This package implements a few species distribution models, including an R link to the 'maxent' model, and native implementations of Bioclim and Domain. It also provides a number of functions that can assist in using Boosted Regresssion Trees.
A good place to start is the vignette, which you can access by typing vignette('sdm', 'dismo')
In addition there are a number of functions, such sampling background points, k-fold sampling, and for model evaluation (AUC) that are useful for these and for other species distribution modeling methods available in R (e.g. GLM, GAM, and RandomForest).
Robert J. Hijmans, Steven Phillips, John Leathwick and Jane Elith