Long-term succession of oribatid mites after conversion of croplands to grasslands

The paper deals with the long-term development (55 years) of oribatid communities (Acari) during grassland succession following the conversion of arable fields. The study was carried out on a chronosequence of temperate grassland sites in the Lahn-Dill-Bergland (Central Hesse, Germany). The “space-for-time” substitution method was applied. Increasing abundance at early stages of the conversion process (until the age of 13-28 years) points to release from the stress exerted by arable management. Saturation of abundance and richness indicates strong limiting forces acting upon the oribatid community at intermediate and late stages of succession. The continuous increase in the dominance of surface-dwelling and non-specialized species suggests a considerable change in the nature of these limiting forces during the successional process. General Regression Model (GRM) analysis revealed an increasing impact of external factors on the oribatid community during grassland succession, and a shift in the major driving forces determining oribatid abundance from soil conditions to vegetation conditions and then to a combined effect of both soil and vegetation conditions.