Thesis Defense Seminar - Meghan Martinez

MARINE BIOLOGY PROGRAM
DEPARTMENT OF LIFE SCIENCES
TEXAS A&M UNIVERSITY - CORPUS CHRISTI

SUBJECT: REEF RESTORATION PROVIDES RESILIENT HABITAT FOR OYSTERS AND FAUNA

MAJOR ADVISOR: Dr. Jennifer Pollack

Severe degradation of oyster reef habitat over the past century has led to associated losses in ecological and economic benefits. Common oyster reef restoration goals target replacement of lost ecosystem services, including habitat provision, by improving the structural and functional quality of lost reef habitats. In July 2017, > 1 M tons of reclaimed oyster shell were used to restore approximately 1.83 ha of oyster reef complex (approximately 610 linear m) in St. Charles Bay, TX. Oysters, epifauna, and infauna were sampled monthly for the first 3 months after construction, and seasonally for a total of 19 months at the restored reef and nearby reference sites. Within the first three months post-construction, mean oyster densities increased >3x, growth rates peaked at 0.41 mm d-1, and the restored oyster population shifted from 100% spat to >90% sub-market size oysters. Although Perkinsus marinus infection was detected on every sampling date on the reference reef, only a single infected oyster was observed on the restored reef, indicating that reef location—away from infected source populations—impeded disease development. Epifaunal density, biomass, and diversity, became similar to that of the reference reef within 4 months post-construction, but a shift in epifaunal community assemblages occurred between the first and the second year post-construction, indicating monitoring periods of >1 year are necessary to capture early faunal community development on a restored reef. Results indicate structural complexity provided by the restored reef promoted oyster and epifaunal community development, and may have supported ecological resilience as minimal impacts to reef structure were observed in the wake of Hurricane Harvey. Infaunal density, diversity, and biomass did not differ between sites adjacent sites versus distant from the restored reef and were governed more by salinity than presence of the restored reef. Results indicate that the restored reef met proposed success metrics within 19 months post construction, and that restored reefs can successfully replace habitat provision ecosystem services lost due to degradation.