Western Indian Ocean coral diversity observations from 1998–2022

Coral reefs are threatened by climate change, thus effective policies and management require spatial prioritization for conservation investments. Our aim was to develop a spatially explicit ecological model to predict current (2020) and future (2050) numbers of coral taxa at moderate scales (i.e., ~6 km2). Our machine learning predictive models of coral community attributes in 7039 mapped reef cells in the western Indian Ocean were based on 35 spatially complete influential environmental proxies trained with ~1000 field surveys. Four models explored: influences of climate change, water quality, direct human-resource extraction, and variable selection processes on numbers of coral taxa. Two predictive models examined the predictions of all variables and compared them to a variable-restricted climate change (8 commonly used variables) and human influence model (9 variables). The most frequently selected temperature variables in all models were the median, skewness, excess heat, rate of te..., Corals were sampled haphazardly while snorkeling or scuba diving in either visually estimated or measured quadrats of ~2 m2 where all corals >5-cm were identified and counted in ~15-20 replicates (McClanahan et al. 2007). We also recorded the depth and habitats of the sites as reef edge, reef crest, reef flat, or reef lagoon. Thus, the values used here were the total number of taxa in ~40 m2. Taxa identification was to the genus level, but Porites colonies were distinguished further as massive, branching, or Porites rus and Galaxea as either G. astreata or G. fascicularis. A total of 67 taxa in 1001 sites were sampled in 6 of the ecoregions. Sixteen observers contributed to the database, but most contributed few sites and three observers combined sampled 939 of the 1001 sites and had non-significant differences between them.
We used one of the latest iterations of coral reef maps to establish reef distribution patterns (https://data.unep-wcmc.org/datasets/1). Specifically, we used th...,