scholarly journals Factors Promoting Coexistence between Endemic Ants and Invasive Wasps

2021 ◽  
Author(s):  
◽  
Catherine Duthie
Keyword(s):  
Invasive Species ◽  
Community Composition ◽  
Isotope Ratios ◽  
Trophic Levels ◽  
Niche Shift ◽  
Niche Separation ◽  
Invertebrate Community ◽  
Nothofagus Forests ◽  
Foraging Pattern ◽  
The Impact

<p>Invasive animals can alter the community composition of native ecosystems by means of competition and predation. In this study I investigated the factors that may facilitate coexistence between endemic ants and invasive wasps. Previous research has shown that entire communities can be impacted by invasions. Endemic species subject to pressure from invasive species may undergo a niche shift to enable coexistence and minimise the impact of this pressure. The invertebrate community composition of Nothofagus forests in the South Island of New Zealand has been altered by predation from Invasive Vespula wasps. Ants and wasps in this ecosystem coexist on the same trophic level; they simultaneously fill multiple trophic roles as primary predators, secondary predators, and primary consumers. The outcome of competition between species such as ants and wasps is not easy to predict, and may vary in different communities and with different densities of competitors. In this dissertation I aimed to determine the extent to which competition occurs between native ants and invasive Vespula wasps, and to investigate the impacts of invasion on the native invertebrate community. I quantified the invertebrate community composition of Nothofagus forests and then experimentally reduced wasp numbers to investigate any changes as a result of a reduction in predation or competition. The observed changes in community composition were as a result of differing abundances of taxonomic groups within my study sites. In order to more robustly determine the community effects of wasp removal it may be necessary to reduce wasp numbers by up to 90% for many years. Even under these conditions, species that are particularly vulnerable to wasp predation or competition may have already been permanently excluded from this system. I then investigated temporal niche shifts by native ants when faced with reduced competition for food resources from invasive wasps. There was an increase in the numbers of ants foraging on honeydew when I experimentally reduced wasp numbers. This increase may be due to increases in both the quantity and quality of the available honeydew. When densities of wasps were substantially reduced there was a difference in the foraging abundances of ants and wasps; however, there was no change in the overall temporal foraging pattern of ants. Isotope ratios and consequently trophic levels of native competitors may change in response to the removal of an invasive species. To test this I examined changes in isotope ratios as a result of removal of wasps. The observed changes in the trophic levels of both ants and wasps appear to be a result of natural seasonal variation in consumption related to the nutritional requirements of the colony. Finally, I examined behavioral interactions between native ants and invasive wasps during foraging. This study has indicated that wasps may find and access resources more readily when ants are present. Native ants may facilitate foraging by wasps, as demonstrated by the increase in wasp numbers when foraging in the presence of ants. Additionally, the impact of competition between wasps and ants is likely to be density dependant. Co-occurrence between endemic and invasive competitors is possible through two important mechanisms, niche separation and behavioural adaptations. Native ants in this system are able to forage in different temporal niches than invasive wasps, and their dominant behaviour serves to diminish competitive interactions. These findings have implications for the ecology of these forests in understanding the considerable impact that invasive species may have on native ecosystems and particularly those species which have similar resource requirements.</p>

scholarly journals Factors Promoting Coexistence between Endemic Ants and Invasive Wasps

2021 ◽  
Author(s):  
◽  
Catherine Duthie
Keyword(s):  
Invasive Species ◽  
Community Composition ◽  
Isotope Ratios ◽  
Trophic Levels ◽  
Niche Shift ◽  
Niche Separation ◽  
Invertebrate Community ◽  
Nothofagus Forests ◽  
Foraging Pattern ◽  
The Impact

<p>Invasive animals can alter the community composition of native ecosystems by means of competition and predation. In this study I investigated the factors that may facilitate coexistence between endemic ants and invasive wasps. Previous research has shown that entire communities can be impacted by invasions. Endemic species subject to pressure from invasive species may undergo a niche shift to enable coexistence and minimise the impact of this pressure. The invertebrate community composition of Nothofagus forests in the South Island of New Zealand has been altered by predation from Invasive Vespula wasps. Ants and wasps in this ecosystem coexist on the same trophic level; they simultaneously fill multiple trophic roles as primary predators, secondary predators, and primary consumers. The outcome of competition between species such as ants and wasps is not easy to predict, and may vary in different communities and with different densities of competitors. In this dissertation I aimed to determine the extent to which competition occurs between native ants and invasive Vespula wasps, and to investigate the impacts of invasion on the native invertebrate community. I quantified the invertebrate community composition of Nothofagus forests and then experimentally reduced wasp numbers to investigate any changes as a result of a reduction in predation or competition. The observed changes in community composition were as a result of differing abundances of taxonomic groups within my study sites. In order to more robustly determine the community effects of wasp removal it may be necessary to reduce wasp numbers by up to 90% for many years. Even under these conditions, species that are particularly vulnerable to wasp predation or competition may have already been permanently excluded from this system. I then investigated temporal niche shifts by native ants when faced with reduced competition for food resources from invasive wasps. There was an increase in the numbers of ants foraging on honeydew when I experimentally reduced wasp numbers. This increase may be due to increases in both the quantity and quality of the available honeydew. When densities of wasps were substantially reduced there was a difference in the foraging abundances of ants and wasps; however, there was no change in the overall temporal foraging pattern of ants. Isotope ratios and consequently trophic levels of native competitors may change in response to the removal of an invasive species. To test this I examined changes in isotope ratios as a result of removal of wasps. The observed changes in the trophic levels of both ants and wasps appear to be a result of natural seasonal variation in consumption related to the nutritional requirements of the colony. Finally, I examined behavioral interactions between native ants and invasive wasps during foraging. This study has indicated that wasps may find and access resources more readily when ants are present. Native ants may facilitate foraging by wasps, as demonstrated by the increase in wasp numbers when foraging in the presence of ants. Additionally, the impact of competition between wasps and ants is likely to be density dependant. Co-occurrence between endemic and invasive competitors is possible through two important mechanisms, niche separation and behavioural adaptations. Native ants in this system are able to forage in different temporal niches than invasive wasps, and their dominant behaviour serves to diminish competitive interactions. These findings have implications for the ecology of these forests in understanding the considerable impact that invasive species may have on native ecosystems and particularly those species which have similar resource requirements.</p>

Limited effects of stocked trout on littoral invertebrates in boreal foothills lakes

2012 ◽  
Vol 69 (1) ◽  
pp. 178-190 ◽  
Author(s):  
Leslie E. Nasmith ◽  
William M. Tonn ◽  
Cynthia A. Paszkowski ◽  
Garry J. Scrimgeour
Keyword(s):  
Community Composition ◽  
Size Structure ◽  
Invertebrate Community ◽  
Negative Effects ◽  
High Productivity ◽  
Recreational Angling ◽  
Key Characteristics ◽  
Littoral Zones ◽  
Littoral Invertebrates ◽  
The Impact

Stocking lakes with trout for the purposes of recreational angling is a management strategy that introduces a new predator into these systems and thus deserves careful scrutiny. To assess the impact of non-native trout on littoral invertebrates in naturally fish-bearing lakes in the boreal foothills of Alberta, Canada, we compared their community composition, abundance, and size structure in stocked (n = 5) and unstocked (n = 6) lakes over a 2-year period. We detected no clear negative effects of introduced trout on invertebrate community composition and only few taxa-specific examples of decreased or increased invertebrate abundance. Furthermore, predation by trout had inconsistent direct effects on the size structure of invertebrate populations. Indirect effects were suggested by increased abundances and sizes of some invertebrate taxa in stocked lakes and might also contribute to the limited overall differences that we observed. We propose that net effects of stocked trout on littoral invertebrates are influenced by key characteristics of receiving ecosystems. In our boreal foothills lakes, dense macrophyte cover in warm littoral zones, high productivity, abundant forage fish, and limited densities of trout all likely combine to allow littoral invertebrate communities to withstand the impact of introduced trout with minimal effects.

scholarly journals Invasive Species Impact: Direct and Indirect Interactions Between Two Stream Snails and Their Algal Resources

2004 ◽  
Vol 28 ◽  
pp. 61-69
Author(s):  
Leslie Riley ◽  
Mark Dybdahl ◽  
Robert Hall, Jr.
Keyword(s):  
Invasive Species ◽  
Resource Competition ◽  
Natural Populations ◽  
Indirect Interactions ◽  
Trophic Levels ◽  
Invasion Success ◽  
Limited Growth ◽  
Grazing Effect ◽  
The Impact ◽  
Invasive Species Impact

We measured the strength of direct and indirect interactions in order to develop a standardized estimate of the impact of an invasive snail on its resource and a competitor. The freshwater New Zealand snail, Potamopyrgus antipodarum, an invasive species in the western U.S., is the most abundant benthic macroinvertebrate grazer in several rivers, where it overlaps with several threatened endemic snails. In one watershed, Potamopyrgus coexists with the snail, Pyrgulopsis robusta, which may be affected by resource competition with Potamopyrgus. In field enclosure experiments, we quantified the direct grazing effect of snails on algae and the indirect effects between consumers. Potamopyrgus significantly limited growth of Pyrgulopsis. In contrast, Pyrgulopsis appeared to facilitate growth of the invasive snail (Potamopyrgus). In natural populations, snail densities were positively correlated over five sites, but negatively correlated at two downstream sites. Interaction strengths between snails and algae were equivalent for both snails at both sites, indicating that invasion success could not be attributed to differences in resource acquisition. However, the overall impact of the invader was much higher at the downstream site when both snail abundance and interaction strengths were considered. Negative individual effects of Potamopyrgus at two trophic levels in conjunction with high Potamopyrgus abundance demonstrated a significant impact of the invader in this lotic community.

scholarly journals Invasion in An Omnivorous Food Web: The Impact of Roles and Different Trophic Levels

2021 ◽  
Author(s):  
Duojie Jiabu ◽  
Weide Li
Keyword(s):  
Invasive Species ◽  
Food Web ◽  
Food Webs ◽  
Habitat Loss ◽  
Habitat Destruction ◽  
Trophic Levels ◽  
Theoretical Research ◽  
Model Framework ◽  
Habitat Loss And Fragmentation ◽  
The Impact

Abstract In the field of ecology, habitat loss and fragmentation are the two main characteristic forms of habitat destruction and the main drivers of species extinction, resulting in the gradual loss of biodiversity. So far, many scholars have made some progress in the theoretical research of the spatial food web, but research on the effect of introducing an invasive species in an omnivorous food web is very rare. In order to explore the impact of invader on the persistence of species in omnivorous food webs, we constructed a model framework to describe the patch occupation of each species in omnivorous systems. Our model results show that invasive species is a prey of species in omnivorous food webs is easier to invade than invasive species is a predator of species in original omnivorous food webs on habitat loss and fragmentation. One conclusion also can be drawn is that when an invasive species is a prey of species in omnivorous food webs, no matter what trophic level the invasive species is invade, it is more successful. But when invasive species is a predator of species in different trophic levels on omnivorous food webs, they show different coexistence patterns. The invasion of a species has little effect upon the stability of original omnivorous food web for habitat loss and fragmentation, and will only make the original omnivorous food web more stable and more complicated. Therefore, we have proved that the omnivorous food web is stable and is not easy to destroy this ecological fact. Some examples to illustrate the reliability of our model results are discussed.

scholarly journals Are Bacterio- and Phytoplankton Community Compositions Related in Lakes Differing in Their Cyanobacteria Contribution and Physico-Chemical Properties?

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 855
Author(s):  
Mikołaj Kokociński ◽  
Dariusz Dziga ◽  
Adam Antosiak ◽  
Janne Soininen
Keyword(s):  
Environmental Factors ◽  
Community Composition ◽  
Phytoplankton Community ◽  
Heterotrophic Bacteria ◽  
Bacterial Community Composition ◽  
Physical Factors ◽  
Research Attention ◽  
Phytoplankton Community Composition ◽  
The Impact ◽  
Bacteria Communities

Bacterioplankton community composition has become the center of research attention in recent years. Bacteria associated with toxic cyanobacteria blooms have attracted considerable interest. However, little is known about the environmental factors driving the bacteria community, including the impact of invasive cyanobacteria. Therefore, our aim has been to determine the relationships between heterotrophic bacteria and phytoplankton community composition across 24 Polish lakes with different contributions of cyanobacteria including the invasive species Raphidiopsis raciborskii. This analysis revealed that cyanobacteria were present in 16 lakes, while R. raciborskii occurred in 14 lakes. Our results show that bacteria communities differed between lakes dominated by cyanobacteria and lakes with minor contributions of cyanobacteria but did not differ between lakes with R. raciborskii and other lakes. Physical factors, including water and Secchi depth, were the major drivers of bacteria and phytoplankton community composition. However, in lakes dominated by cyanobacteria, bacterial community composition was also influenced by biotic factors such as the amount of R. raciborskii, chlorophyll-a and total phytoplankton biomass. Thus, our study provides novel evidence on the influence of environmental factors and R. raciborskii on lake bacteria communities.

scholarly journals Assessing Genotypic and Environmental Effects on Endophyte Communities of Fraxinus (Ash) Using Culture Dependent and Independent DNA Sequencing

2021 ◽  
Vol 7 (7) ◽  
pp. 565
Author(s):  
Anindita Lahiri ◽  
Brian R. Murphy ◽  
Trevor R. Hodkinson
Keyword(s):  
Community Composition ◽  
Environmental Effects ◽  
High Throughput Sequencing ◽  
Fungal Community Composition ◽  
Species Identity ◽  
Ash Dieback ◽  
Hymenoscyphus Fraxineus ◽  
Culture Independent ◽  
The Impact ◽  
Culture Dependent

Fraxinus excelsior populations are in decline due to the ash dieback disease Hymenoscyphus fraxineus. It is important to understand genotypic and environmental effects on its fungal microbiome to develop disease management strategies. To do this, we used culture dependent and culture independent approaches to characterize endophyte material from contrasting ash provenances, environments, and tissues (leaves, roots, seeds). Endophytes were isolated and identified using nrITS, LSU, or tef DNA loci in the culture dependent assessments, which were mostly Ascomycota and assigned to 37 families. Few taxa were shared between roots and leaves. The culture independent approach used high throughput sequencing (HTS) of nrITS amplicons directly from plant DNA and detected 35 families. Large differences were found in OTU diversity and community composition estimated by the contrasting approaches and these data need to be combined for estimations of the core endophyte communities. Species richness and Shannon index values were highest for the leaf material and the French population. Few species were shared between seed and leaf tissue. PCoA and NMDS of the HTS data showed that seed and leaf microbiome communities were highly distinct and that there was a strong influence of Fraxinus species identity on their fungal community composition. The results will facilitate a better understanding of ash fungal ecology and are a step toward identifying microbial biocontrol systems to minimize the impact of the disease.

scholarly journals The importance of species interactions in eco-evolutionary community dynamics under climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anna Åkesson ◽  
Alva Curtsdotter ◽  
Anna Eklöf ◽  
Bo Ebenman ◽  
Jon Norberg ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Community Dynamics ◽  
Evolutionary Dynamics ◽  
Negative Impact ◽  
Trophic Levels ◽  
Temperature Dependent ◽  
Modeling Framework ◽  
Impact Of Climate Change ◽  
The Impact

AbstractEco-evolutionary dynamics are essential in shaping the biological response of communities to ongoing climate change. Here we develop a spatially explicit eco-evolutionary framework which features more detailed species interactions, integrating evolution and dispersal. We include species interactions within and between trophic levels, and additionally, we incorporate the feature that species’ interspecific competition might change due to increasing temperatures and affect the impact of climate change on ecological communities. Our modeling framework captures previously reported ecological responses to climate change, and also reveals two key results. First, interactions between trophic levels as well as temperature-dependent competition within a trophic level mitigate the negative impact of climate change on biodiversity, emphasizing the importance of understanding biotic interactions in shaping climate change impact. Second, our trait-based perspective reveals a strong positive relationship between the within-community variation in preferred temperatures and the capacity to respond to climate change. Temperature-dependent competition consistently results both in higher trait variation and more responsive communities to altered climatic conditions. Our study demonstrates the importance of species interactions in an eco-evolutionary setting, further expanding our knowledge of the interplay between ecological and evolutionary processes.

scholarly journals Temperature rise and parasitic infection interact to increase the impact of an invasive species

2017 ◽  
Vol 47 (5) ◽  
pp. 291-296 ◽  
Author(s):  
Ciaran Laverty ◽  
David Brenner ◽  
Christopher McIlwaine ◽  
Jack J. Lennon ◽  
Jaimie T.A. Dick ◽  
...  
Keyword(s):  
Invasive Species ◽  
Temperature Rise ◽  
Parasitic Infection ◽  
The Impact

Design of a risk assessment methodology for the introduction of invasive species from ship ballast waters

2016 ◽  
Vol 27 (5) ◽  
pp. 474-490 ◽  
Author(s):  
Abderrahmane Bouda ◽  
Nour El Islam Bachari ◽  
Lylia Bahmed ◽  
Ryad Boubenia
Keyword(s):  
Risk Assessment ◽  
Invasive Species ◽  
Ballast Water ◽  
Quantitative Risk Assessment ◽  
Content Type ◽  
International Convention ◽  
Environmental Similarity ◽  
Process Factors ◽  
Shipping Traffic ◽  
The Impact

Purpose – Ballast water of merchant ship is a source of introduction of invasive species around the globe. The purpose of this paper is to present a quantitative risk assessment applied to a model port, the Port of Arzew in Algeria, and based on an analysis of this port’s shipping traffic. Design/methodology/approach – The risk assessment for introduction of invasive species is interpreted in the form of a probabilistic process, with a combination of two probabilities. The first probability is related to the ability of a species to arrive to the destination (recipient port), depending on the quantity of water ballast discharged and the duration of voyage. The second one is based on the species ability to survive in their new environment, which depends on the environmental similarity between donor port and Arzew port. Findings – This assessment’s outcome consists on a classification of scenarios regarding their acceptability. Consequently, it helped to classify donor ports according to a risk scale, from low risk to high-risk donor ports. Research limitations/implications – The phenomenon of invasion of aquatic species is a complex process. Factors such as adaptation and tolerance of species, the attendance or absence of predators, were not taken into account in this study. Practical implications – This study could be used by the maritime administration as a decision-making tool regarding the issue of exemptions under the IMO International Convention on the Management of Ballast Water and Sediments 2004. Originality/value – This is one of the first known studies in Algeria and dealing with ballast water management. The results of this assessment provide useful information to policy makers, in order to develop a national strategy to reduce the impact of shipping pollution on the marine environment.

scholarly journals Diet composition of the invasive red-whiskered bulbul Pycnonotus jocosus in Mauritius

2010 ◽  
Vol 26 (3) ◽  
pp. 347-350 ◽  
Author(s):  
Jannie Fries Linnebjerg ◽  
Dennis M. Hansen ◽  
Nancy Bunbury ◽  
Jens M. Olesen
Keyword(s):  
Invasive Species ◽  
Introduced Species ◽  
Native Species ◽  
Diet Composition ◽  
Ecological Perspective ◽  
Positive Interactions ◽  
Invasional Meltdown ◽  
Ecological Processes ◽  
Successful Establishment ◽  
The Impact

Disruption of ecosystems is one of the biggest threats posed by invasive species (Mack et al. 2000). Thus, one of the most important challenges is to understand the impact of exotic species on native species and habitats (e.g. Jones 2008). The probability that entire ‘invasive communities’ will develop increases as more species establish in new areas (Bourgeois et al. 2005). For example, introduced species may act in concert, facilitating one another's invasion, and increasing the likelihood of successful establishment, spread and impact. Simberloff & Von Holle (1999) introduced the term ‘invasional meltdown’ for this process, which has received widespread attention since (e.g. O'Dowd 2003, Richardson et al. 2000, Simberloff 2006). Positive interactions among introduced species are relatively common, but few have been studied in detail (Traveset & Richardson 2006). Examples include introduced insects and birds that pollinate and disperse exotic plants, thereby facilitating the spread of these species into non-invaded habitats (Goulson 2003, Mandon-Dalger et al. 2004, Simberloff & Von Holle 1999). From a more general ecological perspective, the study of interactions involving introduced and invasive species can contribute to our knowledge of ecological processes – for example, community assembly and indirect interactions.

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