Ecohydrological models have progressively advanced in complexity by incorporating the latest knowledge from hydrology, ecology, and related disciplines. Recent developments include coupling hydrological processes with detailed dynamic vegetation responses to environmental cues, soil biogeochemical dynamics, and the integration of human activities. These activities range from the management of forests and croplands to the operation of built infrastructure such as reservoirs. Advancements in mechanistic approaches offer significant opportunities to translate fundamental knowledge into actionable strategies for a sustainable future, encompassing infrastructure planning and resilient water resource management. However barriers in their implementation include lack of a unified computational framework and lack of data to support the development of such a framework.
In this study, we present a unified computational framework demonstrating how ecohydrological modeling can inform the design of a sustainable future. Our applications address key areas such as forest and cropland management, sustainable agriculture, climate-resilient infrastructure, and sustainable water resource management. Specifically, we introduce multiple new mechanistic hydrological, plant physiological, and infrastructure processes into the ecohydrological and ecosystem model T&C. We also address challenges related to model application in data-scarce contexts and propose a roadmap for leveraging mechanistic ecohydrological modeling to develop actionable design principles for achieving a sustainable, net-zero future.
How to cite: Paschalis, A., Zhang, Z., Buckley, J., Gu, R., Jones, G., Yan, J., and Maddah Sadatieh, M. S.: Consolidating ecohydrological modelling advances to translate science into action, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10334, https://doi.org/10.5194/egusphere-egu25-10334, 2025.
Climate extremes, such as droughts associated with low soil water availability, significantly impact plant carbon uptake by reducing net primary productivity (NPP). NPP is crucial for regulating atmospheric CO2 and maintaining the carbon balance of an ecosystem. Given the increased frequency and intensity of droughts under climate change, it is important to assess the shifts in the ecosystem functioning to ecological droughts. Using the outputs from 6 Earth System Models, we analysed impacts of droughts on NPP over 21st century in India. We tested two hypotheses: first, that there will be an intensified reduction in NPP due to the increased frequency and intensity of droughts, and second, that there will be a decreased ecosystem resilience (greater NPP reduction per drought event) under warming climate. In this study, we used a multi-dimensional resilience index (MDRI) to quantify the response of ecosystems to droughts, which jointly considers the resistance and recovery time after the disturbance. Our results show a significant increase in extreme and moderate droughts over 21st century, while mild droughts remained stable. The NPP reduction during extreme droughts is projected to be three times greater under the SSP2-4.5 scenario and six times greater under the SSP5-8.5 scenario compared with the baseline scenario. Due to longer recovery times and moderate resistance, the Western Ghats and lower Himalayan ecosystems exhibited low to moderate resilience. In contrast, high resistance and shorter recovery times resulted in very high resilience for the Northeastern regions. We found an increasing trend in the resistance, probably benefitting from carbon fertilisation, and decreasing trend in recovery rate, probably related to warming. Our findings do not support the second hypothesis, as we found no significant changes in ecosystem resilience due to trade-offs between resistance and recovery. This understanding can inform conservation strategies to mitigate the adverse effects of climate extremes on ecosystems that should be accounted in design of mitigation and adaptation plans.
How to cite: Bejagam, V. and Sharma, A.: Enhanced impact of droughts on ecosystem functioning despite unchanged resilience under climate change, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14696, https://doi.org/10.5194/egusphere-egu25-14696, 2025.
Alpine mountain ecosystems in the tropical Andes are critical water sources for both human societies and natural systems. These regions store and gradually release water from glaciers, regulate runoff patterns, support irrigated agriculture, facilitate hydropower generation, and sustain delicate ecosystems. The catchments in the tropical Andes are characterized by complex mountainous topography, diverse climates, and dynamic land-use changes. The rapid expansion of agriculture and urbanization has driven significant deforestation, followed by forest recovery efforts, which have substantially altered evapotranspiration patterns and runoff dynamics. In addition, climate change has accelerated glacier retreat and shifted precipitation patterns, causing profound impacts on hydrological processes and ecosystem dynamics. Despite these significant changes in blue, green, and white water fluxes in the region, severe data limitations impede the understanding of regional ecohydrological cycles under the changing environment as well as the development of high-resolution eco-hydrological models.
Our study addresses these gaps by employing innovative computational modelling alongside in-situ and remote sensing observations. We conducted hyper-resolution simulations of coupled water, energy, and carbon dynamics in the tropical Andes using the physics-based T&C model, which we parameterized with data from multiple sources. This approach allowed us to analyse the fate of blue, green, and white water fluxes under climate change scenarios. To streamline regional studies in terms of scalability and applicability, we developed automated input data preparation and model parameter generalization algorithms integrating machine learning and remote sensing methods for the physics-based model. This not only allows flexibility when composing catchment plant functional types (PFTs) but significantly speeds up the model setup process. Validation of the algorithm is through plot-scale simulations using PLUMBER2 sites and spatial scale simulations using CARAVAN catchments before expanding the simulations to larger extents in the tropical Andes.
As a proof of concept, we applied our methodology to the Vilcanota catchment in Peru, a catchment around 9000 square kilometres. This catchment presents complex land uses ranging from glacial coverage above treeline, diverse natural vegetations and intricate crop rotation systems and an elevational span of 4,000 meters.
How to cite: Gu, R., Buytaert, W., Zhang, Z., Becker, R., and Paschalis, A.: Ecohydrological Modelling and Performance Evaluation of a Large-scale Land Surface over the Central Andes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12213, https://doi.org/10.5194/egusphere-egu25-12213, 2025.
We study the biogeomorphologic feedbacks between landforms, vegetation, water and soils using a landscape evolution model in response to anthropogenic pressures and climate variability. We first investigate the impact of seasonal variability of vegetation pools on erosion mechanisms. We use a landscape evolution modelling framework that includes mechanistic representations of hydrology and vegetation, to capture the effect of seasonal rainfall variability on different biomass above and below ground pools and the associated erosion protection. Rainfall leads to both runoff (erosion potential) and vegetation growth (erosion protection), but these two effects are not synchronized. Results for a Eucalyptus savanna landscape in the Northern Territory (Australia) suggest that maximum erosion events tend to occur early during the rainy season when vegetation protection is not strong, and that different pools have varying protection effects and timing through the year. We show that these dynamic effects and feedbacks need to be included to assess climate impacts in restoration and/or mitigation studies.
We then examine the effect of shifts in vegetation structure resulting from anthropogenic activities, which affect water and sediment redistribution in semiarid areas of Australia with sparce vegetation cover. The study areas have patterned Mulga vegetation composed by mixed herbaceous and woody plant species, that evolve responding to competition and facilitation interactions. We analyse modelling results from the coupled landform evolution-vegetation model on water redistribution and erosion to investigate how changes in biomass cover that alter the hydrologic response and lead to impacts on ecosystem functioning are linked to loss of resources leading to degraded states (identified from remote sensing data). These results are used to examine the potential impact of varying management strategies and the implications for the productivity of Australian rangelands.
How to cite: Saco, P., Quijano, J., and Rodriguez, J.: Life and landscapes down under: Modelling the effect of biogeomorphologic feedbacks to investigate human and climate change effects on landscape function., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19422, https://doi.org/10.5194/egusphere-egu25-19422, 2025.
Stomata, small openings on leaves, are critical for regulating the exchange of water vapor (transpiration) and carbon dioxide (assimilation) with the atmosphere. Thus, stomata serve as a key interface between plant physiological processes and ecosystem water and carbon fluxes. The "optimal stomatal control" hypothesis suggests that stomatal behavior is optimized dynamically in a way to achieve maximum carbon uptake given limited water availability for transpiration between rainfall events. The theoretically optimal stomatal conductance follows a consistent slope λ between transpiration (E) and carbon assimilation (A), i.e. λ = ∂E/∂A.
Due to the inability to measure λ directly, the theory has only been tested by fitting leaf gas exchange measurements to models of photosynthesis and transpiration, with the frequent outcome of apparently strongly varying and inconsistent values of λ. However, it is unclear whether such results are due to model and measurement uncertainty or indeed contradict the theory of optimal stomatal control.
After developing an experimental approach to measure λ directly at the leaf scale, we investigate how far λ is consistent between leaves of the same plant or even between plants, under unstressed, single-stress, and combined stress of heat and drought conditions. By combining our measurements with classical leaf gas exchange modeling, we bridge the gap between experimental and theoretical studies of stomatal optimization. Additionally, we measure water use efficiency, photosynthetic capacity, and biomass to link stomatal control mechanisms to plant physiological functioning. Our results provide insights into how stomatal response to heat and drought stress influences water-carbon trade-offs at the leaf level. Scaling up leaf-level behavior to the ecosystem, e.g. with the help of terrestrial biosphere models, opens new possibilities for predicting water resource dynamics, optimizing water resource management in agricultural systems, and improving ecosystem management strategies. Assessment of stomatal control strategies of different plants can also enhance our ability to select heat- and drought-resilient crop varieties for a changing environment.
How to cite: Seeburger, P. and Schymanski, S. J.: Experimental Assessment of Optimal Stomatal Control under Drought and Heat Stress, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15796, https://doi.org/10.5194/egusphere-egu25-15796, 2025.
Turbulence velocity, water vapor concentration, and temperature fluctuations above a Mediterranean forested canopy from a 2-year experiment whereby variability in mean wind direction interrogates different levels of topographic complexity are analysed and reported. The overarching goal was to explore how the velocity and scalar statistics are impacted by terrain variability and what are the consequences of such terrain variability on similarity arguments and the energy balance closure (EBc).
The data were first separated by different wind sectors and analysed for near-neutral conditions. It was found that the down-slope effective momentum roughness length was smaller than its up-slope counterpart. However, the normalized relation between vertical velocity standard deviation (σw) and friction velocity (u*) was insensitive to the mean wind direction (i.e. σw/u*=Aw - a constant around 1.1-1.2). The heat flux similarity relations were investigated in two ways: the first uses a conventional flux-variance form whereby the turbulent vertical heat flux <w'T'> was related to u* and temperature standard deviation (σT) using a similarity coefficient (i.e. <w'T'>=C1σT u*). The second evaluates the much less studied relation between the horizontal heat flux <u'T'> and <w'T'> (i.e. <u'T'>=-C2<w'T'>), where C2 was previously reported to vary between 2 and 4 for 'flat-world' near-neutral conditions. The findings suggest that C1 was close to expectations from flat-world studies but C2 was smaller in magnitude yet independent of mean wind direction.
When repeating the same analysis for water vapor concentration fluctuations, similarity theory failed on both accounts for almost all mean wind directions. In fact, for some wind direction sectors, including the upwind sector, no relation between <u'q'> and <w'q'> was found. Next, EBc was considered. In this analysis, soil heat flux (Gs) was not measured due to the high rock content at the site. Using literature values, it was assumed that Gs was about 15% of the measured net radiation (Rn). The EBc did not exhibit appreciable sensitivity to mean wind direction, with sensible and latent heat flux explaining some 80-85% of Rn-Gs across different mean wind directions.
Guided by recent findings about a connection between the anisotropy in the Reynolds stress tensor and deviations in flux-variance similarity relations, the EBc was re-examined using the anisotropy classification of a barycentric map (isotropic, two-component axisymmetric and one-component turbulence) and the conventional invariance map (or its transformed version to underscore nonlinearities in the return to isotropy in the pressure-strain interaction). While the down-slope runs were dominated by one-component and isotropic cases, the upslope runs were dominated by two-component axisymmetric cases. For near isotropic cases, the EBc was improved but not significantly. Other measures that seek to delineate the nonlinearities in the return to isotropy and deviations from isotropic cases were also considered.
Future work seeks to expand this analysis for diabatic conditions to assess the role of thermal stratification and topography simultaneously on similarity theory, EBc, and invariance analysis of the turbulent stress tensor. Moreover, the flux variance similarity relation as well as the relations between longitudinal and vertical CO2 fluxes will also be considered.
How to cite: Sirigu, S., Katul, G., Montaldo, N., and Corona, R.: Biosphere-atmosphere water vapor and heat fluxes from a forested ecosystem situated on complex terrain: Similarity, anisotropy, and the energy balance closure, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11497, https://doi.org/10.5194/egusphere-egu25-11497, 2025.
Large-scale ecological restoration (ER) in semiarid regions is often associated with substantial terrestrial water storage (TWS) depletion. This study challenged previous estimates by demonstrating the critical importance of considering other human activities when assessing ER impacts on TWS. Using a novel analytical framework integrating GRACE satellite data and ground observations, we analyzed TWS changes in China’s Mu Us Sandyland under two scenarios: with and without considering mining and farming activities. Our results show that ER consumed TWS at an average rate of 11.7 ± 12.2 mm yr-1 from 2003 to 2022. Neglecting the impacts of mining and farming led to a 251% overestimation of ER's effect on TWS. This study provided a more nuanced understanding of water resource dynamics in restored ecosystems, emphasizing the need for comprehensive approaches in TWS assessments and informing sustainable land management strategies globally.
How to cite: Shen, X. and Jia, X.: Disentangling Ecological Restoration's Impact on Terrestrial Water Storage, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2654, https://doi.org/10.5194/egusphere-egu25-2654, 2025.
Orals: Tue, 29 Apr | Room 2.44
The snow-dominated headwaters of the Colorado River are water towers of the south-western US. Together with an increasingly unsustainable water demand downstream in the Colorado basin, the transition to low- or no-snow conditions upstream in the coming decades has been profoundly altering hydrological regimes and water resources for ecosystems and societies. Looking at the “supply side” of this crucial issue, several studies in the intensively-monitored East River catchment in the Upper Colorado River (spanning shrub-dominated montane valley bottoms, subalpine forests and alpine barren hilltops) have pointed at snowmelt as a main driver of runoff generation and a significant contributor to plant-available green water during the growing season. Yet, a spatially-explicit analysis linking plant water use and runoff generation is lacking. Here we present how observations of stable isotopes of water (2H and 18O) in the precipitation and stream water, combined with spatio-temporal observations of snow cover and depth with multiple datasets related to the hydrometry and the energy budget, can be used to constrain and evaluate an ecohydrological modelling tool to then track snowmelt contributions to runoff and plant water use. Over the 2014-2020 time period, we deployed a new version of the spatially-distributed, process-based model EcH2O-iso. The multi-objective calibration yielded a overall good model-data fit across critical zone interfaces and scales (stream, soil, snowpack, groundwater, ET), hinting at the model's ability to capture water fluxes, stores and mixing patterns in the catchment. A set of virtual tracers, tagging snowmelt and lateral saturated flow, further enabled to quantify the large contribution of snowmelt to stream discharge (60-80%) and root uptake (50-70%), much in line with previous independent, spatially-lumped estimates. We further evidence that snowmelt contributions to stream discharge both mobilizes fast surface pathways (runoff in Spring, dominant) and slower lateral groundwater flow downhill and seepage, with corresponding water ages up to several decades. Indeed, this baseflow remains significant in the growing season (~25% of outlet discharge or more), and we find that snowmelt makes up ~60% of groundwater recharge, again in agreement with previous estimates. From this catchment-scale picture, we further explore the spatial patterns of water ages and snowmelt fraction in blue and green water across the ecoclimatic zones of this catchment.
How to cite: Kuppel, S., Carroll, R., Ulrich, C., Williams, K., and Sprenger, M.: Snowmelt contributions to green and blue water fluxes: a model-data approach in a snow-dominated mountain catchment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18500, https://doi.org/10.5194/egusphere-egu25-18500, 2025.
Forests are essential regulators of water, energy, and carbon cycles, emphasizing the need for sustainable forest management under changing climate conditions. Forest management practices, including regeneration and structural changes, impact species composition and densities which have feedback effects on the water balance, partitioning into blue and green water fluxes, and the ecohydrological resilience of these ecosystems. Quantifying and understanding these impacts is critical for maintaining water availability, sustaining livelihoods, and reducing disaster risks, especially in drought-prone regions. This study investigates blue and green water partitioning and its implications for ecosystem resilience under generic forest management scenarios using modelling experiments. These explore variations in forest density, tree species composition (e.g., deciduous, coniferous, agroforestry), and root distribution. Using the tracer-aided conceptual ecohydrology model Ecoplot, baseline simulations (2000–2024) were conducted in the drought-sensitive Demnitzer Millcreek catchment, Germany. The model was calibrated and validated with seven years of soil moisture data and three years of soil water isotope data using a multi-criteria approach. Results showed that coniferous forests transpire more water than deciduous forests and agroforestry stands, while mixed forests enhance ecosystem resilience during droughts by increasing blue water fluxes. Significant differences in water partitioning between dry and wet years were observed across contrasting management scenarios. The findings underscore the importance of mixed forests in mitigating drought impacts and offer a framework for quantifying, visualizing and communicating the implications of land use changes on water availability. These insights are critical for informed decision-making and stakeholder engagement, highlighting the need for integrated strategies to improve forest resilience and ensure sustainable water resource management.
How to cite: Jiang, C., Tetzlaff, D., Wu, S., and Soulsby, C.: Effects of Forest Management Scenarios on Water Partitioning and Ecosystem Resilience: Insights from Long-Term Tracer-Aided Ecohydrological Modelling in a Drought-Sensitive Lowland Catchment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3760, https://doi.org/10.5194/egusphere-egu25-3760, 2025.
Freshwater systems such as rivers, streams, and groundwater are critical for the ecosystem functioning, as they shape the fate of solutes in terrestrial environments. Runoff and leaching waters drain superficial and deep soil layers, vegetation, and rock weathering zones, transferring nutrients and other compounds to downstream ecosystems and eventually to oceans. Freshwaters also facilitate chemical reactions, such as ion exchange, mineral precipitation, and biological uptake, which dictate solute concentrations and forms during transport. The transport of nutrients and other solutes is crucial to the productivity and health of aquatic and riparian ecosystems. For example, the delivery of organic carbon supports the dynamics of the microbial and food web, while transport of metals and pollutants impacts water quality, affecting drinking water sources, aquatic life, and ecosystem services. Catchment hydrologic response and connectivity must be carefully untangled in order to characterize fluvial and aquatic metabolism and the fluxes of exchange between soil, water, and the atmosphere.
Our research focuses on the Rio Valfredda, a pristine mountain stream network draining a 5.3 km2 catchment in the Italian Alps, with the ultimate goal of linking carbon (C) cycling patterns with hydrologic traits. To that end, extensive data acquisition and field campaigns have been carried out since November 2023. Activities include the measurement of dissolved oxygen (DO) and C dioxide (CO2), along with environmental ancillary variables such as photosynthetic active radiation, temperature, barometric pressure, pH, total alkalinity, dissolved inorganic C (DIC) and electrical conductivity, in different reaches. Water stable isotopes (δ18O and δ2H) are also being monitored in several springs and tributaries of the stream network, at the catchment outlet, and in the precipitation at three different altitude rain gauges.
By comparing the isotopic signatures of water in precipitation and streamflow, we develop a modeling framework to reconstruct the spatial variation in water transit time distribution (TTD) across multiple Valfredda sub-catchments. Variations in TTD across catchment springs, tributaries, and the outlet reveal the spatial heterogeneity of hydrologic connectivity and act as indicators of lateral inputs to the stream. TTD results are thus compared with the available environmental data collected within the Valfredda network to unravel sub-catchment transport dynamics and their effect on the C exchange fluxes in the critical zone. We focus specifically on the spatial variation of DIC, connecting its behavior to the proportion of young water mobilized within the system, proving the age of mobilized water serves as a proxy for the transfer of DIC from green to blue ecosystems.
We believe our approach marks a significant advancement in understanding freshwater solute transport and the coupling dynamics of water and C cycling at the catchment scale and can ultimately support resource management and pollution mitigation efforts, contributing to the long-term sustainability of aquatic ecosystems.
How to cite: Grandi, G., Presotto, F., Peschiutta, M., Durighetto, N., Masiol, M., Stenni, B., Botter, G., and Bertuzzo, E.: Linking catchment transit time heterogeneity with fluvial metabolism to unravel carbon cycling in an alpine stream network, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9875, https://doi.org/10.5194/egusphere-egu25-9875, 2025.
Biodiversity loss is a growing threat to natural ecosystems, driven by a combination of anthropogenic and natural factors (e.g., urbanization, deforestation, and, notably, climate change). Such factors can alter wildfire regimes, with the possible consequent creation of more available space for the establishment of invasive alien species. These, often highly adaptable and with rapid growth capabilities, can profoundly alter local ecosystems, disrupt hydrological processes, and reduce native biodiversity.
Among the most concerning invasive species, Ailanthus altissima has rapidly spread across the globe. Ailanthus is distinguished by its ability to adapt to a wide range of environmental conditions. It is resilient to extreme temperatures, able to grow on various soil types, and tolerant of high levels of air pollution, making it adapted also to disturbed/degraded environments. The species can regenerate even when it is cut or burned. Seed dispersal occurs through wind, but also via water, animals, and humans. Ailanthus demonstrated a strong dependence on water availability, employing deep root systems and efficient water uptake strategies to thrive in water-limited environments. This exacerbates competition with native species, particularly in regions under hydric stress, where Ailanthus can monopolize water resources and disrupt local ecohydrological balance, such in the case of Mediterranean ecosystems.
This work presents ALIAS (Ailanthus Locator and Identification Algorithm Suite), a machine learning-based classifier based on the Support Vector Machine (SVM) model, that uses high-resolution PlanetScope satellite imagery, designed to enable accurate remote detection of Ailanthus in specific areas of interest. ALIAS was calibrated by focusing on the presence of Ailanthus along transportation corridors, where species frequently establishes itself due to the wind generated by vehicles facilitating seed dispersal, and in hydrologically connected areas, such as riparian zones. Validation was conducted in an area with a confirmed invasion, i.e., the “Vallone Piano della Corte” Nature Reserve (Sicily, Italy). It represents a sensitive site where local biodiversity and water resources are threatened by dense clusters of Ailanthus. Over the past four decades, the species has progressively expanded, creating populations that competed with native plants and disrupted the natural ecosystem balance. Particularly, four distinct clusters of Ailanthus were identified on the south-facing slope of the site. In contrast, the north-facing slope hosts native flora, i.e., Quercus pubescens forest stands. A diachronic analysis was also performed, reconstructing the invasion of Ailanthus from the late 1980s and performing field surveys with drone acquisitions to obtain the current distribution and the area of invasion. These historical insights were critical for validating ALIAS and demonstrating its reliability.
The results obtained highlight classifier’s potential as a predictive tool for identifying regions at high risk of invasion, particularly in hydrologically sensitive areas. By enabling efficient monitoring of Ailanthus in both confirmed and potentially at-risk zones, ALIAS provides critical insights into the ecohydrological dynamics of invasive species. Furthermore, the classified images resulting from the use of the classifier form the basis for validating vegetation dynamics models (e.g., CATGraSS model), able to reconstruct invasion dynamics and to predict the future expansion of Ailanthus under different climate change and hydrological scenarios.
How to cite: Noto, L. V., Alongi, F., De Caro, D., Badalamenti, E., Capodici, F., Da Silveira Bueno, R., Pumo, D., La Mantia, T., and Ciraolo, G.: ALIAS: A Remote Sensing Approach to Monitor Ailanthus altissima Invasion and its Ecohydrological Impacts, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18565, https://doi.org/10.5194/egusphere-egu25-18565, 2025.
Agricultural drainage systems are essential for managing water levels in farmland, yet they often prioritize conveyance efficiency over ecological function, contributing to biodiversity loss and water quality degradation. Remediation measures, such as two-stage ditches, re-meandering, and bank regrading, are typically aimed at reducing sediment and nutrient loads, but frequently neglect habitat complexity and biodiversity. This study investigates how these remediation practices influence macroinvertebrate communities in agricultural ditches across central and southern Sweden, highlighting novel insights on integrating ecological considerations into drainage system design. We evaluated ecological impacts across 18 paired sites, each consisting of an upstream conventional trapezoidal channel and a downstream remediated section. Water chemistry, sediments, and channel morphology were measured alongside macroinvertebrate sampling, while trait-based analyses were conducted to assess macroinvertebrates’ utility as bioindicators of water quality. Bayesian linear mixed-effects (BLM) models were used to determine the relative influence of climate, region, and remediation efforts on biodiversity outcomes. Results indicate that remediated sections generally supported slightly higher species richness than upstream controls, suggesting modest ecological benefits. However, Shannon and Simpson indices revealed no significant differences in community evenness, and macroinvertebrate composition varied substantially among sites, with no distinct patterns separating remediated and non-remediated sections. The BLM confirmed that remediation had a small but positive effect on species richness, though climatic and regional factors also emerged as key drivers of macroinvertebrate diversity. Our findings show that ditch remediation does not negatively affect aquatic biodiversity and may confer slight ecological gains. Future remediation efforts could further enhance biodiversity by emphasizing habitat complexity. Overall, this study underscores the value of integrating biodiversity considerations into agricultural water management and calls for additional research on structural complexity and natural geomorphological processes, thereby promoting multifunctionality in agricultural drainage systems.
How to cite: Livsey, J., Wynants, M., Hallberg, L., and Bieroza, M.: Ditch Design and Ecological Outcomes: Investigating the Link Between Agricultural Drainage, Macroinvertebrates, and Water Quality in Sweden, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17766, https://doi.org/10.5194/egusphere-egu25-17766, 2025.
The interaction between hydrological and biogeochemical processes, combined with the variability across diverse vegetation ecosystems, presents significant challenges in developing mathematical models for water and carbon exchanges. As a result, research on carbon sink calculations specific to watersheds remains limited. This study aims to address this gap by exploring the link between hydrological and carbon cycles within a watershed using the Gridded Surface/Subsurface Hydrologic Analysis (GSSHA). Focusing on the Lanyang River in Yilan, Taiwan, the research simulates hydrological changes during rainfall events, analyzing key parameters such as water depth, flow, and evaporation to gain insights into the river's hydrological cycle. By linking hydrological and carbon cycles, this research aims to provide insights into carbon dioxide emissions from watersheds. The findings could be applied to inform policy development for reducing watershed-based carbon emissions and enhancing carbon sink potential.
How to cite: Liao, T.-Y. and You, J.-Y.: Coupling Hydrological Modeling with Carbon Flux Calculations: A GSSHA-Based Approach for Evaluating Carbon Emissions in Watersheds, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7974, https://doi.org/10.5194/egusphere-egu25-7974, 2025.
Understanding how environmental change drives compositional change in ecological communities is a central goal in ecology. Trait-based approaches have been useful in understanding how compositional change is mediated by the traits of a community’s members. However, in trait-based approaches, the link between community composition and function is often lost. Here, we derive a quantity – which we call the principal trait – linking the community weighted mean traits with principal components of community composition. We demonstrate the usefulness of this approach with nearly five decades of phytoplankton monitoring data from Lake Constance. We find that the same tradeoff between the resource acquisition traits phosphate affinity and light affinity emerged during the summer bloom in response to long-term changes in nutrient status, but also in response to seasonal changes in light availability from winter to spring. We show that emergence of these tradeoffs was associated with two different compositional shifts, which depended on the requirement of the community to be defended against grazing.
How to cite: Pranger, A., Diehl, S., and Peeters, F.: The link between community composition and function is a useful tool in ecology – demonstration using five decades of phytoplankton data from Lake Constance, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16415, https://doi.org/10.5194/egusphere-egu25-16415, 2025.
The Tibetan Plateau (TP), also known as the Asian water tower, becomes warmer and wetter in recent decades. This has led to drastic permafrost degradation, increased soil erosion and higher greenhouse gas emissions from water bodies, profoundly altering the regional carbon cycle. With continued climate change, there are ongoing debates on whether the TP will undergo a transformation from a carbon sink to a source. Currently, the magnitudes of carbon fluxes transferring from terrestrial to aquatic systems are highly uncertain due to the unique hydrothermal conditions of permafrost region. This uncertainty arises because very few studies have comprehensively quantified the full range of carbon fluxes, including vertical carbon fixation, respiration and lateral carbon transport in different forms, i.e., DOC, POC and DIC. Here, we develop a process-based distributed water-carbon coupling model (GBEHM-C) applicable for permafrost region, which integrates the vertical water-heat-carbon fluxes between atmosphere, vegetation and soil, the lateral water-carbon fluxes transported from hillslopes to the river channels, as well as the water-carbon dynamics in river networks along the river routing process. The model is then applied in the Yellow River Source Area (YRSA) in the northeastern TP which helps quantify the net ecosystem carbon budget (NECB) at the catchment scale. According to the simulation results, the NECB of the YRSA was 4.27 Tg C/yr on average, and showed an increasing trend during 1960-2019. The lateral carbon fluxes accounted for 16.8% of the NECB and should not be overlooked. It’s also found that the alpine steppe ecosystem performs as a net carbon source in the YRSA. The future risk of carbon source-sink transformation mainly depends on the net carbon fixation by vegetation, carbon release from permafrost, and the intensity of lateral carbon transport driven by hydrological processes. Our study provides critical insights into the dynamics of water and carbon fluxes in the TP and offers valuable guidance for water resource and ecological management in alpine river systems.
How to cite: Leifang, L., Taihua, W., Jingjing, Y., Haiyan, Y., and Dawen, Y.: Development of a process-based distributed water-carbon coupling model integrating terrestrial and aquatic systems in permafrost region, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7904, https://doi.org/10.5194/egusphere-egu25-7904, 2025.
Posters on site: Mon, 28 Apr, 08:30–10:15 | Hall A
Globally and regionally, large efforts had been made on spatial relationships between forest growth and precipitation. Yet, substantial uncertainty still surrounds generalities describing their temporal relationships. A lack of experimental evidence that combines increased and decreased precipitation treatments to verify their relationships at site-level. Additionally, we do not know whether water in the deep soil profile drives the discrimination of their relationships when decreased vs. increased precipitation changes become extreme. To obtain generalities describing patterns of ecosystem sensitivity to altered precipitation, our experiment was manipulated precipitation throughfall through gravity-driven transfer from the decrease precipitation treatment plots (–30%, –50%, –65%) to the increase precipitation plots (+30%, +50%, +65%) from mild, moderate to extreme level in a temperate deciduous forest (planting Black locust) on the Chinese Loess Plateau. Over the 3 years, the decreased and increased precipitation treatment caused the largest reduction and increment in soil water by 0.9% and 1.4%, soil water variability by 5.2% and 8.8%, leaf area index (LAI) both by 0.4 m3/m3, diameter at breast height (DBHPPT) by 0.18 cm and 0.34 cm, and forest biomass change ratio (FBCR) by 18% and 33%, respectively. Soil water showed nonlinear positive responses to the precipitation change, while forest growth (i.e., LAI, DBHPPT and FBCR) had linear positive responses to the soil water change. The mean sensitive of forest growth was higher to altered increase precipitation than decrease precipitation. Planting forest of Black locust showed high drought tolerance but rapid growth pattern and soil water uptake to decreased vs. increased precipitation. The growth pattern of forest corresponded to the large depleted soil water in the deep soil profile. We conclude that the strategies of forest responses to the soil water condition play an essential role in regulating the asymmetric response. Our findings emphasize that soil water will play an essential role in regulating forest growth along precipitation gradients. The positive asymmetric response of forest growth to altered precipitation indicates that the intensified interannual variability in the future may positively affect the variability of forest growth.
How to cite: Zhou, Z., Wang, Y., and Peng, S.: The causal role of soil water in asymmetric sensitivity of forest growth from a filed precipitation manipulation experiment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21383, https://doi.org/10.5194/egusphere-egu25-21383, 2025.
The global climate and environment are undergoing rapid changes, impacting hydrological processes through shifts in climate patterns, escalating CO2, and vegetation dynamics. Accurately predicting and quantifying the contribution of these factors to water yield (WY) has become a significant challenge in water resource management and climate adaptation studies. This study proposed an improved WY attribution analysis framework to address the impacts of climate change, vegetation structural change, and CO2-induced physiological change on WY in China. During the study period (1982-2017), changes in climate, vegetation, and CO2 concentrations significantly affected WY, with the magnitude of these impacts varying across different regions. Climate change (especially precipitation change) was found to be the primary driver of WY changes, particularly in the Northwest River Basin, the Southwest River Basin, and parts of the Yangtze River Basin, the Southeast River Basin, and the Pearl River Basin. The vegetation change, including the land cover change and the NDVI change, was the second largest factor influencing WY, especially in central China, where vegetation changes led to a general decrease in runoff. Although the increase in CO2 concentration reduced transpiration by inducing stomatal closure, the effect was relatively small. And it resulted in an overall increase in runoff across China. This study provides important theoretical support for water resource management and offers new perspectives for climate change adaptation strategies, vegetation restoration, and water resource management.
How to cite: Shen, H. and Yang, H.: Enhanced understanding of dominant drivers of Water Yield change across China through the improved attribution analysis framework, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3060, https://doi.org/10.5194/egusphere-egu25-3060, 2025.
Throughfall is a critical component of the hydrological cycle, representing the majority of precipitation that reaches the ground contributing to soil water fluxes under vegetation canopies. It occurs through several mechanisms: as free throughfall (FR), splash throughfall, and canopy drip (CD) (Levia et al., 2019). Important progress has been made in investigating throughfall dynamics and drop size distribution (DSD) using disdrometers to understand the sub-canopy hydrologic and erosional processes. In the present study, we seek to quantify the relative proportions of throughfall components beneath isolated birch and pine trees using drop size data from OTT Parsivel disdrometers. Simultaneous measurements of drop size data for open rainfall and throughfall were conducted from July 2022 to July 2024 at an experimental urban park in Ljubljana, Slovenia. The partitioning of throughfall drops into FR, SP, and CD was carried out according to the protocol outlined by Levia et al. (2019). Analysis of drop counts indicates that throughfall drops originating from CD represent a significantly smaller fraction (<2-7%) of the total throughfall drop number compared to SP (60-69%) and FR (20-30%) for both tree species regardless of phenoseasons. However, in terms of drop volume, CD has the largest proportion for birch trees during the leafed period (40%) and for pine trees during both periods (70%). Due to the deciduous nature of birch trees, FR accounts for the largest volume percentage (42%) during the leafless period. Whereas the higher CD in pine trees is hypothesized to be attributed to the needle structures and waxy coating, which facilitates lateral flow of water that can lead to the formation of larger drops as smaller droplets coalesce before dripping to the ground. While the SP constitutes the largest proportion of the throughfall drop number, it represents a smaller percentage of throughfall volume due to its smaller drop diameters. The impact of larger drops hitting the foliage generates splash droplets, particularly during intense rainfall events and strong winds. This observation is reflected in the DSD of throughfall as the relative volume of drops >3.0 mm is higher under both trees than those in open rainfall across phenoseasons. The median drop diameter (D50) of throughfall is on average higher than the open rainfall, except for the leafless birch tree. Our study shed further insights into the rainfall partitioning process and serves as an initial step toward linking different types of TF inputs to water-mediated processes below the canopy. For instance, do areas with higher water inputs from CD exhibit variable and higher soil moisture? This may help improve our understanding of forest/tree canopy–water interactions.
Acknowledgment: This work was supported by the P2-0180 research program through the Ph.D. grant to the first author, which is financially supported by the Slovenian Research and Innovation Agency (ARIS). Moreover, this study was also carried out within the scope of the ongoing research projects J6-4628, J2-4489, and N2-0313 supported by the ARIS and SpongeScapes project (Grant Agreement ID No. 101112738), which is supported by the European Union’s Horizon Europe research and innovation programme.
How to cite: Šraj, M., Bezak, N., Radulović, L., and Alivio, M. B.: The partitioning of throughfall under urban tree canopies: a case study for birch (Betula pendula Roth.) and pine (Pinus nigra Arnold), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3655, https://doi.org/10.5194/egusphere-egu25-3655, 2025.
The ecological environment of semiarid regions is fragile, and localized vegetation restoration is close to the sustainable development limit of regional water resources, presenting new ecological-water resource conflicts. To study the influence of vegetation dynamics on the water cycle process in semiarid regions affected by climate change, this study constructed a random forest model based on long-term field observation data, used high-resolution remote sensing images as input data, extracted the zoning of vegetation types, and analyzed the pattern of vegetation succession. The results of zoning were then introduced into BTOP (block-wise use of TOPMODEL and the Muskingum-Cunge method) to obtain continuous spatial and temporal hydrological data, and the long-term cumulative effect of vegetation dynamics on key water cycle elements in the watersheds was revealed on the basis of analyzing the changes in the state of the vegetation and the factors affecting it. It was found that the vegetation cover in the Hailar River Basin, which is located in the semiarid zone, showed a fluctuating trend in the last 5 years of the 21st century, and the growth curve began to decline, which may be related to the contradiction between the current status of the basin's water resources and the growth of vegetation; specifically, the existing vegetation cover may have exceeded the critical point of the basin's balanced development in terms of vegetation and hydrology. Under the multiyear average precipitation conditions, the evapotranspiration before and after the change in vegetation in the basin increased by 15.6%, the surface stream-flow decreased by 20.9%, and the base flow decreased by 12.3%. Additionally, the vegetation cover and the type of succession increased the water consumption of the vegetation in the basin to a certain extent and reduced the runoff in the basin. However, the current 21.9% decrease in precipitation and the 20.3% depletion of vegetation are critical. If vegetation continues to expand, water consumption in the watershed will increase without limits, reduce surface runoff and groundwater recharge, weaken soil water storage capacity, and lead to more drought in arid areas. Therefore, as an important means of regional ecological restoration, it is still necessary to carry out a comprehensive assessment of the existing water resources of the watershed and set the upper limit of water demand for vegetation in the vegetation restoration project to restore the ecological health of the watershed under the condition of normal vegetation growth and to ensure the sustainable development of the watershed's water resources.
How to cite: Wang, L., Wang, G., Xue, B., Aa, Y., Wang, Y., and Wu, J.: Analysis of the cumulative impact of vegetation dynamics on water cycle processes in semiarid basin under climate change, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4675, https://doi.org/10.5194/egusphere-egu25-4675, 2025.
Mangroves are one of the vital ecological environments along tropical coasts, serving not only as natural barriers against tides and protecting shorelines but also as ideal habitats for the reproduction and habitation of aquatic life. Additionally, mangroves themselves hold substantial economic and medicinal value. However, the construction and operation of upstream hydraulic engineering projects at river estuaries have altered the hydrological characteristics downstream of the dam. These changes impact the freshwater area, salinity, distance of salty tides upstream, and sediment distribution at the estuary, significantly affecting the growth and reproduction of regional mangrove forests. This study focuses on the Xin’ying Bay estuary in the Beimen River of China, utilizing a three-dimensional hydrodynamic and salinity diffusion mathematical model to investigate the effects of varying discharge rates on distance of salty tides upstream, freshwater area, and the maximum salinity of the cross section. The study selects Rhizophora stylosa Griff and Avicennia marina (Forssk.) Vierh as key species within the estuarine mangrove ecosystem, using salinity as a critical ecological factor to establish the relationship between salinity and flow in typical sections, thereby constructing a research system for optimal ecological water requirements for mangrove ecosystems. The results show that there is a negative correlation between the distance of salty tides upstream, the maximum salinity of the section and the discharge flow, while there is a positive correlation between the area of the freshwater area and the discharge flow. A discharge rate of 1.86 m3/s (20% of the multi-year average flow at the dam site) in July and 3.25 m3/s (35% of the multi-year average flow) in August and September can meet the salinity requirements necessary for the maturation of embryos and growth of seedlings in Rhizophora stylosa Griff and Avicennia marina (Forssk.) Vierh. This study establishes a comprehensive system for studying mangrove ecosystems and their ecological water requirements, achieving the goals of ecological protection and quantifiable, manageable environmental water needs. The findings also provide new perspectives and significant references for understanding and protecting mangrove ecosystems.
How to cite: Chen, X., Liang, R., Wang, Y., and Li, K.: Study on ecological water demand in mangrove ecosystem utilizing salinity as a key habitat indicator, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8274, https://doi.org/10.5194/egusphere-egu25-8274, 2025.
High dams have brought significant benefits but have also led to reduced river connectivity and aquatic habitat fragmentation, negatively affecting fish activities such as migration, spawning, and foraging. Additionally, total dissolved gas (TDG) supersaturation caused by dam discharge presents a further ecological challenge, making fish highly susceptible to gas bubble trauma (GBT), which can disrupt normal behavior and even result in mortality. Consequently, fish are subjected to the dual threats of dam barriers and TDG supersaturation. While fish passage facilities can partially mitigate the barrier effect, the swimming performance of fish in TDG supersaturation exposure is critical for successful passage. This study employed a swimming tunnel respirometer (Loligo Systems SW10150, Denmark) to investigate the critical swimming speed (Ucrit) and endurance of juvenile Myxocyprinus asiaticus and Procypris rabaudi in TDG supersaturated water. The results from one-way ANOVA revealed that the Ucrit of M. asiaticus significantly decreased to 76% and 60% of the control group (12.31 BL/s) at 140% and 150% TDG levels, respectively. P. rabaudi showed even weaker tolerance to TDG supersaturation exposure, with significant reductions in Ucrit at 130%, 140%, and 150% TDG levels, corresponding to 81%, 71%, and 51% of the control group (13.63 BL/s), respectively. Both species were able to swim for at least 200 minutes at velocities of 0.6 - 0.8 Ucrit at TDG levels below 130% and showed significantly reduced endurance at TDG levels of 140% or higher. A significant decline in sustained swimming distance was observed at 130% or higher TDG levels. The swimming distance of fish decreased by at least 12% compared to the control group, with the reduction reaching 86% at 150% TDG level. It is indicated that a TDG level of 130% represents a critical threshold for fish survival. This study provides valuable insights into the behavioral responses of fish to TDG supersaturation exposure. The finding is crucial for understanding the impacts of TDG supersaturation on fish and for informing strategies aimed at mitigating the ecological risk associated with dam operations. Furthermore, this study offers vital support for the development of effective fish passage solutions.
How to cite: Wang, H., Wang, Y., Li, K., and Liang, R.: Swimming performance of fish in TDG supersaturated water, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8704, https://doi.org/10.5194/egusphere-egu25-8704, 2025.
There are a multitude of studies that look at the impact of changes in streamflow and water quality on aquatic biodiversity both regionally and globally. However, few studies have considered the direct effects of hydrological alterations on biodiversity at high spatial resolution. This is due to the fact that only a limited number of hydrological models can produce relevant information for assessing ecological impacts at the relevant spatial resolution. One approach for such ecological assessments builds upon species distribution models (SDMs). Studies that usually couple the hydrologic and (SDMs) typically employ hydrologic models on a 10km spatial resolution or coarser. Using the Rhine basin as a case study, we link two hyper resolution models (models at a 1km spatial resolution) for hydrology (PCRGLOBWB2) and species distribution (Random Forest) to i) develop a framework for evaluating climate impacts on biodiversity, and ii) assess the suitability of current and future freshwater habitats for fish species. Preliminary results demonstrate the feasibility of this framework for identifying the historic biodiversity values for the Rhine and for developing indicators to monitor changes in aquatic biodiversity.
How to cite: Steyaert, J. C., Bierkens, M. F. P., Jones, E. R., Sutanudjaja, E. H., Marquez, J. R. G., Domisch, S., and Wanders, N.: Evaluating climate change impacts on biodiversity using hyper resolution hydrologic modelling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8898, https://doi.org/10.5194/egusphere-egu25-8898, 2025.
The process of rainfall interception is an important part of the hydrological cycle in many regions. The rainfall which is intercepted by vegetation evaporates into the atmosphere, while throughfall and stemflow contribute to runoff generation, control soil moisture and affect soil erosion. These topics are closely connected to the aims of the ongoing bilateral research project between University of Ljubljana, Slovenian Forestry Institute and TU Wien. The project focuses on the understanding of the effect of meteorological and vegetation characteristics on changes in raindrop microstructure. The rain drop diameter and velocity of raindrops under vegetation, which reach the ground by dripping from leaves and branches as throughfall, are different than diameter and velocity of rain drops above the canopy.
The research is based on the high-resolution disdrometer measurements of open rainfall and throughfall. Measurements are ongoing on three different study sites, including single urban trees and urban mixed forest in Slovenia, as well as maize field in a small agricultural basin (HOAL) in Austria. Collected data are used to determine and compare raindrop distributions and their changes under the vegetation. For each study site the single rain events were selected based on similar properties (i.e. rainfall amount, duration or intensity). The event-based analysis taking into account 5-minute time step was used to determine how different vegetation types influence changes in rain drop size and velocity of throughfall drops in comparison to open raindrops.
Acknowledgment: This contribution is part of the ongoing research project entitled “Evaluation of the impact of rainfall interception on soil erosion” supported by the Slovenian Research and Innovation Agency (J2-4489) and the Austrian Science Fund (FWF) I 6254-N.
How to cite: Zabret, K., Alivio, M. B., Radulović, L., Parajka, J., Szeles, B., Marjanović, D., Vilhar, U., Pavčič, J., and Šraj, M.: How vegetation alters the properties of raindrops, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8930, https://doi.org/10.5194/egusphere-egu25-8930, 2025.
Critical swimming speed (Ucrit) of fish is a fundamental metric for evaluating fish swimming performance. It provides an estimate of the maximum aerobic swimming speed of a fish, and is widely used to inform fish passage design, and habitat assessment. Ucrit is typically determined using a respirometer test through incremental velocity tests where flow velocity increases periodically until fish gets fatigue. In incremental tests, the choice of time step, Δt is critical and varies significantly across studies, ranging from 15 to 200 minutes. This study investigates the influence of Δt on Ucrit for a Labeo rohita (a species of carp in the family Cyprinidae, native to south Asia). In this study, Δt = 15, 30, and 60 minutes are considered. Juvenile Labeo rohita (body length: 6.8–12 cm, weight: 15–30 g) were tested in a custom-built 10L respirometer at IIT Madras, India.
Ucrit values in incremental velocity tests were 4.58 ± 0.18 BL/s, 4.21 ± 0.13 BL/s, and 3.72 ± 0.10 BL/s at Δt = 15, 30, and 60 minutes respectively. Additionally, fixed velocity tests conducted at flow velocity of 4.5 BL/s and 3.5 BL/s (< Ucrit), showed that fatigue times (30 and 80 minutes) exceeding the predicted maxima based on Ucrit (15 and 60 minutes). These findings suggest that Ucrit is sensitive to the chosen time step and further experiments with varying Δt could be used to determine optimal value. This will enhance understanding of the trade-offs between shortening time steps and biological interpretation of results.
Keywords: Critical swimming speed, respirometry, time step, incremental velocity, fixed velocity Labeo rohita
How to cite: Daksh, K., Malasani, G. C., Chandra, V., and Theodore, C.-S.: Influence of Time Step on Fish Critical Swimming Speed , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10197, https://doi.org/10.5194/egusphere-egu25-10197, 2025.
Mining activities near a lake can significantly impact its water quality and ecosystem. These impacts often arise from the release of heavy metals, sediments, and nutrients into the lake via surface runoff or groundwater seepage. Elevated levels of these substances can disrupt natural equilibrium, leading to problems such as acidification, eutrophication, and contamination of aquatic habitats. This study applies the AQUATOX model to assess the effects of mining on the water quality and ecosystem of a boreal lake. The research was carried out in a small humic boreal lake Sulkavanjärvi in the central part of Finland (63°06′50′′N, 27°41′30′′E) (area 3.1 km2, mean depth 3.7 m, max depth 17 m). It is located close to an open pit apatite (major source of phosphorus) mine from which surface runoff and groundwater discharge contamination is suspected. The model simulates key pollutants, including nutrients and sediments, while incorporating multiple trophic levels such as planktonic algae, invertebrates, and diverse fish species. The lake is covered by ice from November to April and ice cover condition was applied when the water temperature dropped below 3 °C. The water mass was allowed to stratify into epilimnion and hypolimnion at the 3 °C temperature difference. Modeled time series of food web compartment biomass were obtained and analyzed for the modeling period 01.01.2011 - 31.12.2021. The nutrient and oxygen dynamics were evaluated with an emphasis on forecasting the impact of various contamination scenarios on the local ecosystem.
How to cite: Kortunova, K., Kokkonen, E., Huttula, T., and Kolehmainen, M.: Modeling the impact of mining on water quality and ecosystem in the boreal Lake Sulkavanjärvi, Finland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12764, https://doi.org/10.5194/egusphere-egu25-12764, 2025.
Climate change is causing severe impacts in mountainous regions, leading to "greening" as vegetation densifies and shifts upslope as a response to rising temperatures. This vegetation change affects the hydrological cycle, influencing aspects like infiltration, retention, and evapotranspiration, which in turn alters water availability in both mountain catchments and downstream areas. As snow and ice storage decrease, understanding these hydrological effects becomes increasingly important for human water security.
To investigate how mountain vegetation changes could affect hydrology, we established 40 vegetation plots in the alpine Meretschi Catchment (6.2 km2) in Switzerland in five vegetation classes: bare, pioneer, grass, dwarf shrubs and larger shrubs/forest. At each plot we measured soil temperature and soil moisture with TOMST-TMS4 loggers at 15-minute intervals over the period 2023-2024. In addition, we collected and derived data on plot species composition, soil characteristics and topography. Using uni- and multivariate statistical analyses (Spearman, non-metric multidimensional scaling (NMDS) with post-hoc and Kruskal-Wallis with Dunn test) , we investigated interactions between vegetation, soil properties, topography, microclimate and hydrology (soil moisture, saturated conductivity (Ksat) and snowmelt driven moisture increase).
Our results show that:
- Soil moisture responds differently under different vegetation classes. Bare and pioneer classes have relatively low soil moisture values, while grass, dwarf shrub and larger shrubs/forest have higher values. Dwarf shrubs distinguish themselves from the others by having low soil moisture values during winter. This means that shifting vegetation due to greening is likely to affect the hydrology in a mountain catchment.
- Soil characteristics seem to be closely linked to soil moisture and vegetation following the same division. This is likely due to soil developmental properties of the vegetation.
- Topography has weak links to hydrology, with only elevation negatively correlating with soil moisture. This indicates that the differences hydrological response found between the vegetation classes cannot be attributed to differences in slope or aspect.
- Temperature showed to be variable between plots and vegetation classes resulting in differences in snow cover durations. For dwarf shrubs it was very noticeable that the melting period set in earlier and was shorter. This did not reflect in the snowmelt driven moisture increase.
Our research shows that in the Meretschi Catchment hydrological factors such as soil moisture and Ksat are influenced by vegetation. This indicates that changing vegetation might considerably alter the present-day hydrology of mountain catchments. While other contributing factors, such as soil properties, topography, and climate are important, vegetation is key in understanding the complexities of the hydrological system.
How to cite: Duurkoop, L., Brakkee, E., van de Lisdonk, D., Haagmans, D., Immerzeel, W., Wagner-Cremer, F., Kraaijenbrink, P., and Eichel, J.: Influences of vegetation, soil properties, topography and microclimate on alpine catchment hydrology, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18761, https://doi.org/10.5194/egusphere-egu25-18761, 2025.
