Potential distribution of two economic laver species-Neoporphyra haitanensis and Neopyropia yezoensis under climate change based on MaxEnt prediction and phylogeographic profiling

Climate change is altering geographic and phylogeographic distribution of macroalgae, laying great impacts on their conservation and sustainable utilization. The potential distribution of two dominant cultured seaweeds-Neoporphyra haitanensis and Neopyropia yezoensis was predicted under present and three representative concentration pathways (RCP 2.6, 4.5, 8.5) for 2050 s using the maximum entropy model (MaxEnt). The area under the receiver operating characteristic curve (AUC) was 0.998 for N. haitanensis and 0.992 for N. yezoensis, indicating high modelling accuracy. Sea surface temperature contributed mainly to the models. In addition to the predominant distribution in their native habitats in Northwest Pacific, high suitability along the east coast of North America and trans-hemispheric distribution was predicted for both species. In 2050 s, high-latitudinal and offshore expansion was observed, increasing over the present distribution area by 10.75%∼26.13% for N. haitanensis and 18.97%∼26.48% for N. yezoensis. Current geographic distribution centroid of N. yezoensis was located in Seocheon and the centroid shifted northeastward to the Sea of Japan in 2050 s. The most specific haplotypes or high genetic variations (based on chloroplast rbcL sequences) were identified in both regions. Current and future centroids of N. haitanensis were located in East China Sea, where the highest genetic diversity was identified. The overall haplotype and nucleotide diversity of both species was at low levels while the haplotype distribution showed spacial heterogeneity, more diversified at the convergence zones of warm and cold ocean currents. The overlapping between N. yezoensis and N. haitanensis geographic distribution centers and species’ genetic diversity hotspots implied their ability to adapt to future climate change. These findings provided vital information for conservation and sustainable utilization of these important intertidal seaweeds to address the global climate challenges.