How Ponto-Caspian invaders affect local parasite communities of native fish

Area of Science:

• Ecology
• Parasitology
• Invasive Species Biology

Background:

• Invasive species pose a significant global ecological threat, yet their impact on native parasite communities remains understudied.
• Parasites are crucial indicators of ecosystem health, making their response to invasions vital for understanding ecological dynamics.
• Ponto-Caspian species, including amphipods and gobiids, have invaded German rivers, acting as hosts for local parasites.

Purpose of the Study:

• To investigate how invasive species affect native fish parasite communities and dynamics.
• To analyze changes in host-parasite interactions over time due to invasions.
• To identify key parasite species associated with Ponto-Caspian invasions in German rivers.

Main Methods:

• Comparative study of parasite communities in four German rivers: three invaded (Rhine, Ems, Elbe) and one uninvaded (Schwentine).
• Utilized historical literature data to compare pre- and post-invasion parasite community status in Rhine and Elbe rivers.
• Identified specific parasite species (Pomphorhynchus laevis and Raphidascaris acus) and invasive fish hosts (gobiids).

Main Results:

• Significant differences observed in parasite communities of native fish between invaded and uninvaded rivers.
• Pomphorhynchus laevis and Raphidascaris acus identified as key parasite species linked to Ponto-Caspian invasions.
• Increased infection rates in native fish suggest parasite spill-back (R. acus) and spill-over (P. laevis).

Conclusions:

• Invasive Ponto-Caspian species alter native fish parasite communities, with implications for host-parasite interactions.
• Invasive fish act as competent hosts, facilitating parasite spill-back and spill-over dynamics.
• Consequences for native parasite communities include reduced prevalence and potential extinction of parasite species.