1. EFFECTS OF VEGETATION AND WATER SEASONAL VARIATION ON HABITAT USE OF HERONS (AVES, ARDEIDAE) IN TONGA LAKE (NORTH-EAST ALGERIA). Authors: SOUMIA DJAMAI, FATEH MIMECHE, ETTAYIB BENSACI, AHLAM CHETTIBI.2. SURFACE WATER QUALITY ASSESSMENT IN SEMI-ARID REGION (EL HODNA WATERSHED, ALGERIA) BASED ON WATER QUALITY INDEX (WQI). Authors: AMEL FERAHTIA, MOHAMMED TAHAR HALILAT, FATEH MIMECHE, ETTAYIB BENSACI.