This issue of Aquatic Invasions presents six articles on the presence and distribution of invasive species, showcasing diverse methods and findings.

The first article takes the readers to Italy where researchers looked at environmental conditions influencing the early colonization stage of Ludwigia hexapetala, an aquatic plant. The study demonstrated that L. hexapetala can grow in a wide range of environmental conditions in Italy. Based on this information, sites that are most at-risk of invasion were identified which aids in managing the species.

Aquatic invasions traverse to China to report on the effects of water temperature on the growth of invasive perennial herbaceous plant Myriophyllum aquaticum in the second article. Myriophyllum aquaticum is threatening ecosystems, including rice paddy fields and shallow lakes in southern China. Myriophyllum aquaticum growth and development were significantly affected by different water temperatures although this plant exhibits robust adaptability toward various temperatures which makes it a successful invader in China.

The third article takes the reader back to Europe to report on salinity tolerances of Conrad’s false mussel (Mytilopsis leucophaeata cochleata) and zebra mussel (Dreissena polymorpha) in Netherlands. The study revealed that the western part of the North Sea canal with relatively high salinity harbours the highest densities of M. leucophaeata cochleata in the Netherlands. The study also confirmed that M. leucophaeata cochleata coexists with D. polymorpha at salinities below 4.

Transatlantic crossing to the west is the fourth article which reported on a series of studies on the rediscovered calico crayfish (Faxonius immunis) population in Vilas County, Wisconsin, USA. Authors investigated the biotic interactions of rusty crayfish (F. rusticus) and F. immunis. The study revealed that although F. rusticus were consistently dominant over F. immunis, competition between the two species potentially prevents the spread of the calico crayfish.

Still in the USA, the fifth article reports on a benthic amphipod Apocorophium lacustre, rapidly establishing in the Illinois, Upper Mississippi, and Ohio river systems. Authors collected data to understand the factors influencing A. lacustre distribution and its threat to the Great Lakes. A. lacustre was found in the lower six pools of the Illinois Waterway and positively associated with temperature and downstream distance. These findings are of broad interest to risk assessment and invasion forecasting in other regions where A. lacustre have been or may be introduced.

Lastly, again still in the USA, the sixth article reports on the distribution of Asian swamp eels (Monopterus albus/javanensis) in Florida. This study used records from continuous long-term monitoring programs, sporadic monitoring studies, and online databases to reconstruct swamp eel presence across Florida. Swamp eels are currently spreading unchecked across Florida.