Plant functional diversity across two elevational gradients in serpentine and volcanic soils of Puerto Rico

Abstract

Mountains are model systems for understanding the mechanisms that underlie patterns of biodiversity and ecosystem function. This study disentangles the effects of climatic and edaphic properties on patterns of trait variation across two mountains, tests foundational assumptions of trait-based approaches, and tests the stress dominance hypothesis of decreasing trait variation with increasing environmental stress. The results suggest that elevation as a proxy of abiotic conditions is not enough to generalize the variability of plant strategies across mountains. The ability to distinguish trait variation in different environments depends on the type of trait used, due to variable strength of trait-environment relationships. These results suggest that trait-environment relationships may vary in predictable ways across environmental gradients. Even though serpentine plant communities were more functionally dispersed compared to volcanic communities (contrary to the stress dominance hypothesis), this can be explained by complex interactions between climatic and edaphic properties.

Mountains are model systems for understanding the mechanisms that underlie patterns of biodiversity and ecosystem function. This study disentangles the effects of climatic and edaphic properties on patterns of trait variation across two mountains, tests foundational assumptions of trait-based approaches, and tests the stress dominance hypothesis of decreasing trait variation with increasing environmental stress. The results suggest that elevation as a proxy of abiotic conditions is not enough to generalize the variability of plant strategies across mountains. The ability to distinguish trait variation in different environments depends on the type of trait used, due to variable strength of trait-environment relationships. These results suggest that trait-environment relationships may vary in predictable ways across environmental gradients. Even though serpentine plant communities were more functionally dispersed compared to volcanic communities (contrary to the stress dominance hypothesis), this can be explained by complex interactions between climatic and edaphic properties.