The water hyacinth ( Eichhornia crassipes solms) in the Nile system, Egypt

Abstract

Eichhornia crassipes was recorded in Egypt in the last decade of the 19th century, but it did not reach the plague proportions exhibited in the Nile Delta until recent times. The construction of a series of river control schemes caused several ecological changes in the Niel system, which encouraged the growth and spread of Eichhornia in almost all the aquatic habitats in the Nile system. The present study shows clearly the fast growth of Eichhornia in the Egyptian Nile system. A plantlet with 450 cm 2 basal area, 40 g fresh weight and 7.4 leaves, attained a basal area of 1.0827 m 2, fresh weight of 1.244 kg and had 208 leaves after 50 days in a drainage ditch (from September 6th to October 26th, 1973). During that period, a plant would produce about 43 new offsets on the average. The consequences would be disastrous if an Eichhornia plant reaches the open water reservoir of Lake Nasser. Such a plant, after 200 days during the growing season, would produce 3, 418,800 new offsets with an area of 14, 928 m 2. In winter, the plant growth is very slow and even death and decomposition of some parts of the plant occur.