Review on aquatic macrophytes in Lake Manzala, Egypt

Abstract

Lake Manzala is considered as an ecosystem of extreme importance to man and biodiversity. This article presents an overview on the different changes of Lake Manzala in terms of plant distribution, diversity, area of vegetation cover, in addition to the benefits and uses offered by such plants. Eleven aquatic macrophyte species dominated by Potamogeton pectinatus, Eichhornia crassipes, Pistia stratiotes, Phragmites australis, Typha domingensis and Echinochloa stagnina, were recorded in the Lake. As a result of climatic changes and human impacts, this Lake faced many environmental problems and intensive pressure that resulted in changing its ecological features, including the decrease in both bare lands (from 52.45 to 45.50%) and water bodies (from 28.19 to 19.32%), as well as the increase in the vegetation cover (from 19.36 to 35.18%) throughout the period from 1992 to 2019. After the beginning of the Egyptian government's development process at the northern and center sectors of the Lake, the inflow of saline water increased, the concentration of chlorophyll “a” decreased from 4.372 mg m−3 in 2015 to 3.725 mg m−3 in 2018, and water quality showed remarkable enhancement. However, the other parts of Lake Manzala were still suffering from the dense vegetation cover that affected its water quality. Aquatic macrophytes are considered as a massive source of raw material for the industrial production of paper pulp, biofuel and natural therapeutics, beside their effective role in their natural habitat and in the remediation of wastewater. Nevertheless, the rapid growth of macrophytes may cause many environmental problems. The data in this article give decision-makers options for achieving sustainability in future development projects related to Lake Manzala, as well as insights in the assessment and management of pollution in this coastal shallow lagoon.