Les perturbations climatiques et leurs incidences possibles sur l'ecosystème forestier de la Mahouna Guelma

Abstract

Mediterranean ecosystems are considered paricularly sensitive to climate change. Any change of climatic factors affects the structure and the functioning of these ecosystems and has influence on the plant productivity. The main objective of this work is to characterize one of the Mediterranean ecosystems; the forest of the Mahouna (located in the North East of Algeria) in point of view of edaphic, vegetation and their climate link using meteorological data (precipitation and temperatures for a period of 30 years) and satellite imagery for the period from 1987 to 2015. The analysis of vegetation enables to determine 46 botanical families with dominance of phanerophytes and therophytes, which grow on rich soils in organic matter, with an acid pH, variable texture from sandy-loamy, silty-sandy to clay or very clay at different places. The diachronic study of this massive shows a reduction in the area of plant cover in the order of 1.97%. The climate analysis indicates an increase in the monthly average maximum temperatures, with a highly significant warming of 0.12 ° C for the spring season and the rainfall is variable from one year to another and tends to a more and more dry years . The three-hours thermal data for the period from 2000 to 2010 highlights 502 days of cold stress and 373 days of heat stress, affecting plant productivity, where there was a decrease in NDVI values of vegetation exposed to thermal stress periods.