Derived variables and coordinates to assess the ecological relevance of multiscale bathymetry for coral species distribution modelling across the Great Barrier Reef

With constant improvements in the accuracy and availability of open-source
digital elevation models (DEMs) comes a need to properly understand the
relevance of their derived topographic variables in ecological research,
particularly in marine environments. Here, we provide data and scripts
used to investigate the ecological relevance of two open-source
bathymetric models for deriving topographic variables to perform species
distribution modelling of coral across the Great Barrier Reef (GBR),
Australia. We illustrate our methods with a case study based on three
common Acropora coral species (A. hyacinthus, A. spathulata, A.
kenti) across 23 reefs of the GBR, where we produce high
performing distribution maps using purely topographic variables derived
from three open-access bathymetry models.  A script is provided
to first download and process bathymetry DEMs from the Allen Coral Atlas
and the DeepReef projects, before performing a multiscale generalisation
to acquire these DEMs at  15m, 30m, 60m, 100m, 120m
resolutions.  From these DEMs, we provide code for deriving 14
topographic variables used in analyses. We provide the csv files
containing values of the DEM and topographic variables at random
assessment points across the 23 reefs,  as well as at the coral
colony sample sites. The script contains all analyses, including DEM
vertical depth assessment, variable correlations, and MaxEnt species
distribution models.