Data from: Effects of grass functional diversity on invasion success by exotic grasses in Cerrado grasslands

Invasive species pose significant challenges to successful restoration
efforts worldwide. A strategy to reduce invasions is to establish
communities consisting of species with varied ecological strategies. These
strategies typically align along the conservative and plant size axes, and
more recently, along a belowground collaboration axis. However, we lack
understanding of how the diverse ecological strategies of Cerrado grass
species, their combinations, and their interactions with soil conditions
can mitigate invasions. Here, we investigated how native grass communities
composed of species with different ecological strategies affect the
invasion success in two soil types of abandoned pastures in the Cerrado.
Specifically, we tested the hypothesis that greater above- and belowground
functional diversity reduces exotic species invasion. We also evaluated
whether the isolated effects of native species on invasion were positive
or negative. We installed an experiment with species richness ranging from
zero to eight native grass species. In November 2019, we sowed species
combinations to create communities composed by species with different
ecological strategies. We quantified the aboveground biomass of exotic
species as a measure of invasion. To characterize the species'
ecological strategies, we measured five functional traits. Functional
diversity of maximum height and specific root length (SRL) had the highest
predictive power, however, the most parsimonious model included only SRL
diversity, which represents the collaboration axis. Native aboveground
biomass was also negatively related to exotic species biomass.
Furthermore, invasion was greater in less stressful soil conditions but
did not interact with diversity. The effect of native species varied from
facilitation to competition, with the annual fast-growing native species
favouring invasion. Synthesis and applications. Our results show that
greater functional diversity of combined above- and belowground traits
reduces invasion success, shedding light on an underexplored role of SRL
diversity. The competitive and facilitative effects of different native
species highlight the need for careful selection of the species to be used
in restoration programs. Furthermore, the absence of interaction between
diversity and soil types highlights the need for an integrated management
of the functional composition and edaphic factors to increase resistance
to invasion in these Neotropical grass communities.