scholarly journals Differential germination strategies of native and introduced populations of the invasive species Plantago virginica

NeoBiota ◽  
2019 ◽  
Vol 43 ◽  
pp. 101-118
Author(s):  
Xinyu Xu ◽  
Lorne Wolfe ◽  
Jeffrey Diez ◽  
Yi Zheng ◽  
Hui Guo ◽  
...  
Keyword(s):  
Plant Traits ◽  
Rapid Evolution ◽  
Climatic Conditions ◽  
Introduced Populations ◽  
Introduced Range ◽  
Native Populations ◽  
Selection For ◽  
Native North America ◽  
Germination Traits

Germination strategies are critically important for the survival, establishment and spread of plant species. Although many plant traits related to invasiveness have been broadly studied, the earliest part of the life cycle, germination, has received relatively little attention. Here, we compared the germination patterns between native (North America) and introduced (China) populations of Plantagovirginica for four consecutive years to examine whether there has been adaptive differentiation in germination traits and how these traits are related to local climatic conditions. We found that the introduced populations of P.virginica had significantly higher germination percentages and faster and shorter durations of germination than native populations. Critically, the native populations had a significantly larger proportion of seeds that stayed dormant in all four years, with only 60% of seeds germinating in year 1 (compared to >95% in introduced populations). These results demonstrate striking differences in germination strategies between native and introduced populations which may contribute to their successful invasion. Moreover, the germination strategy of P.virginica in their native range exhibited clear geographical variation across populations, with trends towards higher germination percentages at higher latitudes and lower annual mean temperatures and annual precipitation. In the introduced range, however, their germination strategies were more conserved, with less variation amongst populations, suggesting that P.virginica may have experienced strong selection for earlier life history characteristics. Our findings highlight the need to examine the role of rapid evolution of germination traits in facilitating plant invasion.

EICA 2.0: a general model of enemy release and defence in plant and animal invasions.

2020 ◽  
pp. 192-207
Author(s):  
Richard Honor ◽  
Robert I. Colautti
Keyword(s):  
Invasive Species ◽  
Natural Enemies ◽  
General Model ◽  
Rapid Evolution ◽  
Common Garden ◽  
Enemy Release ◽  
Introduced Populations ◽  
Introduced Range ◽  
Common Garden Experiments

Abstract Plants and animals have evolved a variety of strategies to limit the negative fitness consequences of natural enemies (i.e. herbivores, predators, parasites and pathogens). Demographic bottlenecks occurring during the invasion process reduce the number of co-introduced natural enemies, providing opportunities to study rapid evolution in environments with different or reduced enemy loads. Enemy release theory provides a set of hypotheses and predictions about the role of natural enemies in the proliferation of invasive species. This body of theory includes the Enemy Release Hypothesis (ERH) and the related Evolution of Increased Competitive Ability Hypothesis (EICA), but there is often confusion about these hypotheses and the data needed to test them. We introduce a simple, general model of enemy release to identify and clarify some of the key assumptions and predictions implicit in enemy release theory and its impacts on invasion. Although introduced populations likely benefit from a reduction in the direct fitness impacts of natural enemies in the early stages of invasion, an evolutionary shift in resource allocation from defence to growth and reproduction is much less likely and depends on a delicate balance between the fitness costs and benefits of defence and the fitness impacts of natural enemies in both the native and introduced ranges. Even when the abundance of natural enemies is lower in the introduced range, the majority of scenarios do not favour evolution of less defended genotypes that are more competitive or more fecund, contrary to predictions of EICA. Perhaps surprisingly, we find that the level of damage by natural enemies in field surveys is not generally a good parameter for testing enemy release theory. Instead, common garden experiments characterizing fitness reaction norms of multiple genotypes from the native and introduced range are crucial to estimate the historic rate of adaptive evolution or predict it into the future. Incorporating spatial autocorrelation and methods from population genetics can further improve our understanding of the role of enemy release and evolution in the proliferation of invasive species.

EICA 2.0: a general model of enemy release and defence in plant and animal invasions.

2020 ◽  
pp. 192-207
Author(s):  
Richard Honor ◽  
◽  
Robert L. Colautti ◽  
Keyword(s):  
Invasive Species ◽  
Natural Enemies ◽  
General Model ◽  
Rapid Evolution ◽  
Common Garden ◽  
Enemy Release ◽  
Introduced Populations ◽  
Introduced Range ◽  
Common Garden Experiments

Plants and animals have evolved a variety of strategies to limit the negative fitness consequences of natural enemies (i.e. herbivores, predators, parasites and pathogens). Demographic bottlenecks occurring during the invasion process reduce the number of co-introduced natural enemies, providing opportunities to study rapid evolution in environments with different or reduced enemy loads. Enemy release theory provides a set of hypotheses and predictions about the role of natural enemies in the proliferation of invasive species. This body of theory includes the Enemy Release Hypothesis (ERH) and the related Evolution of Increased Competitive Ability Hypothesis (EICA), but there is often confusion about these hypotheses and the data needed to test them. We introduce a simple, general model of enemy release to identify and clarify some of the key assumptions and predictions implicit in enemy release theory and its impacts on invasion. Although introduced populations likely benefit from a reduction in the direct fitness impacts of natural enemies in the early stages of invasion, an evolutionary shift in resource allocation from defence to growth and reproduction is much less likely and depends on a delicate balance between the fitness costs and benefits of defence and the fitness impacts of natural enemies in both the native and introduced ranges. Even when the abundance of natural enemies is lower in the introduced range, the majority of scenarios do not favour evolution of less defended genotypes that are more competitive or more fecund, contrary to predictions of EICA. Perhaps surprisingly, we find that the level of damage by natural enemies in field surveys is not generally a good parameter for testing enemy release theory. Instead, common garden experiments characterizing fitness reaction norms of multiple genotypes from the native and introduced range are crucial to estimate the historic rate of adaptive evolution or predict it into the future. Incorporating spatial autocorrelation and methods from population genetics can further improve our understanding of the role of enemy release and evolution in the proliferation of invasive species.

Genetic comparison of introduced and native populations of common buckthorn (Rhamnus cathartica), a woody shrub introduced into North America from Europe

2020 ◽  
Vol 13 (2) ◽  
pp. 68-75
Author(s):  
Alexis Wafer ◽  
Theresa M. Culley ◽  
Kala Stephens ◽  
J. Ryan Stewart
Keyword(s):  
Genetic Variation ◽  
North America ◽  
The United States ◽  
Genetic Admixture ◽  
Biological Traits ◽  
Rhamnus Cathartica ◽  
Early 19Th Century ◽  
Introduced Populations ◽  
Introduced Range ◽  
Native Populations

AbstractIntroduced from Europe to North America in the early 19th century as an ornamental shrub and for medicinal purposes, common buckthorn (Rhamnus cathartica L.) has since spread and naturalized throughout regions of the United States and Canada. The purpose of this study was to investigate levels of genetic variation and population differentiation in R.cathartica in its introduced range in North America compared with its native range in Europe to better understand patterns of spread. By analyzing introduced and native populations using microsatellite markers, we found that introduced populations generally exhibited similar or slightly lower levels of genetic variation compared with native populations, consistent with a slight bottleneck effect. Introduced populations contained many different genotypes, indicating genetic admixture, rather than one or few genotypes. In a few cases, populations had been misidentified in the field and were glossy buckthorn (Frangula alnus Mill.; syn. Rhamnus frangula L.). Overall, there was no substantial genetic differentiation detected between native and introduced populations of R. cathartica. Invasive spread in this species is likely due to its past horticultural history as well as adaptive biological traits such as competitive behavior, potential allelopathy, and seed dispersal via birds.

scholarly journals Rapid reshaping: the evolution of morphological changes in an introduced beach daisy

2019 ◽  
Vol 286 (1897) ◽  
pp. 20181713 ◽  
Author(s):  
Claire R. Brandenburger ◽  
William B. Sherwin ◽  
Stephanie M. Creer ◽  
Robert Buitenwerf ◽  
Alistair G. B. Poore ◽  
...  
Keyword(s):  
Introduced Species ◽  
Morphological Changes ◽  
Leaf Shape ◽  
Rapid Evolution ◽  
Source Population ◽  
Total Biomass ◽  
Introduced Plants ◽  
Introduced Populations ◽  
Introduced Range ◽  
Eastern Australia

Thousands of species have been introduced to new ranges worldwide. These introductions provide opportunities for researchers to study evolutionary changes in form and function in response to new environmental conditions. However, almost all previous studies of morphological change in introduced species have compared introduced populations to populations from across the species' native range, so variation within native ranges probably confounds estimates of evolutionary change. In this study, we used microsatellites to locate the source population for the beach daisy Arctotheca populifolia that had been introduced to eastern Australia. We then compared four introduced populations from Australia with their original South African source population in a common-environment experiment. Despite being separated for less than 100 years, source and introduced populations of A. populifolia display substantial heritable morphological differences. Contrary to the evolution of increased competitive ability hypothesis, introduced plants were shorter than source plants, and introduced and source plants did not differ in total biomass. Contrary to predictions based on higher rainfall in the introduced range, introduced plants had smaller, thicker leaves than source plants. Finally, while source plants develop lobed adult leaves, introduced plants retain their spathulate juvenile leaf shape into adulthood. These changes indicate that rapid evolution in introduced species happens, but not always in the direction predicted by theory.

scholarly journals The Role of Inter- and Intraspecific Variations in Grassland Plant Functional Traits along an Elevational Gradient in a Mediterranean Mountain Area

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 359
Author(s):  
Letizia Di Biase ◽  
Simone Fattorini ◽  
Maurizio Cutini ◽  
Alessandro Bricca
Keyword(s):  
Plant Traits ◽  
Central Italy ◽  
Seed Mass ◽  
Elevational Gradient ◽  
Climatic Conditions ◽  
Relative Role ◽  
Mountain Area ◽  
Local Conditions ◽  
Intraspecific Variations

Elevational gradients offer special opportunities to investigate the relative role of intraspecific and interspecific trait variations in relation to stress gradients. We used an altitudinal gradient in the Mediterranean (Mt Velino, Central Italy) to study (1) how community-weighted means (CWM) and nonweighted means (CM) vary with elevation for plant height, specific leaf area, and seed mass; and (2) how variation patterns differ for inter- and intraspecific functional variability. We tested (1) if elevation influences community functional composition on the basis of the adaptive value of plant traits and (2) if the latter shows intraspecific variations according to the species’ ability to cope with local conditions. We found that different traits showed different patterns, which can be linked to the function they express. Differences between communities were influenced more by differences between their traits (CM) than by the relative species coverage (CWM). Both highest and lowest elevations were the most selective due to their particularly severe climatic conditions. Intermediate elevations were the most favorable thanks to less constraining climatic conditions. Interspecific trait variability was the most relevant component, indicating a low plant ability to cope with environmental variations through phenotypic plasticity.

scholarly journals New and Emerging Therapies in the Management of Bladder Cancer

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1146
Author(s):  
Chelsea K. Osterman ◽  
Matthew I. Milowsky
Keyword(s):  
Bladder Cancer ◽  
Checkpoint Inhibitors ◽  
Treatment Options ◽  
Rapid Evolution ◽  
New Agents ◽  
Drug Conjugates ◽  
Emerging Therapies ◽  
Improved Outcomes ◽  
Selection For

The treatment landscape for bladder cancer has undergone a rapid evolution in the past five years with the approval of seven new agents. New classes of medications have improved outcomes for many patients who previously had limited treatment options, but there is still much to learn about how to optimize patient selection for these agents and the role of combination therapies. The aims of this review are to discuss these newly approved agents for bladder cancer and to feature promising drugs and combinations—including immune checkpoint inhibitors, targeted therapies, and antibody–drug conjugates—that are in development.

scholarly journals Natural selection and outbreeding depression suggest adaptive differentiation in the invasive range of a clonal plant

2018 ◽  
Vol 285 (1882) ◽  
pp. 20181091 ◽  
Author(s):  
Pauline O. Pantoja ◽  
C. E. Timothy Paine ◽  
Mario Vallejo-Marín
Keyword(s):  
Natural Selection ◽  
Clonal Plant ◽  
Phenotypic Selection ◽  
Lateral Spread ◽  
Outbreeding Depression ◽  
Invasive Range ◽  
Introduced Populations ◽  
Introduced Range ◽  
Native Populations ◽  
Floral Displays

Analyses of phenotypic selection and demography in field populations are powerful ways to establishing the potential role of natural selection in shaping evolution during biological invasions. Here we use experimental F 2 crosses between native and introduced populations of Mimulus guttatus to estimate the pattern of natural selection in part of its introduced range, and to seek evidence of outbreeding depression of colonists. The F 2 s combined the genome of an introduced population with the genome of either native or introduced populations. We found that the introduced × introduced cross had the fastest population growth rate owing to increased winter survival, clonality and seed production. Our analysis also revealed that selection through sexual fitness favoured large floral displays, large vegetative and flower size, lateral spread and early flowering. Our results indicate a source-of-origin effect, consistent with outbreeding depression exposed by mating between introduced and native populations. Our findings suggest that well-established non-native populations may pay a high fitness cost during subsequent bouts of admixture with native populations, and reveal that processes such as local adaptation in the invasive range can mediate the fitness consequences of admixture.

scholarly journals Effects of latitudinal variation on field and common garden comparisons between native and introduced groundsel (Senecio vulgaris) populations

2019 ◽  
Author(s):  
Bi-Ru Zhu ◽  
Xiao-Meng Li ◽  
Da-Yong Zhang ◽  
Wan-Jin Liao
Keyword(s):  
Plant Height ◽  
Rapid Evolution ◽  
Common Garden ◽  
Phenotypic Traits ◽  
Senecio Vulgaris ◽  
Chinese Populations ◽  
Introduced Populations ◽  
Native Populations ◽  
Latitudinal Clines ◽  
European Populations

Abstract Background: Field and common garden comparisons are commonly performed to test the rapid evolution of increased vigor in introduced plant populations. Latitudinal clines in phenotypic traits can obscure such evolutionary inferences, particularly when native or introduced populations are distributed across large geographic ranges. We tested whether the latitudinal clines influence the comparisons between introduced and native populations of Senecio vulgaris. We compared plant height, number of branches and number of capitula in the field in Europe and China, and in a common garden in Switzerland.Results: The Chinese introduced populations performed better than the European native populations in the field in terms of plant height and number of capitula, which was consistent with the prediction of the evolution of increased competitive ability (EICA) hypothesis. The Chinese populations exhibited more capitula than the European populations when the latitudinal cline was considered in the common garden comparison. When we compared the traits of the northeast Chinese, southwest Chinese and European populations in both the field and common garden, the northeast Chinese populations, at latitudes similar to those of the European populations, exhibited greater plant size and more capitula than the European populations in both the field and common garden. However, the southwest Chinese populations, at latitudes that are much lower than those of the European populations, did not perform better in terms of reproduction than the native populations.Conclusion: Latitudinal clines in phenotypic traits should be considered in field and common garden comparisons when introduced populations are geographically structured.

scholarly journals Examining the Role of Acculturation in E-Cigarette Use among U.S. Immigrant Adults

2021 ◽  
Vol 18 (7) ◽  
pp. 3658
Author(s):  
Sunday Azagba ◽  
Lingpeng Shan
Keyword(s):  
Host Country ◽  
Odds Ratio ◽  
Multivariable Analysis ◽  
Population Data ◽  
Cultural Norms ◽  
Cigarette Use ◽  
Length Of Residence ◽  
Native Populations ◽  
The U.S

Evidence suggests that as immigrants’ length of residence in the host country increases, they may integrate their behavior and norms to align with the new community’s cultural norms. The current study examined e-cigarette use among immigrants in the U.S., and whether the length of residence in the U.S. is associated with e-cigarette use among immigrants compared to the native-born population. Data were drawn from the 2014/15 and 2018/19 Tobacco Use Supplement to the Current Population Survey. Multivariable logistic regression was used to compare differences in e-cigarette use between native-born populations and immigrants, when immigrants’ length of residence in the U.S. was considered. Among immigrants, the prevalence of ever and current e-cigarette use increased significantly from 2.5% and 0.5% in 2014/2015 to 3.2% and 0.8% in 2018/2019, respectively. Multivariable analysis showed that immigrants had significantly lower odds of ever e-cigarette use compared to the mainland-born citizen (0–5 years in the U.S., adjusted Odds Ratio (aOR) 0.57, 95% Confidence Interval (CI) 0.46–0.69; 6–10 years, aOR 0.51, 95% CI 0.41–0.63; 11–20 years, aOR 0.45, 95% CI 0.39–0.53; 20+years, aOR 0.68, 95% CI 0.62–0.76). Similar results were found for current e-cigarette use, with immigrants being less likely to be current users. Findings that e-cigarette use among all immigrants—regardless of years living in the U.S.—was consistently lower than among the native-born population run contrary to the notion that as length of stay increases, health behaviors between immigrants and native populations of the host country become similar.

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