Trends and drivers of land cover changes in a tropical urban forest in Ghana

Abstract

This study employed a mixed-methods approach to investigate the trends and drivers of land use and land cover changes from 1991 to 2015 in an urban forest reserve in Ghana. The specific objectives were to: i) determine the extent of land cover changes in the urban forest, and ii) ascertain the factors driving land cover changes in the urban forest. The study employed Landsat satellite images using ENVI to detect trends of land cover changes from 1991 to 2015. A questionnaire survey was used to solicit information on the socio-economic drivers of land cover changes from households in four fringe communities of the urban forest. The results showed that built up and bare areas recorded an increase between 1991 and 2015, with a decline in forests as well as shrubs and grasslands. The study showed that, forest decreased from 387.83 ha in 1991 to 341.28 ha in 2015, indicating a class change of 12.0%. Shrubs and grassland also decreased from 24.56 ha in 1991 to 11.77 ha in 2015, representing a class change of 52.1%. Built-up and bare areas changed from 36.278 ha in 1991 to 95.618 ha in 2015, representing class change of 163.57%. Overall, the study established that 59.34 ha of the Achimota Forest Reserve has been lost or converted to built-up and bare areas between 1991 and 2015. Study respondents identified urbanisation as the most important cause of land cover change. Other factors driving land cover changes reported included fuel wood harvesting and logging, agriculture, lack of forest guards, a lack of enforcement of laws on forest and annual fires. Based on these findings, the study concluded that human activities were driving considerable land cover changes in the urban forest. These changes could have significant implications for the long-term sustainability of the urban forest. Therefore, the study recommended that government takes steps to protect the urban forest from further land cover changes, as built up and bare areas have increased by more than double its size since 1991.