Over the last decades, Fucus vesiculosus, an ecologically important macroalga in the German Baltic Sea, has shown a massive retreat from the deeper zones of its former distribution presumably due to low light co-acting with other potential stressors such as high temperature, fouling, and grazing. Global warming may increase abiotic as well as biotic pressures and exacerbate environmental conditions in coastal ecosystems. The present study focussed on the effects of single or subsequently combined stressors on survival and palatability of juvenile F. vesiculosus. Fucoid offspring were exposed to high temperature and/ or feeding pressure. Feeding preference of Idotea baltica was quantified in a pellet assay calculated as an odds ratio. High temperature significantly impaired the survival of juvenile fucoids. Neither single nor combined stress considerably influenced the feeding preference of I. baltica. Surprisingly I. baltica strictly avoided pellets with juvenile F. vesiculosus compared to adult F. vesiculosus. Avoidance tended to be less pronounced in juvenile fucoids previously stressed by high temperature. Obviously grazing does not induce anti-herbivore defence, but rather the young plants appeared constitutively well-protected against isopod feeding. These results contradict the prevailing opinion that juvenile F. vesiculosus is more susceptible to herbivore grazing than adult F. vesiculosus.
Content:
Regional Activities:
Looking Back on Five Years of RADOST;
RADOST Final Conference Takes Stock, Looks Ahead;
Looking Back: Comments on RADOST;
Bay of Kiel Climate Alliance Seeks to Make the Region a Climate Conscious Vacation Destination;
What’s Next after RADOST?
New Web Tool: “Northern German Climate Monitor”;
International Activities:
RADOST at the European Maritime Day;
Contributions wanted for ECCA Conference 2015;
Publications:
Communicating Adaptation to Regional Climate Change Impacts;
New RADOST reports;
Third Special Edition of “Coastal & Marine“