ORIGINAL RESEARCH article

Front. Ecol. Evol.

Sec. Conservation and Restoration Ecology

Volume 13 - 2025 | doi: 10.3389/fevo.2025.1602543

This article is part of the Research TopicConservation and Restoration in the OceansView all articles

Determining the diversity and relative abundance of coral taxa in wild spawning slicks for effective restoration

Provisionally accepted
  • 1University of Algarve, Faro, Portugal
  • 2Australian Institute of Marine Science, Townsville, Australia
  • 3Australian Institute of Marine Science, Perth, Australia
  • 4Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
  • 5National Marine Science Centre, Faculty of Science and Engineering, Southern Cross University, Coffs Harbour, Australia

The final, formatted version of the article will be published soon.

Coral reefs are increasingly threatened by climate change-induced stressors, including marine heatwaves, which can lead to coral mortality, reduced reproductive output, and compromised natural recovery. Successful coral reef recovery requires the settlement of coral larvae and recruitment in degraded areas, replenishing coral communities and promoting resilience. Some restoration strategies involve utilizing natural spawning slicks, composed of coral gametes and embryos, to produce larvae to reseed reefs. However, verifying the taxonomic composition of these slicks is challenging. Here, we tested the performance of two coral ITS primer sets, CoralITS2 and CoralITS2_acro, on mock communities to evaluate their ability to capture genera composition and relative abundances. Both primer sets demonstrated high accuracy (>97%) in detecting and quantifying coral taxa. Subsequently, these primers were applied to wild-collected spawning slicks from the Great Barrier Reef, revealing variation in scleractinian (reef-building) coral community composition among slicks. For the CoralITS2_acro assay, Acropora was consistently the most abundant resolved genus detected across wild slick sample sites, with the exception of samples from the Whitsundays region, where Platygyra was dominant. The CoralITS2 assay successfully differentiated reef-building (Scleractinian) corals from other cooccurring spawning taxa, such as soft corals, anemones, and sponges, and revealed that these other co-spawners dominated slicks at two sites. Our findings underscore the potential of eDNAbased monitoring as a scalable tool to confirm the presence and relative abundance of diverse coral assemblages in natural slicks, informing restoration efforts. By enabling the characterization and comparison of slick composition across large spatial and temporal scales, eDNA metabarcoding can support restoration practices that align with the ecological requirements of reef ecosystems, safeguarding biodiversity and promoting resilience against future disturbances.

Keywords: biodiversity1, EDNA2, ITS23, metabarcoding4, Great Barrier Reef5, Coral seeding6, Monitoring7

Received: 29 Mar 2025; Accepted: 04 Jun 2025.

Copyright: © 2025 Marquardt, Elder, Yeoh, Randall, Heyward, Harrison, Logan and Howells. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Bailey Marquardt, University of Algarve, Faro, Portugal

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.