Off-road motorcycle circuits support long-term persistence of bees and wasps (Hymenoptera: Aculeata) of open landscape at newly formed refugia within otherwise afforested temperate landscape

Newly formed refugia for open landscape species within otherwise afforested temperate landscape suffer from a lack of sustainability. Here, we test the hypothesis proposing off-road motorcycling as a long-term stressor, which could be responsible for the long-term sustainability of afforested habitat patches, particularly those formed in (post-)industrial areas, such as sandpits, claypits, quarries and ash and slug tailing ponds. To test this hypothesis, we analyzed assemblages of bees and wasps (Hymenoptera: Aculeata) within 19 off-road motorcycle circuits distributed across the Czech Republic, representing circuits subject to high- and low-intensity use, as well as recently closed circuits. Off-road motorcycle circuits were associated with specific assemblages of bees and wasps, many of which were of conservation interest. Open landscape species, in particular, as well as those requiring the presence of solitary, sun-exposed trees, thrived under such conditions. Formation of off-road motorcycle circuits, particularly those with low intensity traffic, should be considered an appropriate tool supporting the biodiversity in the highly cultivated landscape of Central Europe, as they host highly diverse assemblages of specialist pollinators and other hymenopterans. Aculeata were sensitive to both the presence and intensity of off-road traffic. The species richness and abundance of red-listed Aculeata were associated with the presence of a fine-grained substrate, low-intensity off-road traffic and high diversity of E2 plant species and E1 red-listed plant species. In contrast, the overall abundance of Aculeata was not sensitive to any of these factors. There were no aculeate families specifically associated with closed off-road motorcycle circuits. Off-road motorcycle circuits should be considered to be an appropriate form of reclamation of closed quarries, sandpits and claypits, considering that off-road motorcycles can potentially be used as a management tool to block the afforestation of habitats formed at post-industrial sites.