Insights into the functional ecology of páramo plants in Colombia

Paramos are exceptionally species-rich tropical alpine ecosystems that provide several important ecosystem services, including carbon storage and water provision. The responses of paramo plant species to climatic change are largely unknown, but classifying species by functional type and ecological strategy can help reduce complexity for modeling and conservation efforts. We measured 22 traits in 42 plant species with various growth forms in the Colombian Andes. We classified plant ecological strategies using CSR (C: competitor, S: stress tolerator, and R: ruderal) analysis and identified plant functional types (PFTs) using hierarchical clustering of principal components. Additionally, we calculated the functional originality of each species to identify species with unique trait combinations. We identified a high degree of convergence among traits and strategies, with most species characterized by the S and SC strategies. Considering the full set of traits, only three PFTs were identified: one composed of forbs and shrubs with tender leaves (PFT1), another composed only of species with rosettes form (PFT2), and a third composed of shrubs with tough leaves (PFT3). Values of functional originality were generally low, suggesting high redundancy in plant traits. PFT2 species, mostly rosettes, exhibited the highest functional originality of all the groups. Our results imply the existence of a limited set of ecophysiological strategies in the paramos, likely driven by the extremely stressful conditions in these systems. This functional redundancy may indicate heightened vulnerability to environmental changes; however, the presence of multiple species with shared functional traits could provide some resilience to disturbance.