Reducing nitrogen inputs mitigate <i>Spartina</i> invasion in the Yangtze estuary

This dataset includes data obtained from landscape-scale surveys and three field experiments. To explore how N reductions contributed to native community recovery in estuarine marshes degraded by plant invasions. Using ongoing, landscape-scale N reductions in the Yangtze River, we conducted landscape-scale surveys to determine the responses of <i>Phragmites australis</i> patches in their density (no. km-2) and size (m2 per patch) in <i>Spartina alterniflora</i>-invaded marshes before and after reducing N inputs in the Yangtze estuary from 2009 to 2020 using satellite images.To uncover the mechanisms driving this temporal response of <i>P. australis</i> patches, we investigated how the growth performances (maximum NDVI) of <i>S. alterniflora</i> and <i>P. australis</i> responded to decreased N inputs at landscape scales.We then validated the growth dynamics (aboveground biomass, g/m2) of both species in the ambient plots of the SINE experiment after reducing N inputs.Furthermore, we determined how the competitive impacts (dominance as represented by aboveground biomass ratio in the mixed stands) of S. alterniflora on <i>P. australis</i> responded to reduced N conditions by transplanting previously N-fertilized and unfertilized <i>S. alterniflora</i> from the SINE experiment into plots with ambient and enriched N conditions and co-planting it with <i>P. australis</i>.Lastly, we used the framework of modern coexistence theory to characterize the changes in competitive outcomes between <i>S. alterniflora</i> and <i>P. australis</i> by evaluating niche and relative fitness differences under ambient and enriched N conditions in existing <i>P. australis</i> patches in the <i>S. alterniflora</i>-invaded marshes.