Study of the lichens of the Moroccan atlantic coast Safi-Essaouira: Bioindication of air quality and limiting factors

Abstract

In order to estimate the global air pollution of the Moroccan Atlantic coast Safi-Essaouira, we have used a qualitative approach based on the spatial distribution of saxicolous-calcicolous lichens that reflect special ecological and pollution conditions. The measurement of the beta diversity by the calculation of the Jaccard index makes it possible to quantify the similarity between the studied sites and has made it possible to measure the gradient of change of this diversity along an increasing gradient of the pollution supposed high in the industrial zone of the Safi city and decreasing going north or south. The hierarchical clustering has made it possible to partition the seven studied sites into two different classes and differentiate four groups of indicator species of poleotolerance and eutrophication. The identification of 36 species of lichens including indicator species of SO2 and NOx pollutions, the study of the impact of climate and pollution on the lichens biological spectrum, and the exploitation of the poleotolerance index and eutrophication index were necessary to elucidate the global air quality of the region.