Resumen

RAMIREZ RAMIREZ, María Isabel; JIMENEZ CRUZ, Margarita  y  MARTINEZ PACHECO, Anuar Iram. Road structure and road density in the Monarch Butterfly Biosphere Reserve, Mexico. Invest. Geog [online]. 2005, n.57, pp.68-80. ISSN 2448-7279.

As an internationally known example of the phenomena of migration and hibernation, the Monarch Butterfly Biosphere Reserve (MBBR) has become one of the most emblematic Protected Natural Areas of Mexico. Nevertheless, the MBBR is still facing severe fragmentation, disturbance and loss of forest cover. Roads are landscape elements well known as a cause of disturbance and deforestation. Using digital aerial photographs mosaics at 1:20 000 from March 2003, and GPS georeferenced tracks, we identified 2 574 kilometers of roads inside the MBBR limits; 55% are earthen roads and 37% are foot paths, both opened for firewood collection and utilization of wood products, whereas paved and gravel roads represent only 2% and 6%, respectively, of the road network. These 2 256.3 kilometers of roads yield an average road density of 4.7 km/km², but analysis at the scale of individual land holdings, particularly in Michoacan state, revealed even higher density values, up to 13.6 km/km². Also, taking into account the average width of each roadbed type, we estimate that 880 hectares of the Reserve are covered by roads. That has consequences over the vegetation, soil, drainage and accessibility to resources.

Palabras llave : Road ecology; road density; protected natural areas; monarch butterfly; Mexico.