AFLP markers reveal high clonal diversity and extreme longevity in four key arctic‐alpine species

Abstract

We investigated clonal diversity, genet size structure and genet longevity in populations of four arctic-alpine plants (Carex curvula, Dryas octopetala, Salix herbacea and Vaccinium uliginosum) to evaluate their persistence under past climatic oscillations and their potential resistance to future climate change. The size and number of genets were determined by an analysis of amplified fragment length polymorphisms and a standardized sampling design in several European arctic-alpine populations, where these species are dominant in the vegetation. Genet age was estimated by dividing the size by the annual horizontal size increment from in situ growth measurements. Clonal diversity was generally high but differed among species, and the frequency distribution of genet size was strongly left-skewed. The largest C. curvula genet had an estimated minimum age of c. 4100 years and a maximum age of c. 5000 years, although 84.8% of the genets in this species were <200 years old. The oldest genets of D. octopetala, S. herbacea and V. uliginosum were found to be at least 500, 450 and 1400 years old, respectively. These results indicate that individuals in the studied populations have survived pronounced climatic oscillations, including the Little Ice Age and the postindustrial warming. The presence of genets in all size classes and the dominance of presumably young individuals suggest repeated recruitment over time, a precondition for adaptation to changing environmental conditions. Together, persistence and continuous genet turnover may ensure maximum ecosystem resilience. Thus, our results indicate that long-lived clonal plants in arctic-alpine ecosystems can persist, despite considerable climatic change.

Small-scale patterns in snowmelt timing affect gene flow and the distribution of genetic diversity in the alpine dwarf shrub Salix herbacea

“…Third, a disruption of the microhabitat differentiation in years with extreme weather could create gene flow across an otherwise stable phenological barrier. Because some S. herbacea clones may live for several centuries (Beerling, 1998;De Witte et al, 2012), such a sporadic connection may be more frequent in the dwarf willow than in other plant species. Finally, the absence of population differentiation in the presence of phenological barriers may be due to recent ancestry.…”

“…Its estimated maximum age is 450 years (De Witte et al, 2012), and its estimated maximum horizontal size is 10 m (Stamati et al, 2007). Average age and genet size have been reported to be o100 years (De Witte et al, 2012) and 0.96 m 2 (Reisch et al, 2007), respectively. We sampled S. herbacea at 12 sites in the Swiss Alps near Davos in the summer of 2010 (Table 1), on three different mountains (Schwarzhorn, Jakobshorn and Wannengrat, on average 10.3 km apart).…”

“…herbacea is a dioecous, prostrate dwarf shrub with wind-dispersed seeds that grows as an extensive ramifying system (Beerling, 1998). Its estimated maximum age is 450 years (De Witte et al, 2012), and its estimated maximum horizontal size is 10 m (Stamati et al, 2007). Average age and genet size have been reported to be o100 years (De Witte et al, 2012) and 0.96 m 2 (Reisch et al, 2007), respectively.…”

Sexual reproduction efficiency and genetic diversity of endangered Betula humilis Schrk. populations from edge and sub-central parts of its range

“…However, the patterns of genetic structuring within and between populations established after the glacial retreat have since been modified by the life history traits of species (e.g. mating system, clonal reproduction and seed dispersal -Glémin et al 2006;Alsos et al 2012;De Witte et al 2012), the ongoing evolutionary processes that shape current populations (e.g. mutation, selection, genetic drift and gene flow - Mitton and Duran 2004;Jadwiszczak et al 2012b) as well as fragmentation of habitats resulting mainly from anthropopression .…”

Geographical differentiation of Dryas octopetala in Europe based on morphological features

“…Dryas octopetala reproduces both generatively and clonally, which is typical for plants of cold climates, and individuals can reach the maximum age of 500 years, but populations are predominated by young genets. Such a structure of the population enables the species to adapt to changing environmental conditions and persist in them (de Witte et al 2012). Although seeds of Dryas octopetala are adapted for long-distance wind dispersal, the rates of seedling establishment are low which limits the flow of new genotypes into populations.…”