Topic
Alliaria
About: Alliaria is a research topic. Over the lifetime, 30 publications have been published within this topic receiving 1080 citations.
Papers
TL;DR: It is conclusively demonstrated that deer are required for garlic mustard success; its local extinction is projected where deer are absent, the first definitive support connecting overabundant ungulates to enhanced invader success, with broad implications for biodiversity and ecosystem function.
Abstract: A major goal in ecology is to understand mechanisms that increase invasion success of exotic species. A recent hypothesis implicates altered species interactions resulting from ungulate herbivore overabundance as a key cause of exotic plant domination. To test this hypothesis, we maintained an experimental demography deer exclusion study for 6 y in a forest where the native ungulate Odocoileus virginianus (white-tailed deer) is overabundant and Alliaria petiolata (garlic mustard) is aggressively invading. Because population growth is multiplicative across time, we introduce metrics that correctly integrate experimental effects across treatment years, the cumulative population growth rate, λc, and its geometric mean, λper-year, the time-averaged annual population growth rate. We determined λc and λper-year of the invader and of a common native, Trillium erectum. Our results conclusively demonstrate that deer are required for the success of Alliaria; its projected population trajectory shifted from explosive growth in the presence of deer (λper-year = 1.33) to decline toward extinction where deer are excluded (λper-year = 0.88). In contrast, Trillium’s λper-year was suppressed in the presence of deer relative to deer exclusion (λper-year = 1.04 vs. 1.20, respectively). Retrospective sensitivity analyses revealed that the largest negative effect of deer exclusion on Alliaria came from rosette transitions, whereas the largest positive effect on Trillium came from reproductive transitions. Deer exclusion lowered Alliaria density while increasing Trillium density. Our results provide definitive experimental support that interactions with overabundant ungulates enhance demographic success of invaders and depress natives’ success, with broad implications for biodiversity and ecosystem function worldwide.
151 citations
TL;DR: Compared offspring from several native and introduced Alliaria populations with respect to their palatability to insect herbivores and their tolerance to simulated herbivory, there was no indication of a difference in tolerance between native andintroduced populations or of a trade-off between tolerance and resistance.
Abstract: The European herb garlic mustard (Alliaria petiolata) is a serious invader of North American deciduous forests. One explanation for its success could be that in the absence of specialized herbivores, selection has favored less defended but more vigorous genotypes. This idea was addressed by comparing offspring from several native and introduced Alliaria populations with respect to their palatability to insect herbivores and their tolerance to simulated herbivory. Feeding rates of a specialist weevil from the native range were significantly greater on American plants, suggesting a loss of resistance in the introduced range. In contrast, there was significant population variation but no continent effect in the feeding rates of a generalist caterpillar. After simulated herbivory, A. petiolata showed a substantial regrowth capacity that involved changes in plant growth, architecture, and allocation. Removal of 75% leaf area or of all bolting stems reduced plant fitness to 81% and 58%, respectively, of the fitness of controls. There was no indication of a difference in tolerance between native and introduced Alliaria populations or of a trade-off between tolerance and resistance.
105 citations
TL;DR: The results show that the New World taxa of Thlaspi form a monophyletic group that should be assigned to Noccaea and that the North American “T. montanum” appear to be unrelated to the European plants referred to this species.
Abstract: Nuclear ribosomal (ITS) and plastid (trnL-trnF) DNA sequence data from representatives of most New World species of Thlaspi (Brassicaceae), including the widespread North American T. montanum, have been studied to investigate their relationship to the Eurasian members now placed in the genus Noccaea, especially the European T. montanum (= N. montana) complex. ITS sequence data of the New World taxa were added to a previously published data set, which includes sequences of representative taxa of 11 of the 12 genera segregated from Thlaspi, to elucidate overall relationships within Thlaspi s.l. Sequences from Callothlaspi, Kotschyella, Masmenia, Microthlaspi, Neurotropis, Noccaea, Noccidium, Pseudosempervivum, Raparia, Thlaspi s.s., Thlaspiceras, and Vania, as well as of the closely related genera Bivonaea, Alliaria, Peltaria, and Teesdalia, were included in the study. The results show that the New World taxa of Thlaspi form a monophyletic group that should be assigned to Noccaea and that the North...
70 citations
TL;DR: It is indicated that glyphosate reduces Alliaria without negatively impacting native species and that some native species respond positively to a single-year reduction in this invasive biennial.
Abstract: Restoration often includes control of invasive plants, but little is known about how native plant communities respond to this control. The biennial Alliaria petiolata (M. Bieb.) Cavara and Grande (garlic mustard) is one of the most prevalent invasive plants in forests of eastern North America. We investigated the effects of the herbicide Round-up (glyphosate) on Alliaria and the response of the forest floor plant community to the herbicide and the subsequent decline of Alliaria .I n an old-growth Acer–Fagus stand and a second-growth Liriodendron-dominated stand in Hueston Woods State Nature Preserve, Ohio, United States, we spot applied Round-up in November 2000 and 2001 in 25 1 · 1–m plots and maintained 25 control plots. Herbicide decreased Alliaria density in both stands and reduced the density of other species in leaf during treatment (mostly exotic winter annuals) in the old-growth stand. Treatment did not affect the initial density of the Alliaria cohort that germinated in the spring of 2001, but decreased the 2002 cohort. Community differences were found in the old-growth stand after Alliaria reduction, specifically greater cover of spring ephemerals in the herbicide treatment. In the second-growth stand, herbicide treatment increased reproduction of the late-summer perennial, Phryma leptostachya. These results indicate that glyphosate reduces Alliaria without negatively impacting native species and that some native species respond positively to a single-year reduction in this invasive biennial.
69 citations
TL;DR: The spread of Alliaria officinalis and Glecoma hederacea, the most frequent exotic species, was inhibited by forest fragmentation, and species richness of exotics followed a similar pattern.
Abstract: -The objective of this study was to investigate specific effects of disturbance on exotic species in floodplain environments and to provide baseline data on the abundance of exotic herbs in the Potomac River floodplain. Frequency of exotics generally increased with man-made disturbance (forest fragmentation and recreational use of land) and decreased with increasing flooding frequency. Species richness of exotics followed a similar pattern. Some variation was found in individual species' responses to disturbance. The spread of Alliaria officinalis and Glecoma hederacea, the most frequent exotic species, was inhibited by forest fragmentation.
64 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 1 |
| 2018 | 2 |
| 2017 | 1 |
| 2016 | 1 |
| 2015 | 3 |
| 2014 | 3 |