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Mardi 23 novembre 2021

Kelly Cobourn (Virginia Tech) présentera "Forest transitions and ecosystem collapse: an analysis of the role of substitutability between primary and secondary forests", co-écrit avec Gregory Amacher, Philippe Delacote et Haoyu Wang.

Résumé :

Across the developing world, the deforestation of primary, native forests supports economic activity at the cost of environmental degradation with global, long-term consequences. Events like record-setting wildfires in the Amazon highlight the potential for deforestation to drive ecosystems past potentially irreversible tipping points, such as a shift from tropical forest into grassy savanna. Investments in reforestation with secondary forests are one potential tool to avert or delay tipping points, but the success of this strategy depends on the degree to which secondary and primary forests are substitutes in the production of ecosystem services. We develop a dynamic optimization model and numerical simulation to explore how deforestation, reforestation, and the degree of substitutability between forest types affects the likelihood that a forest system will cross a tipping point. We demonstrate that if the ecosystem services provided by secondary forests do not offset the losses from deforestation, collapse may occur despite ongoing investments in planting, especially if the costs of securing land tenure are high. Conversely, our results suggest that secondary forest management practices and species selection that increase the substitutability of secondary for primary forests can play an important role in avoiding or slowing costly ecosystem change.