Changes in the pH and other soil chemical parameters in soil surrounding wood ant (Formica polyctena) nests

Several previous studies reported on how the chemistry of the wood ant nest differs from the chemistry of the surrounding soil. There is enhanced amount of nutrients and cations in the ant nest and pH also differs from the nest surroundings. In this contribution, we focused on changes in soil chemistry with distance from the nest. Samples of mineral soil 0–5 cm deep were taken in grid pattern at 1–19 m from six Formica polyctena nests in a spruce forest in the Czech Republic.Soil pH decreased with distance; pH decreased rapidly between 1 to about 8 m and then decreased more slowly. The decrease in pH corresponded with the increase in organic matter content with distance from the nest. Organic matter content was significantly and positively correlated with available Ca and K, i.e., available Ca and K increased with distance from the nest. The changes in organic matter content, pH, and available Ca were caused by ants collecting and using needles as building material. Wood ants can affect soil properties by rearranging organic matter, in nest surroundings.

Research highlights
► Wood ant increased pH in nest margin and surrounding soil.
► pH increase in nest margin is connected with accumulation of basic cations.
► pH increase in surrounding soil is affected by litter removal.
► Litter removal caused decrease in content of humic acids which cause pH increase.