Changes derived by the silvopastoral management in Nothofagus antarctica forests of Tierra del Fuego compared to other productive environments

Abstract

Silvopastoral systems (SPS) are suggestedto promote a balance between productivealternatives and ecological values. The aim of thisstudy was to determine the changes generated bySPS (thinning + livestock) in Nothofagus antarctica(ñire) forests compared to other productive environments(unmanaged forests, dry grasslands, wetgrasslands). A total of 16 areas (4 treatments x 4replicates) were selected in El Roble ranch (Tierradel Fuego, Argentina), where 50 variables were surveyedthrough plots (forest structure, forage, animals,biodiversity) and sampling in soil pits. Indicesfor each component and univariate analyses wereperformed to compare the studied environments.The results showed that SPS generate significantchanges in the studied components, causing positiveand negative synergies on the studied variables(e.g., forage biomass increases 1.5 times, p = 0.008).These changes promoted new productive environmentswith intermediate characteristics betweenforests and grasslands (dry and humid). It wasobserved that tree roots, unlike herbs and grasses,were located not only in the upper layer, but alsoappear in higher percentages at deeper layers (e.g.,tree roots between 20 and 30 cm soil depth are comparableto those values found between 0 and 10 cm,p = 0.035). These results allowed us to identify thefactors of change in the studied components, as wellas potential indicators for monitoring. Understandingthe dynamics and interactions among the differentecosystem components, allowed to generate newproposals that must be economically viable (e.g.,management costs vs. growth of trees and forage)and environmentally sustainable (e.g., conservationof the original biodiversity).