Study on growth and photosynthesis traits of the invasive species Coreopsis lanceolata and its co-occuring species in contrasting light conditions.
To better understand its invasion mechanism and comprehensive control, we compared the morphological and physiological traits of C. lanceolata with those of its co-occurring species Bidens bipinnata and Rumex japonicus under two different irradiance treatments (full irradiance and 31% of the full irradiance), then analyzed the correlation between those traits and invasiveness. It was found that C. lanceolata was a light-favoring species, and that the high relative growth rate (RGR) and photosynthetic capacity based on mass basis (Am) contributed to improve its competitiveness under high light environment. In partly shaded conditions, the significant decrease in RGR and Am of C. lanceolata reduced its competitiveness. However, other traits related to biomass allocation and resource capture-related traits, such as leaf area ratio (LAR), stem mass ratio (SMR), leaf mass ratio (LMR) and specific leaf area (SLA) were not always higher for C. lanceolata than for its co-occurring species even under high light environment. The reaction norm of C. lanceolata to light showed a master-of-some-trades pattern, which means that C. lanceolata could only increase population densities under favorable conditions.