Sequencing data for: Chronosequence of invasion reveals minimal losses of population genomic diversity, niche expansion, and trait divergence in the polyploid, leafy spurge

Rapid evolution may play an important role in the range expansion of
invasive species and modify forecasts of invasion, which are the backbone
of land management strategies. However, losses of genetic variation
associated with colonization bottlenecks may constrain trait and niche
divergence at leading range edges, thereby impacting management decisions
that anticipate future range expansion. The spatial and temporal scales
over which adaptation contributes to invasion dynamics remain unresolved.
We leveraged detailed records of the ~130-year invasion history of the
invasive polyploid plant, leafy spurge (Euphorbia virgata), across ~500km
in Minnesota, U.S.A. We examined the consequences of range expansion for
population genomic diversity, niche breadth, and the evolution of
germination behavior. Using genotyping-by-sequencing, we found some
population structure in the range core, where introduction occurred, but
panmixia among all other populations. Range expansion was accompanied by
only modest losses in sequence diversity, with small, isolated populations
at the leading edge harboring similar levels of diversity to those in the
range core. The climatic niche expanded during most of the range
expansion, and the niche of the range core was largely non-overlapping
with the invasion front. Ecological niche models indicated that mean
temperature of the warmest quarter was the strongest determinant of
habitat suitability and that populations at the leading edge had the
lowest habitat suitability. Guided by these findings, we tested
for rapid evolution in germination behavior over the time course
of range expansion using a common garden experiment and temperature
manipulations. Germination behavior diverged from early to late phases of
the invasion, with populations from later phases having higher dormancy at
lower temperatures. Our results suggest that trait evolution may have
contributed to niche expansion during invasion and that distribution
models, which inform future management planning, may underestimate
invasion potential without accounting for evolution.