CONICET | Buscador de Institutos y Recursos Humanos

Overgrazing and hydrocarbon exploitation generate the most significant environmental impacts in the Monte Austral. This ecoregion harbours the most productive oil/gas area in the country; more than 12,000 active wells. To construct each drilling location the natural system is completely destroyed within an area of at least one hectare/well. The natural recovery process of disturbed areas is very slow in arid ecosystems due to the low resilience of the system. In this context, the focus of this research was to determine patterns of post-disturbance plant succession in scarified soils, a mechanical decompaction technique widely applied in the region since 1998 but never validated. In 190 sites scarified during 1998-2010, ecological attributes were quantified (Braun-Blanquet adjusted method). At each well location three sites were evaluated: (1) natural, (2) treated, and (3) operational (disturbed areas without treatment). A discriminant analyses (DA) allowed identifying cover and diversity (H index) as the best predictors for distinguishing between those three sites. Scores obtained in DA for the canonical axis 1, which accounts for 97% of the among-sitevariability, were considered as an indicator of ecological restoration. In treated areas this indicator was significantly and positively associated with time since the technique was applied. However, even in locations scarified 8-12 years ago, the ecological restoration levels were lower than standard values in natural areas. Pioneer or ruderal species(Atriplex, Senecio, Hyalis, Glandularia, Salsola, Grindelia) predominate in all rehabilitated locations regardless the restoration time. Implications of scarifying techniques for environmental management are discussed.