Ecological amplitude and indication potential of mining bees (Andrena spp.): a case study from the post-agricultural area of the Kampinos National Park (Poland).

The mining bee (Andrena spp.) play a key role in ensuring plant and animal diversity. The present study examines their diversity in a post-agricultural landscape exemplified by the Kampinos National Park (KNP), a UNESCO Biosphere Reserve in Poland. The following hypotheses were addressed: (H1) the mining bees demonstrate a narrow ecological amplitude, (H2) there are no indicator species for particular habitats, and (H3) the studied mining bees have the same ecological preferences to those presented in the literature. A total of 40 catch per unit effort samples (CPUE) were collected across various habitats with different soil humidity. Forty-six species were recorded, representing 46% of mining bees and approximately 10% of the known Polish bee fauna. Nineteen of the recorded species (41%) were assigned to CR-NT threat categories, indicating that the national park plays a significant role in preserving mining bee species diversity and their conservation. None of the hypotheses (H1, H2, H3) were confirmed. The mining bees were found to demonstrate a wide ecological amplitude. Surprisingly, habitats located in dry and wet soils were both characterised by high abundance and species richness. Seventeen indicators were distinguished among the dominant and rarer species. Our findings suggest that Andrena nigroaenea and A. ventralis (lower humidity), as well as A. alfkenella and A. minutuloides (higher humidity), have different significant relationships with habitat soil humidity to those reported in the literature.