Understanding Habitat Features and Conservation Needs of the Italian Spring Goby (Orsinigobius punctatissimus) in the Lombardy springs area.

The Italian spring goby (Orsinigobius punctatissimus) is an endemic freshwater fish species considered Critically Endangered by the Italian IUCN committee. It is closely associated with highly specific, irreplaceable, and isolated habitats, such as springs and oxbow lakes of the river Po Valley. Lombardy constitutes half of the species' area, although in the past different authors reported this species as extinct in this region. Due to drought of springs, habitat loss, or fragmentation, its population in freshwater ecosystems of Lombardy has been estimated to have decreased by 70% compared to the last decades (Life_Gestire 2020). The current knowledge about the habitat of the Italian spring goby is outdated and based on old qualitative observations. Therefore, the aim of this project is to provide additional data to precisely identify the features of the species' habitat in Lombardy. In order to achieve this, we surveyed about 100 springs between 2023 and 2024, collecting data about biotic and abiotic habitat features. This allowed us to define the relationship between the Italian spring goby presence/abundance and the springs' characteristics. Results showed that the main predictive variables of the presence and abundance are altitude, substrate, average depth, illumination, and retention of organic debris. This study provides novel insights into the physical habitat preferences of the Italian spring goby. Furthermore, we also present updated and new data on the presence of this species in Lombardy.