Forest fragmentation in a forest Biosphere Reserve: Implications for the sustainability of natural habitats and forest management policy in Ethiopia

Abstract

Forest fragmentation is a landscape-level process that comprises forest loss and changes in spatial patterns. Effective forest conservation programs thus require a comprehensive understanding of the relationship between forest cover and the spatial patterns of forest fragments. However, these matters remain less known for ecosystems in tropical regions. Hence, the study examines forest fragmentation of the Kaffa Biosphere Reserve in Ethiopia, which is a forested ecosystem of 744.9 thousand hectares. The study covers 33 years from 1986 to 2019 and forecasts for 2034 and 2049 using Landsat imagery. The land-use and land cover change maps were produced using a supervised classification following the maximum likelihood approach. The study quantified the spatial and temporal trends in forest loss and fragmentation using a multi-temporal satellite and FRAGSTAT raster dataset. The results display the forest areas declined from 46.9 to 30.5% from 1986 to 2019. The fragmentation caused an increase in the number of forest fragments from 4,067 to 8,832 from 1986 to 2019 but is expected to decline to nearly 2,000 in 2049 due to the complete conversion of small size forest fragments into other land use types. In addition, the size of the large core forest areas reduced from 43.7% in 1986 to 6.1% in 2019. The edge density of the forest declined from 30.5 to 27.1 m/ha from 1986 to 2019 and declined to 13 m/ha in 2049. The results confirmed natural and anthropogenic processes (e.g. agricultural and built-up area expansions and road network development) caused forest fragmentation and degradation in the Kaffa Biosphere Reserve. Therefore, the policy-makers should look at new options and revised the existed natural resource conservation strategies to safeguard the remaining natural forest covers.