Land use and their effects on ant communities indifferent vegetation types of cerrado

Abstract

The Cerrado is a biome with high biodiversity, extremely threatened by human activities that promote the loss of species, but it is still neglected in terms of conservation. In this thesis, I evaluate and quantify: i) the impacts of Eucalyptus plantations and pastures on ants from three Cerrado vegetation types: open grasslands, typical and woodland savannas and three strata: arboreal, epigaeic and hypogaeic; ii) the effectiveness of impacted areas in the conserve native Cerrado ants in the same vegetation types. I also present a guide developed for farmers in Cerrado to show aspects that deconstruct common sense about ants, exalt their importance and point out some tips to better land management. The main results show that: i) In general, biodiversity was negatively affected by conversion to Eucalyptus plantations and pastures regardless of vegetation type. But these impacts do not act in the same way. Grass and herbaceous cover was the most important environmental variable correlated with diversity in open grassland and plant richness and litter diversity were the most important environmental variables for ant species in typical and woodland savannas. ii) Eucalyptus plantations and pastures do not retain high levels of ant diversity from native habitats in Cerrado landscapes. Although both modified systems have low conservation values Eucalyptus plantations had a less harmful impact and a slightly higher conservation value when implemented in open grassland and woodland savanna areas while pastures had higher conservation value for typical savannas. Further, structural similarity of modified habitats to native areas is positively correlated with nestedness just in woodland savanna. Also, the conversion of Cerrado to pastures or Eucalyptus is not valuable for huge part of the most representative ants from Cerrado. So, we need to increase the protection of the diversity of all native vegetation found in the Brazilian Cerrado (from open to forested habitats). To help the biodiversity conservation, farmers' awareness becomes a key to decrease the impacts of agroecosystems on biodiversity without losing productivity. This guide (iii) presents the importance of ants for the Cerrado conservation as well as to deconstruct misconceptions and myths that farmers still carry about ants in agroecosystems. I hope that this ecological guide leads to an increase in the basic knowledge about ecology of agricultural systems to farmers and landowners, as well as a demystification of the “bad role of ants”, a common sense.