XVI International Botanical Congess

Palynological analysis allow us to know some ecological conditions of a particular region. The aim of the study is to know the pollen rain patterns of plant communities along an altitudinal gradient between 150 û 3000 m, using correspondence analysis. There were analyzed 15 pollen rain samples of six vegetation types found in the north slope of the Sierra Norte of Oaxaca. The most abundant pollen grains in the palynological spectra were: Pinus, Alnus, Quercus, Hedyosmum and Asteraceae. Other pollen types were frequent through the gradient sampled. The ordination of sites and species, give us an overview of the ecological conditions in function of the axis obtained, in this case the axis 1 could be correlated with annual rainfall or annual average temperature and the axis 2 with disturb intensity.