Spatial and Temporal Patterns in Phenology, Fecundity, and Fertility for Spartina alterniflora in Coastal Georgia

Joesting, H.M.; Gregory, A.; Hinson, J., and Palacios, M., 2026. Spatial and temporal patterns in phenology, fecundity, and fertility for Spartina alterniflora in coastal Georgia. Journal of Coastal Research, 42(4), 769–779. Charlotte (North Carolina), ISSN 0749-0208. The salt-marsh grass Spartina alterniflora plays a critical role in salt-marsh growth and maintenance, and healthy populations are required for salt marshes to persist under future sea-level rise scenarios. However, to determine future population dynamics for S. alterniflora, a fundamental understanding of reproductive ecology is needed. This study contributes to this knowledge by investigating spatial and temporal patterns in S. alterniflora phenology, fecundity, and fertility by assessing proportion of reproductive stems, seed set, seed viability, germination rate, and seedling production for multiple salt marshes in coastal Georgia over several years. Results revealed the timing of peak flowering and seed set for populations during the reproductive season, as well as significant annual and spatial patterns in fecundity and fertility, potentially driven by variation in environmental variables and degree of anthropogenic disturbance. Variation in reproductive output was found within S. alterniflora populations, suggesting that only a few individuals contribute significantly to seedling production each year. These results provide valuable information on phenology and reproductive ecology for this species and contribute to predicting the response of S. alterniflora and salt marshes to future climate change.