An analysis of modern pollen rain on an elevational gradient in the High-Andes of Central Chile (33°)

Abstract

The superficial pollen records are tools for the vegetal reconstruction of a certain area. Like a plant record, pollen can be used to classify plant formations and determine plant diversity. Although some studies show the relationship between pollen and vegetation in Chile, few have explored the pollen diversity in an altitudinal gradient and its sensitivity as a marker of altitudinal belts. Consequently, we used pollen samples of surface soil and by means of morphological identification, cluster analysis and zonation we determined the pollen groups that represent the vegetation floors in an altitudinal gradient. Moreover, we compared pollen diversity among these floors for three basins of the Chilean Central Andes as a comprehensive index of the pollen composition and abundance. In the Laguna del Viento basin, four pollen groups coincided with the plant floors previously defined in the literature: sub Andean, Andean, and High Andean. The latter one was subdivided into two groups. In the El Yeso basin, two pollen groups were determined, all corresponding to the Andean floor, and finally in the El Volcán basin, two pollen groups were recorded that are related to the sub Andean and Andean vegetation floors. On the other hand, only in one basin the pollen diversity decreased with the altitude. These results showed that pollen assemblages can distinguish plant floors, but with a lower resolution than when using established flora, probably due to the pollen taxonomic resolution, differential production and dispersal factors.