Data and code from: Temperature affects the relative importance of phenotypic plasticity and natural selection contributing to the niche breadth of invasive plants

Plant species adapt to changing climates through phenotypic plasticity and
natural selection, affecting invasive plants’ niche breadth. However, our
limited understanding of how temperature affects the relative importance
of phenotypic plasticity and natural selection contributes to invasive
plants' niche breadth across latitudes. Here, we used a model system,
the salt marsh grass Spartina alterniflora, native to the United States
but was introduced into China in 1979, spreading over 20° latitude. We
collected seeds of S. alterniflora from nine locations across different
latitudes in China, measured phenotypic plasticity, natural selection, and
niche breadth of germination and post-germination traits in three
greenhouse common garden experiments (low-latitude: 20.9° N, mid-latitude:
28.3° N, and high-latitude: 37.4° N) spread across the latitude in China.
We found that germination time, germination percentage, germination index,
and seedling survival all increased with latitude within the common
gardens. Germination time showed a lower slope at the high-latitude common
garden sites, but the other variables had higher slopes at the
high-latitude common garden sites. The phenotypic plasticity of
germination and post-germination traits across latitudes decreased with
increasing latitude of origin, similar to germination niche breadth.
Furthermore, temperature negatively affected the natural selection but
positively affected the phenotypic plasticity. These results indicated
that climate-driven selection favors sexual reproduction at higher
latitudes and higher phenotypic plasticity at lower latitudes. Our
findings highlight that phenotypic plasticity and natural selection could
drive the niche breadth across latitudes. This is critical for predicting
the niche breadths of invasive species and the potential management of
biological invasions in future climate conditions.