PLEISTOCENE REEF COMPOSITION DOCUMENTS A HEALTHY ECOLOGICAL BASELINE FOR A SANCTUARY IN NORTHEAST JAMAICA

Abstract

The Pleistocene reef assemblages of northeastern Jamaica provide essential insights into pre-anthropogenic baselines of coral community structure under pristine conditions. Paleoecological analyses of fossil reefs in East Portland reveal substantial differences from modern counterparts. In the fossil fore-reef assemblages at Navy Island and Dragon Point, Acropora cervicornis dominates (∼50% relative coral abundance). At Dragon Point, fossil A. palmata comprises ∼40% of the community, while at Navy Island it is less prevalent (∼10%), with higher abundances of Orbicella spp. (∼20%) and Pseudodiploria strigosa (∼15%). Modern East Portland reefs (2017–2024) exhibit ∼1% live coral cover in 2024 and are dominated by stress-tolerant taxa, including Porites astreoides, Orbicella spp., Agaricia spp., and branching Porites spp., Acropora spp. were absent from monitoring records in 2024, down from 95–60% abundance at fossil sites, representing a functional absence in modern reefs. Ordination analyses show compositional separation between fossil and modern assemblages, with no modern site or year clustering with Pleistocene communities. Analysis of Similarity (ANOSIM) results confirm this pattern with high between-group dissimilarity and greater internal variability in modern reefs. Our results quantify the magnitude of compositional change at a local scale and demonstrate the limitations of space-for-time substitution approaches in northeastern Jamaica. The local Pleistocene record offers a site-specific baseline for restoration, emphasizing recovery of dominant reef-building taxa, such as Acropora spp. Incorporating paleobiological data in conservation plans ensures restoration targets reflect historical reef complexity, ecological resilience, and environmental context while addressing current and future stressors.