The rate of spread of invasive species into new localities is alarming. It is increasingly common that several such species meet at the same locality. These species put severe pressure on local populations of native species. Due to their ability to effectively utilize food resources, changes in the food webs could possibly result in collapses of entire ecosystems.

In this study, we focused on a locality with two, respectively three co-occurring non-native crayfish species – marbled crayfish, spiny-cheek crayfish, and red swamp crayfish. These species belong to important invasive species in Europe. Using stable isotopes analysis, we investigated their trophic niches at the studied locality. We found that the trophic niches of spiny-cheek crayfish and marbled crayfish are reduced in the presence of red swamp crayfish and that this species preys on the formerly mentioned. Thus, we had the opportunity to get a deeper insight into their trophic relationships.

Detailed information can be found in: Veselý, L., Ruokonen, T.J., Weiperth, A., Kubec, J., Szajbert, B., Guo, W., Ercoli, F., Bláha, M., Buřič, M., Hämäläinen, H., Kouba, A., 2021. Trophic niches of three sympatric invasive crayfish of EU concern. Hydrobiologia 848: 727–737.

Fig. 1. Corrected Standard Ellipse Area representing the trophic niche width of the crayfish in the upper (left) and lower (right) sections of the Barát thermal tributary. Specific points and colors represent given species (marbled crayfish = blue ellipse and blue square, spiny-cheek crayfish = gray ellipse and grey circle, red swamp crayfish = red ellipse and red triangles). Ellipses overlap suggest similar food source utilization among crayfish.