Global Kelp Biogeography: Past, Present and Future

Abstract

Aim

We review the past, present and future biogeography of kelps (Order Laminariales), integrating recent advances in phylogeography, population genomics and species distribution modelling to outline the key patterns and processes relevant to kelp biogeography.

Location

Global.

Taxa

Kelp (Order Laminariales).

Methods

We synthesized recent research on the biogeography of kelps, spanning molecular phylogeography to studies aimed at inferring future species distributions. Using this information, we reconstruct past dispersal pathways that kelp species took across ancient oceans, present patterns in kelp biogeography and summarize the changes in kelp diversity and distributions that are expected by the end of the 21st century.

Results

Kelps originated in the North Pacific ~30–35 Ma, which remains the global centre of kelp species diversity. Kelps then dispersed globally via two primary routes: northward through the Bering Strait into the Arctic and Atlantic Oceans, and southward across the equator into the Southern Hemisphere through at least five or six independent trans-equatorial dispersal events. Modern biogeographic patterns have been altered by large-scale climatic impacts, as well as human-mediated species introductions. Future projections indicate continued impacts of climate change on the distribution of kelp species. In particular, we expect species richness to increase at high latitudes and decrease at lower latitudes, depending on the availability of coastline.

Main Conclusions

The global distribution of kelps reflects a complex history of evolutionary diversification, climate change and human influence that continues to reshape the biogeographic distribution of contemporary species. Integrating phylogeographic information, ecological observations and evidence from distribution modelling reveals that kelp biogeography has and will continue to be dynamic through time, providing a powerful case study for understanding how marine foundation species respond to past and future environmental change.