Drivers of mosquito presence and abundance in urban and garden ponds in a European city

Mosquitoes in urban environments are considered unpleasant by citizens, and they can represent serious health risks as vectors of pathogens. Invasive Aedes species are continuously spreading in Europe and have been increasingly reported from urban settlements. Some of these mosquito species have been associated with small artificial habitats. Therefore, their presence may also be expected in small plastic garden ponds, which are numerous in urban settings across many parts of Europe. Here, we aimed to determine whether urban waters host a high abundance of mosquitoes and to identify the potential abiotic, biotic and landscape drivers of mosquito presence and abundance in urban ponds. We sampled 93 urban ponds in the city of Budapest (Hungary), comprising 40 garden ponds and 53 other urban ponds of both natural and anthropogenic origin, across highly urbanised areas and suburban areas with a high green index. We collected data on macroinvertebrate communities, pond management, physico-chemical parameters, and pond characteristics (mainly morphology and vegetation cover) measured in situ . Two different mosquito detection techniques were used: dip-net sampling and environmental DNA (eDNA). While only one invasive species ( Aedes koreicus ) was detected, occurring in two ponds, several other species were present, including potential malaria vectors increasingly reported from urban environments: members of the Anopheles maculipennis complex, An. claviger and An. plumbeus . The presence and abundance of mosquitoes was negatively associated with fish presence, regardless of pond type. Contrary to expectations, urbanisation did not play a major role in explaining mosquito presence or abundance in the sampled ponds. These results highlight the importance of local pond characteristics, and particularly the association between fish presence and mosquito occurrence and abundance although the broader ecological effects of fish on pond communities should also be considered.