|Drenovsky, Rebecca E - JOHN CARROLL UNIVERSITY|
|Martin, Christina E - JOHN CARROLL UNIVERSITY|
|Falasco, Molly R - JOHN CARROLL UNIVERSITY|
Submitted to: American Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 7, 2008
Publication Date: June 1, 2008
Citation: Drenovsky, R., Martin, C., Falasco, M., James, J.J. 2008. Variation in resource acqisition and utilization traits between native and invasive perennial forbs. American Journal of Botany.95(6):681-687. Interpretive Summary: Understanding trait differences that allow invasive plants to outperform natives is a central step in creating weed-resistant plant communities. This study tested the hypothesis that a suite of physiological and morphological traits allow invasives to capture more nutrients than natives. Four native and four invasive species were exposed to two different levels of nutrient availability. Invasives produced more root biomass, allocated root biomass to areas of higher soil fertility and used captured nutrients more efficiently at all nutrient levels. Multiple trait differences appear to give invasives a competitive advantage over most natives in high and low nutrient environments suggesting a potential need to utilize introduced desirable species in restoring weed infested systems.
Technical Abstract: Understanding the factors influencing ecosystem invasibility is a vital, yet elusive, ecological goal. Although some research suggests functional group similarity between native and invasive plants reduces invasibility, other studies indicate only a weak correlation between functional group composition and invasion resistance. We propose large trait variation within traditionally-defined functional groups may hinder invasibility prediction when using a functional group, rather than functional trait, approach. We assessed whether native and invasive forbs differed in functional traits related to resource acquisition and use by comparing morphological and physiological responses among four native and invasive species exposed to heterogeneous (patch) or homogeneous (control) nutrient distribution. Overall, invasives produced more biomass and allocated more biomass belowground compared to natives, regardless of treatment, although in some cases responses were species-specific. Invasives had higher root length density, but lower specific root length, than natives, especially in patch treatments. Invasives also had higher leaf N, photosynthetic rates, and photosynthetic nitrogen use efficiency than the natives, regardless of treatment. Overall, functional traits were more variable within, than between, groups of native and invasive species. Given this variability, we propose focusing on key functional traits influencing ecological processes should better predict invader success and invasion resistance than classical functional groupings.