Monitoring land use and land cover change in mountain regions: An example in the Jalca grasslands of the Peruvian Andes

摘要

Mountains are rich in biodiversity and provide ecosystem services for their inhabitants. These regions are currently threatened by land use and land cover changes (LUCC), therefore an efficient monitoring is required to capture such changes. The aim of this study is to test a landscape change analysis in a mountain region to guide landscape management by including: (1) LUCC trends, (2) LUCC trends across the elevation gradient and (3) changes in spatial configuration. This framework was applied to the Peruvian Jalca grasslands (>3000 m a.s.l.), located in the Tropical Andes for the period 1987-2007. We used object-based classification of Landsat TM and patch metrics for each land cover class. Our results show an overall loss of Jalca (-1.5%/yr) and montane forest and shrubland (-2.8%/yr) with higher rates than other Andean regions. Furthermore, fragmentation is observed for the Jalca while montane forest and shrubland class is not fragmenting but the largest patches are vanishing, potentially affecting the connectivity between natural areas. Agriculture has replaced the Jalca, especially in the upper zones of the Andes showing an upward expansion of crops. However tree plantation and mining had increased more dramatically than agriculture (>9%/yr). Upper and less fragmented jalca areas may be suitable for conservation purposes while agriculture may better expand in already degraded natural areas. Records of changes across the elevation gradient and in spatial patterns result in useful information for decision makers and may improve ecosystem management not only in the Tropical Andes but also in other mountain regions