Regeneration of soils and microgeomorphology in rehabilitated oil/gas fields of Northern Patagonia, Argentina

CIANCIO, M. E.; TCHILINGUIRIAN, P.; CASTRO, M. L.; JUNGES, M. T.; PÉREZ, A. A.; ZULETA, G. A.

Merida

Congreso; SER 2011 - 4th World Conference on Ecological Restoration; 2011

Society of Ecological restoration

In southern Argentina, the Austral Monte ecoregion is characterized by semi-arid shrub steppes where the dynamics of the physical environment is controlled by ephemeral river systems that have areas of accumulation of sandy composition (alluvial fans) and clay (playa lake). Wind is an important agent, eroding sands of fans and depositing toleeward side of the vegetation forming mounds. These are islands of fertility, since they contain the highest concentration of nutrients, moisture and biodiversity within the matrix of bare soil (60% total coverage). Within this context, the focus of this research was to determine the variables and processes that control restoration of postdisturbancesoil and mounds in oil & gas locations scarified since 1998. Geomorphologic attributes were quantified in 190 sites. At each well location three sites were evaluated: (1) natural, (2) treated, and (3) operational (disturbed areas without treatment). A discriminant analysis (DA) allowed identifying the number and height of mounds as the best predictors for distinguishing among those three sites. Scores obtained in DA for the canonical axis 1 wereconsidered as an indicator of soil restoration. In treated areas this indicator was significantly and positively associated with time since the technique was applied. However, even in locations scarified 8-13 years ago, the environmental restoration levels were lower than the observed ones in natural areas. Higher similarity in soil conditions between treated and natural areas were observed in landforms with increased availability of sand.Implications of scarifying techniques for environmental management are discussed.