Meeting Abstract
Outbreaks of crown-of-thorns sea stars (Acanthaster planci) can cause localized extinction of corals, leading to extensive disruption of the coral reef community. However, many broadcast-spawning coral species are capable of rapid recolonization of disturbed sites, which can facilitate recovery. In 2010, a crown-of-thorns outbreak at the south tip of Yap Island led to the near complete local extinction of many Acroporid species. Samples of the table-top coral Acropora hyacinthus were collected prior to this outbreak in 2009. Our objective was to resample new A. hyacinthus coral individuals that have since recruited to this location in order to determine how local extinction and recovery has changed the genetic composition of the population. We utilized genome-wide markers (2b-RAD) to assess changes in genetic diversity and genetic differentiation between the former adult population and the new juvenile population. In order to assess genetic changes that were specifically associated with the local extinction/recolonization event, we also examined differences among adult and juvenile cohorts at two other sites unaffected by disturbance. Our results provide new insight into patterns of coral recruitment at disturbed and healthy reef sites and provide a test of the Sweepstake’s hypothesis, which predicts that variability in the fecundity of marine broadcast-spawning species should result in reduced inter-cohort relatedness among juveniles.
