“Influence of climate change on behavioural traits of Palaemon elegans, an invasive species in the Baltic Sea

Abstract

The Baltic Sea is undergoing changes due to climate change, including an increase in its temperature.This may in turn lead to changes in the traits of the species that inhabit it, including non-endemic,invasive species.Palaemon elegans is a species native to the Atlantic Ocean that has been present in the Baltic Sea since the beginning of this century. Abilities such as high thermal tolerance make it successful in colonising new ecosystems like the brackish waters of this sea. However, less is known about the behavioural traits’ adaptions to these changes. This study aims then to find out how climate change may affect the behaviour of this species. To do so, five behaviours expressed by this species were observed and analysed to see how temperature change, seabed composition and body size influence their expression. The behaviours analysed were aggressiveness, movement frequency, reaction to food stimulus, number of feeding interactions and shelter-seeking.Analyses were conducted using ten-minute videos with ten specimens of P. elegans placed in water tanks and interacting in ecosystems representations with elements typical of the seabed where thisspecies lives, both vegetation and rocks. Student's t-tests in R were then performed to test the significance of possible differences between the behaviours studied and the three parameters that may influence their expression.The results obtained show that the increase in water temperature might indeed lead to an increase in the frequency of the five behaviours studied except in aggressiveness. On the other hand, it was found thatthe composition of the ecosystem does not have a significant influence overall, while body size has a major influence on feeding related behaviours. Therefore,knowing more about changes in the behavior of species susceptible to climate change can be helpful to understand how biodiversity and its distribution will vary in the not so distant and changing future and what consequences it may generate at the ecosystem level.