Temporal variability in epifaunal assemblages associated with temperate gorgonian gardens

Area of Science:

• Marine Biology
• Ecology
• Biodiversity Studies

Background:

• Epifaunal assemblages associated with octocorals are understudied regarding temporal dynamics.
• Octocorals Eunicella gazella and Leptogorgia lusitanica are key habitat formers in South Portugal.

Purpose of the Study:

• To investigate the temporal variability of epifaunal assemblages on Eunicella gazella and Leptogorgia lusitanica.
• To determine the primary drivers (time vs. colony size) of these assemblages' ecological patterns.
• To assess the influence of environmental parameters on temporal variability.

Main Methods:

• Field sampling of epifaunal assemblages on octocorals over time.
• Analysis of assemblage composition, diversity, and abundance.
• Correlation of ecological patterns with environmental variables (temperature, chlorophyll a, particulate organic carbon).

Main Results:

• Temporal variability, driven by environmental changes, was a primary factor influencing epifaunal assemblages, more so than colony size.
• Assemblages were dominated by amphipods, molluscs, and polychaetes, with resident species being consistently dominant.
• Higher species turnover occurred during the spring-to-summer transition, linked to increased seawater temperature.
• Smaller colonies exhibited higher turnover and less diverse/abundant assemblages compared to larger colonies.

Conclusions:

• Temporal variability is a critical consideration for biodiversity assessments of octocoral-associated fauna.
• Environmental parameters significantly influence the temporal dynamics of these epifaunal communities.
• The high biodiversity associated with gorgonian colonies underscores their importance as a priority habitat requiring conservation.