Health & Environmental Research Online (HERO)


Print Feedback Export to File
3286929 
Journal Article 
Invaders do not require high resource levels to maintain physiological advantages in a temperate deciduous forest 
Heberling, JM; Fridley, JD 
2016 
Yes 
Ecology
ISSN: 0012-9658
EISSN: 1920-2005 
WILEY 
HOBOKEN 
97 
4 
874-884 
English 
27220204 
WOS:000373923100007 
Non-native, invasive plants are commonly typified by trait strategies associated with high resource demands and plant invasions are often thought to be dependent upon site resource availability or disturbance. However, the invasion of shade-tolerant woody species into deciduous forests of the Eastern United States seems to contradict such generalization, as growth in this ecosystem is strongly constrained by light and, secondarily, nutrient stress. In a factorial manipulation of light and soil nitrogen availability, we established an experimental resource gradient in a secondary deciduous forest to test whether three common, woody, invasive species displayed increased metabolic performance and biomass production compared to six co-occurring woody native species, and whether these predicted differences depend upon resource supply. Using hierarchical Bayesian models of photosynthesis that included leaf trait effects, we found that invasive species exhibited functional strategies associated with higher rates of carbon gain. Further, invader metabolic and growth-related attributes were more responsive to increasing light availability than those of natives, but did not fall below average native responses even in low light. Surprisingly, neither group showed direct trait or growth responses to soil N additions. However, invasive species showed increased photosynthetic nitrogen use efficiencies with decreasing N availability, while that of natives remained constant. Although invader advantage over natives was amplified in higher resource conditions in this forest, our results indicate that some invasive species can maintain physiological advantages over co-occurring natives regardless of resource conditions. 
Bayesian hierarchical models; forest invasion; functional traits; light addition; nitrogen fertilization; photosynthesis; resource limitation; understory shrubs