Vegetation and land use 2009: Monarch Butterfly Biosphere Reserve, Mexico

The Monarch Butterfly Biosphere Reserve in Mexico, with an area of 56,259 hectares, is one of the most important protected natural areas in the world; each year there arrives in its fir forests (Abies religiosa) a remarkable migratory insect, the Monarch butterfly (Danaus plexippus L.), which sets out from southern Canada and the northern USA on a journey of more than 4,000 km. The vegetation and land use of the reserve has been mapped by photo-interpretation of digital aerial photographs from February 2009 with a spatial resolution of 40 cm per pixel. The photographs were printed at a scale of 1:10000 and interpreted using the conventional techniques of photo-interpretation. The plant communities were confirmed by field surveys and digitized on screen, at an average scale 1:5,000, by means of direct comparison of photographic elements within an ortho-corrected mosaic from 2003 and the interpreted photographs from 2009. Classification of the categories of vegetation and land use, both during photo-interpretation and for the composition of the final map legend, was based on the national forest inventory of Mexico, 2000. This method, using digital aerial photographs and combining techniques of photo-interpretation and geographic information systems, has allowed the production of a detailed map.