Multifaceted biodiversity distributions in the Eastern Bering Sea over the recent decades, 1990-2018

Irene D. Alabia1, Jorge García Molinos1, Sei-ichi Saitoh1, Takafumi Hirata1, Toru Hirawake2 and Franz J Mueter3, (1)Hokkaido University, Arctic Research Center, Sapporo, Japan, (2)Hokkaido University, Faculty of Fisheries Sciences, Hakodate, Japan, (3)UAF, College of Fisheries and Ocean Sciences, Juneau, AK, United States
The Eastern Bering Sea (EBS) is one of the world’s most productive marine environments exposed to drastic climate changes, marked by extreme fluctuations in temperature, seaice concentration, timing and duration. These climatic changes elicit responses in species distribution, abundance, and community composition. Here, we examined the spatial and temporal structures of alpha and beta-diversity across multiple facets (taxonomic and phylogenetic) using species occurrence and abundance data from the NOAA bottom trawl surveys in the EBS over the last 29 years. Our biodiversity analyses focused on 159 marine taxa (69 vertebrates and 90 invertebrate species) that were consistently identified for at least 20 years within the study duration. We divided our 29-year study span into warm (13 years) and cold (16 years) periods to examine and compare the patterns in taxonomic richness, phylogenetic diversity, mean phylogenetic distances, and community assemblages at each prevailing climatic regime. The major abiotic drivers (temperature, depth, seaice concentration and number of days with seaice coverage) of changes for each biodiversity facets will be then assessed using random forest analysis. In doing so, we hope to capture the spatio-temporal patterns of biodiversity redistributions and their environmental drivers in the EBS under contemporary climate. The results from the multifaceted diversity analyses, in turn, could provide information critical for advancing conservation and management strategies in anticipation of climate change impacts.