Assessment of Land Use/Land Cover Change and Morphometric Parameters in the Keta Lagoon Complex Ramsar Site, Ghana

Eric Duku,Precious Agbeko Dzorgbe Mattah,Donatus Bapentire Angnuureng

doi:10.3390/w13182537

Abstract

The rapid urbanization, industrialization, agricultural activities, and increasing trend of some natural hazards, such as climate change, particularly in coastal areas, necessitate the continual assessment of critical but fragile ecosystems like that of the Keta Lagoon Complex Ramsar Site (KLCRS). This productive ecosystem in Ghana faces serious threats from intensive exploitation, physical modification, changes in water regime, and water pollution. The current study employed geospatial and intensity analysis to assess the pattern of land use/land cover (LULC) change for almost the past three decades and morphometric parameters of the KLCRS landscape. Landsat Satellite images for 1991, 2007, and 2020 were acquired to uncover the pattern of LULC change, while morphometric changes were assessed using global Advance Space Thermal Emission and Radiometer (ASTER) digital elevation model (DEM) data and the spatial analyst tools in GIS software. The result established that the acceleration of land transformation was intensive between 2007 and 2020, which could be linked to population growth and increased socio-economic activities. There was a net gross gain of built-up that originated largely from the conversion of marsh, dense vegetation, and cultivated land. Prior to this period, cultivated land recorded net gain (125.51 km2) between 1991 and 2007, whereas dense vegetation and marshland showed a net loss of 151.37 km2 and 2.44 km2, respectively. The gain of cultivated land largely targeted marshland in both time intervals. The construction of saltpans contributed largely to the small increase in water extent. The morphometric analysis revealed the groundwater potential of the KLCRS. The low-lying nature of the landscape makes the area susceptible to coastal flooding. The trend of the observed changes could invariably affect the ecological integrity of the landscape, hence suggesting the need for immediate preparation and implementation of marine and coastal spatial plans by relevant stakeholders.

Highlights

Introduction iationsWetlands are permanent or temporary areas of swamps, marshes, peatland, and fens, including marine areas with a depth not exceeding six meters at low tide [1]
These matrices further present the area of gross loss and gain of each land use/land cover (LULC) category for the two-time intervals (1991–2007 and 2007–2020) and the persistence indicated by the land (387.36 km, 28.10%) and water (291.07 km, 21.11%) The proportion of Keta Lagoon Complex Ramsar Site (KLCRS) land area covered by cultivated land, bareland, and the built-up area was 7.59%, 4.97%, and
Our findings reveal that the natural LULC categories dominated the landscape of KLCRS in all the three time points

Summary

Introduction

Introduction iationsWetlands are permanent or temporary areas of swamps, marshes, peatland, and fens, including marine areas with a depth not exceeding six meters at low tide [1]. Even though wetlands occupy a small portion of the earth’s landscape, they are one of the most valuable natural resources in the world. They provide numerous ecological and socioeconomic benefits that support human livelihoods and wellbeing [3]. In terms of ecological services, the wetland ecosystem is only comparable to rainforest and coral reef ecosystems [4] These services, such as carbon sequestration, nutrients and pollution retention, protection of human settlements from flood, groundwater recharge, and provision of habitat for a rich variety of flora and fauna, are reported by several studies [1,5,6,7,8,9,10,11].

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Results

Discussion

Conclusion