Eco-evolutionary dynamics modulate plant responses to global change depending on plant diversity and species identity

Global change has dramatic impacts on grassland diversity. However, little
is known about how fast species can adapt to diversity loss and how this
affects their responses to global change. Here, we performed a common
garden experiment testing whether plant responses to global change are
influenced by their selection history and the conditioning history of soil
at different plant diversity levels. Using seeds of four grass species and
soil samples from a 14-year-old biodiversity experiment, we grew the
offspring of the plants either in their own soil or in soil of a different
community, and exposed them either to drought, increased nitrogen input,
or a combination of both. Under nitrogen addition, offspring of plants
selected at high diversity produced more biomass than those selected at
low diversity, while drought neutralized differences in biomass
production. Moreover, under the influence of global change drivers, soil
history, and to a lesser extent plant history, had species-specific
effects on trait expression. Our results show that plant diversity
modulates plant-soil interactions and growth strategies of plants, which
in turn affects plant eco-evolutionary pathways. How this change affects
species' response to global change and whether this can cause a
feedback loop should be investigated in more detail in future studies.