Effect of introduced Euphorbia esula on the pollination of Viola pedatifida

Botany ◽  
2009 ◽  
Vol 87 (3) ◽  
pp. 283-292 ◽  
Author(s):  
B. R. Montgomery
Keyword(s):  
Invasive Plant ◽  
Fruit Set ◽  
Seed Set ◽  
Euphorbia Esula ◽  
Native Plant ◽  
Pollination Success ◽  
Heterospecific Pollen ◽  
Competition For Pollination ◽  
Introduced Plants ◽  
Pollen Receipt

Introduced plants may compete for pollination with native plants, resulting in reduced fruit or seed set. In this study, I use several techniques to assess whether the invasive plant Euphorbia esula  L. (leafy spurge, Euphorbiaceae) reduces the pollination success of chasmogamous flowers of the native plant Viola pedatifida G. Don (prairie violet, Violaceae), which has chasmogamous and cleistogamous flowers. Euphorbia pollen was found on most Viola stigmas, suggesting the potential for competition. Additionally, application of Euphorbia pollen to Viola stigmas prior to conspecific pollen reduced seed set. However, natural receipt of Euphorbia and other heterospecific pollen was not associated with decreased fruit or seed set. In the field, fruit set was higher for Viola in sites with Euphorbia despite increased Euphorbia pollen receipt, and seed set did not vary with the presence of Euphorbia. However, there was no significant interaction between the presence of Euphorbia and flower type (cleistogamous or chasmogamous), suggesting that increased fruit set near Euphorbia is unrelated to pollination. This study suggests that Viola and Euphorbia interact through shared pollinators, but there is no evidence that competition for pollination with Euphorbia reduces Viola’s fecundity or results in increased reliance on cleistogamous flowers.

scholarly journals Why so many flowers? A preliminary assessment of mixed pollination strategy enhancing sexual reproduction of the invasive <i>Acacia longifolia</i> in Portugal

Web Ecology ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Manuela Giovanetti ◽  
Margarida Ramos ◽  
Cristina Máguas
Keyword(s):  
Invasive Plant ◽  
Seed Set ◽  
Pollen Grains ◽  
Striking Difference ◽  
Pollination Syndromes ◽  
Pollination Success ◽  
Relative Contribution ◽  
Acacia Longifolia ◽  
Exclusion Experiments ◽  
Pollination Strategy

Abstract. Acacia longifolia, a native legume from Australia, has been introduced in many European countries and elsewhere, thus becoming one of the most important global invasive species. In Europe, its flowering occurs in a period unsuitable for insect activity: nonetheless it is considered entomophilous. Floral traits of this species are puzzling: brightly coloured and scented as liked by insects, but with abundant staminate small-sized flowers and relatively small pollen grains, as it is common in anemophilous species. Invasion processes are especially favoured when reshaping local ecological networks, thus the interest in understanding pollination syndromes associated with invasive plant species that may facilitate invasiveness. Moreover, a striking difference exists between its massive flowering and relatively poor seed set. We introduced a novel approach: first, we consider the possibility that a part of the pollination success is carried on by wind and, second, we weighted the ethological perspective of the main pollinator. During the flowering season of A. longifolia (February–April 2016), we carried on exclusion experiments to detect the relative contribution of insects and wind. While the exclusion experiments corroborated the need for pollen vectors, we actually recorded a low abundance of insects. The honeybee, known pollinator of acacias, was relatively rare and not always productive in terms of successful visits. While wind contributed to seed set, focal observations confirmed that honeybees transfer pollen when visiting both the inflorescences to collect pollen and the extrafloral nectaries to collect nectar. The mixed pollination strategy of A. longifolia may then be the basis of its success in invading Portugal's windy coasts.

scholarly journals Interactive effects of climate change and plant invasion on alpine biodiversity and ecosystem dynamics

2021 ◽  
Author(s):  
◽  
Justyna Giejsztowt
Keyword(s):  
Climate Change ◽  
New Zealand ◽  
Plant Species ◽  
Climate Warming ◽  
Plant Invasion ◽  
Invasive Plant ◽  
Ecosystem Dynamics ◽  
Interactive Effects ◽  
Native Plant ◽  
Competition For Pollination

<p>Drivers of global change have direct impacts on the structure of communities and functioning of ecosystems, and interactions between drivers may buffer or exacerbate these direct effects. Interactions among drivers can lead to complex non-linear outcomes for ecosystems, communities and species, but are infrequently quantified. Through a combination of experimental, observational and modelling approaches, I address critical gaps in our understanding of the interactive effects of climate change and plant invasion, using Tongariro National Park (TNP; New Zealand) as a model. TNP is an alpine ecosystem of cultural significance which hosts a unique flora with high rates of endemism. TNP is invaded by the perennial shrub Calluna vulgaris (L.) Hull. My objectives were to: 1) determine whether species-specific phenological shifts have the potential to alter the reproductive capacity of native plants in landscapes affected by invasion; 2) determine whether the effect of invasion intensity on the Species Area Relationship (SAR) of native alpine plant species is influenced by environmental stress; 3) develop a novel modelling framework that would account for density-dependent competitive interactions between native species and C. vulgaris and implement it to determine the combined risk of climate change and plant invasion on the distribution of native plant species; and 4) explore the possible mechanisms leading to a discrepancy in C. vulgaris invasion success on the North and South Islands of New Zealand. I show that species-specific phenological responses to climate warming increase the flowering overlap between a native and an invasive plant. I then show that competition for pollination with the invader decreases the sexual reproduction of the native in some landscapes. I therefore illustrate a previously undescribed interaction between climate warming and plant invasion where the effects of competition for pollination with an invader on the sexual reproduction of the native may be exacerbated by climate warming. Furthermore, I describe a previously unknown pattern of changing invasive plant impact on SAR along an environmental stress gradient. Namely, I demonstrate that interactions between an invasive plant and local native plant species richness become increasingly facilitative along elevational gradients and that the strength of plant interactions is dependent on invader biomass. I then show that the consequences of changing plant interactions at a local scale for the slope of SAR is dependent on the pervasion of the invader. Next, I demonstrate that the inclusion of invasive species density data in distribution models for a native plant leads to greater reductions in predicted native plant distribution and density under future climate change scenarios relative to models based on climate suitability alone. Finally, I find no evidence for large-scale climatic, edaphic, and vegetative limitations to invasion by C. vulgaris on either the North and South Islands of New Zealand. Instead, my results suggest that discrepancies in invasive spread between islands may be driven by human activity: C. vulgaris is associated with the same levels of human disturbance on both islands despite differences in the presence of these conditions between then islands. Altogether, these results show that interactive effects between drivers on biodiversity and ecosystem dynamics are frequently not additive or linear. Therefore, accurate predictions of global change impacts on community structure and ecosystems function require experiments and models which include of interactions among drivers such as climate change and species invasion. These results are pertinent to effective conservation management as most landscapes are concurrently affected by multiple drivers of global environmental change.</p>

scholarly journals Severely pollen-limited fruit set in a pear (Pyrus communis) orchard revealed by yield assessments and DNA-based paternity assignment of seedlings

2007 ◽  
Vol 13 (3) ◽  
Author(s):  
H. Mattison ◽  
J. Sehic ◽  
H. Nybom
Keyword(s):  
Fruit Set ◽  
Seed Set ◽  
Rapd Analysis ◽  
Total Yield ◽  
Fruit Tree ◽  
Pollen Transfer ◽  
Pear Cultivar ◽  
Pollination Success ◽  
Viable Seeds ◽  
High Yields

In commercial fruit tree orchards, consistently high yields are necessary for a durable economy. The Swedish pear cultivar 'Carola' has been noted for low setting in some orchards, possibly due to insufficient pollination. In this study, fruit set was evaluated in a research orchard where `Carola' had been planted together with four potential pollinators. Total yield and number of fruits was noted during three and four years, respectively. In 2003, seeds were germinated from the harvested `Carola' fruits, and the paternity of three seedlings from 50 trees was determined with RAPD analysis. 'Clapp's Favourite' had sired 39.6% of the seedlings, closely followed by `Seigneur d'Esperen' (30.7%) and 'Clara Frijs' (26.7%) whereas 'Skanskt sockerparon' only sired 1.1% of the seedlings. The remaining 2.3% appeared to have been derived by selfing. Pollen-limited seed set was indicated at surprisingly short distances; accumulated number of fruits on the `Carola' trees was significantly higher when separated by only 2 m from one of the two most efficient pollinators, 'Clapp's Favourite' or 'Seigneur d'Esperen‘, compared to trees 4—l0 in away in the same row. Number of viable seeds per fruit was also higher in fruits from trees immediately adjacent to the pollinators, suggesting an effect of improved pollination success. The importance of very short inter-cultivar distances for efficient pollen transfer became even more clear when comparisons involved the true pollination distances as determined by RAPD; the accumulated yields decreased linearly from 55 kg at a 2 in distance to only 17 kg at 13 m.

scholarly journals Inoculation of pear flowers with Metschnikowia reukaufii and Acinetobacter nectaris enhances attraction of honeybees and hoverflies, but does not increase fruit and seed set

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250203
Author(s):  
Agneta Colda ◽  
Sofie Bossaert ◽  
Christel Verreth ◽  
Bart Vanhoutte ◽  
Olivier Honnay ◽  
...  
Keyword(s):  
Food Production ◽  
Fruit Set ◽  
Seed Set ◽  
Limiting Factor ◽  
World Population ◽  
Floral Nectar ◽  
Natural Habitats ◽  
Factors Affecting ◽  
Pollination Success ◽  
Fruit And Seed Set

Currently, one of the most important challenges is to provide sufficient and affordable food and energy for a fast-growing world population, alongside preserving natural habitats and maintaining biodiversity. About 35% of the global food production depends on animals for pollination. In recent years, an alarming worldwide decline in pollinators has been reported, putting our food production under additional pressure. Therefore, there is an urgent need to find sustainable ways to ensure this crucial ecosystem service. Recent studies have shown that floral nectar is generally colonized by microorganisms, specifically yeasts and bacteria, which may alter nectar chemistry and enhance attraction of pollinators. In this study, we investigated changes in pollinator foraging behavior and pollination success in European pear (Pyrus communis L.) cultivars ‘Regal Red’ and ‘Sweet Sensation’ (red sports of ‘Doyenné de Comice’) after flower inoculation with the typical nectar-inhabiting microorganisms Metschnikowia reukaufii and Acinetobacter nectaris, and a combination of both. Pollination success was monitored by measuring the number of flower visits, fruit set and seed set in two consecutive years, 2019 and 2020. Results revealed that application of a mixture of M. reukaufii and A. nectaris resulted in significantly higher visitation rates of honeybees and hoverflies. By contrast, no effects on flower visits were found when yeasts and bacteria were applied separately. Fruit set and seed set were not significantly affected by any of the inoculation treatments. The only factors affecting fruit set were initial number of flower clusters on the trees and the year. The absence of treatment effects can most likely be attributed to the fact that pollination was not a limiting factor for fruit set in our experiments. Altogether, our results show that inoculation of flowers with nectar microbes can modify pollinator foraging patterns, but did not lead to increased pollination success under the conditions tested.

scholarly journals Pollination success increases with plant diversity in high-Andean communities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sabrina S. Gavini ◽  
Agustín Sáez ◽  
Cristina Tur ◽  
Marcelo A. Aizen
Keyword(s):  
Plant Diversity ◽  
Species Coexistence ◽  
Pollen Grains ◽  
Plant Interactions ◽  
Pollination Success ◽  
Heterospecific Pollen ◽  
Biodiversity Maintenance ◽  
Pollen Receipt ◽  
Facilitative Interactions ◽  
Plant Plant

AbstractPollinator-mediated plant–plant interactions have traditionally been viewed within the competition paradigm. However, facilitation via pollinator sharing might be the rule rather than the exception in harsh environments. Moreover, plant diversity could be playing a key role in fostering pollinator-mediated facilitation. Yet, the facilitative effect of plant diversity on pollination remains poorly understood, especially under natural conditions. By examining a total of 9371 stigmas of 88 species from nine high-Andean communities in NW Patagonia, we explored the prevalent sign of the relation between conspecific pollen receipt and heterospecific pollen diversity, and assessed whether the incidence of different outcomes varies with altitude and whether pollen receipt relates to plant diversity. Conspecific pollen receipt increased with heterospecific pollen diversity on stigmas. In all communities, species showed either positive or neutral but never negative relations between the number of heterospecific pollen donor species and conspecific pollen receipt. The incidence of species showing positive relations increased with altitude. Finally, stigmas collected from communities with more co-flowering species had richer heterospecific pollen loads and higher abundance of conspecific pollen grains. Our findings suggest that plant diversity enhances pollination success in high-Andean plant communities. This study emphasizes the importance of plant diversity in fostering indirect plant–plant facilitative interactions in alpine environments, which could promote species coexistence and biodiversity maintenance.

The effect of invasive Lythrum salicaria pollen deposition on seed set in the native species Decodon verticillatus

Botany ◽  
2011 ◽  
Vol 89 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Elizabeth M. Da Silva ◽  
Risa D. Sargent
Keyword(s):  
Native Species ◽  
Invasive Plant ◽  
Seed Set ◽  
Lythrum Salicaria ◽  
Pollen Deposition ◽  
Native Plant ◽  
Plant Populations ◽  
Hand Pollination ◽  
Whole Plants ◽  
The Impact

Relatively little attention has been paid to pollinator-mediated interactions among invasive and native plants in spite of the fact that pollen transfer between species in invaded communities has been shown to occur. In this study, we investigated the impact of pollen deposition from the invasive plant species Lythrum salicaria on seed set in a native species that is a member of the same family, Decodon verticillatus. Whole plants were subjected to hand pollination by conspecific (D. verticillatus only) or mixed (a 1:1 mixture of D. verticillatus and L. salicaria) pollen to determine if the addition of a mixed pollen load interferes with the ability of D. verticillatus pollen to set seed. We found the mixed pollen treatment reduced D. verticillatus seed set by 33.3% relative to the conspecific pollen treatment. Our study demonstrates that invasive plants have the potential to negatively impact the reproductive success of a native species through pollinator-mediated interactions. We discuss the potential implications of our findings to the evolution and persistence of native plant populations in invaded communities.

scholarly journals Interactive effects of climate change and plant invasion on alpine biodiversity and ecosystem dynamics

2021 ◽  
Author(s):  
◽  
Justyna Giejsztowt
Keyword(s):  
Climate Change ◽  
New Zealand ◽  
Plant Species ◽  
Climate Warming ◽  
Plant Invasion ◽  
Invasive Plant ◽  
Ecosystem Dynamics ◽  
Interactive Effects ◽  
Native Plant ◽  
Competition For Pollination

<p>Drivers of global change have direct impacts on the structure of communities and functioning of ecosystems, and interactions between drivers may buffer or exacerbate these direct effects. Interactions among drivers can lead to complex non-linear outcomes for ecosystems, communities and species, but are infrequently quantified. Through a combination of experimental, observational and modelling approaches, I address critical gaps in our understanding of the interactive effects of climate change and plant invasion, using Tongariro National Park (TNP; New Zealand) as a model. TNP is an alpine ecosystem of cultural significance which hosts a unique flora with high rates of endemism. TNP is invaded by the perennial shrub Calluna vulgaris (L.) Hull. My objectives were to: 1) determine whether species-specific phenological shifts have the potential to alter the reproductive capacity of native plants in landscapes affected by invasion; 2) determine whether the effect of invasion intensity on the Species Area Relationship (SAR) of native alpine plant species is influenced by environmental stress; 3) develop a novel modelling framework that would account for density-dependent competitive interactions between native species and C. vulgaris and implement it to determine the combined risk of climate change and plant invasion on the distribution of native plant species; and 4) explore the possible mechanisms leading to a discrepancy in C. vulgaris invasion success on the North and South Islands of New Zealand. I show that species-specific phenological responses to climate warming increase the flowering overlap between a native and an invasive plant. I then show that competition for pollination with the invader decreases the sexual reproduction of the native in some landscapes. I therefore illustrate a previously undescribed interaction between climate warming and plant invasion where the effects of competition for pollination with an invader on the sexual reproduction of the native may be exacerbated by climate warming. Furthermore, I describe a previously unknown pattern of changing invasive plant impact on SAR along an environmental stress gradient. Namely, I demonstrate that interactions between an invasive plant and local native plant species richness become increasingly facilitative along elevational gradients and that the strength of plant interactions is dependent on invader biomass. I then show that the consequences of changing plant interactions at a local scale for the slope of SAR is dependent on the pervasion of the invader. Next, I demonstrate that the inclusion of invasive species density data in distribution models for a native plant leads to greater reductions in predicted native plant distribution and density under future climate change scenarios relative to models based on climate suitability alone. Finally, I find no evidence for large-scale climatic, edaphic, and vegetative limitations to invasion by C. vulgaris on either the North and South Islands of New Zealand. Instead, my results suggest that discrepancies in invasive spread between islands may be driven by human activity: C. vulgaris is associated with the same levels of human disturbance on both islands despite differences in the presence of these conditions between then islands. Altogether, these results show that interactive effects between drivers on biodiversity and ecosystem dynamics are frequently not additive or linear. Therefore, accurate predictions of global change impacts on community structure and ecosystems function require experiments and models which include of interactions among drivers such as climate change and species invasion. These results are pertinent to effective conservation management as most landscapes are concurrently affected by multiple drivers of global environmental change.</p>

scholarly journals Reciprocal Heterospecific Pollen Interference among Alien and Native Species

2020 ◽  
Author(s):  
Eva M. Malecore ◽  
Sylvie Berthelot ◽  
Mark van Kleunen ◽  
Mialy Razanajatovo
Keyword(s):  
Community Composition ◽  
Native Species ◽  
Fruit Set ◽  
Seed Set ◽  
Biotic Resistance ◽  
Alien Plants ◽  
Phylogenetic Distance ◽  
Explanatory Variables ◽  
Heterospecific Pollen ◽  
Fruit And Seed Set

1. Heterospecific pollen interference has recently been proposed as a mechanism contributing to the success of alien invaders, as heterospecific pollen of alien plants interferes with the reproduction of natives by reducing fruit and seed set. However, no study has looked at the opposite interaction. Moreover, few studies have considered the roles of phylogenetic and trait distances between pollen donors and recipients. 2. We did a large multi-species experiment in which we used alien and native species both as pollen recipients and as pollen donors, and included phylogenetic as well as trait distance as explanatory variables. 3. We found that both alien and native recipients suffered from heterospecific pollen from donors of the opposite status in terms of seed and fruit set. Phylogenetic distance and trait distance both affected heterospecific pollen interference, but the effect depended on recipient and donor statuses. 4. We conclude that heterospecific pollen interference affects both native and alien recipients, thus indirectly altering community composition and increasing biotic resistance against invaders.

Planting native trees to restore riparian forests increases biotic resistance to non-native plant invasions

2021 ◽  
pp. 1-24
Author(s):  
Chad F. Hammer ◽  
John S. Gunn
Keyword(s):  
United States ◽  
Ecosystem Service ◽  
Invasive Plant ◽  
Biotic Resistance ◽  
The United States ◽  
Tree Regeneration ◽  
Tree Planting ◽  
Plant Colonization ◽  
Native Plant ◽  
Native Trees

Abstract Non-native invasive plant species are a major cause of ecosystem degradation and impairment of ecosystem service benefits in the United States. Forested riparian areas provide many ecosystem service benefits and are vital to maintaining water quality of streams and rivers. These systems are also vulnerable to natural disturbances and invasion by non-native plants. We assessed whether planting native trees on disturbed riparian sites may increase biotic resistance to invasive plant establishment in central Vermont in the northeastern United States. The density (stems/m2) of invasive stems was higher in non-planted sites (x̄=4.1 stems/m2) compared to planted sites (x̄=1.3 stems/m2). More than 90% of the invasive plants were Japanese knotweed (Fallopia japonica). There were no significant differences in total stem density of native vegetation between planted and non-planted sites. Other measured response variables such as native tree regeneration, species diversity, soil properties and soil function showed no significant differences or trends in the paired riparian study sites. The results of this case study indicate that tree planting in disturbed riparian forest areas may assist conservation efforts by minimizing the risk of invasive plant colonization.

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