Rehabilitación ecológica en el noreste patagónico: Supervivencia y reclutamiento de especies nativas en suelos con diferentes texturas

Abstract

In the northeastern Patagonian region, soils show marked heterogeneity, mainly due to their texture. It is also observed strong degradation processes in this region. The objective was to estimate survival rate of native species in ecological rehabilitation trials in degraded areas, on soils of different textures, and evaluate recruitment around surviving transplanted individuals at each site. Studies were performed in three sites that had a similar land use history, in loamy, sandy loam and sandy soils. At each site, three 100 m2 plots, excluded from cattle grazing were installed. Individuals of woody (Condalia microphylla, Geoffroea decorticans, Prosopis flexuosa y Schinus johnstonii) and herbaceous (Nassella longiglumis, Nassella tenuis, Pappophorum caespitosum and Piptochaetium napostaense), native species were transplanted. Recruitment was estimated in 50x50 cm plots, leaving the surviving transplanted individual in the center. Survival rate and recruitment were estimated four years after transplantation. Recruitment was categorized into forage and non-forage woody plants and annual or perennial, forage, and non-forage herbaceous plants. Soil texture seems did not influence in survival of herbaceous transplanted species, but it did in a woody plant (S. johnstonii), that was significantly higher in sandy loam soils. Richness of recruited woody and herbaceous species was similar between sites, except for annual non-forage herbaceous plants, being richer in loam and sandy loam sites. Transplanted woody species recruitment was not detected, but recruitment of other native woody species was recorded, and the recruitment of perennial herbaceous species was only of the transplanted species. Recruitment density did not show correspondence with soil texture, except for forage and non-forage annual herbaceous species, that was higher at the loam and sandy loam sites, respectively. Most of the selected species presented survival rates that make them suitable for ecological rehabilitation projects. Seed supply of each site would have a preponderant importance to recruitment recovery.