Structure and conservation status of Araucaria araucana forest outside the natural reserves of Argentina: the case of the Chiuquilihuín Mapuche community.

Resumen

Chiuquilihuín (39° 36´ S and 71° 13´ W, 5,144 ha) is an area of natural grasslands, shrublands and forests, dwelled by 300 native people of the Mapuche ethnic group devoted to extensive cattle ranging, forestry and edible seed gathering. The structure and conservation status of natural forests (27.1 % of total area), and particularly those composed of the vulnerable conifer Araucaria araucana ((Mol.) K. Koch) (“pehuén”) (9.5 %), was evaluated as an indicator of sustainableresource use of this area. Araucaria araucana formed pure and mixed stands, with Nothofagus pumilio ((Poepp. et Endl.) Krasser), “lenga”), and exhibited attributes congruent with a strategy based on large longevity, broad ecological amplitude, shade tolerance, continuous regeneration under canopy and resistance to physical and biological mortality factors. Characteristics of N. pumilio were those of an early successional, gap-dependant tree species. Forest conservation tended to be satisfactory (negligible or moderate timber extraction, absent or slight erosion and adequate regeneration of A. araucana). However, cattle grazing covered 93.3 % of forest land. Though A. araucana seedlings and saplings were abundant and vigorous, reflecting efficient mechanisms of defence against herbivores, those of N. pumilio were very scarce and injured or dead by domestic livestock. In Chiuquilihuín, long-term preservation of A. araucanadepends on maintaining healthy ecosystem components and processes, and particularly N. pumilio regeneration. Consequently, management actions as land-use planning, productive diversification, environmental training, grazing restrictions and stocking reduction, enclosure and tree planting and agroforestry, should be implemented to improve forest conservation.