Protected areas are at the heart of current global policies against the erosion of biodiversity. For instance, to meet the pressing challenge of covering 30% of the surface of the sea under jurisdiction with a network of marine protected areas by 2030, reserve site selection models are increasingly mobilised. These models address the optimisation problem that seeks to cover biodiversity features at a minimum cost on human activities. A presentation set, i.e. a pool of alternative solutions, is often needed to increase the chances of satisfying unmodeled objectives that may be non-negligible in a conservation problem composed of various interests. The widely used Marxan repeats a metaheuristic algorithm based on random processes to produce diversity in the presentation set. Several works already demonstrated how exact optimisation methods outperform meta-heuristics both in computation time and optimality. However, the generation of multiple solutions is still raised as a key feature of metaheuristics. In this work, we proposed two algorithms to generate a presentation set with exact optimisation methods using recursive procedures based on an explicit difference criterion. The resulting alternative solutions were generated by controlling the optimality gap but also the difference with the optimal solution. This work showed that the presentation set offered by metaheuristics can be outstripped by an explicit, transparent and replicable presentation set built by exact optimisation methods. Allowing to understand precisely why and how the result was arrived at, the framework presented here should contribute to a more equitable negotiation among stakeholders engaged in conservation planning processes.