Ecohydrology describes the effects of hydrological processes on ecosystem structure and functioning and the effects of biotic processes on hydrological processes. Recently, there is an increasing emphasis on the role of megafauna, large mammals and birds, on earth system processes, such as nutrient cycling, energy flows and vegetation patterns. Ecohydrology as a field, however, has not yet considered megafauna as central drivers of hydrological processes but focused strongly on the interactions between hydrological processes and plants and soils. Here, we introduce zoohydrology to emphasize the importance of considering the interactions between wild animals and hydrological processes. This includes both the effects of hydrological processes on the occurrence, behavior and life history of animals as well as the effects animals have on hydrology. In this introductory talk, we will outline different pathways through which hydrology affects megafauna and through which megafauna affect hydrological processes using a systems approach. We will illustrate these pathways with concrete examples from different parts of the world and on different species. For example, the importance of hydrological processes and hydromorpho-dynamics for shaping habitats of endangered species, such as the Ganges freshwater dolphin and Bengal tigers in northern India and Nepal, but also for structuring megafauna community dynamics, such as the example of Gorongosa National Park in Mozambique. We will also exemplify how wild animals can affect central hydrological processes in diverse ways; directly (e.g., species such as beaver and hippo as ecosystem engineers of aquatic systems) and indirectly (e.g., elephants that reduce woody cover at large scales, affecting evapotranspiration). Many effects of animals on hydrological processes remain understudied and are often lacking from hydrological models. By introducing the concept of zoohydrology, we stress the potentially pivotal interactions between central hydrological processes, wild animals and their habitats. To unravel the full complexity of these interactions and assess their true importance, zoohydrology must be advocated among scientists, policy makers and practitioners in order to better address biodiversity conservation and restoration, make the concept of environmental flow needs more concrete, and investigate the consequences of biodiversity restoration on hydrological systems.

How to cite: Cromsigt, J., Larsen, A., and Griffioen, J.: An introduction to the concept of Zoohydrology – the interactions between hydrological processes and wild animals, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2096, https://doi.org/10.5194/egusphere-egu24-2096, 2024.

Our landscapes and watercourses face intense pressures from climate extremes, land use change, declining biodiversity and increased demand for water resources. It is increasingly proposed that by working with natural processes, Nature-based Solutions (NbS) can increase resilience to these pressures, providing multiple environmental and societal benefits.

Beavers are the archetypal ecosystem engineers and keystone species, which can profoundly alter ecosystem structure and function, creating complex wetland environments (Brazier et al., 2021). Research has shown the return of the Eurasian beaver (Castor fiber) to European landscapes can provide multiple benefits including for biodiversity and water resource management (Puttock et al., 2021). However, beaver activity such as damming and tree-felling within our intensively managed and populated landscapes can also conflict with existing land use (Auster et al., 2019). Therefore, management and policy frameworks are required which mitigate conflicts and maximise the NbS benefits beavers can bring.

The Making Space for Water Programme (Barclay et al., 2023) will be introduced, which aims to support land managers to build a network of nature rich wetlands across South West England. This project led by Devon Wildlife Trust, in partnership with the University of Exeter and local landowners is the first of its kind in the UK, aiming to work with wild beavers to deliver natural solutions to address societal challenges.  Case studies will be presented discussing how geospatial mapping and modelling, stakeholder engagement and green finance approaches are being implemented to make catchments ‘beaver ready’, target financial support and enable NbS to deliver significant and lasting benefits. It is hoped that the approach adopted in this project alongside discussion of challenges and benefits can contribute towards progress in the mainstreaming of nature-led NbS approaches.

References

Auster, R. E., Puttock, A., & Brazier, R. (2019). Unravelling perceptions of Eurasian beaver reintroduction in Great Britain. Area, area.12576. https://doi.org/10.1111/area.12576

Barclay, H., Holden, M., Puttock, A., & Burgess, P. (2023) Making Space for Water: Investing in nature-based solutions with beavers. https://www.flipsnack.com/devonwildlifetrust/dwt-beaver-green-finance-programme/full-view.html

Brazier, R. E., Puttock, A., Graham, H. A., Auster, R. E., Davies, K. H. & Brown, C. M. . (2021). Beaver: Nature’s ecosystem engineers. WIREs Water. DOI:10.1002/wat2.1494

Puttock, A., Graham, H. A., Ashe, J., Luscombe, D. J. & Brazier, R. E. (2021). Beaver dams attenuate flow: A multi‐site study. Hydrological Processes, 35(2), e14017. DOI:10.1002/hyp.14017

How to cite: Puttock, A., Barclay, H., Holden, M., Burgess, P., and Brazier, R.: Making Space for Water: Investing in Nature-based Solutions with Beavers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4650, https://doi.org/10.5194/egusphere-egu24-4650, 2024.

The UN Decade on Ecosystem Restoration (2021-2030) was declared by the UN General Assembly driven by the global need to support and scale up efforts to prevent, halt and reverse the degradation of ecosystems worldwide. The Food and Agriculture Organization of the UN (FAO) and the UN Environment Programme (UNEP), as leaders of the Decade, are working together with other relevant stakeholders to achieve the Decade’s mission. To do so, focus is given to the development of capacities to empower professionals and institutions involved in the field of restoration to design, implement, monitor and sustain effective restoration initiatives. In the framework of the Best Practices Task Force (TF) of the Decade, partners have jointly developed a Capacity, Knowledge and Learning Action Plan, based on the findings of a global capacity needs assessment, a stocktake of knowledge products and capacity-development activities, and multiple targeted consultations. The plan identifies the gaps where knowledge products or capacity-development initiatives are required across different stakeholder groups, and provides terms of reference for capacity and knowledge development initiatives tailored for those different stakeholder groups. The TF has published the Standards of Practice to guide ecosystem restoration, providing key recommendations in an effort to facilitate the application of the principles for ecosystem restoration. In addition, the TF has created the Framework for the Dissemination of Good Restoration Practices to help practitioners share and consult information about restoration. This framework is in turn part of the UN Decade’s Framework for Ecosystem Restoration Monitoring (FERM), and allows for the collection and documentation of good practices. It also features a common search engine to connect and facilitate retrieving best practices from different relevant platforms, besides the FERM. These resources provide any restoration actor with an essential base for an effective planning, implementation and monitoring of global and local restoration efforts.

How to cite: Besacier, C., Gallo Granizo, C., and Romero Montoya, A.: Fostering forest and landscape restoration under the UN Decade on Ecosystem Restoration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11619, https://doi.org/10.5194/egusphere-egu24-11619, 2024.

Forests and landscapes are fundamentally interconnected, with geomorphic process being modulated by vegetation dynamics, which in turn is influenced by landscape form. Trees play a critical role in shaping landscapes by redistributing sediment across the Earth's surface via gradual processes including tree throw and root growth, and catastrophic processes such as landsliding and debris flows, where spatially variable root cohesion contributes to slope failure likelihood. Conversely, landscape morphology controls the availability of light, water and nutrients for trees and has been observed to dive significant variability in the structure and composition of forests at both local and regional scales. Until recently, our ability to disentangle these processes at broad spatial scales has been limited due to a lack of high resolution data on tree morphology. Advances in Terrestrial Laser Scanning and UAV-LiDAR systems now allow forest plots to be scanned rapidly, capturing the morphology of hundreds of trees alongside the terrain they grow on.

Working across a range of European forest ecosystems, representing a range of climates, we have constructed an unprecedented 3D dataset of European forest-landscape dynamics. From plot-level scans, individual trees are segmented from the digital forest and classified by species. State of the art structural metrics are then computed at an individual, species, and regional level across each distinct climate zone. This pan-European dataset is then coupled with high resolution topographic data, to explore the fundamental linkages between landscapes and vegetation.

How to cite: Grieve, S., Owen, H., Ruiz-Benito, P., and Lines, E.: Forest-landscape dynamics across a climate gradient, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11821, https://doi.org/10.5194/egusphere-egu24-11821, 2024.

Forest restoration faces persistent challenges for its financial viability due to high land opportunity costs and insufficient financial returns from restored areas, such as through payments for ecosystem services and timber production. A potential financial pathway is to develop non-timber forest products with bioeconomic potential. Here, we explore the bioeconomic potential of native tree species growing in different types of new wooded lands in Atlantic forests. First, we established 25 30 𝚡 30 m plots in natural regeneration, degraded forest remnants, and actively managed areas (eucalyptus monoculture and active restoration) in the Paraíba Valley, southeastern Brazil, where we sampled all woody individuals with dbh ≥ 5 cm, totaling 284 native tree species. Then, we conducted a literature review and patent survey on the biotechnological potential of the species sampled. Based on this review and survey, we calculated the proportion of sampled species with patents and assessed the species used and general characteristics of patents registered among prominent companies in the market. We found 168 (70%) species with a biotechnological potential based on the presence/absence of articles reporting uses for medicine, cosmetics, food, and other market segments, such as bioinsecticides, bio fertilization, construction, and manufacturing. In the sampled areas, species offer varied potential for use, with higher potential in spontaneous environments. Araucaria angustifolia was the most extensively studied species, with 246 research papers, followed by Euterpe edulis (205), Baccharis dracunculifolia (188), Dodonaea viscosa (170), Cedrela odorata (158), Copaifera langsdorffii (139) and Hymenaea courbaril (132). We found patents worldwide, distributed across more than 20 countries, for the sampled species. The medicinal use of leaf chemicals accounts for the largest use in our survey. Despite these numbers, we found that less than 5% of the investigated articles reported evaluations of final products, while most provided results from in vitro, in vivo, or chemical analytics descriptions. Most patents registered by companies are related to exotic and non-tree species, many associated with existing commodity chains, reinforcing the need to integrate bioeconomy and forest restoration agendas better.

How to cite: Krainovic, P., Paulo Romanelli, J., Helena Porcari Simões, L., Rodrigues Souza, L., Brower, R., Flávia Boeni, A., G. Massi, K., A. P. Toledo, C., R. Rodrigues, R., C. Souza, V., B. Chaves, R., de-Miguel8, S., and H. S. Brancalion, P.: Bioeconomy gaps and opportunities in restored Atlantic forests, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20606, https://doi.org/10.5194/egusphere-egu24-20606, 2024.

This study presents the preliminary results of the ongoing research project “Re.Nature Cities”, in which  the ability of street trees to act as an effective measure against increased urban air temperatures is evaluated via experimental and simulation means. In the existing literature, numerous studies highlight that the addition of street trees inside the canyons of urban areas may result in a significant reduction of the peak ambient summer Tair, having also a prominent effect on outdoor thermal comfort regulation. Yet, street trees also impact urban ventilation as they act as barriers, disturbing the wind flow and affecting buildings’ energy needs and thermal comfort; the positive effect of wind sheltering during the cold winter period, can be thus significantly counterbalanced during the warmer periods of the year. The existing evidence reveals that the green elements’ implementation in the built environment without holistically accounting for all the vegetation-air-buildings interactions, can even exacerbate human discomfort and deteriorate indoor natural ventilation.

Based on the above, this study evaluates the mitigation potential of a tree type that is commonly encountered in Greek cities – the citrus- since it has low irrigation needs and high drought tolerance. An integrated experimental campaign, employing wind tunnel measurements, albedo and Leaf Area Index/Leaf Area Density (LAI/LAD) measurements is conducted so as to define of the aerodynamic, thermal and foliage characteristics of real trees.  Wind tunnel measurements of total drag are carried out in a wind tunnel section of 3.5m width and 2.5m height, while LAI measurements are conducted using a plant canopy analyzer, with the LAD of each layer (1 m/layer) then calculated from LAI by empirical equations. The obtained values are then used as input parameters in the vegetation model of the ENVI-met microclimate model, which is employed for the evaluation of the thermal environment of typical building blocks in Greece, considering different planting patterns and vegetation coverage scenarios.

The experimental database of foliage, thermal and aerodynamic characteristics of common urban tree species, along with the detailed microclimatic simulations of typical urban districts provide a valuable tool for decision-making regarding the optimal vegetation coverage and the planting pattern for urban areas.

How to cite: Tsoka, S., Pappa, V., Markos, N., and Bouris, D.: Assessing the effect of citrus plant on the improvement of the outdoor thermal environment using wind tunnel and ground-based Leaf Area Index measurements, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20879, https://doi.org/10.5194/egusphere-egu24-20879, 2024.

Connectivity is a crucial property of the riverine landscape. Reduction of connectivity, i.e. habitat fragmentation and isolation effects, impacting ecological functions and biotic communities, is one of the most critical threats to river-floodplain systems. Using a graph theoretical approach for analyzing possible transport pathways in the system (directed, undirected, overland, seepage), we could show that essential ecological functions related to sediment composition and quality, hydrochemical conditions, and macrophyte coverage can be predicted and importance of waterbodies in the network and their main connectivity deficits can be identified. In a second step we are now integrating biotic communities in the predictive framework. Dependent on dispersal model and habitat preferences the different taxonomic groups show clear pattern i.e. drifting invertebrate organisms are highly driven on directed transport whereas fish as active swimmers are more dependent on connectivity in the waterbody network or organism with terrestrial or flying dispersal (amphibia or flying insects) are dependent on overland connectivity. Further they interact with the ecological functions in the system. Using a temporal dataset based on eDNA (environmental DNA) we can further show that ecosystem conditions and distributions of biotic communities are dependent on different transport/movement pathways changing with hydrological conditions (flood to low flow conditions). The dynamic graph theoretic approach can, therefore, be used as an essential tool for prioritizing water bodies for nature-based solutions.

How to cite: Funk, A., Baldan, D., Meulenbroek, P., Pont, D., Recinos Brizuela, S., Bondar-Kunze, E., and Hein, T.: Connectivity as a driver of biodiversity and functioning in riverine landscapes: A dynamic, graph theoretic approach., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19044, https://doi.org/10.5194/egusphere-egu24-19044, 2024.

Zebra mussels (Dreissena bugensis) and quagga mussels (Dreissena polymorpha) are invasive throughout much of the northern hemisphere. Whilst much attention has been paid to their role in altering aquatic systems via their filter feeding, little attention has been given to their role as geomorphic agents, or the relationships between geomorphology and their ecosystem engineering. We aimed to understand the controls and feedbacks between fluvial geomorphology and Dreissenid mussel invasion, utilising field, laboratory, and numerical modelling approaches. We found important consequences for both geomorphology and ecosystems, with mussel invasion significantly impacting annual sediment transport rates, and positively facilitating the invasion of further priority invasive species.

Quagga mussels attach to benthic sediments using byssal threads, which affects sediment stability and thereby broader river geomorphology. At an invaded gravel bed river, quagga mussels attached >500 g m^-2 of mineral sediments together. In ex situ flume experiments, this process increased critical shear stress by 40%. Numerical modelling of flow at the study river was used to upscale these stresses to estimate changes to sediment transport over a recorded five-year flow period, which indicated that typical densities of quagga mussels may reduce the occurrence of a geomorphically active flood event from Q₃₀ to Q₂, and reduce sediment transport by 74%. Thus, substantial alterations to bedload sediment transport may occur following quagga mussel invasion.

Dreissenid mussels are also ecosystem engineers, where their shells provide a unique stable habitat in fine-grained rivers. Field surveys found that mussel shells positively facilitate macroinvertebrate communities, but preferentially facilitate co-evolved, high-priority invasive amphipods. The construction of a spatial model of riverbed grainsize across England and Wales, combined with an analysis of Environment Agency nationwide presence/absence records, identified that ecosystem engineering by zebra mussels was particularly powerful in fine-grained river systems to other invasive taxa. Supporting mechanistic aquarium experiments indicated that the ecosystem engineering of zebra mussels may support the invasions of high-profile amphipod species into otherwise unfavourable habitats, which could not be invaded without mussel engineering. Channelisation and dredging, which simplify river channels, may benefit Dreissenid mussel ecosystem engineering and the facilitation of other invasive species. Instead, Nature-based Solutions could be employed to restore the geomorphic functioning of systems, which may improve resilience against high-priority invasive species.

How to cite: Sanders, C.: Geomorphic invaders: Geomorphic potential and landscape controls on the biogeomorphology and ecosystem engineering of Dreissenid mussels, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15884, https://doi.org/10.5194/egusphere-egu24-15884, 2024.

Cyanobacterial bloom induced by water eutrophication is one of the most serious ecological problems in freshwater lakes. Water diversion, transferring external freshwater into lakes, is proved to be the eco-hydraulic engineering measure rapidly relieving cyanobacterial blooms in eutrophic lakes. To explore the response of phytoplankton community to the changed aquatic habitat influenced by water diversion, we constructed the microcosm experiment modeling water diversion from Yangtze River to Lake Taihu in the laboratory, with one control group and three flow discharges groups of external freshwater from Wangyu River diversion channel during the summer water diversion period. Each modeling microcosm ecosystem had a volume of 5 L and was studied for a period of 20 days (10 days for the water diversion period and 10 days for the stop period). The results showed that the responses of physicochemical parameters in lake microcosms were sensitive, reflecting by the variations in contents of aquatic dissolved oxygen, total nitrogen, total phosphorus and dissolved silicate positively correlated with the flow discharges. During the period of water diversion, the cell abundances of Cyanophyta in all treat groups decreased significantly, while the abundances of Bacillariophyta increased, especially in the group with the highest flow discharge. The diversity and dominant species in phyla of Cyanophyta and Bacillariophyta were changed by water diversion and evidently in the highest flow discharge group. On the 20th day of the stop period, the relative proportion of Microcystis spp. recovered, and Pseudanabaena spp. became one of dominant cyanobacterial species in treat groups, which was related to the dominance of Pseudanabaena spp. in the external river water. The redundancy analysis between aquatic physicochemical parameters and phytoplankton communities revealed that variations in contents of aquatic dissolved oxygen, total nitrogen and dissolved silicate were the dominant environmental factors influencing lacustrine phytoplankton community in addition to the allochthonous inputs from external freshwater. However, the recovery of Microcystis spp. during the stop period of water diversion demonstrated that water diversion from Yangtze River to Lake Taihu has no sustainable effect on changing the dominance of Microcystis spp. in lakes in short time, although the diversity and phytoplankton community composition shifted during water diversion.

How to cite: Dai, J., Wu, X., and Wu, S.: Resilience of lacustrine phytoplankton community to the short-term river-to-lake water diversion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21127, https://doi.org/10.5194/egusphere-egu24-21127, 2024.

Nature-based solutions (NBSs) have been promoted as a holistic way to solve a variety of societal issues while benefiting biodiversity at the same time. To date, applications of NBS approaches that help ensure food security have yet been systematically reviewed. In this paper, we critically review the specific NBSs for food security, highlighting their limitations, to provide recommendations that promote their applications for improving global food security. Our systematic review of nearly 700 peer-reviewed articles indicated that many NBS approaches can be applied to enhance food security dimensions individually or together. However, there is a strong bias towards food availability and not enough research has been done to link NBSs with
improvements in food access and utilization. Over 80% of the reviewed papers were of short-term studies or without specific timeframes, and 25% offered no information on economic effectiveness of NBSs. Environmental benefits of NBSs were explicitly described in about 60% of these papers, and biodiversity enhancement was measured in only about 10%. We, therefore, recommend future applications of NBSs to safeguard food security be shifted to food access and utilization with careful consultation with local communities to address their specific context, using indicators that are easily measured and managed. Systematic monitoring regime and robust and diversified financial support system are also equally important in efforts to successfully implement NBSs. Moreover, environmental and societal benefits, especially water productivity and biodiversity, must be incorporated into the planning and design of NBSs.

How to cite: Ho, L., Nguyen, M., Babel, M. S., and Park, E.: Nature-based solutions for improving food security: A systematic globalreview, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3786, https://doi.org/10.5194/egusphere-egu24-3786, 2024.

The rapid population growth rate is associated with an increased number of residential buildings worldwide; thereby, the massive consumption of building materials causes negative environmental consequences such as the depletion of natural resources and rising non-renewable energy use. To address the environmental, societal, and economic challenges, using Nature-based Solutions (NbS) in residential building materials became essential and considered a catalyst tool for realizing sustainable development goals (SDGs) of the UN 2030 agenda. Consequently, using green building materials (GBM) based on NbS as a long-term strategy should be considered during the whole building life cycle for applying sustainability. This research aims to investigate the potential role of using NbS in residential building materials to achieve SDG and develop a framework for assessing and identifying the direct and indirect inner relationships that affect resource efficiency, cost-effectiveness, and building occupants' comfort level. The research attempts to answer how using NbS in residential building materials can contribute to achieving SDG. The eco-friendly approach was used based on a comprehensive literature review to identify the sustainability indicators for using the GBM. The system dynamics (SD) is also used for estimating and quantifying the selected materials through the building life span, starting from the early design stage until demolition and disposal to landfill. The causal loop diagram (CLD) was created based on the data collected from the residential building case study in New Capital Administrative in Egypt after applying the sustainability indicators, followed by critical analysis to identify the realization of the SDGs. The results showed the framework promotes the potential benefits of using NbS in residential building materials. GBM has significantly contributed to achieving several SDG goals and their targets. The study recommended that the selection of alternative materials and the occupant's comfort level deserve more attention from the early design stage and need more consideration.

Keywords, Green Building Materials, Nature-based Solutions, System Dynamic, Sustainable Development Goals, Egypt

How to cite: Marey, H., Kozma, G., and Szabó, G.: The Role of Using Natural-Based Solutions in Residential Building Materials for Achieving Sustainable Development Goals, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6592, https://doi.org/10.5194/egusphere-egu24-6592, 2024.

The concentration of atmospheric carbon has overpassed 420ppm calling for urgent action to mitigate climate change and remain below the 1.5-degree warming agreed in the Paris climate agreement. The construction industry, with energy consumption included, is with about 40% a significant contributor to the global carbon emissions. Within concrete production, cement accounts for 90% of the emissions. Notably, cement production alone accounts for 8% of global carbon emissions.

Fly ash is amongst the most used of all Supplementary Cementitious Material (SCM). However, its availability is becoming an issue since many coal power plants are shutting down in Europe. Moreover, its environmental profile is questionable. Fly ash is a side product of a carbon intensive industry. Nonetheless, no environmental load has been allocated to it until now.

This study investigates how Volcanic Pozzolan from Iceland (VPI) in concrete compares to traditional concrete and VPI to fly ash, as well as the potential of reducing carbon emissions in concrete production by using VPI as SCM and substitute for cement.

To assess the environmental impacts of VPI and fly ash in cement production, we conducted a Life Cycle Assessment (LCA). For this purpose, we used the GaBi software and relied on primary data from the developers, Heidelberg Materials, and secondary data from the Ecoinvent database.

Our preliminary results reveal that the utilization of VPI as SCM yields an important reduction in carbon emissions compared to Ordinary Portland Cement (OPC) concrete. This notable decrease in carbon footprint positions VPI as a compelling alternative for sustainable concrete production. Two primary factors support this assertion: i) preliminary tests affirm the comparable properties of VPI concrete to OPC, and ii) the diminishing availability of fly ash in Europe necessitates alternative sources, often located at considerable distances, thereby escalating transportation-related emissions.

In conclusion, the integration of VPI emerges as a viable strategy to combat climate change and curtail the carbon footprint of the concrete and construction industry. This initiative aligns with global environmental objectives outlined in the Paris Agreement, United Nations Climate Change Conference, and the Nordic commitment to carbon neutrality by 2040. Embracing VPI as a sustainable alternative in concrete production reflects a positive stride towards achieving these critical environmental milestones.

How to cite: Costa, D., Heinonen, J., Finger, D., Bjarnadóttir, S., Ögmundarson, Ó., Wigum, B., Þorsteinsson, B., and Adolfsdóttir, H.: The potential of Volcanic Pozzolan from Iceland (VPI) in concrete production to reduce the carbon footprint, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4763, https://doi.org/10.5194/egusphere-egu24-4763, 2024.

Biochar is a sustainable carbonaceous solid material derived from biomass pyrolysis, which abides to circular economy principles in several ways that concern both its production and its several application fields. Biochar is produced by valorizing different organic waste biomass, such as agricultural waste, municipal solid waste, sewage sludge and industrial biowaste, to create a beneficial and valuable product that can then be used in many fields. Thus, biochar production serves perfectly the circularity paradigm as it renders a previously considered waste material to a valuable input material for a new production process. The grounds for the increasing use of and interest in biochars is their favourable physicochemical characteristics, such as the high carbon, macro- and micro- nutrient content, the high porosity and specific surface area, and the abundance of surface functional groups.

Biochar can be effectively used as soil amendment providing fertilizing properties to the applied soil that leads to higher crop production and increased crop nutrient content and quality. At the same time, it provides a stable source of carbon to the soil for several years after its application, contributing this way to CO₂ mitigation. Biochar can also be used as an adsorbent due to its carbonaceous porous structure to remediate polluted soil, water and wastewater from either organic or/and inorganic pollutants, even in low pollutant concentrations.

Τhis abstract will present a comprehensive range of studies on biochar production from different sources and its use in different sectors. One of the latest applications is its use as a substrate in Constructed Wetlands for sustainable wastewater treatment, in order to enhance the various pollutant removal/transformation processes. Three different research studies will be presented where biochar was produced from green waste (e.g., olive tree branches) and used as substrate in various Constructed Wetland pilot units that treat domestic wastewater, landfill leachate and olive mill wastewater as an ecological treatment technology.

Furthermore, an agronomic application of biochar as soil amendment in a pot experiment for the cultivation of lettuce will be shown. Finally, the environmental application of biochar produced from sewage sludge as adsorbent will be presented towards the decontamination of water and wastewater from organic emerging micro-contaminants.

How to cite: Regkouzas, P., Asimakoulas, I., Athanasiadou, E., Koukouraki, E., and Stefanakis, A.: The role of biochar in a circular economy: from agriculture to water and wastewater treatment applications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6788, https://doi.org/10.5194/egusphere-egu24-6788, 2024.

Wastewater treatment generates a by-product material known as sewage sludge. In many countries, most of the produced sludge is disposed in landfills, following a linear management strategy that is based on mechanical and chemical methods for limited dewatering and daily transportation to landfills. This strategy is rather expensive and unsustainable and possesses several environmental risks such as groundwater pollution, insufficient sludge drying and stabilization, high carbon footprint etc. Ecological engineering concepts and technologies can provide a circular sludge management strategy that focuses on the utilization of this valuable by-product with the smallest possible environmental impact.

This work will present an ongoing large research study that investigates different technologies and methods towards transforming this organic by-product to a beneficial material with the minimum environmental impact. Specific tasks of the project are:

• A setup of 16 pilot-scale units of the sustainable technology of Sludge Treatment Wetlands for sewage sludge treatment. The pilot units have different operation and construction properties, such as planted/unplanted, presence of earthworms, different substrate thickness, different loading rates, in order to eventually result in a highly efficient and optimized design configuration.
• Composting of sewage sludge along with the reed biomass from the constructed wetlands
• Production of biochar using sewage sludge and reed biomass as raw materials

The experimental results of the first operational year of this project will be presented.

The studied circular model for sludge management will be evaluated regarding the reduction of greenhouse gas emissions due to the non-use of mechanical dewatering methods, avoidance of high energy and chemicals consumption, and cessation of daily transport and disposal in landfills. The various organic materials that are produced will be assessed based on their quality properties and will further be tested by application to tomato crops for the estimation of yield improvement. Ultimately, an assessment of the economic, technical, environmental and social parameters of all methods and material cycles and studied management scenarios, will be carried out in order to determine the optimal circular management strategy.

How to cite: Asimakoulas, I., Regouzas, P., Koukouraki, E., and Stefanakis, A.: Circular management of sewage sludge for the sustainable dewatering and reuse of biosolids: an experimental study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7697, https://doi.org/10.5194/egusphere-egu24-7697, 2024.

Raceway open systems are a highly promising, eco-friendly methodology for wastewater treatment. To assess how effectively nutrients and organic matter were removed from primary and secondary treated wastewater, two laboratory-scale open-raceway algal-bacteria ponds were used. The reactors were operated at organic loading rates (OLR) ranging from 29 to 95 and 9 to 38 g sCOD m³/d, for primary and secondary effluent, respectively. The hydraulic retention time (HRT) of both reactors dropped progressively from 5.5 to 2.2 d, and they thereafter ran at a HRT of 1.1 d. After 130 days, a high biomass concentration of around 2.2 g/ L was maintained with both substrates. Reactors were shown to be functional even at lower HRT levels by the quick removal of organic matter and nutrients. In less than 12 hours, the highly active biomass that was produced with both substrates resulted in the almost complete removal of organic matter and nutrients.
With its exceptional settling capabilities, the algal-bacteria biomass may settle in less than ten minutes. The algal-bacteria content of biomass was 18.3 to 16.5% for lipids, 72.5 to 72.6% for proteins, and 2.6 to 3.2% for carbohydrates. The findings of the present work show that syntrophic algal-bacteria biomass is effective for the high-rate treatment of municipal wastewater. The low operational cost as well as the potential nutrient recovery and biomass valorization make the algal-bacteria process a circular-green model for wastewater management .

How to cite: Biliani, S. and Manariotis, I.: Algal-bacteria raceway ponds for circular wastewater treatment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7812, https://doi.org/10.5194/egusphere-egu24-7812, 2024.

Over the past century, the nitrogen pollution problem has grown concomitantly with population growth, intensified agricultural practices, and a warming climate. In Europe, the presence of excess nitrogen in the environment has already exceeded safe planetary boundaries, posing a threat to Earth’s water supply and biodiversity.

While considerable efforts are now focused toward mitigating this problem through increased regulatory measures on wastewater treatment plants and implementation of better agricultural management practices, there is a growing interest in the use of wetlands as nature-based solutions (NBS) to improve water quality and, in particular, to reduce nitrogen loading to downstream water.

Despite these benefits, wetlands are among the most degraded ecosystem in Europe, having experienced significant shrinkage over the past centuries, now constituting only one-third of their 1700 extent. This decline is largely attributed to agricultural expansion on drained productive wetland soils, while also contributing to increased nitrogen pollution from excess use of fertilizers.

To address these issues, starting from nitrogen surplus data and current wetland extent at European scale we estimate with a physically-based model that current removal potential of wetlands is about 1113 ± 101 kt of N per year (~6.5% of total N surplus in European soil). The significance of wetlands in water quality remediation is underscored by the fact that this nitrogen would otherwise enter the river network and, subsequently, the sea. Given that the current riverine loads in EU watersheds amount to about 2730 kt N per year, the loss of current wetlands would increase this figure by over 40%, with detrimental consequences for the status of surface waters and the eutrophication of coastal areas.

We propose a set of restoration scenarios, along with the associated costs, for the restoration of wetlands that have been drained for agricultural purposes. Our analysis aligns with the objective of the Nature Restoration Law, requiring EU member states to implement effective restoration measures to cover at least 20% of the EU’s land and sea areas by 2030. We show that by restoring 2.6% of EU land (equivalent to 20% of historical wetlands), we could nearly double the current nitrogen uptake (2108 ± 187 kt of N per year), and significantly improve riverine water quality by reducing more than 30% of their loads to the sea. In addition, wetland restoration will offer a wide array of ecosystem co-benefits from flood prevention and carbon sequestration to provision of critical habitat for specialized flora and fauna.

How to cite: Bertassello, L., Basu, N., and Feyen, L.: Enhancing Nitrogen Removal in European River Basins: The Crucial Role of Wetland Conservation and Restoration as Nature-Based Solutions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11118, https://doi.org/10.5194/egusphere-egu24-11118, 2024.

BirdWatch, funded by the Horizon Europe Program, focuses on improving the state of biodiversity of the EU's agricultural landscape, in line with major policy targets of the EU Green Deal, the EU Biodiversity Strategy for 2030, and the Farm to Fork Strategy. A healthy agricutural ecosystem forms the necessary basis for the provision of nature-based solutions and, eventually, for the resilience of our society.

Leveraging Copernicus satellite data, the project assesses agricultural areas to identify their suitability for farmland birds and strategises ways to enhance ecological conditions. As indicator species, birds offer insights into overall biodiversity health, contributing to a broader understanding of ecosystem well-being.

The project employs species distribution modeling to link bird occurrence data with habitat requirements, establishing models that gauge habitat suitability and the likelihood of an area being suitable for specific bird species. Utilising remote sensing data, BirdWatch quantifies essential environmental descriptors such as structural variability, land cover type, crop type, mowing intensity and soil moisture. These parameters are then fed into the habitat models to assess landscape suitability.

Knowing the state of habitat suitability and the habitat requirements, BirdWatch identifies which of the agroecological schemes under the EU’s Common Agricultural Policy (CAP), have to be applied to improve the farmland conditions. The agri-environmental schemes are selected in such a way to ensure that they are not in conflict with any spatial or ecological requirements.

Here, BirdWatch uses spatial optimisation, taking into account both the ecological requirements and the economic and operational constraints of the farmers who need to implement the agri-environmental measures as part of their obligations under the CAP.

Benefiting from Copernicus program's high temporal resolution, BirdWatch evaluates the success of agri-environmental measures and makes adjustments as needed.

Upon project completion, the service will be accessible through a web-based GIS application in the project regions of Flanders, Germany, Lithuania, and South Tyrol.

How to cite: Frick, A., Scholz, N., Gey, S., Zurell, D., Wiedenroth, L., Kadunc, N. O., Vesel, N., Rosier, I., Hendrix, R., de Meyer, A., Sonnenschein, R., Tufail, B., Ventura, B., Orlickas, T., and Rimgaila, M.: BirdWatch - a Copernicus-based service for the improvement of habitat suitability of farmland birds in the EU, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7509, https://doi.org/10.5194/egusphere-egu24-7509, 2024.

Vertical greenery (VG) provides mutliple ecosystem services and diverse forms of implementation. Benefits are linked to maintenance, irrigation, and appropriate planning. The focus of the Fabikli project was to apply these aspects to educational purposes in three highschools in Berlin. This case study delineates the planning, implementation, maintenance, and educational operation of the project.

Complications arose due to planning errors and the still pending building permit of the systems, demonstrating the cumbersome administrative barriers regarding VG. Three energy-efficient rainwater irrigation systems and and a supporting structure that can be harvested from the ground were developed and implemented. Maintenance of these systems is designed to be infrequent and accessible, with low-tech solutions ensuring easy repairs.

At the center of the educational offer were the multidimensional issues addressed by the implemented VG systems. Examples include urban heat stress, land and water use, and CO₂ sequestration. The school personal was directly involved in the participation process. Consequently, teachers incorporated the VG-topic creatively into their classes. Here we present the harvest of the VG as an exemplary illustrative showcase.

In addition, the project aimed at a multiplication and propagation of similar systems, which did occur, but with serious design flaws. This demonstrates the importance of appropriate planning, implementation, and continuous attendance, even for low-tech solutions.

In conclusion, schools offer an influential societal overlap between generations and functions such as teachers, parents, or administration. VG can convey several key aspects of environmental education about the ecology with cities.

How to cite: Kluge, B. and Dahm, Y.: Climate adaptation through educational vertical greenery in high schools: key lessons from the city of Berlin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16707, https://doi.org/10.5194/egusphere-egu24-16707, 2024.