Term of Award

Spring 2023

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.


Department of Biology

Committee Chair

Heather Joesting

Committee Member 1

Michele Guidone

Committee Member 2

Lissa Leege


Coastal salt marshes are valuable ecosystems under threat from climate change and sea level rise. Living shorelines offer a promising solution, often incorporating the foundational salt marsh species Spartina alterniflora due to its ability to tolerate natural stressors and maintain sediment stability. However, research suggests that seed-based propagation protocols should be developed on a local scale due to the genetic heterogeneity within and between S. alterniflora populations. Here, we attempt to contribute to the development of one such protocol for coastal Georgia S. alterniflora.

In Fall 2021, seeds were collected bi-monthly from four marshes of varying ocean proximity and stratified in several types of storage vessels. Following this, seed viability was assessed, and seeds from spikelets with >10% viability were placed under germination trials. Plants were then moved to a greenhouse and grown for 10 weeks in a factorial combination of saltwater/freshwater x potting soil/salt marsh inoculated soil. During this growth period, plants were measured weekly for stem height, diameter, and number of ramets, and every three weeks for leaf chlorophyll content. At the end of the experiment, all plants were harvested, measured for root length, and dried for determination of aboveground and belowground biomass.

Variation in seed set, viability, and germination rate was observed across sites, with the most inland site striking an optimal balance between seed set, viability, and germination. Across collection dates, variation was observed in seed set and germination rate, with the November collection periods having the greatest number of seeds per spikelet and germination rate. There was an effect of storage vessel on post-stratification viability, but there was no relationship between measured seed viability and seed germination. Plants grew best in inoculated soils and when watered with fresh water, growing faster, taller, developing greater biomass, and maintaining greater leaf chlorophyll concentrations. We recommend that seeds be collected from inland marshes and be stratified in spacious containers over the winter. While optimal conditions for germination remain elusive, plants grow best in freshwater and with the addition of natural salt marsh soil.

Research Data and Supplementary Material


Justin Hinson Thesis Appendix.pdf (84 kB)
Contains Appendix Tables A-1 and A-2