Estimating the Environmental Costs of Africa’s Massive “Development Corridors”

Abstract

In sub-Saharan Africa, dozens of major "development corridors" have been proposed or are being created to increase agricultural production [1-4], mineral exports [5-7], and economic integration. The corridors involve large-scale expansion of infrastructure such as roads, railroads, pipelines, and port facilities and will open up extensive areas of land to new environmental pressures [1, 4, 8]. We assessed the potential environmental impacts of 33 planned or existing corridors that, if completed, would total over 53,000 km in length and crisscross much of the African continent. We mapped each corridor and estimated human occupancy (using the distribution of persistent night-lights) and environmental values (endangered and endemic vertebrates, plant diversity, critical habitats, carbon storage, and climate-regulation services) inside a 50-km-wide band overlaid onto each corridor. We also assessed the potential for each corridor to facilitate increases in agricultural production. The corridors varied considerably in their environmental values, and many were only sparsely populated. Because of marginal soils or climates, some corridors appear to have only modest agricultural potential. Collectively, the corridors would bisect over 400 existing protected areas and could degrade a further ~1,800 by promoting habitat disruption near or inside the reserves. We conclude that many of the development corridors will promote serious and largely irreversible environmental changes and should proceed only if rigorous mitigation and protection measures can be employed. Some planned corridors with high environmental values and limited agricultural benefits should possibly be cancelled altogether. VIDEO ABSTRACT.

Agriculture production as a major driver of the Earth system exceeding planetary boundaries

“…Development corridors are seen as a way of transforming agriculture in developing countries to higher levels of productivity. These development corridors risk major fragmentation and occupation of existing forests, especially in the tropics, with potentially disastrous consequences for biosphere integrity (Laurance et al 2015). Climate change and habitat fragmentation are facilitating the spread of exotic invasive species into natural habitats at an unprecedented level with alarming consequences for biodiversity and ecosystem function.…”

From local scenarios to national maps: a participatory framework for envisioning the future of Tanzania

“…In the BAU scenario, lack of improvement in productivity and agricultural practices is expected to affect local food security in the next decades (MAFAP 2013, URT-MAFSC 2013) and/or induce vast LULCC, with commensurate impacts on water and climate regulation, biodiversity (Green et al 2013, Kideghesho et al 2013, Caro and Davenport 2015 and livelihoods (URT 2011). Expansion of large-scale international commercial farming may play a critical role in the next decade (Rulli et al 2013, Laurance et al 2015. A review of investment policies in Tanzania (OECD 2013) largely confirmed the regional stakeholders' vision that land tenure insecurity and a heavy bureaucratic burden have discouraged foreigner investors to date, and thus slowed the implementation of development corridors championed at national scale.…”

Assessing large-scale wildlife responses to human infrastructure development

“…However, large-scale consequences of these trends remain unknown (8). Global and continental schemes for prioritizing road building have recently been proposed to limit the environmental costs of infrastructure expansion while maximizing its benefits for human development (9,10). The refinement of these zoning plans would greatly benefit from more detailed estimates of the imprint of infrastructure on wildlife populations.…”

“…The burgeoning availability of detailed geospatial layers of infrastructure contrasts with the lack of quantification of their effects, which still relies on expert knowledge and is mostly based on single species or local studies (14). As a result, mapping of the area of influence of infrastructure ranges from a few hundred meters (15) up to 50 km (10,11,16,17).…”