Influence of Sphagnum harvesting on arthropod fauna and vegetation with a focus on beetles (Coleoptera) and ants (Hymenoptera: Formicidae)

Abstract

The harvesting of living peat moss (Sphagnum spec.) for various industrial applications has become increasingly prevalent. The harvesting process involves manual or mechanical extraction of Sphagnum fragments with minor to significant alterations of the habitats. This study investigates the impact of Sphagnum harvesting on arthropod fauna and vegetation structure at two donor sites with small-scale Sphagnum harvest in northwestern Germany. In the first year after the harvest, comparative surveys were carried out between harvested and unharvested reference areas. Arthropods living in and on the upper Sphagnum layer were studied by manually extracting quadrat samples. Vegetation surveys focused on the vascular plant composition and Sphagnum layer thickness as key habitat parameters. Results indicate no substantial effects on the total numbers for most arthropod orders. In contrast, the frequency of ant workers and the number of ant nests were considerably lower in harvested areas compared to reference areas. Vegetation analysis revealed that the shortening of the Sphagnum hummocks led to a homogenization of the vegetation structure and alterations in species composition in favor of moisture-loving species. Although no significant effects on total beetle populations were observed, the abundance of bog generalists and specialists was significantly reduced in harvest areas. Certain species displayed preferences for harvested or reference areas. Future harvesting practices should consider preserving vulnerable arthropod species and restricting harvesting to a small scale to mitigate adverse effects on bog ecosystems.