The effects of ant nests on soil fertility and plant performance: a meta-analysis

FARJI-BRENER, ALEJANDRO G.; WERENKRAUT, VICTORIA

JOURNAL OF ANIMAL ECOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2017 vol. 86 p. 866 - 877

0021-8790

1. Ants are recognized as one of the major sources of soil disturbance world-wide. However,this view is largely based on isolated studies and qualitative reviews. Here, for the first time,we quantitatively determined whether ant nests affect soil fertility and plant performance, andidentified the possible sources of variation of these effects.2. Using Bayesian mixed-models meta-analysis, we tested the hypotheses that ant effects onsoil fertility and plant performance depend on the substrate sampled, ant feeding type,latitude, habitat and the plant response variable measured.3. Ant nests showed higher nutrient and cation content than adjacent non-nest soil samples,but similar pH. Nutrient content was higher in ant refuse materials than in nest soils. The fertilizereffect of ant nests was also higher in dry habitats than in grasslands or savannas.Cation content was higher in nests of plant-feeding ants than in nests of omnivorous species,and lower in nests from agro-ecosystems than in nests from any other habitat.4. Plants showed higher green/root biomass and fitness on ant nests soils than in adjacent,non-nest sites; but plant density and diversity were unaffected by the presence of ant nests.Root growth was particularly higher in refuse materials than in ant nest soils, in leaf-cuttingant nests and in deserts habitats.5. Our results confirm the major role of ant nests in influencing soil fertility and vegetationpatterns and provide information about the factors that mediate these effects. First, ant nestsimprove soil fertility mainly through the accumulation of refuse materials. Thus, differentrefuse dump locations (external or in underground nest chambers) could benefit different vegetationlife-forms. Second, ant nests could increase plant diversity at larger spatial scales onlyif the identity of favoured plants changes along environmental gradients (i.e. enhancingb-diversity). Third, ant species that feed on plants play a relevant role fertilizing soils, whichmay balance their known influence as primary consumers. Fourth, the effects of ant nests asfertility islands are larger in arid lands, possibly because fertility is intrinsically lower in thesehabitats. Overall, this study provide novel and quantitative evidence co