Cryptic coral community composition across environmental gradients
Cryptic genetic lineages can respond differently to environmental change, yet their community‑level patterns remain poorly understood. Using 2b‑RAD sequencing of six coral species around St. Croix, USVI, this study identifies multiple cryptic coral lineages and examines how their community composition shifts across environmental gradients. Depth emerged as the strongest predictor—more influential than ecoregion and all other abiotic variables—indicating strong depth‑related environmental filtering. These findings show that cryptic coral communities are shaped by both depth and local conditions, with unknown drivers still to be resolved. Understanding this turnover is essential for coral outplanting, as locally adapted lineages may differ in fitness across environments, influencing long‑term restoration success.
Subject Tags
- Habitat restoration
- Reefs
Abstract
Cryptic genetic variation is increasingly being identified in numerous coral species, with prior research indicating that different cryptic genetic lineages can exhibit varied responses to environmental changes. This suggests a potential link between cryptic coral lineages and local environmental conditions. In this study, we investigate how communities of cryptic coral lineages vary along environmental gradients. We began by identifying cryptic genetic lineages within six coral species sampled around St. Croix, USVI based on 2b-RAD sequencing data. We then analyzed associations between the distributions of cryptic lineages across the six coral species (i.e., “cryptic coral community composition”) and ecoregions, or geographically distinct environmental conditions. Our findings show that depth is a more significant predictor of community composition than ecoregions and is the most influential factor among the 40 abiotic variables that characterize ecoregions. These results imply that cryptic coral communities are influenced by both depth and local environmental conditions, although the exact environmental factors driving these patterns remain unknown. Understanding community turnover across a seascape is important to consider when outplanting corals to restore a reef, as locally-adapted lineages may have differential fitness in different environmental conditions.
Citation
Cabacungan, G. N., Waduwara Kankanamalage, T. N., Azam, A. F., Collins, M. R., Arratia, A. R., Gutting, A. N., ... & Black, K. L. (2025). Cryptic coral community composition across environmental gradients. PLoS One, 20(2), e0318653. https://doi.org/10.1371/journal.pone.0318653
TNC Authors
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Alexandra N. Gutting
The Nature Conservancy