Urban Beetle Diversity in Natural History Collections—A Hundred-Year Perspective

Abstract

Natural history museum collections are essential for understanding biodiversity and environmental changes, especially in large cities with rapid urbanization. While the collaboration between curators and taxonomists with ecologists becomes more frequent, the museum collections still are not used to their full potential. This study aimed to digitize beetle specimens from Zagreb, which are kept in the Croatian Natural History Museum collections, provide recent nomenclature, analyse the proportion of currently endangered species, georeference, and compare the sampling locations with today’s iNaturalist citizen science records, as well as land cover changes between the time of collection creation and now. Comparing the sampling locations of collection specimens and citizen science records, it is possible to track the city’s expansion. Beetle family composition is more similar in the city centre than on the outskirts of Zagreb, where land cover changes are more pronounced. The districts in the northern part of Zagreb held higher numbers of threatened saproxylic beetles in both museum collections and citizen science records, highlighting the importance of urban parks and forests and providing insights into potential conservation threats. Museum collections have proved to be a valuable source of biodiversity records frozen in time, helping us track the urban beetle fauna decline.