Roots are responsible for plant productivity via water and nutrient acquisition, and as such, below-ground plant traits play a pivotal role in the responses of vegetation to climate variability and disturbances. However, evidence suggests that communities dominated by plants with fixed (non-plastic) traits for resource acquisition often confer greater ecosystem resilience to extreme events than communities exhibiting higher trait plasticity. To characterize degree of plasticity in plant communities, we investigated the variability of root functional traits in dominant species. We analyzed 4970 observations across 1062 species for measurements of root characteristics, including carbon concentration, carbon to nitrogen ratio (C:N), diameter, specific root length, and tissue density recorded in the TRY Plant Trait Database. We analyzed data using R to determine degrees of variance within trait measurements across multiple environments, and to affirm species strategies for growth and nutrient acquisition. To determine the inherent plasticity of selected traits, we performed regression analysis between observations for two or more traits and examined correlation strength within species, genera, and among all data. Data was separated into categories based on growing location (laboratory, mesocosm, field) to partition data from undisturbed systems while also allowing for comparisons in data by collection method and treatment.
Results/Conclusions
There was a negative powered relationship between specific root length and diameter (y=1.539x-0.38) among all data with a moderate correlation of R2=0.57, however the strength of correlation increased significantly for observations grouped by species. Comparisons of individuals grown indoors or within mesocosms exhibited greater correlation for all measured morphological traits than data sets from individuals collected from outdoor areas, although this trend often reversed with C:N included as a variable. Analysis of root C:N against specific root length showed a nitrogen saturation point (maximum root nitrogen content) between 20-24 C:N ratio for 206 described species, however six species reached C:N values of 10.86 to 12.86. Analysis of the correlation between measured morphological characteristics, with consideration to root C:N ratio and environmental conditions, provides insight into the degree of plasticity inherent in functional traits. Comparisons between our calculations of variability within root traits and observations of species resilience to disturbance from literature showed a fair amount of agreement for dominant species. Our poster will extrapolate the usefulness of phenotypic variance as a proxy for ecosystem resilience. These results provide characterization of resource acquisition strategy based on root morphological traits.