Characterization of Nothofagus pumilio (Lenga) understory in managed and unmanaged forests of central Patagonia, Argentina

Abstract

In managed forests, biodiversity conservation is crucial for the sustainable use of ecosystem resources. In the Patagonian-Andes forests of Argentina, lenga (Nothofagus pumilio) is the most important native tree because of its ecological functions and economic importance as a timber provider. In this study, we determined how the shelterwood-cut system impacts understory vegetation attributes in three sites representing typical lenga forests of central Andean-Patagonia. In each site, two 250-m2 treatment plots (managed and unmanaged) were established, and canopy cover, soil temperature, and moisture were determined. Within plots in 10 randomly placed 0.25-m2 microplots, we determined plant cover, from which we calculated diversity attributes. Canopy cover and soil moisture were higher in unmanaged treatments, whereas the reverse was true for soil temperature. The Shannon-Wiener index showed similar values (~1), whereas species richness was slightly higher in unmanaged (4.8 < 0.5) than in managed treatments (3.8 < 0.3). Generally, native plants dominated the understory (~40%), whereas exotic species were rare (~1%). Shrub cover was higher in managed (24.1 < 4.2) than in unmanaged (9.5 < 1.7) treatments, whereas herbaceous species dominated unmanaged forests. These results confirm that the shelterwood-cut system may be used for diversity conservation in Patagonian lenga forests.