Conservation problems of the Córdoba mountain grassland ecosystems.

CINGOLANI A. M., GIORGIS M. A. & RENISON DANIEL

Bariloche

Congreso; VI Southern Connection Congress; 2010

The present treeline in the Córdoba mountains (central Argentina) is ca. 1300 m asl, and has traditionally been considered as climatically determined. Grassland and rocky habitats dominate the landscape above the treeline (up to the highest summit at 2800 m asl) coexisting with small patches of Polylepis australis woodlands. These woodlands are restricted to deep ravines and rocky outcrops, habitats that were traditionally considered as more favourable due to their microclimatic conditions. In opposition to this view, our studies suggest that if fire and herbivory were excluded, climate would not restrict tree development. In this scenario, an almost continuous woodland matrix could dominate the landscape up to the summit. The composition of such matrix would be influenced by the present day scarce native propagule sources (including both high and low mountain tree species), and the abundant propagules of alien invasive species. Supporting our idea, a recent world-wide study determined that growth-season mean temperatures of most tree-lines in the world are between 6 – 7 ºC, far less than those found in our mountains at the highest altitudes. As livestock is now the main herbivore in the area, and fires are in almost all cases human caused, we sustain that our present grasslands are at a great extent anthropogenic, and could potentially be managed as a woodland ecosystem, where grassland species survive in patches within a woodland matrix.