Are ant assemblages of Brazilian veredas characterised by location or habitat type?

Wetland areas in the Brazilian Cerrado, known as “veredas”, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species.Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted “veredas”. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat

Galls of the temperate forest of southern South America: Argentina and Chile. In: Neotropical Insect Galls

South American temperate forests are of special conservation concern due to their highly endemic flora and fauna, and the occurrence of unique plant-animal interactions. Yet, knowledge regarding gall inducers diversity is limited although increasing rapidly in the last two decades. Here, we performed a review of the literature, supplemented with field collected data by the authors, in order to provide the most up to date knowledge of gall inducers\u2019 diversity associated with native woody species of the temperate forest of Chile and Argentina. We present data for 90 morphospecies of galls associated with 39 host-plant species (21 genera, 15 families), spanning insects and arachnids of at least 6 orders and nematodes. Most of this richness is associated to the best surveyed host-plant genus, Nothofagus, with up to 43 morphospecies of galls in just 8 dominant tree species. Moreover, we provide evidence that gall species richness across all woody host-plant species decreases with elevation, probably driven by decreased temperature and number of available host-plant species. However, this overall trend vary among host plant species and scales of observation. Overall, the study of gall diversity and the biotic and abiotic factors that shape their distribution in these austral forests offer an exciting and fertile field for future research. Besides emphasizing the need for more in depth taxonomic and diversity studies of the gall fauna of these forests, we propose several future lines of research that promise to further elucidate our understanding of the evolution of plant-gall interactions in these forests