Abstract ID: 3.13112 | Not reviewed | Requested as: Talk | TBA | TBA

Studies on how functional characteristics of plant communities respond to elevation and the associated climatic gradient have so far been spatially restricted and performed over single slopes or mountain ranges. These studies also vary in their designs, objectives and coverage of traits sampled. Here we present the first global study of community trait patterns (including community mean traits and functional diversity of the community) along elevational climatic gradients in natural vegetation and disturbed roadside habitats. Moreover, we analyze how functional changes in response to climate differ between communities when considering native plant species versus all community members. To do so, we compiled a unique database of primary data, including standardized vegetation surveys and in-situ trait collection from over 1000 species (within the scope of the Mountain Invasion Research Network) in 18 mountain ranges around the world. We measured nine key functional traits related to resource acquisition and growth, then calculated community weighted trait means and five measures of functional diversity. We observed a switch from conservative plant communities in natural habitats to acquisitive in roadside habitats, which was further enhanced by the presence of non-natives. Whereas, plant size economic traits were driven by abiotic characteristics (i.e., elevation and habitat type) rather than non-natives. The presence of non-natives reduced functional diversity, and this reduction was particularly noticeable in roadside habitats. Higher elevations are associated with communities with smaller plants and host lower functional richness. Press disturbance in roadside habitats seems to facilitate the introduction and spread of non-native plants, and likely selects for acquisitive plants, thereby reducing functional diversity. Our models explain three quarters of the variation in global functional traits, and 60-86% of the variation in functional diversity measures. Our results corroborate a growing body of literature showing that non-native plants alter native community structure in plant communities, we extend this to show that functioning is also reduced. We present how these relationships change regionally. Our results provide a baseline for predicting how plant communities respond to the interactive effects of global change drivers.