Dr Ljiljana Iveša1, Mr Andrea Bilajac1, Mr Edi Gljušćić1, Dr Shannen Maree Smith1
1Ruđer Bošković Institute, Center for Marine Research, Rovinj, Croatia
In the northern Adriatic Sea, the fucalean species Gongolaria barbata used to inhabit sheltered habitats such as bays, lagoons and rockpools, forming dense canopies from 0.5-3 m deep. After the general decline of fucalean species along the Istrian Coast (northern Adriatic), an isolated population of G. barbata was discovered in a lagoon and remains the only true marine forest of this species. Extreme winter and summer temperatures have not affected the population, suggesting that the specific environmental conditions in the lagoon serve as a refuge for G. barbata. In this study, abundance and morphological features of G. barbata in the lagoon were analysed in summer 2021. In addition, the effects of extremely warm temperature conditions on the thalli of G. barbata were tested experimentally under laboratory conditions. The survival of thalli from the lagoon was tested over two months in aquaria at temperatures of 28 °C, 30 °C, 32 °C, 34 °C and at a control temperature of 18 °C. Only at 34 °C was the temperature detrimental, causing complete thalli necrosis. At all other temperatures, despite some necrosis, thalli began to regenerate and thrive after being brought to 18 °C. Our results provide valuable insight into the temperature tolerance thresholds of G. barbata on a smaller scale. For future predictions on the vulnerability of fucalean populations in refugia such as lagoons and rockpools under changing climatic conditions, further studies on the ecological resilience and recruitment potential of G. barbata populations under the effects of extreme temperature conditions are needed.
Presentation Slides – Ljiljana Ivesa
Biography:
Ljiljana Iveša is a senior research associate at the Center for Marine Research in Rovinj, Ruđer Bošković Institute, Croatia. Her field of research includes taxonomy and ecology of macrophytobenthos (seaweeds and seagrasses), ecology of coastal habitats of the natural rocky shore and artificial hard surfaces and assessment of the ecological status of coastal waters using macroalgal assemblages. Her current research is focused on ecology of canopy-forming species of the order Fucales and distribution patterns of non-indigenous species.
