XVth Congress of the European Society for Evolutionary Biology, Lausanne, Switzerland, August 10th–14th 2015 [email protected] Climate change responses in canopy-forming seaweeds Jueterbock A. 1 , Hoarau G. 1 1 Faculty of Biosciences and Aquaculture, University of Nordland, Bodø, Norway Background Climate change affects seaweed meadows on temperate rocky shores Canopy-forming seaweeds provide foundational habi- tat for diverse ecosystems. Along their southern edges of distribution, however, seaweeds are threat- ened with extinction due to climate change. To pre- dict the impact of climate change on temperate and sub-polar seaweed meadows, we used a multidisci- plinary approach integrating ecological (migration, acclimation) and evolutionary (adaptation) responses to increased temperatures. year 1999 year 2010 90% abundance decline in Fucus serratus Migration Niche modeling [1], [4] Present-day conditions [5] Occurrences Variable 1 Variable 2 Variable 3 Realized niche space 2100 Species Distribution predictions Range-limiting factors TEMPERATE REGION ARCTIC REGION Biggest ecological changes expected in the warm temperate and Arctic regions A1B SREC predictions to year 2200 (intermediate CO 2 emission scenario) Fucus serratus Fucus vesiculosus Ascophyllum nodosum Fucus distichus Minimum SST ( ◦ C ) Mean SST ( ◦ C ) Max. SST ( ◦ C ) Mean SAT ( ◦ C ) Min. Diff. Atten. (m −1 ) Mean Salinity (PSU ) Mean Nitrate (moll −1 ) Min. Chlorophyll (mg /m 3 ) Mean Calcite (mol /m 3 ) SST ( ◦ C ) SAT ( ◦ C ) Variable 1 Variable 2 Variable 3 Acclimation Heat-stress response [3] Sampling of Fucus serratus Norway Denmark Brittany Spain Acclimation at 9 ◦ C, 4 weeks Heat stress, 6 individuals/population 1h Stress 24h Recovery 9 ◦ C 20 ◦ C 24 ◦ C 28 ◦ C 32 ◦ C 36 ◦ C T( ◦ C) Time Highest risk of extinction from an ancient glacial refugium in Spain. Risk to lose unique genetic variation Constitutive shsp gene expression before heat shock 23 weeks acclimation 7 weeks acclimation Normalized expression High constitutive stress in Spain Heat shock response of shsp gene expression after 24h recovery Fold change Reduced responsiveness in Spain Adaptation Genetic changes [2] Adaptive responsiveness highest in Brittany and likely insufficient in Spain Sampling of Fucus serratus (50-75 indiviuals/population) ∼ year 2000 ∼ year 2010 Spatial (environmental) effects Temporal changes 1 decade of selection Genotyping for 31 microsatellite markers (20 EST-linked) Effective population size N e (Reflecting adaptive capacity)) ∼ 2000 ∼ 2010 18 63 207 23 Norway Denmark Brittany Spain 32 61 210 26 Allelic richness ∼ 2000 ∼ 2010 3.1 4.6 8.0 4.0 Norway Denmark Brittany Spain 3.3 4.8 7.9 4.6 Significant decline Temporal outlier loci 0% 6% 23% 13% Norway Denmark Brittany Spain References [1] Jueterbock, A.; Tyberghein, L.; Verbruggen, H.; Coyer, J.A.; Olsen, J.L. & Hoarau, G. (2013): Climate change impact on seaweed meadow distribution in the North Atlantic rocky intertidal. Ecology; Evolution 5(3):1356–1373 [2] Jueterbock, A. (2013): Climate change impact on the seaweed Fucus serratus, a key foundational species on North Atlantic rocky shores. PhD Thesis, University of Nordland [3] Jueterbock, A.; Kollias, S.; Smolina, I.; Fernandes, J.M.O.; Olsen, J.L.; Coyer, J.A. & Hoarau, G. (2014): Thermal stress resistance of the brown alga Fucus serratus along the North-Atlantic coast: Acclimatization potential to climate change. Marine Genomics 24393606 [4] Jueterbock, A.; Smolina, I.; Coyer, J.A. & Hoarau G. (In Preparation): The fate of arctic Fucus distichus under climate change: an ecological niche modeling approach. [5] Tyberghein, L.; Verbruggen, H.; Pauly, K.; Troupin, C.; Mineur, F. & De Clerck, O. (2011): Bio-ORACLE: a global environmental dataset for marine species distribution modelling. Global Ecol. Biogeogr. 21(2):272–281 Conclusions Opening of new seaweed habitat in the Arctic and disappearance of seaweed habitat from warm-temperate regions can disturb species interactions and ecosystem services in the associated rocky-shore ecosystems. The integration of plastic and adaptive responses improved the predictive power of our niche models to project range shifts and extinction risks under climate change. The remaining key question is whether the adaptive potential of seaweeds is high enough to save their southern centers of genetic variation in ancient glacial refugia.