Effects of simulated herbivory and resource availability on native and invasive exotic tree seedlings
نویسندگان
چکیده
The introduced tree, Sapium sebiferum, is a serious invader throughout the southeastern United States. Low herbivore loads, commonly attributed to high herbivore resistance, are assumed to give Sapium a competitive advantage over native vegetation. Because herbivory resistance is considered energetically expensive, we predicted that if Sapium experienced higher levels of damage its growth would significantly decrease. We examined the effects of different levels of simulated leaf herbivory on the growth of Sapium and Celtis laevigata, a native tree, at three levels of nitrogen and three levels of light availability. Potted seedlings were grown in a complete factorial design. Stem height growth rate, diameter growth rate and plant mass of both Sapium and Celtis were significantly affected by shade and nitrogen treatments. Nitrogen increased the growth of both species and seedlings in shaded conditions grew larger than those in ambient sunlight. Simulated leaf herbivory had a significantly negative impact on diameter growth rate and plant mass of Celtis. Surprisingly, neither Sapium height growth rate, diameter growth rate, nor any measure of plant mass were significantly affected by simulated leaf herbivory. Rather, Sapium exhibited considerable phenotypic plasticity and was able to compensate for leaf damage in all resource conditions. Our findings suggest herbivory tolerance is a previously unappreciated trait of Sapium that, in conjunction with phenotypic plasticity and low levels of herbivory in its introduced range, likely contributes to its inva-
منابع مشابه
Effects of simulated herbivory and resources on Chinese tallow tree (Sapium sebiferum, Euphorbiaceae) invasion of native coastal prairie.
Trade-offs associated with maintaining herbivory resistance and herbivory tolerance are frequently inferred in plant life histories. Invasive success for many non-native plants is often attributed to novel resistance that repels native herbivores. Chinese tallow tree (Sapium sebiferum, Euphorbiaceae) is a non-native invader that threatens ecosystems throughout the southeastern United States, in...
متن کاملNotes and Discussion Damage Induced Production of Extrafloral Nectaries in Native and Invasive Seedlings of Chinese Tallow Tree (Sapium sebiferum)
—We conducted a pot experiment examining the effects of simulated leaf herbivory and supplemental soil nutrients on extrafloral nectary (EFN) glands of Sapium sebiferum seedlings derived from native Chinese and invasive Texas seed stock. We predicted that simulated herbivory and increased soil nutrients would increase EFN activity. We also predicted that Chinese genotypes would have greater EFN...
متن کاملNotes and Discussion Damage Induced Production of Extrafloral Nectaries in Native and Invasive Seedlings of Chinese Tallow Tree (Sapium sebiferum)
—We conducted a pot experiment examining the effects of simulated leaf herbivory and supplemental soil nutrients on extrafloral nectary (EFN) glands of Sapium sebiferum seedlings derived from native Chinese and invasive Texas seed stock. We predicted that simulated herbivory and increased soil nutrients would increase EFN activity. We also predicted that Chinese genotypes would have greater EFN...
متن کاملInvasive ecotypes tolerate herbivory more effectively than native ecotypes of the Chinese tallow tree Sapium sebiferum
1. The evolution of increased competitive ability (EICA) hypothesis proposes that exotic plants often become invasive because they have evolved reduced allocation to defence and increased allocation to growth and reproduction in response to low herbivore loads. Previous studies with Chinese tallow tree Sapium sebiferum support EICA predictions of invasive North American ecotypes displaying rapi...
متن کاملInteractions between resource availability and enemy release in plant invasion.
Understanding why some exotic species become invasive is essential to controlling their populations. This review discusses the possibility that two mechanisms of invasion, release from natural enemies and increased resource availability, may interact. When plants invade new continents, they leave many herbivores and pathogens behind. Species most regulated by enemies in their native range have ...
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