Mapping spatial dynamics of carbon storage and emissions across conservation lands in Nebraska, USA

Conservation lands play a critical role in carbon sequestration, yet spatially explicit assessments of carbon dynamics across interior U.S. freshwater ecosystems remain limited. This study addresses the gap by integrating the InVEST carbon storage and sequestration model with site-specific inundation frequency data to evaluate carbon dynamics across 48,363 conservation sites in Nebraska, USA. Results confirm substantial carbon storage within these lands. Among conservation sites, the mean carbon storage potential for Conservation Reserve Program (CRP) is 70.7 MgC/ha and Wetland Management Areas (WMA) 103.1 MgC/ha, Wetland Reserve Program (WRP) 101.9 MgC/ha, and Waterfowl Production Areas (WPA) 101.4 MgC/ha. Higher carbon densities were associated with forested wetlands, emergent herbaceous wetlands, and deciduous forests, often in areas with high (> 75%) inundation frequency. High carbon storage was concentrated primarily in WMA, WPA, and WRP conservation site types that pair land cover types (i.e., forested habitats, woody wetlands) with hydrological and management regimes. CRP sites reflect their predominance of grasslands and croplands and contribute significantly to overall conservation carbon stock. Spatial heterogeneity in carbon dynamics was closely linked to inundation frequency and land management practices. Areas with frequent inundation showed increased carbon accumulation. These conservation lands functioned as net carbon sinks due to sequestration outweighing methane and nitrous oxide emissions. These findings underscore the ecological value of Nebraska's conservation lands and their vital role in agricultural conservation policy. Hotspot analysis identified carbon-dense areas, providing a clear view for targeted conservation and restoration on these lands.