Giada Riva1,2, Gauff Robin1,2, Almetwaly Hassan1, De Battisti Davide1, De Lauretis Serena1, Macrì Nicole1,2, Noguès Quentin1, Riedel Joana1, Barausse Alberto1,2, Patarnello Tomaso1,2, Airoldi Laura1,2
1Università di Padova, Italy - 2NBFC National Biodiversity Future Center, Italy
Urbanization is a global phenomenon that is increasingly impacting natural environments, from terrestrial to aquatic ecosystems. On land, extensive studies show that urbanization leads to biotic homogenization - the process by which two or more spatially separated communities become increasingly similar over time - by selectively filtering for certain species while facilitating the dispersal of others. However, the effects of urbanization on marine biotic homogenization remain poorly understood. To address this knowledge gap, we conducted a mobile campaign in September October 2023, sampling urban, periurban and natural rocky habitats across seven biogeographical sectors spanning about 2000 km of the Italian coastline. Our study aimed to assess the possible effects of marine urbanization on the taxonomic, structural, and functional homogenization of shallow subtidal benthic communities. Data were collected through photographic and destructive sampling of species associated to artificial and natural hard substrata, while key ecosystem functions were assessed through in situ measurements of benthic metabolism and photosynthetic activity. We observed a consistent decrease in species and functional richness from natural to urban sites, indicating strong environmental filtering in urban habitats. However, none of the tested metrics provided evidence of biodiversity or functional homogenization. This contrasting result with terrestrial systems is likely driven by the distinct mechanisms of species dispersal in marine environments, where human activities - such as ship traffic - play an important role in driving species distribution. Our findings challenge the assumption that urbanization leads to biotic homogenization in marine ecosystems in the same way it does on land. A deeper understanding of how urbanization affects marine biodiversity and ecosystem function is needed, with implications for conservation and management strategies in coastal environments.
Biography
Second year PhD student in marine ecology at the University of Padova, Italy. She graduated in Marine Biology with a master’s degree thesis on the impact assessment of bottom trawling on seabed integrity. She is currently working on a PhD project, in collaboration with the National Biodiversity Future Centre, about the monitoring of biodiversity in urbanized marine coastal areas along the Italian coasts. She likes macroalgae taxonomy and diving.