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

Abstract

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 impacts and their interactions in the Baltic Sea region

“…Extractive aquaculture includes filtering organism such as bivalves, but also macroalgae and other plants like seaweed (Critchley et al, 2019;Weinberger et al, 2020) and reed (Karstens et al, 2019). Similar to seaweed farming, mussel farming has the potential to reduce the environmental impact of marine aquaculture by acting as a nutrient sink, transferring nutrients 1440 into harvestable biomass ("mussel mitigation farming", Petersen et al, 2014;Holbach et al, 2020).…”

“…In the Baltic Sea region, there is also a strong interest in wetland farming and reed harvest (Karstens et al, 2019). While the blue mussel is a candidate for a "blue" solution for pelagic nutrient abatement on the local scale, reed (Phragmites australis), represents a "blue-green" catch crop for nutrient runoff and habitat enhancement in the inner littoral zone.…”

Management and Ecosystem Services of Halophytic Vegetation

“…Other regulatory services, such as bioremediation by microorganisms, smell reduction, wind protection, seed dispersal, maintaining populations and habitats (including gene pool protection), weathering processes and their effect on soil quality, decomposition and fixing processes, and their effect on soil quality which were researched for wetlands (Karstens et al 2019), could be partly applicable on coastal and inland wetland saline habitats, but there are limited information for more accurate interpretations.…”

Expert-Based Assessment and Mapping of Ecosystem Services Potential in the Nemunas Delta and Curonian Lagoon Region, Lithuania

“…ES matrix and mapping output will help to identify the areas with the highest ES potential and the general patterns of ES potential distribution in the territory, thereby supporting ecosystem-based decision-making, landscape management and territorial planning. Some recent studies have highlighted habitats as the most relevant assessment unit for management needs along the coastline and surroundings [38,39]. In the present study, effort is made to include habitats (Sites of Community Importance) as expert-based assessment units, and an extensive list of ES is incorporated to address all nature values in the territory, as well as relationships between ES and their spatial patterns.…”