Heterogeneous trait responses of Páramo plant species and community to experimental warming.

Understanding the impact of climate change on the functional trait composition (and hence ecosystem functioning) of tropical alpine regions is critical for predicting biodiversity responses. We tested the effects of a decade of warming on the morphological, chemical and genomic traits of Páramo species using open-top chambers (OTCs). We conducted vegetation surveys and collected samples from individuals inside and outside the OTC plots to estimate differences between treatments (warming versus control). Vegetation cover decreased over time in both treatments suggesting a potential decline in soil moisture in our study area. Warming led to a reorganization of the trait space and trait network structure. Species showed a wide range of responses to warming, with significant changes across different trait combinations. Nevertheless, we did not find significant differences in trait values or the direction of change between species whose percentage vegetation cover increased in OTC (or decreased less) over time, compared with control. Community-weighted mean values of plant height, leaf area, leaf dry matter content, genome size, leaf C and P, significantly increased over time only in OTC plots (i.e. traits associated with carbon storage and decomposition). While warming and reduced soil moisture lead to heterogeneous species responses without a clear winning trait strategy, changes at the community level may have important implications for Páramo ecosystem functioning.