Des relations existent entre la pluviométrie et les autres facteurs écologiques de la région de Djelfa (Algérie). Des liaisons linéaires non significatives existent également entre la série des variables climatiques (la température, l'amplitude diurne et la pluviométrie ayant la plus grande variabilité) et la série des variables du marché (prix et offre). En effet, l'offre et le prix des différentes catégories de mouton sur le marché de gros de Djelfa sont sujets à des variations saisonnières qui expriment des corrélations positives ou négatives d'autant moins marquées que les coefficients de corrélation (r) ne sont pas voisins de -1 ou de + 1. On sait, par exemple, que dans les périodes de sécheresse, la tendance est d'anticiper les ventes afin de se prémunir contre la dépréciation excessive. À l'inverse, suite à des hausses jugées excessives en cours d'année, l'acheteur peut différer son achat en attendant que le prix retombe à des niveaux jugés raisonnables avec un retour à la normale du climat. Il semble donc que les systèmes d'élevage du milieu étudié peuvent raisonnablement pallier les handicaps suscités par les variations climatiques de courte période grâce aux différentes mesures antirisques mises en oeuvre au niveau des systèmes de production de mouton.
Abstract
Impact of climatic fluctuations on pastoral livestock prices on the bulk market of Djelfa (Algeria)In Algeria, the majority of pastoral livestock production systems are located in the steppe, in particular in the Djelfa region (Algeria). Pastoral livestock production systems with a variety of characteristics have been developed in response to agro-ecological opportunities, demand for livestock commodities and remote social pratices (three pastoral livestock production systems are identified). The main livestock product of the region, red meat, is primarily directed towards the domestic market through the large market of Djelfa. The conclusions which emerge from this study can be formulated as follows: i) The coefficients (CV) for the series of climatic variables, in particular rainfall (CV=17.59 to 82.70%), fluctuate more than those of market variables (CV =8.92 to 24.74%) and the CV rainfall level shows the widest gap among the climatic factors: CV rainfall=82.70%, CV (temperature and daytime temperature amplitude)=17.59 to 49.60%); ii) In 2002, the averages of daytime temperatures and temperature amplitudes were respectively lower and higher than the seasonal norms, in particular at the end of winter. In spite of this situation, the offer on the market and price of the animals fluctuated less than the monthly or seasonal climate factors due to the various specific strategies of each pastoral livestock system and the seasonalities of the activities of sheep farming and croppping; iii) Apart from those of the teg, the price and destocking of female animals were somewhat more sensitive to the differences than the others (CV females=16.80 to 22.65%, CV males=13.83 to 15.33%) though there were no significant correlations; iv) In general, there are n...