association between fresh water snails, macrophytes and water quality in different water courses in Egypt

ABSTRACT

The pattern of association between freshwater snails and macrophytes in relation to some water quality parameters were studied in 258 sites representing the Nile River. main branches, canals and drainages in Menia. Giza. Helwan, Cairo. Qalyubiya, Esmailia. Behaira and Damietta Governorates during May 2008 - March 2009. The survey study collects 15 aquatic plant species and 13 snail species. Statistical analysis showed high significant correlation between snails and plants [r = 0.462]. The examined sites were divided into four categories, sites with plant only [20%], sites with snails only [7%], sites free from both plants and snails [9%] and the biggest category which include sites with both plants and snails [64%]. Results showed that free sites characterized by the highest concentrations of cadmium, lead, mercury, sodium and potassium. Plant sites were characterized with the highest concentration of dissolved oxygen. Snail sites characterized with highest concentration in calcium. Sites in which snails associated with plants were characterized with higher ranges of chemicals, dissolved oxygen and conductivity than that observed in sites with snails only and this indicates the helpful role of plants for increasing snail tolerance to unfavorable conditions