based on elevation and vegetative structure, with the three main types of páramo vegetation unequally distributed throughout different zones. , more than 3,000 plant species have been discovered in the páramo. Superpáramo is at the highest elevation and is usually considered to be the transition zone between the higher, permanent snow region and the lower grass páramo zone. The superpáramo zone is generally narrow and exists atop loose stones and sandy soils at about . It has the lowest air temperature, precipitation level, soil water-holding capacity, and nutrient content of all the zones. Being the highest in elevation, it also has the highest levels of solar radiation and night frost. For this reason, vegetation in the superpáramo must be highly resistant to such severe fluctuations in weather. Air temperatures are low—cold at night and cool during the day—with daily oscillations greater than the oscillations of monthly averages. Due to its localization on high mountains, this area is the least disturbed by humans and contains the most endemic species of all the zones. Flora includes Azorella pedunculata of the family Apiaceae and species from the families Asteraceae, Fabaceae, and Ericaceae. The most broadly described zone is the grass páramo. Grass páramos cover large areas of mountain ranges, while others are limited to small areas on slopes and summits of very high mountains. The term páramo is sometimes used to refer to this specific type. It has continuous vegetation and plant cover with a "yellowish to olive–brown" look due to the combination of dead and living grasses. The grass páramo extends from approximately , and is composed of mostly tussock grasses. Calamagrostis intermedia and other grasses of the genera Calamagrostis and Festuca tend to dominate this zone. Other common vegetation includes large and small shrubs, stunted trees, cushion plants, herbs, and rosette plants. While these are the dominant species, grass páramos can also contain tall- and short-grass communities, including herbaceous and woody vegetation. Due to its easier access and high levels of grass, this zone is more impacted by humans and suffers from both burning and grazing activities. Subpáramo is the lowest and most diverse zone. At , it is a shrub-dominated zone that combines aspects of both the grass páramo above and the forest below. Along with shrubs, this zone also contains small, scattered trees which gradually transition into the grasses and herbs of the grass páramo above. Plant communities in