THE ANT FAUNA OF THE CERRADO: DIVERSITY, ECOLOGICAL DRIVERS, AND HUMAN PRESSURES IN A GLOBAL BIODIVERSITY HOTSPOT

As in many other terrestrial ecosystems, ants are a dominant insect group in the savannas, forests and grasslands that together compose the Brazilian Cerrado. Myrmecological research in this biome started more than one century ago and here we show that the scientific knowledge about this insect group and the representativeness of Cerrado ants in Brazilian entomological collections has grown enormously during the past few decades. Based on diverse sources we estimate that total ant diversity in the Cerrado may reach 700-900 species, many of which remain unnamed. Yet, local diversity can be quite high, with intensive surveys showing the presence of over 200 species in a single locality. Both variation in tree cover and vertical stratification can help to explain the high number of species coexisting locally, given that different species tend to be associated with different vegetation types or with different nesting and/or foraging strata (arboreal or ground). Species turnover is particularly high between adjacent forest and savanna habitats. Fire suppression can transform open savanna areas into dense savannas or forests, thereby reducing ant diversity at the landscape level. However, reintroducing fire allows the return of open savanna specialists. The rapid conversion of the Cerrado native vegetation has a negative impact on ant diversity, but the magnitude of this effect is much higher in lands devoted to intensive agriculture (rather than to pastoralism or plantation forestry), as it affects not only the richness of species but also the functional and phylogenetic diversity of ant communities. Maintaining habitat heterogeneity and integrating ants into biodiversity-friendly agriculture are key to safeguarding ecosystem functions and services in the Cerrado.