Wetland greenhouse gas response, biomass, and plant height to experimental warming, flooding, and herbivory, Yukon-Kuskokwim Delta (Western Alaska, USA) (2024)

This dataset was created to understand greenhouse gas responses (carbon dioxide and methane), plant community biomass, and three dominant plant species height (Carex rariflora, Carex lyngbyei, and Salix fuscescens) to warming, flooding, and herbivory in the Yukon-Kuskokwim (Y-K) Delta (western Alaska, USA). We conducted a two-year field experiment in which we passively increased temperatures, simulated periodic tidal flooding at two intensity levels (low and high), and applied an herbivory treatment (grazing, fecal addition, and trampling) during the 2023 and 2024 summer growing season; however, only the 2024 data are presented. Our treatments reflect changes expected in the Y-K Delta in the next 10-20 years. We conducted the experiment in two wetlands (lowland and upland wetland) with different elevations and flooding histories: a wet sedge-shrub meadow and a transitional wet community between the meadow and tundra. Greenhouse gas fluxes were taken once a week in the summer using static chambers for a total of 9 measurements. We characterized aboveground plant-community structure using the point intercept frequency methodology (PIM). We clumped vascular plant species into five broad plant functional groups: graminoids, deciduous and evergreen shrubs, forbs, and standing-dead graminoids. When measuring plant height, we chose the same five intercepts for each species on the PIM gridded frame and selected the closest individual.