Topic
Sapium
About: Sapium is a research topic. Over the lifetime, 221 publications have been published within this topic receiving 4062 citations.
Papers published on a yearly basis
Papers
TL;DR: Results provide evidence for facilitation as a mechanism involved in tree invasions of grasslands, and the marked response of Sapium to the combination of nitrogen and shade suggests that these positive feedbacks may be particularly strong for this alien plant species.
Abstract: Summary 1 The first trees establishing in grasslands may indirectly favour their seedlings in competition with neighbouring herbaceous vegetation by increasing soil fertility with nitrogen-rich litter and by reducing light levels under their canopies. It is predicted that increasing soil nitrogen availability will accelerate invasion of trees by stimulating their growth more than that of herbaceous species. Decreasing light availability is predicted to increase tree invasion by limiting the growth of herbaceous vegetation more than that of trees (competitive release). 2 We tested these predictions using Chinese tallow tree ( Sapium sebiferum ), which is an aggressive alien invader of grasslands in the southern USA, and Hackberry ( Celtis laevigata ), which is a native tree common in these grasslands. 3 Nitrogen and light were manipulated in two factorial field experiments in grasslands in Texas, USA. In the first, nitrogen was increased and light was decreased in plots with planted Celtis or Sapium seedlings. In the second experiment, light availability to planted Celtis or Sapium seedlings was increased by holding back prairie vegetation. 4 In the first experiment, growth of Celtis and Sapium seedlings increased with nitrogen fertilization while the above-ground biomass of prairie vegetation did not change. Prairie vegetation biomass decreased and tree seedling growth increased under shading. Sapium ’s growth increased dramatically in the treatment with combined nitrogen and shade. Sapium survival decreased when shade was applied. 5 In the second experiment, Sapium growth increased with increased light. Thus, increased Sapium growth at low light levels in the shade experiment was probably a consequence of decreased competitive interference from prairie vegetation, rather than better absolute performance of Sapium in low light levels. 6 These results provide evidence for facilitation as a mechanism involved in tree invasions of grasslands. Changes in resource levels, perhaps in combination with other factors, may explain rapid conversion of grassland communities to woodlands after the first pioneer trees are established. The marked response of Sapium to the combination of nitrogen and shade suggests that these positive feedbacks may be particularly strong for this alien plant species.
202 citations
TL;DR: The results of these experiments suggest that the success of Sapium may depend on high rates of seed input into these ecosystems and high growth potential, as well as performance advantages of seedlings caused by low rates of herbivory.
Abstract: The Enemies Hypothesis predicts that alien plants have a competitive ad- vantage over native plants because they are often introduced with few herbivores or diseases. To investigate this hypothesis, we transplanted seedlings of the invasive alien tree, Sapium sebiferum (Chinese tallow tree) and an ecologically similar native tree, Celtis laevigata (hackberry), into mesic forest, floodplain forest, and coastal prairie sites in east Texas and manipulated foliar fungal diseases and insect herbivores with fungicidal and insecticidal sprays. As predicted by the Enemies Hypothesis, insect herbivores caused significantly greater damage to untreated Celtis seedlings than to untreated Sapium seedlings. However, contrary to predictions, suppression of insect herbivores caused significantly greater in- creases in survivorship and growth of Sapium seedlings compared to Celtis seedlings. Regressions suggested that Sapium seedlings compensate for damage in the first year but that this greatly increases the risk of mortality in subsequent years. Fungal diseases had no effects on seedling survival or growth. The Recruitment Limitation Hypothesis predicts that the local abundance of a species will depend more on local seed input than on com- petitive ability at that location. To investigate this hypothesis, we added seeds of Celtis and Sapium on and off of artificial soil disturbances at all three sites. Adding seeds increased the density of Celtis seedlings and sometimes Sapium seedlings, with soil disturbance only affecting density of Celtis. Together the results of these experiments suggest that the success of Sapium may depend on high rates of seed input into these ecosystems and high growth potential, as well as performance advantages of seedlings caused by low rates of herbivory.
157 citations
TL;DR: Although grasshoppers preferred to feed on Texas Sapium when offered a choice in the laboratory, extremely low herbivory levels in the field may have allowed the Texas seedlings to outperform the China seedlings in the common garden.
Abstract: Invasive plants are often larger in their introduced range compared to their native range. This may reflect an evolved reduction in defense and increase in growth in response to low herbivory in their introduced range. Key elements of this scenario include genetic differences in defense and growth yet uniformly low rates of herbivory in the field that dissociate defense and herbivore damage for alien species. We conducted a laboratory experiment with Melanoplus angustipennis grasshoppers and Chinese Tallow Tree seedlings (Sapium sebiferum) from its native range (China) and its introduced range (Texas, USA) where it is invasive. We caged grasshoppers with pairs of Sapium seedlings from the same continent or different continents. The amounts of leaf area removed from Texas and China seedlings, and their height growth rates, were indistinguishable when both seedlings in the pair were from the same continent. However, when grasshoppers had a choice between seedlings from different continents, they removed more Texas Sapium foliage than China Sapium foliage and height growth rates were higher for China Sapium seedlings compared to Texas seedlings. Grasshopper growth rates increased with greater Sapium foliage consumption. In a common garden in Texas, Sapium seedlings from Texas grew 40% faster than those from China. Chewing insect herbivores removed little Sapium foliage in the field experiment. Although grasshoppers preferred to feed on Texas Sapium when offered a choice in the laboratory, extremely low herbivory levels in the field may have allowed the Texas seedlings to outperform the China seedlings in the common garden. These results demonstrate post-invasion genetic differences in herbivore resistance and growth of an invasive plant species together with a decoupling of defense and herbivore choice in the introduced range.
151 citations
TL;DR: Results point to the presence of inhibitorychemical substances in the extracts, indicating an allelopathic potential for the five species evaluated, including Cecropia pachystachya Trec.
Abstract: Allelopathy is characterized by harmful or beneficial effects on vegetation development, caused by chemical substances produced and released into the environment by the plant. Aiming to assess the allelopathic potential of Brazilian species, aqueous leaf extracts of Cecropia pachystachya Trec. (Urticaceae), Peltophorum dubium (Spreng.) Taub. (Fabaceae), Psychotria leiocarpa Cham. & Schltdl (Rubiaceae), Sapium glandulatum (Vell.) Pax (Euphorbiaceae), and Sorocea bonplandii (Baill.) Burger, Lanj. & Boer (Moraceae) were tested on lettuce using germination and growth bioassays. In these bioassays, aqueous leaf extracts were used at concentrations of 2 and 4%, prepared by static maceration with cold and hot water. The five species extracts delayed lettuce germination and produced toxic effects on seedling growth, with root reduction and debility. The results point to the presence of inhibitorychemical substances in the extracts, indicating an allelopathic potential for the five species evaluated.
125 citations
Journal Article•
TL;DR: These and other characters, such as its adaptability to a wide range of soils and its ease of dispersal via birds, water, and humans, suggest that this introduced species has a high risk potential as an invasive plant outside of cultivation.
Abstract: A native of eastern Asia, in the same latitudes as the southeastern United States, the Tallow-tree (or popcorn-tree) has long been a popular landscaping choice in this region, for its brilliant fall color, distinctive seed capsules, and easy care as an ornamental. It is shade-, sun-, drought-, flood-, freeze, and salt-tolerant, as shown in recent experiments. These and other characters, such as its adaptability to a wide range of soils and its ease of dispersal via birds, water, and humans, suggest that this introduced species has a high risk potential as an invasive plant outside of cultivation. Surveys conducted by Florida's Department of Environmental Protection demonstrate the increased spread of Tallow into disturbed and undisturbed, upland and wetland sites, with one large wetland site south of Gainesville, Florida having more than 10,000 Sapium trees that have become naturalized. Over half (57 %) of Florida's counties now have naturalized populations of the tree. Current options for control of this hardy plant are also provided.
93 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2020 | 4 |
| 2019 | 1 |
| 2018 | 12 |
| 2017 | 6 |
| 2016 | 7 |