Dataset: Long-term trends and interannual variability in tidal wetland gross primary production across the conterminous United States

Journal of Geophysical Research—submitted paper.

Tidal wetlands are critical carbon sinks, yet their response to ongoing environmental change remains uncertain across the conterminous United States. To address this gap, we quantified long-term trends and interannual variability in tidal wetland gross primary production (GPP; g C m⁻² d⁻¹) using a 20-year (2001–2020) satellite-based dataset. We also examined regional differences and the relative influence of climate drivers versus vegetation canopy on GPP dynamics. At the continental scale, GPP increased by approximately 6% over two decades, with the strongest gains in the South Atlantic and Gulf regions. Gulf wetlands exhibited the highest productivity, while Pacific and northern Atlantic wetlands were substantially lower, reflecting climatic gradients. Decomposition analysis indicates that rising shortwave radiation and air temperature are the primary drivers of productivity increases, outweighing declines in vegetative canopy coverage and apparent greenness. Interannual variability was modest overall but greatest in the Western Gulf, where episodic disturbances such as hurricanes and drought exert strong influence. These findings suggest that recent productivity gains are driven largely by climate forcing rather than vegetation changes, underscoring the need to incorporate climatic drivers into tidal wetland carbon models and management strategies.