Data from: Dual drivers of plant invasions: Enemy release and enhanced mutualisms

Invasive plants often express aboveground traits, such as higher growth
than native plants, which promote their success. This may reflect low
levels of invertebrate herbivory and/or high rates of arbuscular
mycorrhizal fungi (AMF) association. However, the root traits that
contribute to invasive success are less well known. Moreover, the combined
roles of aboveground herbivory, AMF and root traits in the invasion
process are poorly understood.We conducted field surveys at 17 sites along
a latitudinal gradient in China (22.77 °N to 42.48 °N) to investigate the
relationships among aboveground herbivory, AMF colonization and root
traits for five pairs of closely related invasive and native Asteraceae
plant species. We experimentally manipulated aboveground insect feeding
for two of these pairs of plant species in a middle latitude (34.79 °N)
common garden. We measured aboveground invertebrate abundance, leaf
damage, AMF colonization, root morphological traits associated with
nutrient uptake, and root soluble sugar concentrations.In the field
survey, invasive plants had lower leaf damage and Hemiptera abundances
plus higher AMF colonization, thinner roots with more surface area and
higher concentrations of root soluble sugars than native plants. Leaf
damage decreased with increasing latitude for native plants. In the common
garden, invasive plants had lower leaf damage and Hemiptera abundances
plus higher AMF and greater surface area of fine roots than native plants.
Leaf damage and Hemiptera reduced AMF colonization via a phenotypic effect
of reduced fine root soluble sugars.Our results indicate that low
aboveground invertebrate herbivory on invasive plants contributes to their
success directly by increasing their growth and indirectly via root
soluble sugars that increase their AMF colonization. Invasive plants
appear to benefit from greater root volume and surface area but this did
not vary with latitude or aboveground invertebrate herbivory. These
results highlight the importance of considering above- and belowground
processes simultaneously to understand how they interact to determine
plant invasion success.