Restoration of riparian forest corridors: eight years monitoring the diversity of soil ants in an Andean rural landscape

Ecological restoration of riparian forest corridors at the landscape scale can facilitate recruitment of certain flora and fauna, thus possibly helping to maintain viable wildlife populations. We evaluated ecological restoration of three corridors between two protected Andean forests. Soil ants and eight environmental variables focused on edaphic conditions were monitored for 8 years following restoration activity. Soil ants were collected in pitfall traps and by leaf litter extraction on 21 plots classified into five types of habitat: large forest patches, riparian forests, two types of restoration corridors on former timber and pasture land (R-Forestry and R-Pasture, respectively), and Pasture. A total of 132 ant species belonging to 40 genera were found. Among these, 112 species were found in Forests, 105 in Riparian, 80 in R-Forestry, 79 in R-Pasture and 63 in Pasture. Composition analyses (canonical correspondence analysis and NMDS) showed that the ant community in restoration corridors and pastures is far from resembling that of the forests. Yet, there is biological progress with respect to the Pasture. Gnamptogenys bisulca and Pheidole pygmaea were indicator species for advanced restoration progress because of their close association to forests, while Linepithema piliferum indicated a reversal of restoration progress due to its preference for open habitats. Since both ant richness and composition in restored areas do not yet resemble the reference forest ecosystem, we suggest that other interventions such as restoring wider corridors and changing to wild-friendly agriculture around the reserves might improve restoration efforts in Andean landscapes.