scholarly journals Competitive Interactions of Flowering Rush (Butomus umbellatus L.) Cytotypes in Submersed and Emergent Experimental Aquatic Plant Communities

Diversity ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 40 ◽  
Author(s):  
Nathan E. Harms

The ability to invade communities in a variety of habitats (e.g., along a depth gradient) may facilitate establishment and spread of invasive plants, but how multiple lineages of a species perform under varying conditions is understudied. A series of greenhouse common garden experiments were conducted in which six diploid and four triploid populations of the aquatic invasive plant Butomus umbellatus L. (Butomaceae) were grown in submersed or emergent conditions, in monoculture or in a multispecies community, to compare establishment and productivity of cytotypes under competition. Diploid biomass overall was 12 times higher than triploids in the submersed experiment and three times higher in the emergent experiment. Diploid shoot:root ratio was double that of triploid plants in submersed conditions overall, and double in emergent conditions in monoculture. Relative interaction intensities (RII) indicated that triploid plants were sixteen times more negatively impacted by competition under submersed conditions but diploid plants were twice as impacted under emergent conditions. Recipient communities were similarly negatively impacted by B. umbellatus cytotypes. This study supports the idea that diploid and triploid B. umbellatus plants are equally capable of invading emergent communities, but that diploid plants may be better adapted for invading in submersed habitats. However, consistently lower shoot:root ratios in both monoculture and in communities suggests that triploid plants may be better-adapted competitors in the long term due to increased resource allocation to roots. This represents the first examination into the role of cytotype and habitat on competitive interactions of B. umbellatus.

2012 ◽  
pp. 66-77 ◽  
Author(s):  
I. A. Lavrinenko ◽  
O. V. Lavrinenko ◽  
D. V. Dobrynin

The satellite images show that the area of marshes in the Kolokolkova bay was notstable during the period from 1973 up to 2011. Until 2010 it varied from 357 to 636 ha. After a severe storm happened on July 24–25, 2010 the total area of marshes was reduced up to 43–50 ha. The mean value of NDVI for studied marshes, reflecting the green biomass, varied from 0.13 to 0.32 before the storm in 2010, after the storm the NDVI decreased to 0.10, in 2011 — 0.03. A comparative analysis of species composition and structure of plant communities described in 2002 and 2011, allowed to evaluate the vegetation changes of marshes of the different topographic levels. They are fol­lowing: a total destruction of plant communities of the ass. Puccinellietum phryganodis and ass. Caricetum subspathaceae on low and middle marches; increasing role of halophytic species in plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. typicum on middle marches; some changes in species composition and structure of plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. festucetosum rubrae on high marches and ass. Parnassio palustris–Salicetum reptantis in transition zone between marches and tundra without changes of their syntaxonomy; a death of moss cover in plant communities of the ass. Caricetum mackenziei var. Warnstorfia exannulata on brackish coastal bogs. The possible reasons of dramatic vegetation dynamics are discussed. The dating of the storm makes it possible to observe the directions and rates of the succession of marches vegetation.


1990 ◽  
Vol 68 (8) ◽  
pp. 1780-1787 ◽  
Author(s):  
Denise M. Seliskar

Scirpus americanus Pers., a major dune slack plant in coastal sand dune ecosystems, differs in height along transects ranging between the lowest and highest elevational areas of slacks located along the coast of Delaware, U.S.A. Using reciprocal transplant and common garden experiments, results suggest that environmental factors rather than hereditary traits are more important in accounting for the differences in plant morphology expressed in the field. Dune slack plants are exposed to stresses of waterlogging and sand accretion in their natural environment. In controlled greenhouse experiments waterlogging was shown to inhibit stem growth and cause an increase in aerenchymatous tissue, whereas periodic sand deposition caused an increase in the plant height of Scirpus.


Author(s):  
Richard Honor ◽  
Robert I. Colautti

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.


2010 ◽  
Vol 3 (2) ◽  
pp. 182-189
Author(s):  
Monica L. Pokorny ◽  
Jane M. Mangold ◽  
James Hafer ◽  
M. Kirk Denny

AbstractInvasive plants need to be managed after wildfire to suppress the invasive plant and to maintain or restore a desired plant community. Our study tested treatments that influence species availability and performance following a disturbance (wildfire). The overall objective was to determine the ability of herbicide and revegetation treatments to restore spotted knapweed–infested areas to desired plant communities after wildfire. The study consisted of a factorial combination of three herbicide application treatments (broadcast application, spot application, and no herbicide) and three seed mixture treatments (grass-only seed mix, a grass and forb seed mix, no seeding). Picloram was used for the herbicide. Both the broadcast and spot picloram application methods decreased spotted knapweed cover and density up to 80% while increasing desired grass cover and density up to 20% compared with the control. However, broadcast spraying picloram decreased species richness from 5.7 to 3.6 species 0.1 m−2 and decreased desired forb density and cover compared with spot-applied picloram treatment. Spot spraying resulted in an increase in other undesired forbs compared with broadcast spraying. Seeding with desired species had no effect on spotted knapweed cover or density. Spot spraying may help maintain desired species richness while managing spotted knapweed.


2018 ◽  
Vol 285 (1884) ◽  
pp. 20181072 ◽  
Author(s):  
Shiyun Qiu ◽  
Xiao Xu ◽  
Shuangshuang Liu ◽  
Wenwen Liu ◽  
Jing Liu ◽  
...  

Flowering synchrony can play an important role in plants' reproductive success, which is essential for the successful establishment and spread of invasive plants. Although flowering synchrony has been found to be closely related to climatic factors, the effects of variation in such factors along latitudinal gradient on flowering synchrony and the role of flowering synchrony in the reproductive success of invading populations remain largely unexplored. In a 2-year field study, we examined the latitudinal variation of flowering phenology, especially flowering synchrony, in an invasive plant, Spartina alterniflora , along coastal China, and its relationship with population seed set across three climatic zones. We found that first flowering date was delayed, and flowering synchrony increased with increasing latitude. Flowering synchrony was negatively related to temperature during flowering season but not to soil properties or precipitation, suggesting that climate has shaped the latitudinal pattern of flowering synchrony. Moreover, a positive correlation between flowering synchrony and seed set across latitudes indicates the possible role of flowering synchrony in the latitudinal pattern of sexual reproduction in S. alterniflora . These results suggest that, in addition to the effects of climate on the growth of invasive species, climatic factors can play an important role in the invasion success of alien plants by regulating the flowering synchrony and thus the reproductive success of invasive plants.


Author(s):  
Richard Honor ◽  
◽  
Robert L. Colautti ◽  

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.


2017 ◽  
Vol 10 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Daniel R. Tekiela ◽  
Jacob N. Barney

Ecological impacts from invasive plants that have been identified include reductions in biodiversity, changes in resource cycling, and disruptions of ecosystem function. To mitigate these negative ecological impacts, managers work to remove invasive plants. However, removal does not necessarily immediately lead to a return to the uninvaded ecological state. Similarly, the accumulation rate of ecological impacts following invader establishment is almost entirely unknown for most species, hindering identification of optimal management times. The accumulation and loss (so-called legacy effects) of impacts following invader establishment and removal represent an “invasion shadow.” To begin to understand invasion shadows, we measured the changes in biotic and abiotic ecological impacts during establishment and following removal of the forest understory invader Japanese stiltgrass. We found that when the abiotic metrics were considered, seeded areas became more functionally similar to the invaded landscape and removed areas became more similar to the uninvaded landscape. However, while the plant community did not change in a 3-yr period during a new invasion, following invader removal, it became less similar to both the invaded and uninvaded landscape altogether, suggesting legacies. Surprisingly, all changes occurred almost immediately and persisted following invader establishment and removal. Our results show, at least in a 3-yr period, that ecosystems can respond to changes in invader abundance, and in some cases simply removing the invader could result in long-term changes to the resident plant community.


Koedoe ◽  
2014 ◽  
Vol 56 (1) ◽  
Author(s):  
Benjamin J. Wigley ◽  
Herve Fritz ◽  
Corli Coetsee ◽  
William J. Bond

The role of grazers in determining vegetation community compositions and structuring plant communities is well recognised in grassy systems. The role of browsers in affecting savanna woody plant communities is less clear. We used three long-term exclosures in the Kruger National Park to determine the effect of browsers on species compositions and population structures of woody communities. Species assemblages, plant traits relating to browsing and soil nutrients were compared inside and outside of the exclosures. Our results showed that browsers directly impact plant species distributions, densities and population structures by actively selecting for species with traits which make them desirable to browsers. Species with high leaf nitrogen, low total phenolic content and low acid detergent lignin appeared to be favoured by herbivores and therefore tend to be rare outside of the exclosures. This study also suggested that browsers have important indirect effects on savanna functioning, as the reduction of woody cover can result in less litter of lower quality, which in turn can result in lower soil fertility. However, the magnitude of browser effects appeared to depend on inherent soil fertility and climate.Conservation implications: Browsers were shown to have significant impacts on plant communities. They have noticeable effects on local species diversity and population structure, as well as soil nutrients. These impacts are shown to be related to the underlying geology and climate. The effects of browsers on woody communities were shown to be greater in low rainfall, fertile areas compared to high rainfall, infertile soils.


2008 ◽  
Vol 99 (3) ◽  
pp. 229-243 ◽  
Author(s):  
S.S. Schooler ◽  
P.B. McEvoy ◽  
P. Hammond ◽  
E.M. Coombs

AbstractInvasive plants have been shown to negatively affect the diversity of plant communities. However, little is known about the effect of invasive plants on the diversity at other trophic levels. In this study, we examine the per capita effects of two invasive plants, purple loosestrife (Lythrum salicaria) and reed canary grass (Phalaris arundinacea), on moth diversity in wetland communities at 20 sites in the Pacific Northwest, USA. Prior studies document that increasing abundance of these two plant species decreases the diversity of plant communities. We predicted that this reduction in plant diversity would result in reduced herbivore diversity. Four measurements were used to quantify diversity: species richness (S), community evenness (J), Brillouin's index (H) and Simpson's index (D). We identified 162 plant species and 156 moth species across the 20 wetland sites. The number of moth species was positively correlated with the number of plant species. In addition, invasive plant abundance was negatively correlated with species richness of the moth community (linear relationship), and the effect was similar for both invasive plant species. However, no relationship was found between invasive plant abundance and the three other measures of moth diversity (J, H, D) which included moth abundance in their calculation. We conclude that species richness within, and among, trophic levels is adversely affected by these two invasive wetland plant species.


Author(s):  
Daniel Sol ◽  
Oriol Lapiedra ◽  
César González-Lagos ◽  
Miquel De Caceres

Growing evidence that individuals of many generalist animals behave as resource specialists has attracted research interest for its ecological and evolutionary implications. Although variation in resource preferences is critical for developing a general theory of individual specialization, it remains to be shown whether diverging preferences can arise among individuals sharing a similar environment and whether these are stable enough to be ecologically relevant. We addressed these issues by means of common garden experiments in feral pigeons (Columba livia), a species known to exhibit resource specialization in the wild. Food-choice experiments on wild-caught pigeons and their captive-bred descendants showed that variation in food preferences can easily arise within a population and that this variation may represent a substantial fraction of the population niche. However, a cross-fostering experiment revealed that the genetic and early common-environment components of food preferences were low, reducing their stability and eroding niche variation in the long-term.


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