Pollen approach and evolution of the floristic biodiversity of the humid and salty zone of the Fetzara lake (Northeast of Algeria)

Abstract

The study of pollen grain deposits in two transects of Fetzara lake (North/East of Algeria) was confronted with the floristic environment cover. This study required an inventory of vegetation (264 species) supported by archival documents (ancient botanical studies) and pollen analyzes (86 taxa). A total of 12 surface pollen samples was collected, then, chemically treated according to the standard method. Percentages of pollen were calculated in all samples. The results have showed that the current deposits palynomorphes in lake surface sediments reflect the regional vegetation of the watershed. The differential distribution indicates a dominance of nonarboreal pollen (52%) represented by the Asteraceae, Poaceae and Asphodelaceae on two transects. This reflects the current state of the vegetation cover, further, the presence of Alnus probably comes from the wet complex Guerbès Sanhadja, while that of Pinus, Quercus and Pistacia come from the bushes and the degraded subery of the Edough. The dominance of halophyte species such as Suaeda maritima L. and Salsola soda, as well as pollen from Chenopodiaceae, confirms the salinity of the environment. The richness of the site of aquatic and semiaquatic vegetation such as Typha domingensis (Pers.) Steudel, Juncus acutus L. and Myriophyllum verticillatum L. indicates the existence of water less than a wet period in the site. The study also showed the presence of a large amount of damaged pollen, probably related to poor conservation conditions and especially the moisture and desiccation phenomena that prevail on the surface of the soil.