The origin of the serpentine endemic Minuartia laricifolia subsp. ophiolitica by vicariance and competitive exclusion

Abstract

Serpentine soils harbour a unique flora that is rich in endemics. We examined the evolution of serpentine endemism in Minuartia laricifolia, which has two ecologically distinct subspecies with disjunct distributions: subsp. laricifolia on siliceous rocks in the western Alps and eastern Pyrenees and subsp. ophiolitica on serpentine in the northern Apennines. We analysed AFLPs and chloroplast sequences from 30 populations to examine their relationships and how their current distributions and ecologies were influenced by Quaternary climatic changes. Minuartia laricifolia was divided into four groups with a BAPS cluster analysis of the AFLP data, one group consisted only of subsp. ophiolitica, while three groups were found within subsp. laricifolia: Maritime Alps, north-western Alps and central Alps. The same groups were recovered in a neighbour-joining tree, although subsp. ophiolitica was nested within the Maritime Alps group of subsp. laricifolia. Subspecies ophiolitica contained three different chloroplast haplotypes, which were also found in the Maritime Alps group of subsp. laricifolia. Given its high genetic diversity, subsp. ophiolitica appears to have arisen from subsp. laricifolia by vicariance instead of by long-distance dispersal. Genetic and geographic evidence point to the Maritime Alps populations of subsp. laricifolia as the closest relatives of subsp. ophiolitica. We hypothesize that M. laricifolia was also able to grow on nonserpentine rocks in the northern Apennines during glacial periods when the vegetation was more open, but that only the serpentine-adapted populations were able to persist until the present due to their competitive exclusion from more favourable habitats.

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

“…However, no differences in genetic diversity between metallicolous and nonmetallicolous populations have been consistently found in the species investigated to date (Vekemans and Lefèbvre, 1997;Quintela-Sabarís et al, 2010), such as A. halleri (Pauwels et al, 2005), A. bertolonii (Mengoni et al, 2003) and M. laricifolia ssp. ophiolitica (Moore et al, 2013), and neither have they been found here (Table 2). However, the bottlenecks in question would need to have been quite recent to stand out in this way, and gene flow and accumulation of new mutations would later erode the signal of any putative bottlenecks (Vekemans and Lefèbvre, 1997).…”

“…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). In a subsequent phase, non-serpentine progenitors can re-invade and come into secondary contact with serpentine populations (depleted species-recolonisation scenario).…”

Prolonged isolation and persistence of a common endemic on granite outcrops in both mesic and semi‐arid environments in south‐western Australia

“…The patterns revealed in S. glauca and K. pulchella illustrate that isolation on granite outcrops is not restricted to rare species, but appears also to be common in widespread granite‐endemic species. This pattern of long‐term isolation, indicating SWAFR granite outcrops as ancient islands, differs from other phylogeographical studies of inselberg and serpentine endemics, where Pleistocene climatic fluctuations had influenced range dynamics (Mayer & Soltis, ; Boisselier‐Dubayle et al ., ; Moore et al ., ).…”

“…This result builds on the general patterns of population differentiation that have been observed in some (e.g. Barbará et al ., ; Boisselier‐Dubayle et al ., ; Moore et al ., ) but not all (see Duputié et al ., ) rocky inselberg and serpentine plants, through providing an understanding of the trends in population isolation of edaphic islands in common species and in mesic versus semi‐arid environments.…”

Molecular Biogeography of the High Mountain Systems of Europe: An Overview

“…the plants Adonis distorta, Androsace mathildae, Aquilegia bertoloni, Soldanella calabrella), hence supporting the evolutionary independence of this area. However, many taxa also show high similarity with counterparts in the south-western Alps and offer evidence of glacial gene flow between these mountain ranges during cold phases (Moore et al 2013;Louy et al 2014b). A particularly interesting case involves representatives of the beetle species complex Oreina alpestris/speciosa.…”