Ecosystem services in coastal Phragmites wetlands at the southern Baltic Sea: nutrient regulation, water purification and erosion control

Coastal wetlands can provide a variety of ecosystem services such as protection against coastal erosion, pollutant buffering or nutrient regulation. Biological, physical and chemical processes in coastal wetlands need to be studied in order to understand how such services are supplied and might change under human influences. In this thesis often neglected coastal wetlands at the southern Baltic Sea are investigated with regard to nutrient regulation, erosion control and water purification

‘The Good, the Bad and the Ugly’ of terminology in Cross Domain Fusion: Introduction of the Dialogue:Wiki

This article is a contribution to the Informatik Spektrum special issue „Cross-Domain Fusion“ – Heft 2. Terminologies are paramount to establish robust communication within interdisciplinary working groups inside and outside academia. To find the “common language” is hence essential and sometimes a long way to go. Within the idea of Cross Domain Fusion, we want to tackle this issue from the very beginning. Therefore, we set up a database based on the open source MediaWiki content management system. In this dictionary, a dedicated consortium from different disciplines evaluates terminologies used in Cross Domain Fusion and provides them within the Dialogue:Wiki. The aim is to provide accessible insight into commonalities and differences between different domain-specific terminologies to foster cross domain exchange

Expert-Based Evaluation of Ecosystem Service Provision in Coastal Reed Wetlands Under Different Management Regimes

A characteristic feature of lagoons and estuaries along the Baltic Sea is the dominance of reed (Phragmites australis) along their coasts. Reed wetlands are ecologically valuable ecosystems and play an important role for nutrient and matter cycling as well as for biodiversity. They provide a broad spectrum of ecosystem services and have been utilized by humans already for centuries. We assess the ecosystem service provision of reed wetlands and analyze how this is affected by different management scenarios and how the results of an expert-based ecosystem service assessment can be used in practice. Because of strong internal gradients and interactions with the surrounding, coastal reed belts show a higher ecosystem service provision compared to homogeneous inland reed. The three different coastal management scenarios are (1) winter harvest of reed, (2) summer harvest of reed, and (3) grazing by livestock. According to the views of 18 involved experts from Lithuania, Poland, and Germany, winter harvest is regarded as the scenario with the lowest conflict potential between nature protection and reed utilization. Experts expect no changes or even slight increases for regulating and cultural services. However, experts see the need to establish a sustainable and regionally anchored winter harvest concept. Summer harvest and grazing entail the risk to change the ecosystem structure and could lead to a shift in vegetation pattern toward short salt marsh grassland. Experts expect a slight decrease in regulating services. In particular, erosion control, biodiversity, and nutrient sequestration are rated controversially. To our experience, these expert-based ecosystem service assessments can support policy implementation (e.g., NATURA 2000, European Water Framework Directive or Marine Strategy Framework Directive). It can serve as a tool that allows stakeholders to visualize trade-offs, analyze patterns and processes at regional scales, and hence facilitate decision-making

Human-Induced Hydrological Connectivity: Impacts of Footpaths on Beach Wrack Transport in a Frequently Visited Baltic Coastal Wetland

Coastal wetlands depend on vertical accretion to keep up with sea level rise in cases where embankment restricts accommodation space and landward migration. For coastal wetland survival, autogenic productivity (litter, root decay) as well as allogenic matter input are crucial. Beach wrack composed of seagrass and algae can serve as an important allogenic matter source, increase surface roughness, elevate the backshore, and influence the blue carbon budget. The objective of this study is to understand how human footpaths in a frequently accessed Baltic coastal wetland influence beach wrack transport and accumulation. Beach wrack monitoring during the winter storm season 2021/2022 was conducted in high spatial and temporal resolution with bi-weekly UAV flights. Object-based identification, segmentation, and classification of orthophotos with open-source software allowed the detection of beach wrack patches with a mean area of 0.6–2.7 m². Three major storm events occurred during the monitoring period (Arwen, Malik, Eunice). Regardless of wind speed or direction, the main accumulation zones remained stable. The east-west footpath that crosses the coastal wetland and connects the tourist hotspots served as a “highway” for water-mediated transport of beach wrack. Total area covered by beach wrack fluctuated between 1,793 and 2,378 m² with a peak after storm Malik in January 2022. The densely accumulated beach wrack along the main east-west footpath formed an elongated micro-cliff-like structure and limited landward transport. The identified transport patterns and accumulation hotspots are a starting point for further research on how beach wrack behaves in (waterlogged) coastal wetlands compared to decomposition on sandy beaches

Ecosystem service assessments within the EU Water Framework Directive: marine mussel cultivation as a controversial measure

To combat the persistent eutrophication in coastal waters, sustainable sea-based measures are recommended. Yet, they are the subject of controversial stakeholder discussion, which hampers the implementation and planning process. The aim of this study is to evaluate if a participatory mapping (PM) approach and ecosystem service assessments (ESA) can be suitable tools within Water Framework Directive (WFD) implementation to support the communication with different target groups to improve and accelerate the planning and realization of new sea-based mitigation measures. We conducted three stakeholder-based PMs to visualize the perception of sea-based mitigation measures in coastal waters and seven different ESAs to investigate the perceptions of different mussel cultivation scenarios as mitigation measures. The PMs showed that ecological measures were preferred. The ESA approach showed that, while experts rated mussel cultivation scenarios positively overall, non-expert stakeholders still seemed skeptical and preferred alternative measures like floating wetlands. The methodological results indicate that PM can be a cost-effective tool to visualize stakeholders’ perceptions, but it needs to be applied with an ESA to be beneficial for the WFD implementation process. A web-based ESA improves the discussion with stakeholders and can reveal potential misperceptions and concerns faster and lead to a more focused discussion

Expert-based evaluation of ecosystem service provision in coastal reed wetlands under different management regimes

A characteristic feature of lagoons and estuaries along the Baltic Sea is the dominance of reed (Phragmites australis) along their coasts. Reed wetlands are ecologically valuable ecosystems and play an important role for nutrient and matter cycling as well as for biodiversity. They provide a broad spectrumof ecosystemservices and have been utilized by humans already for centuries. We assess the ecosystem service provision of reed wetlands and analyze how this is affected by different management scenarios and how the results of an expert-based ecosystem service assessment can be used in practice. Because of strong internal gradients and interactions with the surrounding, coastal reed belts show a higher ecosystem service provision compared to homogeneous inland reed. The three different coastal management scenarios are (1) winter harvest of reed, (2) summer harvest of reed, and (3) grazing by livestock. According to the views of 18 involved experts from Lithuania, Poland, and Germany, winter harvest is regarded as the scenario with the lowest conflict potential between nature protection and reed utilization. Experts expect no changes or even slight increases for regulating and cultural services. However, experts see the need to establish a sustainable and regionally anchored winter harvest concept. Summer harvest and grazing entail the risk to change the ecosystem structure and could lead to a shift in vegetation pattern toward short saltmarsh grassland. Experts expect a slight decrease in regulating services. In particular, erosion control, biodiversity, and nutrient sequestration are rated controversially. To our experience, these expert-based ecosystem service assessments can support policy implementation (e.g., NATURA 2000, European Water Framework Directive or Marine Strategy Framework Directive). It can serve as a tool that allows stakeholders to visualize trade-offs, analyze patterns and processes at regional scales, and hence facilitate decision-making

Stepping stones along urban coastlines-improving habitat connectivity for aquatic fauna with constructed floating wetlands

Urban development along coastlines is accompanied by habitat fragmentation and loss of habitat connectivity, particularly affecting the habitat and nursery function of estuarine areas for migratory marine species. Constructed floating wetlands, deployed as ‘stepping stones’ along urban coastlines where natural wetlands are missing, offer the potential to partially replace lost ecosystem services. Originally developed for wastewater treatment, constructed floating wetlands are now used to improve landscape aesthetics or create habitats for aquatic fauna and birds. This study presents a toolkit to identify appropriate sites for stepping stones using open source data and open source software alone. The toolkit was used to identify 85 potential installation sites along the German Baltic Sea coast, a large proportion of which are located in protected areas offering synergies with nature conservation measures. Though the sites are often located in protected areas, the field investigation revealed that natural vegetation is largely absent from the estuaries near urban areas. Constructed floating wetlands can never replace ‘core areas’ in ecological networks, but they can serve as stepping stones improving habitat connectivity, especially for diadromous fish species such as the threatened European eel. To ensure not only structural connectivity, but also functional connectivity, restoration efforts at the land-sea interface must be holistic and include adequate hydrologic connectivity

From coastal geomorphometry to virtual environments

Communicating environmental change and mitigation scenarios to stakeholders and decision-makers can be challenging. Immersive environments offer an innovative approach for knowledge transfer, allowing science-based scenarios to be discussed interactively. The use of such environments is particularly helpful for the analysis of large, multi-component geospatial datasets, as commonly employed in the classification of ecosystems. Virtual environments can play an important role in conveying and discussing the findings gathered from these geomorphometric datasets. However, textured meshes and point clouds are not always well suited for direct import to a virtual reality or the creation of a truly immersive environment, and often result in geometrical artifacts, which can be misinterpreted during the import to a game engine. Such technical hurdles may lead to viewers rejecting the experience altogether, failing to achieve a higher educational purpose. In this study, we apply an asset-based approach to create an immersive virtual representation of a coastal environment. The focus hereby is on the coastal vegetation and changes in species distribution, which could potentially be triggered by the impact of climate change. We present an easy-to-use blueprint for the game engine EPIC Unreal Engine 5. In contrast to traditional virtual reality environments, which use static textured mesh data derived from photogrammetry, this asset-based approach enables the use of dynamic and physical properties (e.g. vegetation moving due to wind or waves), which makes the virtual environment more immersive. This will help to stimulate understanding and discussion amongst different stakeholders, and will also help to foster inclusion in earth- and environmental science education

Indications from C:N:P Ratios in Surface Sediments along Land-to-Sea Gradients to Support Coastal Nutrient Management

Shallow, semi-enclosed coastal systems are particularly prone to eutrophication. Depending on local site conditions and historical nutrient legacies, sea-based measures might be necessary in addition to land-based nutrient removal. In this study, C:N:P ratios were combined with open-source bathymetric information and linked with the prevailing geomorphological and sedimentological regimes to gain insights into nutrient hotspots and understand their sources and fate in coastal waters. Land-based sediment samples were taken behind outlets at three sites in Eckernförde Bay (Baltic Sea), and complemented with ship-based sampling at locations approximately 8 m and 12 m water depth. The total carbon, nitrogen and phosphorus concentrations in surface sediments increased at deeper sites. This suggests that an increased downslope particle transport and deposition regime, based on local geomorphology, might influence nutrient hotspots to a larger extent than proximity to sources (e.g., outlets). Overall, the recorded C:N ratios (mean = 28.12) were closer to the ratio of terrestrial plants than those of marine phytoplankton, indicating allochthonous sources of organic matter

Constructed floating wetlands made of natural materials as habitats in eutrophicated coastal lagoons in the Southern Baltic Sea

Eutrophication remains an environmental challenge in lagoons along the Southern Baltic Sea. Floating islands planted with emergent macrophytes are an option to remove nutrients from eutrophicated waters. Furthermore, floating wetlands offer other ecosystem services such as the provision of habitats. Numerous scientific studies have been conducted; however most remain on the laboratory scale. This research explores the challenges associated with installations in coastal environments and focuses on sustainability of the island design, the habitat function as well as nutrient removal. Most floating wetland designs use polyethylene, polypropylene, polyurethane or polyvinyl alcohol foam to ensure the buoyancy. For this study an artificial polymer free island design was developed and tested. The floating constructions in the Darss-Zingst-Bodden-Chain were planted with native macrophytes which have the potential to act as ‘biodiversity-supplements’ to the adjacent coastal wetlands: Bolboschoenus maritimus, Carex acutiformis, Iris pseudacorus, Juncus effesus, Lythrum salicaria, Schoenoplectus lacustris, Typha latifolia. The chosen macrophytes survived fluctuating salinities. After three months the above-ground biomass was harvested and analyzed for the nutrient concentrations. Phosphorus concentrations were highest in L. salicaria and nitrogen in I. pseudacorus. Video monitoring and field observations were applied in order to observe animals. Birds did not use the floating wetlands as breeding grounds, but the grey heron (Ardea cinerea) was a common visitor for foraging. Especially surprising was the large amount of juvenile eels (Anguilla anguilla). A diverse and large root network below the floating islands boosts not only nutrient removal but serves as a shelter and refuge for fish such as the endangered eel