Data for: Soil microbes alter competition between native and invasive plants

Invasive plants can alter soil microbial communities and generate positive
plant-soil feedbacks that facilitate their performance, but the magnitude
and direction of feedbacks may change with novel conditions under climate
change. We assessed how potential soil legacy effects of plant invasion
and simulated drought influenced plant performance and competition in the
longleaf pine ecosystem. We collected soil from a four-year factorial
invasion (cogongrass, Imperata cylindrica) by drought (simulated with
rainout shelters) field experiment and used it as live or sterilized soil
inoculum in a greenhouse experiment that included two native foundation
species, longleaf pine (Pinus palustris) and wiregrass (Aristida stricta),
and cogongrass, grown individually or in competition. There was no
evidence of biotic soil legacy effects of invasion or drought for any
plant species, but microbes played a significant role in competition. When
plants were grown alone, the invader had 12% greater biomass in live soil
than sterile soil but both native species had 25% less biomass in live
soil. When grown in competition, these effects were reversed for
cogongrass (37% smaller in live soil) and pine (17% larger in live soil).
In competition, the three species grown in sterile soil produced similar
amounts of biomass, whereas live soil created a competitive hierarchy
where pine was more competitive than wiregrass and cogongrass. Synthesis:
These results emphasize the importance of soil biota in native plant
restoration because, although the invader was highly successful when grown
alone, plant-microbe interactions influenced the outcome of competition
between native and invasive species by promoting native longleaf pine.
There was little evidence that invasive cogongrass inhibited native plants
via biotic soil legacies, instead, results suggested that plant-soil
interactions can be highly resilient to global change such that the biotic
legacy of invasion and drought may not promote or inhibit invasion.