Assessing the impact of linear infrastructure on landscape connectivity: a worked example from South Sudan and Uganda

Human infrastructure development is a major cause of environmental fragmentation, which threatens biodiversity globally. Fragmentation and its consequences are particularly pronounced in developing countries, where rapid economic growth and infrastructure development often have devastating impacts on biodiversity and ecosystems. Strategies to halt biodiversity loss require the protection of ecological connectivity between areas of high conservation importance, but this is often overlooked in environmental planning and infrastructure impact assessment. In this study, we provided a worked example demonstrating how structural landscape connectivity can be integrated into the impact assessment of new linear infrastructure projects in two developing countries: South Sudan and Uganda. To achieve this aim, we (i) created macro-regional ecological networks under two scenarios, i.e. the present landscape and a future scenario that also includes the planned linear infrastructure, (ii) assessed future changes in landscape connectivity due to their implementation, and (iii) identified which linear infrastructure will pose the greater threat to ecological corridors and will impact the integrity of the ecological network. Specifically, we prioritized conservation areas with high biodiversity, threatened species and minimal human disturbance and identified the corridors connecting them. The impact of the planned linear infrastructure on corridors was assessed by quantifying the changes in connectivity between the two scenarios, both at the landscape level and in proximity of each linear infrastructure. The proposed approach could provide a basis for informing conservationists, policy makers and environmental planners in prioritising actions to maintain and restore ecological connectivity and promoting its inclusion in environmental planning and impact assessments.