Ants as bioindicators of vegetation structure and soil fertility: monitoring the restoration of a riparian forest

Abstract

The usage of faunal indicators such as ants can allow a better comprehension of the trajectory of ecosystems under restoration, when compared to parameters related only to vegetation, mainly regarding ecosystem functions, since many species respond to environmental changes. The objective of this study is to evaluate if the structure and composition of ant species vary in relation of vegetation structure and soil fertility in an area of riparian forested restored five years ago and two adjacent control areas, pasture and forest remnant, along a gradient of soil fertility. We expected that the structure and composition of ant assemblages are positively related by soil fertility (bottom-up effect) and forest structure. The three areas were subdivided in six blocks each along the soil fertility gradient, and ants were sampled using 180 pitfalls. We will use the scores of two Principal Components Analyses, on the vegetation structure and soil attributes as explanatory variables in a structural equations modelling approach to evaluate the soil indirect effect (via the effect on vegetation) and direct effects on diversity descriptors. The variation in ant species composition will be evaluated with Redundancy Analysis (RDA). The results of this study will enable the improvement of biological indicators for the monitoring of restored areas aiming the recovery of ecosystem functions.