The research team, affiliated with the Laboratory of Zoology at the University of Mons in Belgium, conducted field missions annually over four consecutive years, from 2022 to 2025. Sampling occurred in early July, covering a substantial elevational gradient from 910 meters to 2,474 meters across five municipalities in the Departments of Alpes-Maritimes and Alpes-de-Haute-Provence. The sampling strategy encompassed accessible areas near Peyresq, including hiking trails and roadside habitats, while also covering three distinct ecological zones: the montane level (approximately 910–1,600 m), characterized by mixed broadleaf and coniferous forests; the subalpine zone (1,600–2,200 m), dominated by coniferous forests such as *Larix decidua*; and the alpine zone (above 2,200 m), consisting of open habitats like alpine grasslands. Efforts were made to distribute sampling sites across slopes and solar exposure to account for local topoclimatic variability, although the study acknowledged that human pressure in the immediate area is low, the landscape has been significantly shaped by rural exodus, leading to the closure of montane grasslands.

The resulting dataset, which adheres to the Darwin Core standard, contained 4,502 specimens, of which 4,007 were identified to species level, representing 241 species. Analysis of the taxonomic coverage revealed thatAndrenidae, Apidae, Colletidae, Halictidae, Megachilidae, and Melittidae were the six families represented. Among the identified species, Bombus was the most abundant genus, with 1,954 specimens recorded. However, the study also noted that 496 specimens (11%) could not be identified to species level, primarily comprising *Bombus sensu stricto* subspecies and *Halictus aff. adjikenticus*. This rigorous taxonomic work, performed by specialists, ensured high data quality, with all specimens digitized and deposited in the collection of the University of Mons, making the findings openly accessible via GBIF.

To assess the completeness of the inventory, researchers employed species accumulation curves and the Chao1 estimator, an abundance-based method that predicts unseen species based on the frequency of rare taxa. Based on the full four-year dataset, the Chao1 estimator predicted a total species richness of 271.9 species, with a 95% confidence interval ranging from 248.2 to 295.7 species. The observed richness of 241 species therefore represents approximately 88.6% of the estimated bee fauna detectable during the mid-July sampling period. This finding underscores the significant biodiversity present in the region, yet the researchers cautioned that this estimate is limited, as the study was restricted to a single period of the season, meaning species with spring or autumn phenologies were likely missed, suggesting the total richness of the study area is likely higher than 275 species.

The conservation relevance of this inventory is highlighted by the presence of several threatened species. Of the 241 species identified, six are classified as threatened according to the European Red List of Bees, comprising one Endangered (EN) species and five Vulnerable (VU) species. Additionally, nine species were classified as Near Threatened (NT) and three as Data Deficient (DD). Mountain bees are particularly vulnerable as cold-adapted species are forced to shift upslope, facing limited dispersal possibilities between isolated massifs, while land-use changes, such as pastoral abandonment, can lead to habitat closure.

Specific threatened species documented include *Halictus carinthiacus* (Endangered), which is characteristic of alpine regions and inhabits open, thermophilic environments in montane and subalpine zones, and *Bombus pomorum* (Vulnerable), which is historically widespread but has been extirpated from large portions of its former range across Europe. Other vulnerable species identified include *Nomada rhenana*, *Lasioglossum euboeense*, *Lasioglossum laeve*, *Trachusa interrupta*, and *Bombus pomorum*. These species often exhibit specialized ecological niches; for example, *Lasioglossum euboeense* is a thermophilic species associated with warm, dry, steppic environments and dry grasslands, while *Trachusa interrupta* is specialized on Caprifoliaceae species, further illustrating the complex ecological relationships within this Alpine-Mediterranean interface.

The study also documented several species typical of the dual Alpine–Mediterranean character of the Peyresq area, such as *Bombus mendax*, *Nomada gransassoi*, *Megachile parietina*, and *Osmia inermis*. These species, whose European distributions are often restricted to mountainous regions, collectively emphasize the unique biogeographical value of the study system. For instance, *Megachile parietina* is specialized on Fabaceae and often builds nests on rocky substrates, while *Osmia inermis* is polylectic, showing visitation across four plant families but with a strong preference for Loteae. The presence of these regional specialists underscores the importance of maintaining open, flower-rich grasslands, which are crucial habitats for these specialized pollinators.

Despite the high quality of the curated dataset and its public accessibility through GBIF, the researchers identified inherent limitations. The sampling effort was heterogeneous and non-standardized across years, introducing biases in detectability and relative abundance. Furthermore, the spatial constraint to accessible areas around Peyresq and the temporal restriction to early July mean that the full extent of the regional bee fauna remains unexplored. Future research must aim to extend both the spatial and temporal scope of sampling, specifically by including lower-elevation Mediterranean habitats and conducting surveys across a broader seasonal window. Expanding sampling into currently under-surveyed areas, including protected zones like the Mercantour National Park, is essential to improve regional coverage and enhance the dataset’s value for long-term biodiversity monitoring and conservation strategies in these fragile mountain ecosystems.

Subject of Research: Assessment of wild bee diversity and conservation status in the southern French Alps.

Article Title: Wild bee diversity in the village of Peyresq and the surrounding areas in the southern French Alps

Article References: Benrezkallah, J., Brau, T., Carion, F., De Tandt, B., Devorsine, R., Dorio, L., Duez, T., Evrard, D., Flaminio, S., Ghisbain, G., Herinckx, A., Leconte, C., Lemaire, S., Maugendre, A., Michez, D., Naveaux, A., Reverte, S., Rigaut, B., Santerre, R., … Gérard, M. (2026). Wild bee diversity in the village of Peyresq and the surrounding areas in the southern French Alps. Biodiversity Data Journal, 14, Article e213911. https://doi.org/10.3897/BDJ.14.e213911

Image Credits: AI Generated

DOI: 10.3897/BDJ.14.e213911

Keywords: Wild Bees, Alpine Ecosystem, Biodiversity, Conservation, French Alps, Entomology, IUCN Red List, Pollinators, Mediterranean Biogeography, Wild, diversity, village