Biomass allocation of tidal freshwater marsh species in response to natural and manipulated hydroperiod in coastal deltaic floodplains

Deltaic floodplains are highly vulnerable to relative sea level rise (RSLR) depending on the sediment supply from river channels that provides elevation capital as adaptation mechanism. In where levees have restricted coastal deltaic floodplains, diversions been proposed a restoration strategy increase allowing for marshes establish and cope with RSLR. The response of wetlands surface has well-defined estuarine marshes, but models floodplain not resolved. Here we coupled field observations biomass plots mesocosm experiment (‘marsh organ’) remote sensing techniques assess allocation tidal freshwater marsh species in gradients hydroperiod Wax Lake Delta (WLD), Louisiana, U.S.A.. We found that, contrary salt-tolerant species, Colocasia esculenta aboveground (AGB) is strongly positively correlated percent inundated time (R 2 = 0.79, P < 0.001), increasing (mean ± 1SE) 186 69 g/m supratidal zone 1422 148 beyond its natural occurrence range lower intertidal zone. Belowground consistently exceeded AGB at 2363 294 average across treatments. also C. expanded coverage area by 31% five years consistent growth emergence WLD's subaqueous platforms, reflecting this ability higher inundation time. contrast earlier studies conducted brackish saline settings, longer hydroperiods had negative effects accumulation, our data suggest can caused diversions. • Tidal adapted broader ranges. Hydrogeomorphic zones control distribution production. increased track speed islands' expansion gain. Ecogeomorphic feedbacks following help sustain stable shorelines.