Multiscale variability in coral recruitment in the Mascarene Islands: From centimetric to geographical scale

PLoS One. 2019 Mar 22;14(3):e0214163. doi: 10.1371/journal.pone.0214163. eCollection 2019.

Abstract

Coral recruitment refers to the processes allowing maintenance and renewal of coral communities. Recruitment success is therefore indispensable for coral reef recovery after disturbances. Recruitment processes are governed by a variety of factors occurring at all spatial and temporal scales, from centimetres to hundreds of kilometres. In the present context of rising disturbances, it is thus of major importance to better understand the relative importance of different scales in this variation, and when possible, the factors associated with these scales. Multiscale spatio-temporal variability of scleractinian coral recruitment was investigated at two of the Mascarene Islands: Reunion and Rodrigues. Recruitment rates and taxonomic composition were examined during three consecutive six-month periods from regional to micro-local scales (i.e. from hundreds of kilometres to few centimetres) and between two protection levels (no-take zones and general protection zones). Very low recruitment rates were observed. Rodrigues displayed lower recruitment rates than Reunion. Recruit assemblage was dominated by Pocilloporidae (77.9%), followed by Acroporidae (9.9%) and Poritidae (5.2%). No protection effect was identified on coral recruitment, despite differences in recruitment rates among sites within islands. Recruits were patchily distributed within sites but no aggregative effect was detected, i.e. the preferentially colonised tiles were not spatially grouped. Recruits settled mainly on the sides of the tiles, especially at Rodrigues, which could be attributed to the high concentration of suspended matter. The variability of recruitment patterns at various spatial scales emphasises the importance of micro- to macro-local variations of the environment in the dynamics and maintenance of coral populations. High temporal variability was also detected, between seasons and years, which may be related to the early 2016 bleaching event at Rodrigues. The low recruitment rates and the absence of protection effect raise questions about the potential for recovery from disturbances of coral reefs in the Mascarene Islands.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anthozoa* / classification
  • Conservation of Natural Resources
  • Coral Reefs*
  • Indian Ocean Islands
  • Population Dynamics
  • Seasons

Grants and funding

This work was supported by: Western Indian Ocean Marine Scientific Association, MARG I_2015_19 (WIOMSA) (https://www.wiomsa.org) to FJ; Direction des Relations Internationales, Université de La Réunion (https://www.univ-reunion.fr/page-accueil-lien-direct-services/dri-direction-des-relations-internationales) AAP DRI 2017 n°1 to LP; Direction des Relations Internationales, Université de La Réunion, AAP DRI 2018 n°1 (https://www.univ-reunion.fr/page-accueil-lien-direct-services/dri-direction-des-relations-internationales) to LP; CALIBIOME Fonds Européen de Développement Régional (FEDER), PO FEDER 2014-2020 (www.feder.public.lu/) to LP & MA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.