Land evaluation and carbon flux estimation to reinforce natural protected areas: a case study in Southern Mexico

Forest-protected areas contribute to sequestration of CO_2, but its establishment in regions where human settlements already exist conflicts with food production. There is a need to develop tools for evaluating the sustainability of land use options in such areas. The objective of the present study was to work out a procedure based on land evaluation and scenario analyses. It was tested in a study area, which is a part of a terrestrial reserve in southeastern Mexico. Requirements for agriculture and forest were matched against the variability in land characteristics to outline physical suitability for current and potential use of land. The effect on C-flux of seven scenarios with different degrees of contribution from areas of agriculture and forest in relation to current land use intensity and proportions (24% agriculture) was estimated. The scenarios were: (1) conversion of forest to agriculture (+ 24%), (2) improved land conditions by application of fertilizers (± 0% agriculture), (3) conversion of agriculture to forest (+ 12%), (4) as (1) with improved land conditions, and (5), (6), (7) as (2), (3) and (4), respectively, but with silvopastoral/agroforestry system in agriculture area. After 20 years, in relation to the start (year 0), baseline (continuation of current land use) showed a sequestration of 10356.5 Gg CO₂, scenario 1 an emission of 230.1 Gg and scenario 2–7 sequestrations of 2998.5–14958.0 Gg. The methodology is promising and can be used as a framework for applications at different scales.