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.

Dispersal ability is a key determinant of the realized species niche. Yet, whether dispersal ability influences environmental specialization and exerts a direct, indirect, or null effect on species' tolerances is still unclear. Here, we ask whether and how dispersal ability can shape both the realized and fundamental niches. Focusing on plants, invertebrates, and vertebrates of the topographically complex Atlantic Rainforest, a top global biodiversity hotspot, we further evaluate how dispersal ability correlates with species range shifts in response to climate change. We find that high-dispersal species have broader thermal tolerances relative to low-dispersal taxa. When projected in geographic space, the data predict widespread upslope range shifts of the Atlantic Rainforest biodiversity with the intensity and direction depending on the species-specific trends depending on dispersal ability. These upslope movements, in turn, may negatively impact the native communities intrinsically associated with the Atlantic Forest mountaintops. Under the warmest climate scenario predicted for the end of the 21st century, the models project that those species with the lowest dispersal ability, particularly low-dispersible ectotherms, will be the most impacted by local extinctions. In turn, the wider thermal tolerance of high-dispersible species will reduce shifts in their geographical range due to climate change. Given the rapid rate of habitat conversion experienced by this and other landscapes worldwide, we argue that the smaller endurance of low-dispersible species to environmental changes deserves special attention, as dispersal ability appears relevant for biodiversity management in a warmer world, especially in threatened species-rich regions such as this.