Data from: On the road: postglacial history and recent expansion of the annual Atriplex tatarica in Europe

Aim: The Holocene history of annual plant species is at best shadowy
because, for most, the palaeobotanical data is scarce or absent. Hence,
there is limited information on their glacial refugia and postglacial
colonisation pathways. Also, little is known how human activity has
affected their expansion. Here, we outline the joint influences of
postglacial colonisation and recent expansions on the genetic diversity of
the continental, sub-halophyte species Atriplex tatarica during the late
Pleistocene and the Holocene. Location: Europe. Taxon: Atriplex tatarica
(Amaranthaceae) Methods: We analysed 780 individuals from 80 populations
throughout the current European distribution range, employing chloroplast
DNA sequences and microsatellite markers. Results: Five haplotype lineages
were recognised based on the results of the cpDNA phylogenetic analyses.
These lineages originated 0.43−0.22 my BP. Bayesian clustering analyses
divided populations of A. tatarica into two clusters: (i) populations in
the Pannonian Basin and the Bohemian Massif and (ii) populations in the
North European Plain, the Balkan Peninsula, the Carpathian Arc and the
Pontic region. The ABC approach provided the strongest statistical support
for a model proposing refugia in the Balkan Peninsula and the Pannonian
Basin. Expansions from these refugia occurred around 7,000 yr BP. Main
conclusion: Atriplex tatarica represents a continental species growing
exclusively in man-made habitats. It serves as a phylogeographic model for
annual ruderal taxa currently spreading in central Europe along highways
and representing a large group of alien plant species, the so-called
archaeophytes. Atriplex tatarica survived the last glaciation in both a
southerly located Balkan refugium and in a more northerly refugium in the
Pannonian Basin. From these, the species has colonised Europe as a result
of expansion of humans and the anthropogenic climate change. The massive
colonisation of central north Europe is very recent, with the expansion
estimated to have occurred only hundreds of years ago.