scholarly journals An invasive herbivore structures plant competitive dynamics

2017 ◽  
Vol 13 (11) ◽  
pp. 20170374
Author(s):  
Lydia Wong ◽  
Tess Nahanni Grainger ◽  
Denon Start ◽  
Benjamin Gilbert
Keyword(s):  
Invasive Species ◽  
Indirect Effects ◽  
Species Interactions ◽  
Native Species ◽  
Community Dynamics ◽  
Aphid Species ◽  
Ecological Communities ◽  
Native Plant ◽  
Native Communities ◽  
Species Invasions

Species interactions are central to our understanding of ecological communities, but may change rapidly with the introduction of invasive species. Invasive species can alter species interactions and community dynamics directly by having larger detrimental effects on some species than others, or indirectly by changing the ways in which native species compete among themselves. We tested the direct and indirect effects of an invasive aphid herbivore on a native aphid species and two host milkweed species. The invasive aphid caused a 10-fold decrease in native aphid populations, and a 30% increase in plant mortality (direct effects). The invasive aphid also increased the strength of interspecific competition between the two native plant hosts (indirect effects). By investigating the role that indirect effects play in shaping species interactions in native communities, our study highlights an understudied component of species invasions.

Presence of invasive Gambusia alters ecological communities and the functions they perform in lentic ecosystems

2017 ◽  
Vol 68 (10) ◽  
pp. 1867 ◽  
Author(s):  
Charles Hinchliffe ◽  
Trisha Atwood ◽  
Quinn Ollivier ◽  
Edd Hammill
Keyword(s):  
Invasive Species ◽  
Species Interactions ◽  
Native Species ◽  
Freshwater Ecosystems ◽  
Trophic Levels ◽  
Ecosystem Functions ◽  
Ecological Communities ◽  
Macroinvertebrate Communities ◽  
Decomposition Rates ◽  
Selective Predation

By acting as novel competitors and predators, a single invasive species can detrimentally affect multiple native species in different trophic levels. Although quantifying invasive effects through single-species interactions is important, understanding their effect on ecosystems as a whole is vital to enable effective protection and management. This is particularly true in freshwater ecosystems, where invasive species constitute the single greatest threat to biodiversity. Poeciliid fishes of the genus Gambusia are among the most widespread invasive species on earth. In the present study of lentic ecosystems (i.e. lakes), we first showed that Gambusia alter zooplankton community composition and size distribution, likely through size-selective predation. Second, we demonstrate that benthic macroinvertebrate communities significantly differ between sites with and without invasive Gambusia. The presence of Gambusia appears to reduce leaf-litter decomposition rates, which is likely an indirect effect of reductions in detritivore abundances. Reductions in decomposition rates found in the present study suggest that through trophic cascades, invasive Gambusia is able to indirectly alter ecosystem functions. The study has highlighted that the widespread effects of invasive aquatic species are able to permeate through entire ecosystems, being more pervasive than previously recognised.

Transient effects of an invasive kelp on the community structure and primary productivity of an intertidal assemblage

2016 ◽  
Vol 67 (1) ◽  
pp. 103 ◽  
Author(s):  
Paul M. South ◽  
Stacie A. Lilley ◽  
Leigh W. Tait ◽  
Tommaso Alestra ◽  
Michael J. H. Hickford ◽  
...  
Keyword(s):  
Invasive Species ◽  
Community Structure ◽  
Primary Production ◽  
Native Species ◽  
Community Dynamics ◽  
Net Primary Production ◽  
Ecological Impacts ◽  
Ecological Communities ◽  
Transient Effects ◽  
Positive Effects

Invasive species can have significant impacts on the diversity and productivity of recipient ecological communities. The kelp Undaria pinnatifida (Harvey) Suringar is one of the world’s most successful invasive species but, although its purported impacts are strong, there is little empirical evidence that it displaces native species. Furthermore, as this species naturalises in local communities, its potential effects on community dynamics have not been well tested. Here, we test the ecological impacts of Undaria in intertidal communities in southern New Zealand using a combination of surveys, a 2.5-year press-removal experiment and in situ measures of net primary production to gauge its impact on community structure and productivity. Undaria had transient effects on the composition of communities, affecting two seasonally abundant species in 1 year, but these impacts did not persist into the following year. Overall, there were only small effects of Undaria removal on diversity and abundance of native algae and invertebrates at two sites. However, the presence of Undaria more than doubled net primary production of recipient communities during its annual peak abundance when it increased biomass by 606gDWm–2. We conclude that the invasion of Undaria represents an additional and substantial carbon subsidy to coastal ecosystems with potentially positive effects on nearshore productivity.

scholarly journals Emerging fungal pathogen of an invasive grass: Implications for competition with native plant species

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0237894
Author(s):  
Amy E. Kendig ◽  
Vida J. Svahnström ◽  
Ashish Adhikari ◽  
Philip F. Harmon ◽  
S. Luke Flory
Keyword(s):  
Invasive Species ◽  
Plant Species ◽  
Fungal Pathogen ◽  
Native Species ◽  
Grass Species ◽  
Leaf Spot Disease ◽  
Native Plant ◽  
Invasive Grass ◽  
Native Plant Species ◽  
Species Specific

Infectious diseases and invasive species can be strong drivers of biological systems that may interact to shift plant community composition. For example, disease can modify resource competition between invasive and native species. Invasive species tend to interact with a diversity of native species, and it is unclear how native species differ in response to disease-mediated competition with invasive species. Here, we quantified the biomass responses of three native North American grass species (Dichanthelium clandestinum, Elymus virginicus, and Eragrostis spectabilis) to disease-mediated competition with the non-native invasive grass Microstegium vimineum. The foliar fungal pathogen Bipolaris gigantea has recently emerged in Microstegium populations, causing a leaf spot disease that reduces Microstegium biomass and seed production. In a greenhouse experiment, we examined the effects of B. gigantea inoculation on two components of competitive ability for each native species: growth in the absence of competition and biomass responses to increasing densities of Microstegium. Bipolaris gigantea inoculation affected each of the three native species in unique ways, by increasing (Dichanthelium), decreasing (Elymus), or not changing (Eragrostis) their growth in the absence of competition relative to mock inoculation. Bipolaris gigantea inoculation did not, however, affect Microstegium biomass or mediate the effect of Microstegium density on native plant biomass. Thus, B. gigantea had species-specific effects on native plant competition with Microstegium through species-specific biomass responses to B. gigantea inoculation, but not through modified responses to Microstegium density. Our results suggest that disease may uniquely modify competitive interactions between invasive and native plants for different native plant species.

scholarly journals Native turncoats and indirect facilitation of species invasions

2018 ◽  
Vol 285 (1871) ◽  
pp. 20171936 ◽  
Author(s):  
Tobin D. Northfield ◽  
Susan G. W. Laurance ◽  
Margaret M. Mayfield ◽  
Dean R. Paini ◽  
William E. Snyder ◽  
...  
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Potential Role ◽  
Indirect Interactions ◽  
Invasion Success ◽  
Competitive Interactions ◽  
Species Invasion ◽  
Species Invasions ◽  
Indirect Facilitation

At local scales, native species can resist invasion by feeding on and competing with would-be invasive species. However, this relationship tends to break down or reverse at larger scales. Here, we consider the role of native species as indirect facilitators of invasion and their potential role in this diversity-driven ‘invasion paradox’. We coin the term ‘native turncoats’ to describe native facilitators of non-native species and identify eight ways they may indirectly facilitate species invasion. Some are commonly documented, while others, such as indirect interactions within competitive communities, are largely undocumented in an invasion context. Therefore, we use models to evaluate the likelihood that these competitive interactions influence invasions. We find that native turncoat effects increase with the number of resources and native species. Furthermore, our findings suggest the existence, abundance and effectiveness of native turncoats in a community could greatly influence invasion success at large scales.

Now that we have our pest-proof fence, are we safe or trapped?

2012 ◽  
Vol 18 (2) ◽  
pp. 77 ◽  
Author(s):  
Heather Parks ◽  
Kyle Clifton ◽  
Lauren Best ◽  
Bridget Johnson
Keyword(s):  
Invasive Species ◽  
New Zealand ◽  
Native Species ◽  
Animal Species ◽  
The Other ◽  
Pest Species ◽  
Native Plant ◽  
Other Hand ◽  
Free Status

PEST-PROOF (exclusion) fences are designed to prevent non-native, predatory and pest species from repopulating an area set aside to protect vulnerable native plant and animal species. Pest-proof fencing provides security from invasive species, but can isolate the native species enclosed within. On one hand, some rare native species exist on the mainland due to the pest-free status achieved through the use of exclusion fences. On the other hand, these reintroduced populations are now isolated a situation where they would not be found naturally (Jamieson et al. 2006). Exclusion fences must be constantly maintained or the sanctuary risks reinvasion. An important question for conservation biologists and managers to answer is therefore — when is exclusion fencing the best option for protecting native species from introduced pests? We have drawn our examples from New Zealand and Australia where progress has been made with regard to the design and utilization of exclusion fences.

scholarly journals The influence of warming and biotic interactions on the potential for range expansion of native and nonnative species

AoB Plants ◽  
2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Betsy von Holle ◽  
Sören E Weber ◽  
David M Nickerson
Keyword(s):  
Plant Species ◽  
Range Expansion ◽  
Species Interactions ◽  
Native Species ◽  
Invasive Plant ◽  
Soil Microbes ◽  
Enemy Release ◽  
Native Plant ◽  
Soil Pathogens ◽  
Microbe Interactions

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.

The impacts of invasive plant species on the biodiversity of Australian rangelands

2006 ◽  
Vol 28 (1) ◽  
pp. 27 ◽  
Author(s):  
A. C. Grice
Keyword(s):  
Invasive Species ◽  
Species Richness ◽  
Plant Species ◽  
Native Species ◽  
Invasive Plant ◽  
Plant Species Richness ◽  
Native Plant ◽  
Weed Species ◽  
Ecological Processes ◽  
Native Plant Species

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.

Implications of agricultural policy for species invasion in shifting cultivation systems

2006 ◽  
Vol 11 (4) ◽  
pp. 429-452 ◽  
Author(s):  
HEIDI J. ALBERS ◽  
MICHAEL J. GOLDBACH ◽  
DANIEL T. KAFFINE
Keyword(s):  
Invasive Species ◽  
Shifting Cultivation ◽  
Native Species ◽  
Numerical Solutions ◽  
Economic Systems ◽  
Species Invasions ◽  
Invasive Grasses ◽  
Land Use Decisions ◽  
The Stability ◽  
The Impact

Policies to influence land use decisions in agriculture or grazing can increase the ability of invasive species to out-compete native species and thereby disrupt seemingly stable ecological-economic systems. Building off of models of interdependent resources, invasive species and soil fertility, this paper develops a model of shifting cultivation decisions for two types of farmers, one who sees the threat of invasive grasses and one who does not. The paper uses numerical solutions to this dynamic decision problem to examine the impact of various policies on farmer welfare and on the stability of the economic-ecological system. Some policies undermine the resilience of the system, while other policies augment the system's ability to withstand species invasions.

scholarly journals Invasibility and Recoverability of a Native Plant Community Following Invasion Depend on its Successional Stages

2020 ◽  
Author(s):  
Hongwei Xu ◽  
Zemin Ai ◽  
Qing Qu ◽  
Minggang Wang ◽  
Guobin Liu ◽  
...  
Keyword(s):  
Exotic Species ◽  
Soil Nutrients ◽  
Native Species ◽  
Panicum Virgatum ◽  
Native Plant ◽  
Bothriochloa Ischaemum ◽  
Poor Growth ◽  
Species Invasions ◽  
Successional Species ◽  
Microbial Residues

Abstract Background: Exotic species invasions represent important causes of biodiversity loss in ecosystems. Yet, knowledge remains limited on the invasion advantage of exotic species (invasibility of native plants) and the ability of native species to recover following invasions at different stages of succession.Results: We selected three grasses (Setaria viridis, Artemisia gmelinii, and Bothriochloa ischaemum) representing early, middle, and late successional species, respectively, and an exotic species (Panicum virgatum) from a stable grassland community. Four types of field soil were collected to treat the three early, middle, and later successional species, plus the exotic species. We examined the invasion ability of the exotic species on native communities and the recoverability of these communities following invasion across succession. We compared the performance of the four plant species grown in their “own” and “other” soils in a 2-year glasshouse experiment. Here we show that exotic species performed better in soils of early and mid-successional species, owing to higher soil nutrients and microbial residues, than in the soil of later successional species. In the soil of exotic species, early and mid-successional species exhibited poor growth, while that of later successional species was unchanged.Conclusions: Our study demonstrated that soil nutrients and microbial residues create a soil legacy regulating the invasibility and recoverability (or resilience) of native plant communities and how it changed with vegetation succession.

scholarly journals A Holling Functional Response Model for Mapping QTLs Governing Interspecific Interactions

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiao-Yu Zhang ◽  
Huiying Gong ◽  
Qing Fang ◽  
Xuli Zhu ◽  
Libo Jiang ◽  
...  
Keyword(s):  
Functional Response ◽  
Species Interactions ◽  
Community Dynamics ◽  
Interspecific Interactions ◽  
Microbial Interactions ◽  
Ecological Communities ◽  
Response Model ◽  
Ecological Interactions ◽  
Dynamic Complexity ◽  
Genome Level

Genes play an important role in community ecology and evolution, but how to identify the genes that affect community dynamics at the whole genome level is very challenging. Here, we develop a Holling type II functional response model for mapping quantitative trait loci (QTLs) that govern interspecific interactions. The model, integrated with generalized Lotka-Volterra differential dynamic equations, shows a better capacity to reveal the dynamic complexity of inter-species interactions than classic competition models. By applying the new model to a published mapping data from a competition experiment of two microbial species, we identify a set of previously uncharacterized QTLs that are specifically responsible for microbial cooperation and competition. The model can not only characterize how these QTLs affect microbial interactions, but also address how change in ecological interactions activates the genetic effects of the QTLs. This model provides a quantitative means of predicting the genetic architecture that shapes the dynamic behavior of ecological communities.

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