IENE 2016

The Tri-National Dja - Odzala - Minkebe Forest landscape (TRIDOM) covers 178000 km² across the borders of Cameroon, Gabon and the Republic of Congo. Almost 97% is covered by sparsely populated lowland tropical rainforest and is globally important for the conservation of large mammals (elephants, gorillas, chimpanzees). Major roads are being built across the TRIDOM, not least to service what is destined to be an emerging iron ore province with several deposits currently being explored and two mining projects ready for exploitation. For decision makers in the area, encouraging investment while respecting the legal and customary rights of local populations and conserving biodiversity represents a major challenge. Conservationists highlight that the infrastructure being built (railroads, roads, powerlines) will have direct and indirect impacts on the ecosystems, especially as they will enable an influx of migrants, which could transform the large intact forest landscape into a mosaic of isolated and thus vulnerable protected areas, no longer fit to conserve its mega-fauna or maintain large scale ecosystem processes. Possible mitigation options include coercive (e.g. anti-poaching patrols) and incentive-based (e.g. support for alternatives such as agroforestry) solutions, which differ in their effectiveness and applicability, in the TRIDOM as anywhere else. Other options include access limitations for new and existing roads, and reclamation of disused roads in forest concessions. To better understand the impact, constraints and limitations of these options, we synthesized available knowledge on the effect of road development in roadless landscapes and used participatory modelling techniques to build a model of the socio-ecological system of the TRIDOM. This model was then used to explore, with stakeholders, future scenarios for the TRIDOM, in terms of infrastructure development and of biodiversity outcomes. Key conclusions from the analysis are that (1) managing these impacts requires a strategic and multi-sectorial landscape-level approach, rather than dealing with each separate project sequentially, which calls for (2) agreement on key biodiversity features and the development of biodiversity metrics for applying the mitigation hierarchy to these features, of which large un-fragmented (roadless) forest blocks are of particular concern, as well as (3) the development of new or improved institutional capacity and engagement, to coordinate and enforce decisions. These conclusions are widely applicable and relevant in a context of expanding infrastructure investments.