The predictive link between the spatial demographic changes of a species and its environment is complex and difficult to detect without detailed models and data from multiple sources. Integrative distributional, demographic, and coalescent modeling (iDDC) integrates simulation-based spatial population genetic and species distribution models (SDMs) to enable testing eco-evolutionary hypotheses given geo-referenced genetic data. Integral to iDDC is the transformation between habitat suitability values and local deme sizes, a key parameter that has not been thoroughly explored or used to test eco-evolutionary hypotheses. In this study, we investigate this parameter’s influence on spatiotemporal demographic inference in two Enyalius lizard species in the Brazilian Atlantic Forest, one with a high-elevation distribution, Enyalius iheringii, and another having a low-elevation distribution, Enyalius catenatus. Since environmental tolerances in high-elevation species are generally broader than in low-elevation species, we test two hypotheses: (1) E. iheringii has higher effective migration compared to E. catenatus; and (2) the relationship between habitat suitability and local deme size is non-linear for E. iheringii and linear for E. catenatus. We find support for (1) and mixed support for (2), where we find strong model support for a non-linear transformation for E. iheringii but also find support (although weak) for a non-linear transformation for E. catenatus. We also generate landscape-wide maps of predicted genetic diversity for both target species. We find that genetic diversity predictions for the E. iheringii correspond with predicted patterns of range stability, while predictions for E. catenatus are distinct from predictions of range-wide stability.