Landslides and Their Contribution to Land-cover Change in the Mountains of Mexico and Central America1

Landsliding is a natural process influencing montane ecosystems, particularly in areas with elevated rainfall and seismic activity. Yet, to date, little effort has been made to quantify the contribution of this process to land-cover change. Focusing on the mountains of Mexico and Central America (M-CA), we estimated the contribution of landsliding to land-cover change at two scales. At the scale of M-CA, we classified the terrain into major landforms and entered in a GIS historical data on earthquakeand rainfall-triggered landslides. At the scale of the Sierra de Las Minas of Guatemala, we investigated Landsat TM data to map rainfall-triggered landslides. During the past 110 yr, >136,200 ha of land in the mountains of M-CA have been affected by landslides, which translates into disturbance rates exceeding 0.317 percent/century. In Sierra de Las Minas, rainfall associated with hurricane Mitch affected 1765 ha of forest, or equivalently, landslides triggered by storms of this magnitude transformed between 0.196 (return time of 500 yr) and 1.290 (return time of 75 yr) percent of forest/century. Although landsliding results in smaller rates of land-cover change than deforestation, we hypothesize that it has a stronger impact on ecosystems, both in qualitative and quantitative terms, given its influence on vegetation and soil. Moreover, interactions between landsliding and deforestation may be altering the expression of this complex process such that the few protected areas in the mountains of M-CA may represent the only possibility for the conservation of this process.