Long distance dispersal in the assembly of floras: A review of progress and prospects in North America

Abstract

Here, we review progress and prospects to explicitly test for long distance dispersal biogeographic events. Long distance dispersal represents a “jump” across some kind of barrier, such as a topographic feature or a zone of unsuitable climate and may include repeated jumps, or stepping‐stone dispersals. Long distance dispersals were considered integral for explaining the organization of biodiversity at large and small scales by early biogeographers, such as Darwin and Wallace. Darwin, Wallace, and others envisioned that long distance dispersals were predictable events because the vectors for dispersal, such as animals, winds, and currents, behaved in non‐random ways. However, these early biogeographers found that dispersal was hard to observe, and, later, with the advent of the theory of Continental Drift, vicariance became regarded as a better scientific explanation for the arrangement of biodiversity, because it represented a falsifiable hypothesis. Thus, long distance dispersal was reduced to a nuisance parameter in biogeography; a random possibility that could never fully be ruled out in a scenario in which evidence supported vicariance. Today, there is strong interest to more fully integrate long distance dispersal into understanding the assembly and organization of biodiversity on earth. In this review, we discuss progress and prospects for explicitly testing long distance dispersal hypotheses including through uses of molecular, morphological, paleontological, and informatics methods. We focus on hypothesis testing of long distance dispersals involved in the assembly of the flora of North America, which is a robust preliminary study system on account of its extant and extinct biodiversity being well‐catalogued.

Untangling the taxonomy of the Cladrastis clade (Leguminosae: Papilionoideae) by integrating phylogenetics and ecological evidence

“…5). Their distribution areas are separated by desert and grassland in western interior North America (Harris & al., 2018). Hence, although St. sect.…”

A population genetics perspective on the evolutionary histories of three clonal, endemic, and dominant grass species of the Qinghai–Tibet Plateau: Orinus (Poaceae)

“…This alternative also requires that the original populations possessed high genetic diversity that has been preserved, at least partially, to present times. High diversity within ancestral populations often results from isolation by vicariance, rather than dispersal, events (Mayr, ; see also Harris, Ickert‐Bond, & Rodríguez, ; Kropf, Comes, & Kadereit, ). Vicariance within the QTP is often invoked to explain commonly observed patterns in the diversification of plant populations or species (e.g., Yang, Li, Ding, & Wang, ), especially the divergence of western lineages, such as O. thoroldii , from eastern ones, such as O. kokonoricus and O. intermedius .…”

Advances in biogeography in the age of a new modern synthesis

“…We hope that this set of papers will stimulate empirical studies as well as the development of methods for integrative biogeographic studies that simultaneously incorporate several lines of evidence, such as phylogenetic/phylogenomic relationships, divergence times, geographic range evolution, functional traits, and ecology, through Bayesian approaches to test biogeographic hypotheses at various scales (Harris et al, ; Hearn et al, ; Paetzold et al, ; Ree & Sanmartín, ; Klaus & Matzke, ).…”