Diversity-Dependent Diversification

Implements maximum likelihood and bootstrap methods based on the diversity-dependent birth-death process to test whether speciation or extinction are diversity-dependent, under various models including various types of key innovations. See Etienne et al. 2012, Proc. Roy. Soc. B 279: 1300-1309, , Etienne & Haegeman 2012, Am. Nat. 180: E75-E89, and Etienne et al. 2016. Meth. Ecol. Evol. 7: 1092-1099, . Also contains functions to simulate the diversity-dependent process.