Challenging the linear forestation narrative in the Neo-tropic: Regional patterns and processes of deforestation and regeneration in southern Mexico

摘要

In the Neotropics increased rates of land use and land cover change (LULCC) and a strong deforestation trend in the second half of the twentieth century have caused environmental degradation and biodiversity loss. This study analysed patterns and processes of LULCC and deforestation for the Grijalva-Usumacinta watershed, one of the hydrologically and biologically most important watersheds in southern Mexico in face of the discussion about beginning forest transitions in the Neotropics. Maps of land use and land cover for 1992, 2002 and 2007 derived from satellite and aerial imagery were analysed to test the hypothesis of changing trends on a regional scale. Change rates and probabilities were calculated for two time periods and dominant LULCC processes were identified. LULCC is complex and cannot be explained by the predominant linear deforestation narrative alone. A crucial finding was an unusually high rate of forest degradation for all primary forest types, being 1.7 times the area of forest deforestation; and that deforestation processes occur mainly in secondary forests. Agricultural activities fostered by public policies are the principal drivers for LULCC, among which pastures have the highest impact on deforestation. Deforestation and LULCC rates and probabilities have stagnated, and natural reforestation has increased. Although these trends are essential for the onset of forest transition, deforestation and degradation outweigh by far vegetation regrowth.