Land use, soil properties and climate variables influence the nematode communities in the Caatinga dry forest

Abstract

Seasonally dry tropical forests are strongly impacted by human activities such as agriculture and ranching, as well as variations in climate conditions. Soil nematodes are sensitive to these changes, given that soil and climate characteristics influence their survival and occurrence. We analyzed the changes in the structure of nematode communities in three different types of land use (agricultural areas, secondary forest and natural forest) in the Caatinga, at Catimbau National Park, Pernambuco, northeastern Brazil. We recorded a total of 17,177 nematode individuals belonging to 104 genera. Nematode abundance and richness were highest in the secondary forest and lowest in the agricultural areas. The total abundance of bacterivores and omnivore-predators was affected by types of land use. Different soil properties as well as monthly mean rainfall and temperature were strongly related to the differences in taxonomic composition among the agricultural areas, secondary forest and natural forest, accounting for 65.42% of the total variation. In general, our results indicate that agricultural activities in the Caatinga negatively affect the nematode communities, and that soil characteristics and climate variables also strongly affect the structure and composition of these communities.