Phylogeography of Camassia quamash in western North America: postglacial colonization and transport by indigenous peoples

Abstract

Recent human activities have spread numerous plant species across the globe, yet it is unclear to what degree historical human activities influenced plant dispersal. In western North America, Camassia quamash was one of the most important food plants for indigenous peoples, who transported its propagules either intentionally or accidentally. We investigated how human and natural dispersal might have contributed to the current pattern of spatial genetic structure in C. quamash by performing phylogeographical surveys at two geographical scales. We sequenced two noncoding regions of chloroplast deoxyribonucleic acid (DNA) in 226 individuals from 53 populations of C. quamash as well as 126 individuals from 21 populations of the non-food plant Zigadenus venenosus. Contrary to the expectation of anthropogenic transport, C. quamash populations did not exhibit weaker genetic structure than Z. venenosus populations. We also failed to find convincing evidence for signatures of transport. Instead, our data showed strong effects of past glaciation and geographical barriers of the mountains in the Cascade Range, Olympic Peninsula and Vancouver Island. West of the Cascades, the species appears to have largely migrated northward from a southern refugium after deglaciation, whereas few populations having a highly divergent haplotype might have survived in southwestern Washington. Our data suggest that despite substantial ethnobotanical evidence for anthropogenic transport, the current pattern of genetic structure of C. quamash does not show any detectable signatures of transport by indigenous peoples and is better understood as the result of natural dispersal processes.

Genetic Structure of Earthworm Populations at a Regional Scale: Inferences from Mitochondrial and Microsatellite Molecular Markers in Aporrectodea icterica (Savigny 1826)

“…For instance, the contribution of historical human activities to the current pattern of spatial genetic structure was documented for numerous plant species (e.g. [70], [71], [72]). Overall, our results suggest both past and ongoing anthropogenic impacts on A. icterica population genetic structure.…”

Comparative phylogeography of two African carnivorans presumably introduced into Europe: disentangling natural versus human-mediated dispersal across the Strait of Gibraltar

“…Although this method was first tested in a case study including introduced populations (Dupanloup et al. , 2002), it is only recently that SAMOVA has been used to investigate translocation patterns (Tomimatsu et al. , 2009).…”

Estimating Temporal Trend in the Presence of Spatial Complexity: A Bayesian Hierarchical Model for a Wetland Plant Population Undergoing Restoration

“…Camas is a facultative wetland forb species associated with seasonally-inundated wet prairies of northwestern USA and southwestern Canada [13], [14]. It reproduces from large heavy seeds and from bulb offsets that often results in patchily distributed but densely populated colonies (Figure 1).…”

“…It reproduces from large heavy seeds and from bulb offsets that often results in patchily distributed but densely populated colonies (Figure 1). The species was highly prized by indigenous people as a food source [13], [14], [15], and was the focus of major historical events that occurred during harvest that are today commemorated in two US National Park Service units. The extent of these wet prairie ecosystems has been drastically reduced in the region as a result of agricultural conversion and other land use practices [16], [17], [18].…”

“…These features are substantial and impede surface and subsurface hydrology. Given the dispersal limitations of the species [14], we considered zones to be functionally disconnected by these historic landscape features. The monitoring program was designed to reflect this spatial structure with a stratified sampling frame [20], ensuring that adequate sampling effort occurred in each of 5 recognized subpopulations (hereafter, “zones”; Figure 2).…”