Table 5.
Arion diversification tests using rate-constant (pure-birth, birth-death) and diversity-dependent diversification decoupled model (DDD), yule-2-rate and time-varying speciation and constant extinction (SPVAR).
| Package | Function | IST | Model | λ 0 or r 0† | Extra parameters | μ 0 | K | AIC | Δ AIC |
|---|---|---|---|---|---|---|---|---|---|
| DDD | dd_ML | yes | Birth-death (λ 0A, μ 0A) | 0.189 | 0.000 | Inf | 31.562 | 11.41 | |
| DDD | dd_ML | yes | DDD ( r 0 A, K A) | 0.586 | ‡ | 23.046 | 20.147 | 0.00 | |
| diversitree | make.bd.t | yes | yule2rate (r 0A, r 1A) | 0.040 | r 1 = 0.285 | ‡ | ‡ | 23.586 | 3.44 |
| diversitree | make.bd.t | yes | SPVAR (r 0A, r 1A, kA) | 0.046 | k = −0.248 | 0.000 | ‡ | 24.278 | 4.13 |
Bold identifies the best-fit model. AIC’s and the difference in AIC’s with the best model (∆AIC) are shown. IST, incomplete sampling taxa; λ 0A, the initial speciation rate in Arion; μ 0A, the initial extinction rate in Arion; μ 0, extinction rate when applicable; KA, carrying capacity parameter of DDD model; r 0 (= λ 0 − μ0), initial net diversification rate for DDD, yule2rate andSPVAR models; r 1 = net diversification rate after the first shift at time t 1; k, parameter of the exponential change in speciation rate for the models SPVAR; † in this study μ0 is zero therefore r 0 is effectively equal to λ 0. ‡ the parameter in the model is fixed to zero.