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Consideration of dispersal processes and northern refugia can improve our understanding of past plant migration rates in North America
Author(s) -
Snell Rebecca S.,
Cowling Sharon A.
Publication year - 2015
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1111/jbi.12544
Subject(s) - biological dispersal , refugium (fishkeeping) , ecology , colonization , temperate climate , vegetation (pathology) , seed dispersal , geography , climate change , population , pollen , biology , habitat , demography , medicine , pathology , sociology
Aim According to the palynological record, rapid plant migrations following the retreat of the last glacier were common in North America and Europe. However, providing an explanation for these rapid migration rates has been challenging considering modern‐day seed dispersal distances. We used the newly developed seed dispersal functionality in a hybrid dynamic global vegetation model ( DGVM ) to simulate two theories that have been proposed to explain rapid plant migrations: long‐distance seed dispersal and northern refugial populations. Location Idealized landscapes representing temperate and boreal regions of North America. Methods Vegetation migration rates for three species ( Acer rubrum , Fagus grandifolia and Picea glauca ) were simulated in response to climate change across a landscape. All simulations included long‐distance seed dispersal; however, we compared landscape colonization rates both with and without the presence of northern refugial populations. Results For all three species, the colonization rates were faster when there was a northern refugial population. Increasing the number of locations of refugia further increased the rate of landscape colonization, and this was most effective when refugial populations were spatially separated. The perceived migration rates (i.e. the time it took to spread the furthest distance away from the southern refugium) were approximately twice as fast when a refugium was present. For example, A. rubrum had a perceived migration rate of 119 m yr −1 without refugia and a perceived migration rate of 204 m yr −1 with a northern refugium. Main conclusions The simulated migration rates that matched the rapid migration rates observed in the pollen record for Acer were only achieved when both long‐distance dispersal and northern refugial populations were included in the simulations. Even with refugial populations, migration rates for P. glauca and F. grandifolia were slower than historical rates. The results of this study are consistent with the hypothesis that plant migration rates calculated from the pollen record overestimate the ability of most species to track rapid climate change.