Ecological role of Acropora palmata for its associated species in barrier reefs

Abstract

Acropora palmata is a key branching coral in the Caribbean, contributing to reef complexity and providing habitat for diverse species. In recent decades, its abundance and distribution have declined, highlighting the need to better understand its ecological role. Visual surveys along linear transects in the Limones and Picudas reefs (Quintana Roo, Mexico) identified macrofaunal species associated with A. palmata and evaluated their interactions to assess habitat use. A total of 81 species were recorded, 34 of which were shared between both reefs. The recorded groups included fish, crustaceans, polychaetes, echinoderms and molluscs. Species composition was similar across both reefs, despite the particular characteristics of each reef. The structure of A. palmata was found to generate spatially heterogeneous areas that function as habitat, refuge, feeding sites and territorial spaces at the colony level. Although the colony-specific area influenced species abundance, no effect on size was detected. These findings indicate that, at the colony scale, A. palmata provides microhabitats that support diverse assemblages across different reef conditions. This suggests a lack of functional redundancy in the region: Acropora cervicornis, its only structural analogue, mainly shelters small-bodied taxa and has become even more depleted, leaving A. palmata’s habitat role without a substitute.