Data from: Predicting the distribution of Mesophotic coral ecosystems in the Chagos Archipelago

To support conservation efforts, accurate mapping of marine organism
community’ distribution has become more critical than ever before. While
previous mapping endeavours have primarily focused on easily accessible
shallow-water habitats, there remains limited knowledge about the
ecosystems lying beyond SCUBA diving depths, such as mesophotic coral
ecosystems (MCEs, ~30-150 m). MCEs are important habitats from an
ecological and conservation perspective, yet little is known about the
environmental factors that shape these ecosystems and their distribution,
particularly in the Indian Ocean region. The goals of this study are to 1)
predict the spatial distribution and extent of distinct benthic
communities and MCEs in the Chagos Archipelago, central Indian Ocean, 2)
test the effectiveness of a range of environmental and topography derived
variables to predict the location of MCEs around Egmont Atoll and the
Archipelago, and 3) independently validate the models produced. In
addition, we compared the MCEs predicted extent in the Archipelago for the
models derived from high-resolution multibeam and low-resolution GEBCO
bathymetry data. Using maximum entropy modelling, all models resulted in
excellent (>0.9) performances, for AUC and threshold-dependent
metrics, predicting extensive and previously undocumented MCEs across the
entire Archipelago, with however, differences in the predicted extent
between the high- and low-resolution models. Independent validation
resulted in fair (>0.7 AUC) and poor (>0.6 AUC) performances
for the high-resolution and low-resolution models, respectively.
Photosynthetically Active Radiation (PAR), temperature, chlorophyll-a and
topographically derived variables were identified as the most influential
predictors. In conclusion, this study provides the first prediction of the
distribution of MCEs and their distinct benthic communities in the
Archipelago. It highlights their significance in terms of potential extent
and response to various environmental factors, supporting decision making
for prioritising future survey sites to study MCEs across the Archipelago
and targeting ecologically important areas for conservation.