Endemism and Speciation in the California Flora

Stebbins, G. Ledyard; Major, Jack

doi:10.2307/1942216

Cited by 384 publications

(309 citation statements)

References 23 publications

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“…As these populations frequently comprise the most evolutionarily divergent lineages (e.g. the light green haplotype at locus CO653303), they are often active areas of speciation [50,51]. Consequently, loss of the Iberian populations of C. crispus might have a major detrimental effect on the evolutionary potential of the species.…”

Section: Discussionmentioning

confidence: 99%

Unique genetic variation at a species' rear edge is under threat from global climate change

2011

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Global climate change is having a significant effect on the distributions of a wide variety of species, causing both range shifts and population extinctions. To date, however, no consensus has emerged on how these processes will affect the range-wide genetic diversity of impacted species. It has been suggested that species that recolonized from low-latitude refugia might harbour high levels of genetic variation in rear-edge populations, and that loss of these populations could cause a disproportionately large reduction in overall genetic diversity in such taxa. In the present study, we have examined the distribution of genetic diversity across the range of the seaweed Chondrus crispus, a species that has exhibited a northward shift in its southern limit in Europe over the last 40 years. Analysis of 19 populations from both sides of the North Atlantic using mitochondrial single nucleotide polymorphisms (SNPs), sequence data from two singlecopy nuclear regions and allelic variation at eight microsatellite loci revealed unique genetic variation for all marker classes in the rear-edge populations in Iberia, but not in the rear-edge populations in North America. Palaeodistribution modelling and statistical testing of alternative phylogeographic scenarios indicate that the unique genetic diversity in Iberian populations is a result not only of persistence in the region during the last glacial maximum, but also because this refugium did not contribute substantially to the recolonization of Europe after the retreat of the ice. Consequently, loss of these rear-edge populations as a result of ongoing climate change will have a major effect on the overall genetic diversity of the species, particularly in Europe, and this could compromise the adaptive potential of the species as a whole in the face of future global warming.

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Section: Discussionmentioning

confidence: 99%

Unique genetic variation at a species' rear edge is under threat from global climate change

2011

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“…One scenario envisages formerly widespread metallophyte species being excluded from non-serpentine sites during post-glacial reforestation because of their low competitiveness on nonmetalliferous soils; the serpentine populations would become separated and disjunct, and because of reduced gene flow progressively differentiate owing to drift and selection. This 'depleted' (or palaeoendemic) species scenario proposed by Stebbins (Stebbins, 1942;Stebbins and Major, 1965), and considered in the serpentine context by Kruckeberg (Kruckeberg, 1954), has been shown to have taken place in the serpentine subspecies Minuartia laricifolia ssp. ophiolitica in the Alps (Moore et al, 2013) and in the Streptanthus glandulosus complex (Mayer et al, 1994).…”

Section: Evolution Of Nickel Hyperaccumulation In Genus Alyssummentioning

confidence: 96%

Evolution of nickel hyperaccumulation and serpentine adaptation in the Alyssum serpyllifolium species complex

et al. 2016

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Metal hyperaccumulation is an uncommon but highly distinctive adaptation found in certain plants that can grow on metalliferous soils. Here we review what is known about evolution of metal hyperaccumulation in plants and describe a population-genetic analysis of the Alyssum serpyllifolium (Brassicaceae) species complex that includes populations of nickelhyperaccumulating as well as non-accumulating plants growing on serpentine (S) and non-serpentine (NS) soils, respectively. To test whether the S and NS populations belong to the same or separate closely related species, we analysed genetic variation within and between four S and four NS populations from across the Iberian peninsula. Based on microsatellites, genetic variation was similar in S and NS populations (average H o = 0.48). The populations were significantly differentiated from each other (overall F ST = 0.23), and the degree of differentiation between S and NS populations was similar to that within these two groups. However, high S versus NS differentiation was observed in DNA polymorphism of two genes putatively involved in adaptation to serpentine environments, IREG1 and NRAMP4, whereas no such differentiation was found in a gene (ASIL1) not expected to play a specific role in ecological adaptation in A. serpyllifolium. These results indicate that S and NS populations belong to the same species and that nickel hyperaccumulation in A. serpyllifolium appears to represent a case of adaptation to growth on serpentine soils. Further functional and evolutionary genetic work in this system has the potential to significantly advance our understanding of the evolution of metal hyperaccumulation in plants.

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“…The 1.5 million km of the northeastern United States feature only 5,500 plant species, only a few hundred of them being restricted to the region. (This review is based on Barbour and Major, 1988;California Department of Forestry and Fire Protection, 1988;Elias and Nelson, 1987;Jones and Stokes Associates, 1987;Keeley, 1988;Raven and Axelrod, 1978;Smith, 1987;Smith and Berg, 1988;Stebbins, 1980;Stebbins and Major, 1965).…”

Section: Mediterranean-type Areasmentioning

confidence: 99%