Aim

The vulnerability of montane species to environmental change has been increasingly recognized over the past decade. However, most of these species are regionally endemic with restricted ranges, limiting dispersal necessary for avoiding extinction. Threats posed for montane lizards could be further complicated in species following Bergmann’s rule, where body size increases with altitude. In this study, we applied a bioclimatic and body mass trait-based species distribution model approach to identify areas suitable for montane endemic skink species of the Cameroon Volcanic Line (CVL) under current and future climates.

Location

Cameroon Volcanic Line

Methods

We recorded occurrence records and measured body mass in the field for skink species endemic to the CVL. We additionally supplemented our occurrence data with records from an online repository. We projected habitat suitability in the region by implementing the occurrence data in the bioclimatic species distribution models. We further integrated both occurrence and body mass information in our trait-based model to project potential body mass.

Results

Projected currently suitable ranges were limited to higher elevation regions, which are inhabited by numerous other threatened amphibian and reptile species. We found that, for our two skink species following Bergmann clines in body mass, trait model predictions covered a slightly larger geographic range than bioclimatic estimates. Under future warming, both models predict substantial contractions in suitable areas, potentially constraining species to mountain tops. Through the trait-based approach, we further detected potential warming-induced body mass reductions in projected suitable areas.

Main conclusions

We thus demonstrate how combining occurrence records with species trait information in predictive modelling can reveal complementary trends for more comprehensive climate change impact assessments. Overall, these challenges towards the persistence of CVL-endemic skink species should prompt urgent responses in national conservation management and local community engagement.

We recorded location (as GPS coordinates) and morphological measurements of skink species found on the mountains of the Cameroon Volcanic Line. We additionally downloaded location data from GBIF for these species to supplement our own dataset.