Likelihood ratio tests between nested site-specific models.^a

aTwice the difference of log likelihood between the two models (χ2) = probability that two models should differ in log likelihood, as much as that observed, given the degree of freedom. Degrees of freedom are equal to the difference in the number of parameters between models; M0 v. M3 = 4, M7 v. M8 = 2, M8a v. M8 = 2, M8a v. M8 = 1. M8a v. M8 comparison significance is determined by a P-value for the 50∶50 mixture of distributions.