The primary objective of this study was to investigate patterns of abundance and diversity among reptiles and amphibians within the protected area of Mount Chelmos, located in Peloponnese, Greece. Our aim was to examine the drivers influencing abundance (for lizards, snakes, chelonians, anurans, urodels) and diversity (for reptiles and amphibians) within the finely-scaled study area and identify biodiversity hotspots. Land cover significantly impacted the abundance and diversity of all studied groups. Elevation had a significant impact on the abundance of snakes, chelonians, and anurans, as well as on reptile and amphibian diversity. Climate influenced all groups except chelonians. Slope significantly impacted anuran abundance and amphibian diversity. Aspect primarily influenced the abundance of lizards, anurans, and urodels, as well as reptile diversity. We have also identified abundance and diversity hotspots, emphasizing the importance of conservation and management efforts. In reptiles, abundance hotspots were predicted in the west, east, and south of the mountainous massif, whereas amphibian abundance hotspots were mapped to the west and east-southeast of the massif. Regarding diversity, the patterns were similar for both reptiles and amphibians, with hotspots emerging in the west, south, and southeast boundaries of the study area, and a few spots north of the mountainous region. Notably, many of these hotspots coincided with areas susceptible to human exploitation and vehicular transit.

Understanding how environmental conditions shape the functional composition of ecological communities is a central goal in community ecology. In this study, we apply this framework to the reptile and amphibian assemblages within Greece’s Mount Chelmos protected area. Based on comprehensive field surveys (2018–2021) across 168 sampling stations, we compiled species trait databases and quantified functional diversity using a corrected Rao’s Q index. We modeled the response of functional diversity to climate, land cover, topography (altitude, slope, aspect), geographic location, and taxonomic diversity, using Generalized Additive Models (GAMs). Additionally, we examined traitspace structure via PCA and evaluated environmental drivers of trait composition with multivariate GAMs. For reptiles, functional diversity was significantly affected by altitude, climate, and aspect, with higher values predicted in water-associated marginal zones surrounding the mountain massif. Traitspace analysis revealed clear ecological structuring along axes related to locomotion, body size, reproductive mode, foraging strategy, and substrate use, shaped by distinct combinations of environmental filters. In amphibians, environmental effects on functional diversity were not statistically significant; however, traitspace showed discernible responses to land cover, climate, and aspect, suggesting weaker—though detectable—filtering processes. Collectively, our findings indicate that Mount Chelmos functions as a system that modulates diversity, with environmental filters operating at fine-to-medium spatial scales to shape the functional composition and diversity of its herpetofauna.