Date of Award
Biology & Earth Science
First Committee Member
Second Committee Member
Acropora cervicornis, Earthquake scarps, Caribbean coral reefs, Historic baseline, Stressors
Caribbean coral reefs have had an 80% decrease in live coral cover over the last several decades and the effect of white-band disease on Acropora species was a major contributor. The loss of Acropora resulted in a decrease of reef rugosity and habitats for fish and reef invertebrates. This paper examines the record of stressors today and in pre-human staghorn communities to examine possible changes. Acropora cervicornis fragments, estimated to be 250-750 years old, were collected from recently exposed earthquake scarps on patch reefs in the South Water Caye Marine Reserve, Central Belize. Skeletal records of stressors included damsel fish chimneys, clubbed and eroded tips representing fireworm predation, and resheeting over dead tissue presumably killed by snail predation or disease. These results were compared to similar data from live A. cervicornis colonies on 18 nearby patch reefs. A. cervicornis comprised most of the subfossil assemblage, but makes up only 1% of the live coral cover today. It is replaced on patch reefs today by branching corals with much less topographic relief such as Agaricia tenuifolia (21%), Porites porites (16%) and Millipora complinata (fire coral, 15%). Damselfish impacts did not change from the pre-human baseline, but the incidence of fireworm predation and disease had both more than doubled. Increased biological stressors on A. cervicornis may result from a loss of fireworm and snail predators such as large fish and lobsters. An increase in fishing regulations in South Water Cay Marine Reserve may be necessary for the reestablishment of thriving staghorn coral communities.
Hargrove, Samantha L., "A Pre-Human Baseline For Stressors Limiting Staghorn Growth: Evidence From Sub-Fossil Skeletons Preserved In Earthquake Scarps, Central Belize" (2016). Distinction Papers. 36.