An integrated analysis of species richness and response traits highlights the functional vulnerability of liverworts along the entire elevational gradient in Colombia

Investigating diversity patterns along elevational clines brings important insights about the responses of biodiversity to environmental changes, with implications for conservation actions. We analysed the species richness and functional patterns of liverworts along the entire elevational gradient (0-5000 m) in Colombia. Published data on elevation ranges and reproductive and morphological traits related to ecological strategies of 705 species of liverworts were compiled. The elevational gradient was divided into 100-m vertical bands. General linear and additive models were used to investigate trends in liverwort richness. The richness of functional entities and functional diversity (Functional Redundancy, Functional Over-redundancy and Functional Vulnerability) were evaluated along the elevational gradient. A unimodal hump-shaped pattern was observed for species richness and functional diversity, with the highest values recorded at intermediate elevations (2000-3000 m). The most representative reproductive and morphological traits explaining the functional differentiation were the presence of monoicous and dioicous reproductive system, lobules, and gametophyte types. We found a high functional vulnerability in high Andean areas (>4000 m), where functional entities were dominated by a single species and the most relevant traits were life forms tolerant to high humidity and dark pigmentation. The ability of liverworts to respond to specific environmental filters underscores the importance of conserving these plants and their ecosystems along the elevational gradient. Conservation actions in this sense are essential to safeguard biodiversity and preserve essential functions in these vulnerable high-mountain environments.