CONTRIBUTION A L'ETUDE DE LA DYNAMIQUE DES POPULATIONS DES RONGEURS SAUVAGES DANS LA ZONE DE BISKRA

Abstract

We have conducted an eco-biological study on wild rodents (i.e., Sand Rat and Shaw’s Jird) in the Region of Biskra (semi-arid region in the south east of Algeria). We have sampled four (04) sites representing the Ziban Region (an alternate name for Biskra): Eastern Ziban (Branis and Sidi-Okba) and Western Ziban (Tolga, Hraichet, and Doucen). The choice is premised by the fact that these regions are rich in agriculture, and the rodents in question appear to pose potential threats to the economic activity and public health (namely, Cutaneous leishmaniasis). The rodents have been captured thanks to mousetraps; biometric measurements have been conducted in the aforementioned field sites. Subsequent laboratory testings on the collected dead rodents have been conducted at the Mohammed Khider University of Biskra. Edaphoclimatic differences of the sites under study as well as the proximity from agricultural fields have shown rodent population variations that present an affinity to being credited field ravagers. Statistical analyses with Principal Component Analysis (PCA) have shown the following findings: The Branis field site characterized by its cold climate and silty-clay soil shows a dominance of the sand rat (scientifically known as Psammomys Obesus). The Sidi-Okba field site characterized by its relatively humid climate and salty silty-clay soil shows the cohabitation of the two species Psammomys Obesus and Shaw’s Jird. Besides, the latter appears dominant in Hraichet field site, because this region is rich in bushy vegetation and silty-clay soil. Psammomys Obesus is clearly dominant in the Doucen field site in comparison with the other species of rodents. It is noteworthy to acknowledge that Psammomys Obesus is endemic and adapted to the surrounding biotope (characterized by considerably rich bushy vegetation and gypsum soil). Factors such as agro-system, relative humidity, soil, and vegetation have an impact on the wild rodent population dynamics, which affects the agro-systems of the oases.