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

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.

NeoBiota ◽  
2020 ◽  
Vol 57 ◽  
pp. 109-131
Author(s):  
Judith Bieberich ◽  
Heike Feldhaar ◽  
Marianne Lauerer

The impact of invasive species is often difficult to assess due to species × ecosystem interactions. Impatiens glandulifera heavily invaded several habitat types in Central Europe but its impact on native plant communities is rated ambiguously. One reason could be that the impact differs between habitat types or even between environmentally heterogeneous patches (micro-habitats) within one habitat type. In the present study a vegetation survey was performed within heterogeneous riverside habitats in Germany investigating the impact of I. glandulifera on native vegetation in dependence of environmental conditions. The vegetation was recorded in summer and spring because of seasonal species turnover and thus potentially different impact of the invasive plant. We found that the cover of I. glandulifera depended on environmental conditions resulting in a patchy occurrence. I. glandulifera did not have any impact on plant alpha-diversity but reduced the cover of the native vegetation, especially of the dominant species. This effect depended on micro-habitat and season. The native vegetation was most affected in bright micro-habitats, especially those with a high soil moisture. Not distinguishing between micro-habitats, plant species composition was not affected in summer but in spring. However, environmental conditions had a higher impact on the native vegetation than I. glandulifera. We conclude that within riparian habitats the threat of I. glandulifera to the native vegetation can be rated low since native species were reduced in cover but not excluded from the communities. This might be due to patchy occurrence and year-to-year changes in cover of I. glandulifera. The context-dependency in terms of micro-habitat and season requires specific risk assessments which is also an opportunity for nature conservation to develop management plans specific to the different habitats. Particular attention should be given to habitats that are bright and very wet since the effect of I. glandulifera was strongest in these habitats.


Author(s):  
Keenan Randall ◽  
Ty Greene ◽  
Melissa Lee ◽  
Carlyn McNabb

Purple loosestrife (Lythrum salicaria) is an invasive plant species that has affected agriculture and wildlife across Canada. The weed is not native to Canada; however in municipalities like Kingston and the surrounding area, it has caused tangible problems. We will strive to engage a government partner (City of Kingston), community organization (ON Invasive Species Awareness Program), and a local resident throughout the completion of our research and regarding the viability of solutions proposed. First, we will examine the origins of the plant in Canada, emphasizing the reproductive characteristics that make the purple loosestrife a powerfully invasive species. Next, we will analyze the impact of the purple loosestrife from three perspectives: (1) the impact on native plant communities; (2) the impact on native animal communities; (3) the impact on human life. We will then evaluate current bio management controls, as utilized by other governments, such as the introduction of another foreign species as a control agent. Specifically, we will examine the potential control systems using the following criteria: (1) ability to control the invasive species; (2) feasibility and cost; and (3) direct and indirect negative impacts. Finally, we will propose a comprehensive strategy for each organization moving forward, allowing for increased community collaboration and, ideally, the elimination and/or control of the invasive species.


Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 813
Author(s):  
Ian Sexton ◽  
Philip Turk ◽  
Lindsay Ringer ◽  
Cynthia S. Brown

The accumulation of live and dead trees and other vegetation in forests across the western United States is producing larger and more severe wildfires. To decrease wildfire severity and increase forest resilience, foresters regularly remove excess fuel by burning woody material in piles. This common practice could also cause persistent ecosystem changes such as the alteration of soil physical and chemical properties due to extreme soil heating, which can favor invasion by non-native plant species. The abundance and species richness of native plant communities may also remain depressed for many years after burning has removed vegetation and diminished propagules in the soil. This adds to the vulnerability of burned areas to the colonization and dominance by invasive species. Research into the use of revegetation techniques following pile burning to suppress invasion is limited. Studies conducted in various woodland types that investigated revegetation of pile burn scars have met with varying success. To assess the effectiveness of restoring pile burn scars in Rocky Mountain National Park, Colorado, we monitored vegetation in 26 scars, each about 5 m in diameter, the growing season after burning. Later that summer, we selected 14 scars for restoration that included soil scarification, seed addition, and pine duff mulch cover. We monitored the scars for four years, pre-restoration, and three years post-restoration and found that the cover of seeded species exceeded the surrounding unburned areas and unseeded controls. The restoration seeding suppressed cover of non-native species as well as native species that were not seeded during restoration. Our results suggest that restoration of pile burn scars could be a useful tool to retard the establishment of invasive plant species when there are pre-existing infestations near scars. However, this must be weighed against the simultaneous suppression of native species recruitment. Monitoring for periods more than three years will help us understand how long the suppression of native and non-native species by restoration species may persist.


AoB Plants ◽  
2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Betsy von Holle ◽  
Sören E Weber ◽  
David M Nickerson

Abstract Plant species ranges are expected to shift in response to climate change, however, it is unclear how species interactions will affect range shifts. Because of the potential for enemy release of invasive nonnative plant species from species-specific soil pathogens, invasive plants may be able to shift ranges more readily than native plant species. Additionally, changing climatic conditions may alter soil microbial functioning, affecting plant–microbe interactions. We evaluated the effects of site, plant–soil microbe interactions, altered climate, and their interactions on the growth and germination of three congeneric shrub species, two native to southern and central Florida (Eugenia foetida and E. axillaris), and one nonnative invasive from south America (E. uniflora). We measured germination and biomass for these plant species in growth chambers grown under live and sterile soils from two sites within their current range, and one site in their expected range, simulating current (2010) and predicted future (2050) spring growing season temperatures in the new range. Soil microbes (microscopic bacteria, fungi, viruses and other organisms) had a net negative effect on the invasive plant, E. uniflora, across all sites and temperature treatments. This negative response to soil microbes suggests that E. uniflora’s invasive success and potential for range expansion are due to other contributing factors, e.g. higher germination and growth relative to native Eugenia. The effect of soil microbes on the native species depended on the geographic provenance of the microbes, and this may influence range expansion of these native species.


2020 ◽  
Vol 58 (1) ◽  
pp. 97-117
Author(s):  
Erica M. Goss ◽  
Amy E. Kendig ◽  
Ashish Adhikari ◽  
Brett Lane ◽  
Nicholas Kortessis ◽  
...  

Non-native invasive plants can establish in natural areas, where they can be ecologically damaging and costly to manage. Like cultivated plants, invasive plants can experience a relatively disease-free period upon introduction and accumulate pathogens over time. Diseases of invasive plant populations are infrequently studied compared to diseases of agriculture, forestry, and even native plant populations. We evaluated similarities and differences in the processes that are likely to affect pathogen accumulation and disease in invasive plants compared to cultivated plants, which are the dominant focus of the field of plant pathology. Invasive plants experience more genetic, biotic, and abiotic variation across space and over time than cultivated plants, which is expected to stabilize the ecological and evolutionary dynamics of interactions with pathogens and possibly weaken the efficacy of infectious disease in their control. Although disease is expected to be context dependent, the widespread distribution of invasive plants makes them important pathogen reservoirs. Research on invasive plant diseases can both protect crops and help manage invasive plant populations.


Botany ◽  
2016 ◽  
Vol 94 (6) ◽  
pp. 481-491 ◽  
Author(s):  
Catherine A. Gehring ◽  
Michaela Hayer ◽  
Lluvia Flores-Rentería ◽  
Andrew F. Krohn ◽  
Egbert Schwartz ◽  
...  

Invasive, non-native plant species can alter soil microbial communities in ways that contribute to their persistence. While most studies emphasize mycorrhizal fungi, invasive plants also may influence communities of dark septate fungi (DSF), which are common root endophytes that can function like mycorrhizas. We tested the hypothesis that a widespread invasive plant in the western United States, cheatgrass (Bromus tectorum L.), influenced the abundance and community composition of DSF by examining the roots and rhizosphere soils of cheatgrass and two native plant species in cheatgrass-invaded and noninvaded areas of sagebrush steppe. We focused on cheatgrass because it is negatively affected by mycorrhizal fungi and colonized by DSF. We found that DSF root colonization and operational taxonomic unit (OTU) richness were significantly higher in sagebrush (Artemisia tridentata Nutt.) and rice grass (Achnatherum hymenoides (Roem. & Schult.) Barkworth) from invaded areas than noninvaded areas. Cheatgrass roots had similar levels of DSF colonization and OTU richness as native plants. The community composition of DSF varied with invasion in the roots and soils of native species and among the roots of the three plant species in the invaded areas. The substantial changes in DSF we observed following cheatgrass invasion argue for comparative studies of DSF function in native and non-native plant species.


2006 ◽  
Vol 28 (1) ◽  
pp. 27 ◽  
Author(s):  
A. C. Grice

Most parts of the Australian rangelands are at risk of invasion by one or more species of non-native plants. The severity of current problems varies greatly across the rangelands with more non-native plant species in more intensively settled regions, in climatic zones that have higher and more reliable rainfall, and in wetter and more fertile parts of rangeland landscapes. Although there is quantitative evidence of impacts on either particular taxonomic groups or specific ecological processes in Australian rangelands, a comprehensive picture of responses of rangeland ecosystems to plant invasions is not available. Research has been focused on invasive species that are perceived to have important effects. This is likely to down play the significance of species that have visually less dramatic influences and ignore the possibility that some species could invade and yet have negligible consequences. It is conceivable that most of the overall impact will come from a relatively small proportion of invasive species. Impacts have most commonly been assessed in terms of plant species richness or the abundance of certain groups of vertebrates to the almost complete exclusion of other faunal groups. All scientific studies of the impacts of invasive species in Australian rangelands have focused on the effects of individual invasive species although in many situations native communities are under threat from a complex of interacting weed species. Invasion by non-native species is generally associated with declines in native plant species richness, but faunal responses are more complex and individual invasions may be associated with increase, decrease and no-change scenarios for different faunal groups. Some invasive species may remain minor components of the vegetation that they invade while others completely dominate one stratum or the vegetation overall.


2021 ◽  
Author(s):  
Valeria Aschero ◽  
Agustina Barros ◽  
Lorena Bonjour ◽  
Ana Mazzolari ◽  
Martín Pérez Sosa ◽  
...  

Abstract While the role of environmental filters, usually described by elevation as proxy, and anthropogenic disturbance as drivers of non-native plant diversity and abundance in mountains have been extensively studied, the impact of herbivores are less explored. Livestock grazing can facilitate the introduction of non-native species by seed dispersal and reduce biotic resistance due to consumption and trampling of native plants, even in the highest protected areas in the Andes. We here explored the effects of elevation, livestock and distance to the road on non-native and native plant distributions. Our results confirm the largely negative relationship of non-native plant richness and cover with elevation, with a peak in richness and cover at low to intermediate elevations. Similarly, we show a strong decline in non-native richness with increasing distance to the road, especially at low elevations, accompanied by a strong negative effect of roads on native species richness. Most importantly, however, we show that the presence of non-native herbivores greatly increases the cover of non-native species away from the roadside, identifying herbivore disturbance as a potential catalyst of non-native plant invasion into natural vegetation of high-Andean protected areas. Our results confirm the often-shown role of disturbance as driver of plant invasions in mountains, yet highlight the interactive effects of disturbance by roads and herbivory: roads funnel non-native species towards higher elevations, while non-native herbivores can promote non-native plant success away from the roadside and into the natural vegetation. Hence, regulating soil and non-native herbivory disturbance is important for minimizing plant invasions at high elevation in the Arid Andes.


2020 ◽  
Vol 12 (15) ◽  
pp. 5951
Author(s):  
Erin M. Garrett ◽  
David J. Gibson

We propose combining the filter framework model of community assembly with the passenger-driver model of non-native species behavior to help clarify the impacts of invasive species in the communities they invade and to guide sustainable management protocols. Observational field surveys and a greenhouse experiment explored the role of the invasive legume Lespedeza cuneata in the communities it invades and how natives in three functional groups—grasses, forbs, and legumes—respond to its presence. Within-site analyses from the field survey revealed differences in invaded and uninvaded areas in half of the sites, suggesting that site-specific characteristics influences whether L. cuneata’s presence corresponds to local differences in species composition. The greenhouse experiment found higher levels of saprophytic and arbuscular mycorrhizal fungi in soil conditioned by L. cuneata than in unconditioned soil. However, competition between L. cuneata or the native congener L. capitata and nine native species illustrated stronger aboveground competitive effects than belowground soil effects due to soil conditioning, with impacts differing among functional groups. The response of L. cuneata was reduced in the presence of grasses and other legumes but not forbs. Assessing the impact of L. cuneata with the combined community assembly model revealed this invasive plant acts as a driver because it alters abiotic and biotic filters to impact species composition. Managing for high grass abundance and planting native legumes will help sustain grasslands from L. cuneata invasion.


2019 ◽  
Vol 124 (3) ◽  
pp. 423-436 ◽  
Author(s):  
Bronwyn M Ayre ◽  
David G Roberts ◽  
Ryan D Phillips ◽  
Stephen D Hopper ◽  
Siegfried L Krauss

Abstract Background and Aims In plants, the spatial and genetic distance between mates can influence reproductive success and offspring fitness. Negative fitness consequences associated with the extremes of inbreeding and outbreeding suggest that there will be an intermediate optimal outcrossing distance (OOD), the scale and drivers of which remain poorly understood. In the bird-pollinated Anigozanthos manglesii (Haemodoraceae) we tested (1) for the presence of within-population OOD, (2) over what scale it occurs, and (3) for OOD under biologically realistic scenarios of multi-donor deposition associated with pollination by nectar-feeding birds. Methods We measured the impact of mate distance (spatial and genetic) on seed set, fruit size, seed mass, seed viability and germination success following hand pollination from (1) single donors across 0 m (self), <1 m, 1–3 m, 7–15 m and 50 m, and (2) a mix of eight donors. Microsatellite loci were used to quantify spatial genetic structure and test for the presence of an OOD by paternity assignment after multi-donor deposition. Key results Inter-mate distance had a significant impact on single-donor reproductive success, with selfed and nearest-neighbour (<1 m) pollination resulting in only ~50 seeds per fruit, lower overall germination success and slower germination. Seed set was greatest for inter-mate distance of 1–3 m (148 seeds per fruit), thereafter plateauing at ~100 seeds per fruit. Lower seed set following nearest-neighbour mating was associated with significant spatial genetic autocorrelation at this scale. Paternal success following pollination with multiple sires showed a significantly negative association with increasing distance between mates. Conclusions Collectively, single- and multi-donor pollinations indicated evidence for a near-neighbour OOD within A. manglesii. A survey of the literature suggests that within-population OOD may be more characteristic of plants pollinated by birds than those pollinated by insects.


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