Dynamics in the Landscape and Ecological Services in System I Drainage Area of Lagos

Abstract

The study examines the implications of urban land uses on hydrological processes and ecological services in system I (OdoIyaAlaro Channel) of the Lagos Drainage Master Plan. Aerial Photography (1965) and Ikonos 2 Imageries (2008 and 2014) were used to assess the land use and land cover changes in a GIS environment. A field survey was carried out to identify plant and fish species within the wetlands. Land use-land cover changes for 1965, 2008 and 2014 show that about 80% of the area has been built-up. Based on environmental change projections using precipitation and land use drivers, it is expected that runoff and peak flow will increase by 6.34, 14.24, and 20.36% for a 50 year medium climate change, a 50 year high climate change and a 100 year high climate change respectively. Some of the flora expected to be lost from the wetlands and creeks based on land use changes include Thuja sp and Ficus sp. This would affect some of the ecological services offered by these plants. Effluent discharge from industries is also putting the fish supply at risk, as species such as Sarotherodo nmelanotheron and Liza falcipinnis are reducing. The study advocates a conservation approach for sustainable urban land use.

Keywords: Land Use-Land Cover Change; Wetland; Ecosystem; Urbanisation; Watershed