Background/Question/Methods:  
The relationship between plant life-history traits and patterns of species diversity is of great relevance to plant community ecology and has considerable implications for conservation and restoration practices.  We examined the effect of life history traits on native species recruitment using data from seed addition studies in restored grasslands throughout the tallgrass prairie biome.  We hypothesized that varying capacities for recruitment among species can be explained by key life history traits and predicted that traits associated with competitive ability such as clonality, nitrogen fixation, large plant size, and large seed mass would be advantageous for recruitment.  To test these hypotheses, metrics of recruitment success were calculated using species establishment data for 190 native species from 54 seed addition experiments in 8 states throughout the Midwest.  Life history data was obtained from published studies, regional floras, and online databases for the following traits: growth form, longevity, photosynthetic pathway, seed mass, clonality, nitrogen fixation, flowering period, flowering duration, plant height, and leaf area.  Statistical analyses were conducted to determine which traits have a significant effect on recruitment.  Significant traits were then entered into multiple regression models to determine which traits most effectively predict species recruitment in tallgrass prairies.
Results/Conclusions:
Our results demonstrated significantly higher recruitment was associated with clonality, greater height, longer flowering period, and later onset of flowering.  Linear regressions also confirmed a significant and positive effect of increased seed mass on recruitment.  However, quadratic regressions of the relationship between seed mass and recruitment were more significant, indicating a unimodal relationship in which species with intermediate seed masses have the highest recruitment.  Nitrogen fixing species also demonstrated significantly greater recruitment, although further analyses suggested that this result is likely an artifact of higher seed mass among nitrogen fixing species.  Among grasses, C₄ species had higher recruitment than C₃ species.  Although trends demonstrated that annual and biennial species have greater recruitment than perennial species and that grasses have greater recruitment than herbaceous species, these results were not significant.  Multiple regression models suggested that seed mass and both the timing and duration of flowering period were the best predictors of recruitment among the life history traits examined in this study.  A greater understanding of the effect of plant life history traits on species recruitment can facilitate the conservation and restoration of diverse plant communities in imperiled ecosystems such as the tallgrass prairie.