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Dryad

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

Abstract

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.