Predicted habitat
The EXP approach selected optimal models with generally smaller predicted habitat among all the approaches given we avoided over prediction while selecting ecologically plausible models. Among the four sequential approaches AUCDIFF approaches generally predicted a larger area as suitable habitat for both the taxonomic groups compared to the two ORTEST approaches when the balance threshold was used. For some species the habitat predicted was several times bigger than that predicted by the EXP approach, thus over predicting. When the less restricted thresholds, considered robust for the species with small occurrence records (Pearson et al. 2007, Warren and Seifert 2011), are used to develop binary suitable habitat maps, as we did here, use of ORTEST approaches may be a better choice over AUCDIFF approaches for optimal model selection. While the use of AUCDIFF approaches may not be useful when a restrictive threshold, like the percentile threshold (Galante et al. 2018), is used, since optimal models selected through AUCDIFF approaches under predicted for some species (Figure 5). Further studies may be required to confirm if there is a true relationship between the thresholds used to derive binary suitable maps and the corresponding model selection approaches used to select the optimal models.
Though the expert approach selected more complex models judged using RM values, ORs, AUCDIFF and average number of parameters, the use of a less restrictive threshold value for producing binary suitable habitat maps helped select ecologically plausible models (Pearson et al. 2007). We suggest the use of ORTESTapproaches over AUCDIFF approaches as either the first line of optimal model screening or by their own to select the final optimal models since optimal models chosen by these approaches had higher correlation with the optimal models chosen by the EXP approach for almost all the parameters we tested. Further, though AUCDIFF approaches selected less overfit models over ORTEST and EXP approaches, AUCDIFFapproaches over predicted the habitat area when the balance threshold (a less restrictive threshold) was used in our case. However, we feel there is a need for further studies using other thresholding rules available in the Maxent result as well as including a broader range of taxonomic groups to assess the generality of our findings.