An Initial Assessment of the Collembola (Hexapoda) Fauna of the Bula Hyrcanian Forest (Iran) at the Interface of Two Biodiversity Hotspots

The Hyrcanian Forests of northern Iran, a UNESCO World Heritage Site, are renowned for their exceptional biodiversity, hosting numerous relict, threatened, and endemic species. Located at the intersection of the Caucasus and Irano-Anatolian biodiversity hotspots, these forests have been extensively studied for vascular plants, but soil arthropods like springtails (Collembola) remain largely understudied. This study aims to fill this gap by conducting a comprehensive survey of the Collembola fauna in the Bula Forest, Mazandaran Province. Sampling covered various substrates (decaying wood, moss, soil and leaf litter) in three forest types: a UNESCO-listed natural forest, a preserved planted forest, and an unpreserved natural forest. 73 Collembola species, belonging to 39 genera and 12 families were recorded. Pseudachorutes vasylii Kaprus’ & Weiner, 2009, Paranura Axelson, 1902 (Neanuridae) and Pseudanurophorus Stach 1922 (Isotomidae) were documented for the first time in Iran. Drepanura Schött 1891 (Entomobryidae), Pachyotoma Bagnall, 1949 (Isotomidae), Mesaphorura hylophila Rusek, 1982, and Mesaphorura macrochaeta Rusek, 1976 (Tullbergiidae) represent first records for the Hyrcanian Forests. To provide a comprehensive overview of Collembola biodiversity in the Hyrcanian forests, the present analysis of samples collected in Bula Forest was integrated with a thorough review of published records from the provinces of Mazandaran, Gilan and Golestan - all of which encompass significant portions of this ancient forest. This study offers one of the most comprehensive inventories of Collembola in the Bula Forest, providing insights into species distribution across microhabitats. The remarkable Collembola diversity underscores the importance of this region for biodiversity conservation.