Modelling the global invasion potential of Pelagia noctiluca under climate change.

Invasive species are recognised as a major driver of global biodiversity loss. In marine ecosystems, blooms of non-native jellyfish species are widely perceived to be increasing globally, with impacts on food webs, ecosystem services, biogeochemical cycles, and coastal livelihoods. Pelagia noctiluca (Forsskål, 1775) is a jellyfish native to the Mediterranean Sea and the northeastern Atlantic Ocean, but has been increasingly associated with recurrent bloom events in non-native regions, which cause adverse ecological and socio-economic impacts. Here, we use an ensemble species distribution modelling framework implemented in the biomod2 package in R to assess the global habitat suitability of P. noctiluca, and to evaluate its present-day and future invasion potential across non-native marine ecosystems. Based on species occurrence records and eight environmental variables, our results indicate that P. noctiluca exhibits high habitat suitability in temperate and subtropical coastal waters, driven primarily by salinity, primary productivity, and sea surface temperature. Ultimately, by projecting a substantial future habitat contraction, our findings strongly contradict the general perception that jellyfish blooms and distribution will universally increase under global climate change.