PleistoDist: A toolbox for visualising and quantifying the effects of Pleistocene sea-level change on island archipelagos

Abstract

Pleistocene sea-level change played a significant role in the evolution and assembly of island biotas. The formation of land bridges between islands during Quaternary glacial maxima, when sea levels were up to 120 metres below present-day sea levels, often facilitated historical dispersal and gene flow between islands that are today geographically disconnected.Despite this, relatively few studies have attempted to quantify the effects of Pleistocene sea-level change on the evolution of island species assemblages.Here we present PleistoDist, an R package that allows users to visualise and quantify the effects of Pleistocene sea-level change on islands over time, and test multiple temporally explicit hypotheses of inter-island dispersal and community assembly.Re-analysing published datasets, we demonstrate how using PleistoDist to account for historical sea-level change can provide greater explanatory power when analysing extant island communities, and show how population genetic simulations can be used to generate spatiotemporally explicit neutral expectations of population genetic structure across island archipelagos.

Global raster dataset on historical coastline positions and shelf sea extents since the Last Glacial Maximum

“…They are also indispensable for testing relationships between species richness and island surface area (ISAR) and isolation (ISIR), especially in the context of extinction debt. Tan et al ( 2022 ) developed an R package to assess the effects of palaeo‐coastline change of archipelagos on gene flow and patterns of community assemblages. Our model can be adapted to study the spatio‐temporal dynamics of marine habitats of specific depth ranges; for instance, coral seas habitats shallower than 40 m. The patterns emerging from the sea‐level rise since 26 kyr bp indicate which areas (shelf seas and islands) respond most radically to sea‐level rise.…”

PleistoDist: A toolbox for visualising and quantifying the effects of Pleistocene sea‐level change on island archipelagos

“…PleistoDist is a free and open‐source package written in R, available at https://github.com/g33k5p34k/PleistoDist (Tan & Gyllenhaal, 2022). The case studies described above are available as vignettes from https://davidbirdtan.com/pleistodist/ and archived on Zenodo at https://doi.org/10.5281/zenodo.7241068 (Tan, 2022).…”