Patterns of green space change and fragmentation in a rapidly expanding city of northern Ghana, West Africa

Abstract

Green spaces such as forests, grasslands, and croplands (including gardens) can be found in urban environments. Although they benefit human and animal well-being, they have become threatened due to rapid urban growth and unplanned development. Yet, little attention has been given to studying the dynamics of urban green spaces in sub-Saharan Africa. In this study, we examined the dynamics of land use and land cover (LULC) change and fragmentation (especially, green spaces) within the second fastest urbanising city in Ghana, Tamale. In particular, we focused our analyses on its urban core (∼5 km radius around the city centre) due to its relevance to urban economy and society. Landsat data was used to estimate fragmentation metrics of past and future LULC changes in the study area from 1990 to 2052. We found clear patterns of green space decline and fragmentation within the urban core: i.e., green spaces became patchy over time and the pattern was expected to continue in the future. Additionally, we found the built-up class benefited from the decline of green spaces with the latter being significantly negatively correlated with human population size. Our investigation reveals that protected forests and tree plantations contributed to a significant proportion of available green spaces in the urban core. However, these areas were becoming increasingly threatened by forest reserve downsizing, indiscriminate activities (e.g., logging and encroachment), and sale of public lands to private developers, practices commonly associated with population growth. Hence, the enforcement of relevant local legislations (e.g., the 2016 Land Use and Spatial Planning Act [Act 925]) coupled with the integration of urban initiatives and policies that encourage green spaces are needed to ensure the sustainability of urban ecosystems for the well-being of humans and the environment.