MEPS prepress abstract  -  DOI: https://doi.org/10.3354/meps12416

Stability and dynamic properties of octocoral communities in the Eastern Tropical Pacific

Catalina G. Gomez*, Hector M. Guzman, Andrew Gonzalez

*Email: catalina.gomezgomez@mail.mcgill.ca 

ABSTRACT: Octocorals are the main foundation species in rocky-wall marine communities off the Eastern Tropical Pacific; however, we have only a poor understanding of how stable these communities are. This study is the first attempt to quantify complex stability properties, such as turnover and recovery time for octocoral species. We use a Markov Chain model with transition probabilities estimated from the field, and compare two oceanographically distinct gulfs within the same latitude in Pacific Panama, the Gulfs of Panama (GP) and Chiriqui (GC). The model was parameterized by monitoring four fixed plots (1 m2) at eight sites from June 2014 to January 2016. The state (occupation) of each point (location) occupied by the holdfast of an octocoral colony was recorded during each survey. Thirteen octocoral species were monitored over 989 points. Octocoral dynamics in the GC, where communities were more species-rich, were three times more stable than communities in the GP, with an estimated turnover time of 4.8 years in GC and 1.5 years in GP. However, communities in the GC took 1.6 times longer to recover after disturbance, with an estimated species-specific recurrence time of 34 years in GC and 21 years in GP, possibly due to strong competition for space with other sessile organisms. In modeled communities, the effect of diversity loss was low at the gulf and study region, but increased significantly at the reef scale, especially in species-poor sites. Additional studies on environmental factors driving stability are needed to fully understand the mechanisms behind our results.