Oribatid mites (Acari: Oribatida): anthropogenic impact indicators in urban forests from La Plata (Argentina)

Abstract

Seven green areas were sampled in the city of La Plata in order to test a human intervention index (IA) for urban soils. This index emerged from a research conducted in the Paseo del Bosque
(La Plata, Argentina) and uses oribatid mites as bioindicators. IA was a good indicator of a human intervention in low impact areas. In high and medium impact areas species dominance, richness and diversity were analysed. Eremobelba zicsii, Opiella nova and Epilohmannia pallida americana were dominant in healthy soils. A density reduction of Hemileius initialis, Scheloribates curvialatus and Protoribates (Triangius) praeoccupatus was observed with and increasing degree of human intervention. We suggest that the density of these species should be included as an estimate of urban soils health. Tectocepheus velatus, Trachyoribates (Rostrozetes) ovulum and Acrotitia clavata were dominant in high impact areas and rare or absent in healthy soils. This finding has led us to regard them as resistant to moderate intervention.