Earthworms, ants and other arthropods as soil health indicators in traditional and no-fire agro-ecosystems from Eastern Brazilian Amazonia

Deforestation of the Amazonian rainforest and conversion to agriculture with the use of fire creates a mosaic of occupied lands and secondary forests. Considering the fundamental role of soil macrofauna and the lack of information about its resilience to deforestation, this study characterized the earthworms, ants and other soil arthropod communities in secondary forests of 40 and 20 years of age and in cropping system and pastures prepared with slash-and-burn or chop-and-mulch in the Brazilian Eastern Amazonia. Soil macrofauna was sampled according to the TSBF (Tropical Soil Biological and Fertility) methodology. Four sub-indices and one macrofauna soil health index were calculated using five principal component analyses. The macrofauna index identified better soil health in chop-andmulch crops, followed by the 40 yr-old forest and the chop-and-mulch pasture. These results confirmed the fundamental role of old secondary forests for soil biodiversity conservation and the potential of the chop-and-mulch technique to mitigate the effects of land use changes

Edge effects and the impact of wildfires on populations of small non-volant mammals in the forest-savanna transition zone in Southern Amazonia

The impact of fire and edge effects on the community of small non-volant mammals was investigated in transitional Amazon forest within a matrix of soybean plantations. The animals were live trapped on 24 line transects, of which 16 were distributed in unburned areas and 8 in a burned area. A total of 11 species was recorded, including six rodents and five marsupials. The abundance and richness of small mammals appeared to decrease in burned areas, although this impact appeared to mask edge effects. In the absence of fire impacts, a positive relationship was found between mammal abundance and the distance from the forest edge. The impact of the edge effect on the diversity of small mammals appears to be influenced by the type of anthropogenic matrix and the ecological characteristics of the different species