Assessment of Landscape Connectivity of Urban Green Infrastructure for Biodiversity Management in Ibadan

Urban Green Infrastructure (UGI) provides multiple benefits, but these are being greatly eroded by urbanization and declining connectivity, which threaten biodiversity in urban centres. This study therefore investigated the connectivity of green spaces in the Ibadan metropolis, Nigeria, using a combination of geospatial technology and landscape metrics. Landsat 5 TM, 7 ETM+, and 8 OLI-TIRS satellite imageries for 2000, 2005, 2010, 2015, and 2020 were used for land use/land cover change detection. Connectivity analysis was conducted with Fragstats metrics using seven indices: Number of Patches (NP), Mean Patch Area (AREA_MN), Mean Area Perimeter Ratio (PARA_MN), Mean Patch Contiguity Index (CONTIG_MN), Largest Patch Index (LPI), Percentage of Landscape (PLAND), and Area-Weighted Mean Patch Fractal Dimension (AWMPFD). The results showed that in 2000, the built-up area covered about 70.66 km² of the total land (51.97 %), whereas green areas covered about 51.17 km² (37.64 %). By 2020, the built-up area had increased from 51.97 % in 2000 to 69.04 %, to the detriment of other land uses, which decreased drastically over the years. Non-UGI areas accounted for 62.01 % of the total area in 2000 and increased consistently to 77.04 % by 2020. There was also a continual increase in the Number of Patches (NP) in green areas. The study established that UGI connectivity in Ibadan is inadequate, with CONTIG_MN declining from 0.41 in 2000 to 0.13 in 2020, while the Percentage of Landscape (PLAND) decreased from 10.62 in 2000 to 4.04 in 2020, indicating a high degree of fragmentation of green spaces. The findings therefore recommend halting the destruction of UGI in Ibadan to prevent further biodiversity loss and ecological decline in the city.