Abstract:

To elucidate the invasion status and driving factors of channeled apple snail (Pomacea canaliculata) in Shanghai’s circum-urban greenbelt park riparian waters, field surveys were conducted between 2023—2024. Spatiotemporal analysis revealed that invasion hotspots clustered in Baoshan, Putuo, Jiading, Changning, and Pudong districts, with snail density positively correlated with external hydrological connectivity. The population activity peaked in July—September, coinciding with an oviposition climax in July—August. Correlation analyses were conducted to identify the key environmental factors influencing snail distribution, activity, and reproduction; the results revealed that water temperature served as the pivotal driver. Specifically, both water temperature and air temperature exhibited a significant positive correlation with snail density and egg mass density. Snail density increased with the elevation of electrical conductivity and turbidity, but showed a decreasing trend with the increase in submerged macrophyte density, total nitrogen, and nitrate nitrogen. Egg mass density declined as NO₃^–-N and dissolved phosphorus concentrations rose, but displayed a positive trend with the increase in ammonia nitrogen concentration. Invasion severity assessment classified most sites as “Occurrence”, whereas specific loci reached “Severe outbreak”. It is imperative that Shanghai’s Circum-urban Greenbelt Parks implement control measures against Pomacea canaliculata.

Key words: Pomacea canaliculata, circum-urban greenbelt of Shanghai, invasion status, environmental factors, risk assessment