Typologie fonctionnelle et taxinomique des pinèdes de l’Algérois et de l’Oranais (Algérie)

Abstract

Functional and taxonomic typology of pine communities in Algiers and Oran areas (Algeria). Standard measurements of biodiversity, such as those based on species diversity and abundance, do not take into account the ecological and evolutionary characteristics of species per se, and provide us with an incomplete understanding of the causes and consequences of changes in biodiversity. Communities of Aleppo pines Pinus halepensis Mill. are under study in two Algerian phytogeographical areas : Algiers’ subhumid and humid bioclimate, and Oran’s semi-arid bioclimate. The purpose of this study is to analyse the floristic diversity of various communities of Aleppo pines, and to provide a typology based on twin approaches : a taxonomic analysis of the flora, and an analysis of the plants’ functional traits in these two areas. Correspondence factor analysis (CFA) has been conducted in both cases, and the results have been compared and discussed. The taxonomic analysis brings out contrasting ecological descriptors (altitude, substrate, etc.) and explains the plants’ distribution in relation to their environmental factors, but reveals no significant difference between the two areas under consideration. The functional analysis allowed for the identification of the main functional traits in each of the areas under study, and helped us define several functional groups in each case. A comparison of the results in both sectors shows that the organization of the Aleppo pine communities under consideration is principled upon phytogeographical, altitudinal, and disturbance gradients. Standard ecological factors evidenced by the taxonomic approach cannot single-handedly explain the dynamics of the communities ; however, their functional traits have clarified and supplemented the flora’s history in these two areas.