Patterns of grazing and phenolic content within restored and natural Spartina alterniflora marshes

Tiana Giovatto
LaTina Steele Dr.

Tiana Giovatto- major is Biology with a minor in Chemistry and graduating May 2021.

Abstract

Spartina alterniflora is an abundant plant species in salt marshes across the United States. Salt marshes provide protection from erosion by trapping sediments and help prevent flooding, but a variety of factors have contributed to the loss of valuable marsh habitats. Restored salt marshes are increasing in number to combat marsh loss, so understanding how restored plants interact with other marsh species is crucial. If restored plants produce fewer chemical defenses or experience more grazing than natural marshes, they might not perform as well as natural marshes. To assess the occurrence of grazing and patterns of chemical defenses in restored vs. naturally occurring S. alterniflora, we collected S. alterniflora leaves from three locations within Stratford Point, Connecticut: 1) planted in 2015, 2) planted in 2017, and 3) naturally occurring. We then used ImageJ to measure the percent area with visible grazing scars on each leaf and calculated the percent area grazed for each leaf. Significantly more grazing occurred in the 2015 planting group in comparison to the 2017 planting and the natural group. To determine if there was a link between chemical deterrent production in the leaves and the amount of grazing on the plants, we measured the phenolic content of freeze-dried and ground leaf tissue using the Folin-Denis assay. Phenolic analysis is still underway, but we expect to see lower phenolics in the more heavily grazed plants. Our results can shed light on the role of herbivores in restored marshes, ultimately improving the success of future marsh restoration projects.

 
May 5th, 1:00 PM May 5th, 4:00 PM

Patterns of grazing and phenolic content within restored and natural Spartina alterniflora marshes

Digital Commons

Spartina alterniflora is an abundant plant species in salt marshes across the United States. Salt marshes provide protection from erosion by trapping sediments and help prevent flooding, but a variety of factors have contributed to the loss of valuable marsh habitats. Restored salt marshes are increasing in number to combat marsh loss, so understanding how restored plants interact with other marsh species is crucial. If restored plants produce fewer chemical defenses or experience more grazing than natural marshes, they might not perform as well as natural marshes. To assess the occurrence of grazing and patterns of chemical defenses in restored vs. naturally occurring S. alterniflora, we collected S. alterniflora leaves from three locations within Stratford Point, Connecticut: 1) planted in 2015, 2) planted in 2017, and 3) naturally occurring. We then used ImageJ to measure the percent area with visible grazing scars on each leaf and calculated the percent area grazed for each leaf. Significantly more grazing occurred in the 2015 planting group in comparison to the 2017 planting and the natural group. To determine if there was a link between chemical deterrent production in the leaves and the amount of grazing on the plants, we measured the phenolic content of freeze-dried and ground leaf tissue using the Folin-Denis assay. Phenolic analysis is still underway, but we expect to see lower phenolics in the more heavily grazed plants. Our results can shed light on the role of herbivores in restored marshes, ultimately improving the success of future marsh restoration projects.