Disturbance driven co-diversification of host and epibiota
Genomic analyses reveal that past habitat disturbance has strongly
shaped contemporary patterns of genetic variation among populations of
interacting intertidal taxa. In the current study, both intertidal
seaweeds (D. antarctica and D. poha ) and their obligate
epifauna (L. segnis and O. neglectus ) show abrupt shifts
in genotype composition that are both spatially and temporally linked to
historic tectonic disturbance. These multispecies signatures thus
highlight community-wide effects of large-scale ecological disturbance.
Indeed, direct observations from recent coastal uplift events in New
Zealand and Chile have reported that vertical displacement of tidal zone
causes widespread extinction of intertidal macroalgae, creating
substantial new intertidal habitats for recolonization (Castilla 1988;
Ortega et al. 2014; Clark et al. 2017; Schiel et
al. 2019). Our genomic findings confirm an historic uplift-driven
elimination of intertidal macroalgal communities, followed by rapid and
parallel recolonization of empty intertidal habitats. These strong and
concordant genomic signatures of historic disturbance persist to present
because early-recolonizing lineages can reach high densities and
subsequently exclude late-arriving individuals (Ibrahim et al.1996; Waters et al. 2013; De Meester et al. 2016), thus
facilitating strong genetic differentiation between ancestral versus
newly colonized areas (Excoffier et al. 2009).