Untersuchung des Beweidungseffektes im renaturierten WWF Augebiet March-Auen auf Biomasse und Biodiversität

Wetlands account for approximately one third of terrestrial carbon storage, act as natural floodcontrol systems, and provide habitats for numerous species threatened with extinction (vgl.REWET 2024b). In the face of anthropogenic climate change, the maintenance and restorationof natural wetlands, such as the floodplains of the March River, are vital for fosteringsustainable and resilient ecosystems. Effective management of nature reserves must thereforeadapt to both current conditions and long-term conservation goals.This bachelor’s thesis examines the impact of horse and cattle grazing in plant species compositionand biomass, using the flood plains of the March River as a case study. In this region,a portion of the meadows is currently being utilised as part of a grazing project aimed at restoringthe area’s former structural diversity. This thesis further explores the relationshipbetween grazing and the distribution of the lance-leaved aster (Symphyotrichum lanceolatum),a potentially invasive species posing a threat to the region’s biodiversity.To address these research questions, it is essential to consider the natural conditions andhistory of the March Auen region, the REWET project, and the role of grazing in conservationareas more broadly. Building on this theoretical foundation, the impact of grazing in the abovementionedarea was examined by assessing plant species composition and biomass in three1-square-metre plots, one of which served as a control to allow for a comparative analysis ofgrazed and ungrazed areas. Data collection occurred over four fieldwork days between Apriland July 2024.The findings of this study revealed key insights into the impact of grazing on plant diversity andbiomass. Across the three plots, a total of 31 plant species were identified, including threeendangered and five critically endangered species. The ungrazed plot exhibited the highestbiomass values, while the grazed plots showed notable improvements in vegetation structure,as illustrated by photographic evidence. These results suggest that grazing may contribute toenhancing biodiversity and improving ecosystem resilience by reducing biomass of dominantspecies, thus preventing overgrowth and creating more varied microhabitats.To gain deeper insights and build on this initial analysis with more comprehensive data, it isrecommended that the monitoring programme continue in future years with adjustments madeto the methodology. This will help refine our understanding of how grazing may impact wetlandecosystems over time.