Data from: Combining niche-shift and population genetic analyses predicts rapid phenotypic evolution during invasion

Rapid evolution of non-native species can facilitate invasion success, but
recent reviews indicate that such microevolution rarely yields expansion
of the climatic niche in the introduced habitats. However, because some
invasions originate from a geographically restricted portion of the native
species range and its climatic niche, it is possible that the frequency,
direction and magnitude of phenotypic evolution during invasion has been
underestimated. We explored the utility of niche-shift analyses in the red
seaweed Gracilaria vermiculophylla, which expanded from the northeastern
coastline of Japan to North America, Europe and northwestern Africa within
the last 100 years. A genetically-informed climatic niche shift analysis
indicates that native source populations occur in colder and highly
seasonal habitats, while most non-native populations typically occur in
warmer, less seasonal habitats. This climatic niche expansion predicts
that non-native populations evolved greater tolerance for elevated heat
conditions relative to native source populations. We assayed 935
field-collected and 325 common-garden thalli from 40 locations and as
predicted, non-native populations had greater tolerance for
ecologically-relevant extreme heat (40ºC) than did Japanese source
populations. Non-native populations also had greater tolerance for cold
and low-salinity stresses relative to source populations. The importance
of local adaptation to warm temperatures during invasion was reinforced by
evolution of parallel clines: populations from warmer, lower-latitude
estuaries had greater heat tolerance than did populations from colder,
higher-latitude estuaries in both Japan and eastern North America. We
conclude that rapid evolution plays an important role in facilitating the
invasion success of this and perhaps other non-native marine species.
Genetically-informed ecological niche analyses readily generate clear
predictions of phenotypic shifts during invasions, and may help to resolve
debate over the frequency of niche conservatism versus rapid adaptation
during invasion.