The relative contributions of climate, soil, diversity and interactions to leaf trait variation and spectrum of invasive Solidago canadensis.

Background: Invasive plants commonly occupy diverse habitats and thus must adapt to changing environmental pressures through altering their traits and economics spectra, and addressing these patterns and their drivers has an importantly ecological and/or evolutionary significance. However, few studies have considered the role of multiple biotic and abiotic factors in shaping trait variation and spectra. In this study, we determined seven leaf traits of 66 Solidago canadensis populations, and quantified the relative contributions of climate, soil properties, native plant diversity, and S. canadensis-community interactions (in total 16 factors) to leaf trait variation and spectrum with multimodel inference.
Results: Overall, the seven leaf traits had high phenotypic variation, and this variation was highest for leaf dry matter content and lowest for leaf carbon concentration. The per capita contribution of climate to the mean leaf trait variation was highest (7.5%), followed by soil properties (6.2%), S. canadensis-community interactions (6.1%), and native plant diversity (5.4%); the dominant factors underlying trait variation varied with leaf traits. Leaf production potential was negatively associated with leaf stress-tolerance potential, and the relative contributions to this trade-off followed in order: native plant diversity (7.7%), climate (6.9%), S. canadensis-community interactions (6.2%), and soil properties (5.6%). Climate, diversity, soil, and interactions had positive, neutral or negative effects.
Conclusions: Climate, soil, diversity, and interactions contribute differentially to the leaf trait variation and economics spectrum of S. canadensis, and their relative importance and directions depend on plant functional traits.