Invasive plants have greater growth than co-occurring natives in live soil subjected to a drought-rewetting treatment

Abstract

Several studies have shown that invasive plant species respond more negatively to drought than native plant species, but little remains understood of how and whether drought-rewetting events may affect growth of invasive and co-occurring native plant species both directly and indirectly through soil microorganisms. In a fully crossed factorial design, we grew individuals of four congeneric pairs of invasive and native plant species in 2.5 L pots that contained live or sterilized field soil under one of three drought treatments: no-drought, drought, drought-rewetting. Results show that drought caused a significantly greater decline in total biomass of invasive plant species than that of native plant species regardless of the presence of live soil microorganisms. However, total biomass of the invasive plant species exhibited a greater recovery from drought following rewetting than did that of the native plant species. Moreover, recovery from drought in invasive plant species tended to be stronger in live soil than in sterilized soil, while for the native plant species, recovery from drought was stronger in sterilized soil than in live soil. Overall, these results suggest that in ecosystems that experience cycles of drought and rewetting, invasive plant species may grow larger than co-occurring native plant species. Moreover, soil microorganisms may facilitate greater recovery from drought in invasive plant species than in co-occurring native plant species. Read the free Plain Language Summary for this article on the Journal blog.