A model to assess restoration of abandoned pasture in Costa Rica based on soil hydrologic features and forest structure

An ecological functional assessment (EFA) was used on 10 southwest Costa Rica sites representing a chronosequence of formerly pastured lands to undisturbed tropical wet forest. Ecological functional assessment is a tool designed to assess wetland functions in the United States that was adapted to upland forests. Models to indicate characteristic soil hydrologic features and soil structure and aboveground spatial structure of habitat were used to examine the degree to which selected sites within the chronosequence approach the undisturbed condition of the natural forest. An index of the functional model for the maintenance of characteristic soil hydrologic features (such as infiltration, bulk density, etc.) showed that the 20-year-old secondary forest was at approximately 60% of the condition of the undisturbed sites, whereas active pasture was evaluated at approximately 20% of the reference undisturbed forest; 4- and 10-year-old sites were intermediate. The spatial structure of habitat model showed that 20-year-old secondary forest was approximately 50% of reference forest, whereas active pasture was approximately 10% of the condition of undisturbed forest; 4-year-old sites were evaluated at approximately 20% and 10-year-old sites at approximately 60% of the reference state. Overall the functional assessment process indicated that degraded tropical wet forest sites have recovered almost 60% of their functional qualities 10 years following pasture abandonment. These results indicate that EFA can be a useful technique for monitoring restoration programs in the tropics.