Thermal vulnerability of native and introduced freshwater gastropods: predicting winners and losers in a warming tropical community

ABSTRACT A common assumption within invasion biology is that successful introduced species are physiologically more competent than native species. Temperature in freshwater ecosystems is a primary factor shaping species distribution and abundance, making thermal tolerance a critical trait to predict the effects of climate change on species locally adapted to their abiotic environment. We hypothesized that introduced species would have a broader thermal tolerance range (TTR) than native species. To test this, we evaluated the thermal tolerance of four native freshwater gastropods species (Aroapyrgus clenchi, Pyrgophorus coronatus, Mexinauta impluviatus and Pomacea flagellata) and two introduced species (Tarebia granifera and Melanoides tuberculata) in the Pantanos de Centla Biosphere Reserve, Mexico. Temperature tolerance ranges were determined using progressive temperature increments of eight temperatures between 19 and 35 °C. All species exhibited a Gaussian distribution in their thermal tolerance and survived relatively high temperatures, as is expected for tropical species. However, species-specific analyses showed that a wider thermal capacity was not an attribute of introduced species. The results show that the native Pomacea flagellata exhibited the widest TTR (38.3 °C), a value that exceeded the TTRs of the introduced species. The smallest native species, Aroapyrgus clenchi and Pyrgophorus coronatus, displayed the lowest thermal capacity, positioning them as potential ‘losers’ under predicted climate warming. Our findings highlight the importance of taking a dynamic perspective when evaluating physiological traits in the context of biological invasions, where evaluating physiological traits of both introduced and native species is critical for predicting community responses to global change and for prioritizing conservation efforts.