The DNA of coral reef biodiversity: predicting and protecting genetic diversity of reef assemblages

Kimberly A Selkoe,Oscar E Gaggiotti,Robert J Toonen,Eric A Treml,Mary K Donovan,Johanna L K Wren

doi:10.1098/rspb.2016.0354

Abstract

Conservation of ecological communities requires deepening our understanding of genetic diversity patterns and drivers at community-wide scales. Here, we use seascape genetic analysis of a diversity metric, allelic richness (AR), for 47 reef species sampled across 13 Hawaiian Islands to empirically demonstrate that large reefs high in coral cover harbour the greatest genetic diversity on average. We found that a species's life history (e.g. depth range and herbivory) mediates response of genetic diversity to seascape drivers in logical ways. Furthermore, a metric of combined multi-species AR showed strong coupling to species richness and habitat area, quality and stability that few species showed individually. We hypothesize that macro-ecological forces and species interactions, by mediating species turnover and occupancy (and thus a site's mean effective population size), influence the aggregate genetic diversity of a site, potentially allowing it to behave as an apparent emergent trait that is shaped by the dominant seascape drivers. The results highlight inherent feedbacks between ecology and genetics, raise concern that genetic resilience of entire reef communities is compromised by factors that reduce coral cover or available habitat, including thermal stress, and provide a foundation for new strategies for monitoring and preserving biodiversity of entire reef ecosystems.

Highlights

Known for their stunning arrays of colours, shapes and life forms, coral reefs are captivating examples of extreme biodiversity
When conservation strategies focus on habitats, communities or ecosystems, as is common for coral reefs, it is important to understand how genetic diversity patterns vary across co-distributed species, because including genetic data can shift conservation priorities dramatically [3]
We investigate how patterns of genetic diversity vary across the Hawaiian Archipelago for a sample of 47 reef-associated animal species and ask if observed variation can be ascribed to potential seascape drivers representing benthic cover, ocean currents, habitat loss caused by sea-level change, temperature stress and other site characteristics

Summary

Introduction

Known for their stunning arrays of colours, shapes and life forms, coral reefs are captivating examples of extreme biodiversity. PLD length min depth depth range habitat specialist uST FCT description species is fish (1) or invertebrate (0) species is endemic to Hawai‘i (1) or widespread in the Pacific (0) pelagic larval duration in days, log transformed maximum body length in cm, log transformed minimum reported depth occurrence in meters, log transformed maximum depth minus the minimum depth, log transformed species is tied to particular reef features (1) or found on most reef types (0) strength of inter-island genetic differentiation strength of regional genetic differentiation (i.e. groups of adjacent islands) using a linear mixed model which designated the species-bymarker label as a random effect (electronic supplementary material, dataset S8) The latter tests the aggregated response of individual species, which does not have to be the same as the response of the aggregated data (composite AR). Model selection was repeated for regional subsets (i.e. seven islands in the NWHI and six in the MHI), motivated by the many differences between these regions that might produce distinct population genetic and ecological dynamics

Results

Findings

Discussion