干旱区生态环境知识资源中心

In arid and semiarid environments seasonality usually exerts a strong influence on the composition and dynamics of the soil community The soil macroarthropods were studied in a Caatinga forest located in the Reserva Particular do Patrimonio Natural (RPPN) Fazenda Almas Sao Jose dos Cordeiros Paraiba Brazil Samples were collected during the dry and rainy seasons following the method proposed by the Tropical Soil Biology and Fertility Program (TSBF) with minor modifications At each station, 15 soil blocks (20 x 20 x 30 cm 12 L) were extracted and divided into three layers A (0-10 cm), B (10 20 cm) and C (20-30 cm) In the rainy and dry seasons 1 306+/-543(se) and 458+/-212 ind m(-2) macroarthiopods were found respectively with 35 and 18 respective taxa recorded The abundant taxon followed by Hymenoptera Formicidae (17 2%), Coleoptera larvae (7 3%) and Araneae (3 5%) In the rainy season abundance in layer A (576+/-138 ind m(-2)) was significantly higher than that of layer C (117+/-64 ind m(-2)), but was not different from layer B (613+/-480 ind m(-2)) was not significantly different compared to layer A (182+/-129 ind m(-2)), but was significantly higher than abudance in layer C (44+/-35 ind m(-2)) During the rainy season layer A (34 taxa) was significantly richer in taxa than layers B (19 taxa) and C (11 taxa) On the other hand during the dry season the richness of layers A (12 taxa) and B (12 taxa) was equal, but significantly higher than that of layer C (6 taxa) Richness of taxa and abudance were positively correlated with soil organic matter and negatively correlated with soil temperature The community of soil macroarthropods in the area of Caatinga studied has taxonomic and funcitonal structures that are relatively complex and is therefore likely to exert an influence on ecosystem productivity due to its physical effects on soil profile and necromass fragmentation as occurs in other arid and semiarid ecosystems throughout the world