Nutrient management represents an enduring effort toward sustainability. However, long-term management planning faces notable challenges, mainly due to substantial investments required under uncertainty of forthcoming climate. To address these challenges, this paper proposes and tests a Multi-climate-scenario (MCS) Multi-epoch Multi-objective Planning (MEMOP) framework (in combination MCS-MEMOP). This framework divides the long-term planning horizon into multiple epochs, allowing nutrient mitigation measures (e.g., fertilization management, filter strip) to be initiated at any epoch, each with its own water quality and investment constraints. To tackle climate uncertainty, it incorporates principles of Robust Decision-Making. MCS-MEMOP generates solution pathways outlining the timeline and progression of management measures, tested here for a case of a small, agriculture-dominated watershed. Considering a single climate scenario, the MEMOP method was compared with Multi-objective Planning (MOP) and Stepwise MOP (SMOP) for a 25-year nutrient management horizon, using the SWAT model to evaluate the test case water quality effects of solution pathways. Results show that MEMOP's multi-epoch approach generates a larger and more diverse set of solutions than MOP and SMOP, offering greater flexibility to select optimal trade-offs among objectives. Additionally, MEMOP solutions exhibit superior cost-effectiveness compared to MOP and SMOP solutions. Applied separately to different climate scenarios, the MEMOP results show that changed climate conditions may significantly alter the Pareto front. In contrast, MCS-MEMOP yields robust solutions that can consistently satisfy 72%∼89% of epoch-specific constraints under new climate conditions in the test case, with a cost increase of 12% that reflects the price of addressing climate uncertainty in this case.

Water balance models provide insights into ongoing changes in the water cycle. Among them, monthly water balance models (MWBMs) are especially suitable for large-sample and global assessments, which are important for adaptation to global environmental change. This study evaluates monthly water balances from 14 models across more than 2,000 global catchments, comparing the modelś capacities to reproduce water-cycle processes and produce results. We showed that most of the considered models produce reasonable runoff simulations across most settings. However, notably not in catchments at latitudes above 60°N or when the ratio of snowfall to total precipitation exceeds 20 %. By contrast, the inclusion of a non-linear snow module enabled the extended models to achieve similarly good performance in snow-affected basins as in non-snow basins. The improved fit was not mainly due to an increased number of fitting parameters, but rather to a better representation of physical processes, including freeze–thaw cycles. Furthermore, models generally performed slightly better in relatively humid regions than in arid ones. For instance, performances were not sensitive to model structure when catchments were humid enough, with approximate thresholds of annual precipitation exceeding 1000 mm and annual runoff exceeding 300 mm. Also, simulation results for larger catchments were frequently more stable than those for smaller catchments. We expect these insights could aid in assessing, identifying, and addressing potential biases in regional water balance modeling studies worldwide, which may be important for finding effective solutions to mitigate the effects of ongoing hydroclimatic change.

Climate change is shifting the suitable habitats for many tree species northwards. Large parts of southern Sweden are projected to become unsuitable for Norway spruce by the end of this century. With the majority of forests in Sweden under management, spruce plays an important role, both economically and in natural ecosystems. Despite its significance, there is limited understanding of whether current trends in spruce prevalence align with the projected changes in habitat suitability. In this study, we addressed this gap by analysing projected range shifts for Norway spruce between 2005 and 2095 under two climatic scenarios (RCPs) and compared them with long-term forest inventory data. Our results show that: (1) In southern Sweden (Götaland), large parts (59.1% for RCP 4.5 and 85.7% for RCP 8.5) of current spruce stands (as by 2005), are projected to fall into areas unsuitable for spruce by 2095. (2) Observed trends in growing stock between 2005 and 2020 are often opposite to those projected for changes in suitability, though trends varied between counties. (3) The growing stock of young trees is increasing across all regions. Combined, these results show a clear mismatch between projected spruce habitat suitability under climate change and current management practices.

Understanding monthly runoff variability, its spatio–temporal characteristics, and key drivers under climate change and human impacts is crucial for long-term water resource management. However, current knowledge remains limited, especially in high-elevation, seasonally cold regions. Focusing on 10 sub-basins along an elevation gradient (1000 to 5900 ma.s.l.) in the hydrologically complex Yalong River basin, China, this study developed an extended Budyko framework based on monthly water balances (2002–2016), explicitly separating snow storage dynamics (ΔS_snow) from other terrestrial water storage changes (ΔS^′), including those related to hydropower reservoir construction. Results showed that snow accumulation and snowmelt are main drivers of runoff seasonality in the upper sub-catchments, and their effects propagate to the lower-elevation snow-free sub-catchments, which are also subject to additional influence from hydropower reservoirs. This created pronounced altitudinal heterogeneity in drivers of monthly runoff, a phenomenon suggested but rarely quantified at high spatio–temporal resolution in other global regions. Furthermore, a decrease in runoff seasonality in the Yalong River at its Yangtze River outlet (that receives water from all 10 investigated sub-basins) was observed, this change appeared unrelated to snow storage changes and was more likely driven by trends in unfrozen precipitation seasonality and/or flow-modulating impacts of reservoirs, natural lakes and groundwater. Future snow thinning may exacerbate these trends. Implementing the variance decomposition method within the extended Budyko framework, the intra-annual runoff variability () was captured by calculating the variance and covariance of influencing factors, achieving R² values above 0.9 in most sub-basins, and the rainfall (P_r) and ΔS^′variances were identified as the main contributors. Methodologically, we have verified the substantial contribution of hydropower reservoir storage changes on total storage changes by independent analysis of reservoir storage data. These findings supported the applicability of the extended monthly Budyko framework for identifying dominant processes in the context of runoff generation and the rapid environmental changes that the Yalong River basin and other cold regions (not least of the Tibetan plateau) are currently experiencing.

Aims: Until the late 19th century, Plasmodium vivax malaria was endemic in most of Europe including in the Nordic countries. In Denmark, Finland, and Sweden, the fluctuations in malaria cases and malaria-attributed deaths are known to have been associated with weather conditions, in particular with mean summer temperature variations. However, to what extent other environmental factors could have increased or decreased the risk of malaria has not previously been evaluated using historical records. Methods: In this study, we illustrate the non-linear association between different environmental variables (temperature, precipitation, and sea-level variations) and symptom-based malaria (case and death) data, using the quasi-Poisson distributed lag non-linear model. The robustness of the model results was examined through sensitivity analysis. Results: The modeling results showed that the risk associated with temperature increased by ∼25% in Denmark and by ∼67% in Sweden and Finland, with a mean summer temperature increase from 16°C to 18°C, was highest at 1–2 lagged years. Furthermore, average precipitation could have a noticeable effect on the malaria risk in Sweden and Finland, but this effect was not observed in Denmark. Environmental perturbations associated with extreme sea levels (>99.7th percentile or <0.1th percentile), including subsequent saltwater intrusion, could lead to increasing malaria risk in low-lying coastal areas. Conclusions: The historical evidence and modeling results suggest that specific weather conditions and extreme events have substantial impacts on malaria in temperate regions.

In cold regions, snow cover and seasonally frozen ground (SFG) exert a substantial influence on hydrological processes, yet their effects – especially at the scale of large basins – remain insufficiently understood due to limited observations and process-based analyses. To address this, we extended the widely used Grid Xinanjiang (GXAJ) hydrological model by developing two physically meaningful yet computationally efficient modules: (i) the GXAJ-S model, which incorporates snowmelt processes, and (ii) the GXAJ-S-SF model, which additionally accounts for freeze–thaw cycles of SFG. These modules strike a balance between physical representation and simplicity, making them applicable in data-sparse cold regions. The model performance was evaluated using multi-source remote sensing/reanalysis data and observed daily runoff, enabling a systematic investigation of how snow and SFG jointly regulate key hydrological processes. The results demonstrate that: (1) including both snowmelt and freeze–thaw processes significantly improves runoff simulation, especially during cold seasons; (2) snow dynamics directly modulates the development of soil freeze–thaw cycles, thereby altering the hydrothermal state of the vadose zone; and (3) the inclusion of the SFG module in the model variant, which already accounted for snowmelt, increased the predicted surface runoff by 39 %–77 % during cold months, reduced evapotranspiration by approximately 85 %, and substantially modified interflow processes, particularly during the early-spring thaw period. These findings provide quantitative evidence of the critical role of SFG in shaping the seasonal hydrological regime of large cold-region basins. Moreover, the modular and transferable design of the snow and SFG components allows for straightforward integration into other hydrological models, offering a valuable tool for hydro-climatic assessments and water resource management in mountainous regions under changing climate conditions.

Context  Flood disturbances act as strong filters on arthropod communities by excluding species that are not adapted to the high water-tables. Sensitive species can survive in these areas by either migrating to more terrestrial habitats or by using dry refuges within the wetland created by topographical heterogeneity.

Objectives  We examined the role of dry refugia and the scale at which these affect arthropod densities, mainly cursorial species, by using previous information on local dryness-wetness of wetlands.

Methods  We selected sites wiith different flooding regimes within a large fen based on used prior information on local dryness-wetness of wetlands at 2 × 2 m resolution. We then used suction sampling to collect abundance data of beetles and spiders, and related these data to flooding regimes at spatial scales up to 26 × 26 m.

Results  These studies indicated that species within Linyphiidae, Staphylinidae and Chrysomelidae were more abundant in the presence of dry refuges at a scale of 10 × 10 m, whereas Salticidae preferred wetter areas. Species within Carabidae, Lycosidae and a number of other taxon groups were indifferent to these structures. Moreover, the data seem to suggest that mainly habitat generalists benefit from the refuges. Accordingly, those groups that were impartial to the dry refuges included almost exclusively species that can be categorised as wetland specialists.

Conclusions  Small-scale refuges in heterogeneously flooded wetlands may be important to consider for guiding contemporary efforts to restore wetlands as a mean to promote biodiversity.

Aim: Aquatic-terrestrial transition zones contain features essential for many species that often benefit wetland biodiversity. Shallow flood-zone areas and reed beds are indicative of natural wetland habitats; however, how such features affect the native arthropod biodiversity in constructed wetlands is scarcely investigated. We asked how these shoreline features, as well as wetland shoreline properties and grazing management, influence riparian arthropod diversities and habitat specializations. Location: Constructed wetlands, Sweden. Taxa: Araneae, Coleoptera, Diptera. Methods: Taxonomic-, phylogenetic- and trait diversities, along with habitat specialist species richness, were measured in riparian spiders, beetles and selected Diptera in 68 constructed wetlands in two regions of Sweden. We ran structural equation models to estimate direct and indirect effects from shoreline slope, flooded grassland, reed areas and grazing management on group diversities, and used multivariate models to determine drivers on habitat specialist species richness. Results: Flooded grassland and reed area, along with shoreline slope influenced arthropod diversities, and responses differed between arthropod groups and diversity metrics. Spider trait diversity was greater in wetlands with larger flooded grassland areas, whilst beetle trait diversity was reduced. Spider phylogenetic diversity was greater in wetlands containing larger reed areas and in wetlands with steeper shorelines. However, species richness in predatory flies was greater in wetlands with more gentle shorelines. Grazing management had limited effects on arthropod diversities; however, species richness in wetland specialist and generalist predatory dipterans was greater in the absence of grazers in wetlands with greater flooded grassland areas. Main Conclusions: As requirements vary considerably among arthropods, care must be taken when constructing and managing wetlands to benefit arthropod biodiversity. The present results suggest wetlands with a varied shoreline, albeit with greater proportions of flood areas, or multiple adjacent wetlands with varying shores in a wet landscape and a mild grazing regiment, would accommodate a more diverse arthropod fauna.

Recognising the need for robust models in predicting groundwater contamination risks from metal(loid)s in contaminated topsoil, this study focuses on the geochemical behaviour of As, Cd, Cu, Pb, Sb and Zn in one of Sweden's most heavily contaminated areas. Samples were collected from the waste zone and underlying subsoil down to 5 m and batch experiments were carried out to assess pH-dependent solubility. The results indicate that Cd, Cu, Pb and Zn are efficiently immobilized in the waste zone, while As(V) and Sb(V) are more easily leached. With the exception of Pb and Cu at high pH, the mobilized metals appear to be predominantly in a truly dissolved state, as confirmed by ultrafiltration at 10 kDa. Speciation modelling using Visual MINTEQ did not suggest a significant role of precipitates such as Zn or Pb arsenates and phosphates, although their involvement could not be ruled out. To better understand sorption/desorption patterns, a multi-surface geochemical model was established, drawing on the Stockholm Humic and CD-MUSIC models for organic matter and Fe/Al (hydr)oxide sorption. However, when default parameters were used, the model consistently overestimated the solubility of Cd, Cu, Pb and Zn in both the waste zone and the uncontaminated subsoil. In contrast, As(V) solubility was generally underestimated, also when the reactive surface area of the Fe- and Al (hydr)oxides was decreased in the model. The model's performance was better for Sb(V), though not without imperfections. When the parameters for organic matter were adjusted such that 100% of the solid-phase organic matter was active with respect to ion binding, but only 25% of the dissolved organic matter, the model description improved considerably for Pb and Cu in the upper soil layers. The model revealed distinct differences in the adsorption behaviour of the metal cations, with Pb being sorbed mostly to Fe/Al (hydroxides), whereas a considerable part of Cu was sorbed to organic matter, particularly in the waste zone. Possibly, the dissolution of easily weatherable metal-containing mineral phases may have contributed to the poor model performance for Cd, Zn and for Cu in the deeper soil layers, although other factors, such as a contribution of hydrous SiO2 or Mn oxides to metal binding, could not be ruled out. Metal sorption to carbonate phases may also have been a contributing factor in the waste zone. Lastly, the reactivity of Fe- and Al (hydr)oxides may have been overestimated by oxalate extraction when default parameters for high-surface-area ferrihydrite were applied. These findings provide valuable insights for environmental management and underscore the need for a more detailed characterization of metal(loid) sorption in contaminated soils, as well as the development of improved modelling strategies to enhance solubility predictions.

Amplified eruptive outbreaks of bark beetles as a consequence of climate change can cause tree mortality that significantly affects terrestrial water and carbon fluxes. However, the lack of field-scale observations of underlying physiological mechanisms currently hampers the expression of such ecosystem disturbances in predictive modelling. Based on a unique flux tower dataset from a subalpine forest located in the Rocky Mountains, mechanisms of stomatal response to an extensive bark beetle outbreak were investigated using various models and parametrizations. The datasets cover a decade, including the periods of pre-infestation, infestation, and post-infestation. Field measurements showed considerable decreases in evapotranspiration (ET), transpiration (T), and leaf area index (LAI) during the two-year infestation period compared to the pre-infestation period. Model interpretations of observed water and carbon fluxes indicated that the overall reductions in T were not solely due to decreased LAI, but also to changes in physiological behaviours. The summer season's canopy-scale stomatal conductance was significantly reduced during the infestation period, from 0.0018 to 0.0011 m s⁻¹. One primary reason for the observed variations is likely that the bark beetle infestation hampers the water transport in the xylem. The damage of xylem has important implications for water use efficiency (WUE), which also significantly influences the parameterization of stomatal conductance. When using stomatal conductance models to forecast ecosystem dynamics, it is crucial to recalibrate the model's parameters to ensure the accurate depiction of stomatal dynamics during various infestation periods. The neglect of the temporal variability of canopy-scale stomatal conductance under ecosystem disturbances (e.g., bark beetle infestations) in current earth system models, therefore, requires specific attention in assessments of large-scale water and carbon balances.