Spatial Variation in Carbon Effluxes Mediated by Grazing–Soil Interactions in a Semi‐Natural Floodplain Grassland of North‐Eastern Belgium

ABSTRACT Permanent grasslands play a vital role in terrestrial carbon sequestration. However, their function as carbon sinks or sources is influenced by environmental factors—such as edaphic properties—and by management practices, notably grazing. Because direct measurement of management effects on soil carbon stocks is challenging, efflux data offer valuable insights into soil carbon dynamics. Yet, the spatial density of such measurements is often insufficient to capture in‐field variability, particularly in heterogeneous landscapes like floodplains. This study investigates how short‐distance variation in edaphic conditions modulates the response of CO 2 and CH 4 effluxes to changes in grazing intensity in a temperate floodplain grassland in the Grote Nete valley, North‐Eastern Belgium. The site is characterised by rapid transitions in vegetation and soil properties over short distances. We conducted tri‐weekly measurements of CO 2 and CH 4 effluxes across 14 plots using a portable closed‐chamber system. These measurements were paired with grazing intensity data derived from GPS tracking, as well as assessments of soil temperature, moisture, texture, carbon stocks, pH and nutrient levels. Our findings reveal pronounced spatial variability in carbon effluxes, both between plots and within individual plots. While soil temperature consistently influenced both CO 2 and CH 4 emissions, the impact of grazing intensity was significantly modulated by local edaphic conditions. For example, CH 4 efflux was more sensitive to grazing in finer‐textured soils. These results underscore the importance of accounting for local heterogeneity and enhancing spatial replication in future studies to develop more precise and site‐specific management recommendations.