Contribution à l’étude de la diversité des vers de terre dans les régions de Ain Roua et El Ouricia

Abstract

This study was conducted in the Wilaya of Sétif, specifically in the regions of Ain Roua and El Ouricia, with the aim of evaluating the diversity, identification, and density of earthworms. Fifteen soil samples were collected from various zones (agricultural lands, mountainous areas, and river zones). The methodology focused on analyzing certain edaphic parameters, notably pH and electrical conductivity, to determine their influence on the distribution of earthworms.The collected data were subjected to statistical processing, including the Shannon index, Chi-square test (X²), and Principal Component Analysis (PCA). The results showed that the substrate in both regions is alkaline, with more or less similar pH values. Electrical conductivity varied according to the soil types: it was very high in the agricultural zone of El Ouricia, high in the agricultural land of Ain Roua, moderate in the mountainous area of Ain Roua, and low in the river zone of Ain Roua.Regarding biological identification, two species of earthworms were recorded at all stations: Aporrectodea rosea and Aporrectodea trapezoides, both belonging to the family Lumbricidae, with variations in eco-morphological categories depending on environmental conditions. The calculated Shannon index yielded a value of 0.86, indicating low diversity. The PCA results indicated that the occurrence and abundance of species are influenced by soil pH. These findings suggest that the agricultural soil in the Ain Roua region offers more favorable environmental conditions for the establishment of earthworms. More in-depth studies are strongly recommended for a better understanding of this category of organisms, which remains poorly known in Algeria.