High Andean grasslands or paramos are considered key ecosystems because of their role to provide and sustain fundamental ecosystem services. Paramos are essential ecosystems for water regulation and carbon reservoirs. Paramos sustain the highest levels of plant diversity among high mountain grasslands in the world. Plant species in this ecosystem are adapted to low mean annual temperature and to extreme changes of daily temperature. Thus, plants exhibit certain characteristics adapted to strategies of resource conservation (e.g., low specific leaf area, long lifespan, small stature, sclerophyllous leaves). These plant characteristics or plant traits could explain patterns in how paramo plant communities structure. Specific leaf area (SLA) and plant height were selected as traits related to resources availability, carbon gain, and plant growth. Here, I studied the intra and interspecific trait variability of vascular plant species registered in small plots of 1 square meter in four paramos located in the southern and eastern Cordillera of Colombia. I focused in how mean trait values and the intraspecific trait variability influence patterns in aboveground biomass, in the abundance and distribution of paramo plant species, and in successional changes. The studies presented in this dissertation are among the firs attempts to systematically collect quantitative information of functional plant traits in the paramo of Colombia at community level. Here, it is shown the significant relationship between the community structure and successional patterns of paramo vegetation and the mean and variability of SLA and plant height of paramo plant species.