Code for: Combined species occurrence and density predictions to improve marine spatial management

R code as used for the publication "Combined species occurrence and density predictions to improve marine spatial management" in Ocean and Coastal Management (2021). Code was used to create a species distribution model to predict probability of occurrence and density for two bivalve species in New Zealand estuaries . Code uses boosted regression trees in the dismo package, combined with a bootstrap approach (code provided by FS, Stephenson et al. 2020). This code combines the probability of occurrence and abundance BRT's and spatial predictions. 3rd party data is not made publicly available yet, so randomly generated data is used as an example. See data availability statement in publication for access to original data