performed well and provides a useful tool for assessing standing waters at risk of eutrophication on a national basis. Inevitably, however, the need for nationally available datasets at Risk Tier 1 results in data resolution issues and errors may occur. The results highlight the importance of data validation using lake-specific information at Risk Tier 2.