Abstract Forested wetlands provide a valuable potential sink for atmospheric carbon, with rates varying between tree communities. Previous studies found that topographic position within the Congaree Swamp (South Carolina, USA) influences flooding regimes, sedimentation processes, and forest community types. We measured aboveground net primary productivity (ANPP) for four distinct tree community types situated within an elevational gradient of this floodplain forest. Twenty data collection sites, blocked by a priori elevational differences, were established along five roughly parallel transects with four 20 × 25-m plots along each transect. Total ANPP was estimated using the sum of annual litterfall (five 0.25 m 2 litter traps/plot) and annual incremental increase in tree biomass. Tree (stems ≥ 10 cm diameter) wood ANPP ranged from 409 to 606 g/m 2 while total litterfall ranged from 678 to 705 g/m 2 . Total ANPP, tree wood biomass, and biomass of reproductive materials (mast) varied annually but sapling biomass, leaf litter, and total litterfall did not. Total and fractional ANPP differed between some forest community types with lowest and highest rates measured in communities occupying high floodplain elevation sites. The community occupying low elevation sites had the lowest rates of total ANPP but highest litter production. The community occupying intermediate floodplain elevation sites had the second highest rates for total, and most measured fractions, of ANPP. Sapling (stems < 10 cm diameter) wood averaged 5.8% of total ANPP for one community, suggesting that, in areas with a moderate to dense sapling layer, sapling wood is an important component of ANPP.

Floods and fires are part of the ecological regime in many wetlands, yet their interconnectedness is poorly explored. Climate extremes, such as droughts and heatwaves, are increasing fire frequency and intensity, while changing rainfall patterns make floods more unpredictable. These events shape wetland physiognomy, species composition, and functioning. Different wetlands experience varying fire exposure; seasonally inundated grasslands burn almost annually, whereas tropical forests rarely catch fire. Some wetlands are more resilient to fire, drought, and floods than others. Communities dependent on wetlands possess ecological knowledge that supports adaptation, enhancing ecosystem resilience. Though often studied separately, floods and fires in wetlands are interrelated. In addition to environmental aspects, social, cultural and associated traditional knowledge dimensions must be included in conservation processes for these environments. A holistic understanding is crucial for conservation. Researchers from sixteen countries propose a new field of study on flood-fire interactions to improve wetland management and sustainability.