The role of ant nests on restoration in degraded ecosystems: effects on soil nutrients and vegetation patterns

ALEJANDRO GUSTAVO FARJI BRENER

Conferencia; International Union for the Study of Social Insects. XVIIIth International Congress.; 2018

Ant nests are one of the major sources of soil disturbance worldwide. But their role in the restoration of degraded ecosystems is still poorly known. Here, I a) summarize via meta-analysis the quantitative evidence of ant nests as source of soil fertility and their effects on plant performance, identifying possible sources of variation of these effects, and b) illustrate some recent examples from the literature and my own studies of how ant nests may play a key role in the restoration of degraded ecosystems. Ant nests showed higher nutrient and cation content than adjacent non-nest soil samples, especially in ant refuse materials. The fertilizer effect 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. Plants showed higher green/root biomass and fitness on ant nest 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-cutting ant nests and in deserts habitats. Overall, these results confirm the relevance of ant nests as soil-nutrient hot spots and their potential to restore degraded ecosystems. Accordingly, several examples illustrate well how ant nests improve the growth of plants in degraded ecosystems from Patagonia, distribute nutrients from rainforest floors, and improve the yield of crops in arid lands via increasing soil water infiltration