Response of earthworms to changes in the aggregate structure of floodplain soils

Abstract

Earthworms are actively involved in the transformation of organic matter and in the formation of water-resistant soil aggregate structure. In the short time perspective earthworms are a factor that affects soil properties. However, other factors also influence soil properties and it is these factors that determine the total level of earthworm abundance and patterns of their spatial distribution. In urban park environments, the recreation load is an additional factor. The recreational load significantly affects the physical properties of the soil. An aggregate soil structure regulates the ratio of solid, liquid, and gaseous soil fractions and thus determines the living conditions of soil animals. Purpose/objective. The study tested the hypothesis about the influence of the aggregate structure of soil on the spatial distribution of earthworms under recreational load conditions. Methodology. Geostatistical methods and evaluation of animal response models to environmental factors. Results/findings. The aggregate structure of the soil is an important factor that affects the spatial patterns of earthworms under recreational load conditions. Earthworms prefer sites with a predominance of meso-aggregates. A recreational load leads to an increase in the proportion of macro- and micro-aggregates, which negatively affects the living conditions of earthworms. Conclusions. The processes of mutual influence of earthworms and soil aggregate structure have different temporal scales: earthworms influence soil structure in the time range of a few days or weeks, and aggregate structure influences in the time range of a few months or years.