scholarly journals Differences in herbivore damage to Arctium minus in open and forest habitats in its non-native range

Botany ◽  
2017 ◽  
Vol 95 (8) ◽  
pp. 841-845 ◽  
Author(s):  
Yoonsoo Lee ◽  
Peter M. Kotanen

Exotic plants do not always escape enemies in new areas; instead, they may be damaged by co-invading non-native enemies or by enemies recruited from native species. However, even when such enemies exist in an invader’s new range, escape may still be possible if particular habitats offer low-damage refuges. In this study, herbivory on the non-native common burdock (Arctium minus (Hill) Bernh.) were compared between open and understory habitats, with high and low sunlight exposure respectively, on five sites in Ontario, Canada. Open-habitat populations showed relatively reduced herbivore damage; this may be due to herbivores occurring less abundantly in open habitats or burdock expressing greater defences in open sites. These results emphasize that enemy release is not an absolute effect, but can depend on an individual’s habitat. As well, they suggest herbivory potentially may help to confine burdock primarily to open habitats.

2021 ◽  
Author(s):  
Inês Cerveira ◽  
Vânia Baptista ◽  
Maria Alexandra Teodósio ◽  
Pedro Morais

Abstract Promoting the consumption of edible aquatic invasive species has gained popularity to minimize its impacts while easing pressure on native resources. Weakfish Cynoscion regalis (Bloch & Schneider, 1801) is one of the most recent invasive fish species in the Iberian Peninsula (Europe) which once sustained an important fishery in the native range (Northwest Atlantic Ocean). Portugal ranks third in the list of the world’s top fish consumers, so promoting a weakfish fishery could at least help minimize the impacts upon native species, since weakfish have innate traits that are likely appreciated by Portuguese fish consumers. However, introducing a new species to consumers is challenging owing to consumers’ habits and unfamiliarity with the species. So, we aimed to (i) evaluate the acceptance of weakfish by a panel of Portuguese fish consumers and (ii) create outreach actions – partnerships with local Chefs and press releases – to explain to a broader public what invasive species are and promote the consumption of edible aquatic invasive species. The survey that we conducted to Portuguese fish consumers showed that weakfish has great chances of being well accepted by the public – 90% of consumers would buy weakfish because they appreciated its appearance, flavour, and texture, besides being a wild fish. The outreach actions reached a few million people because 46 online articles were published, and three news pieces broadcasted on national television. Overall, our strategy greatly increased the public’s awareness about invasive species, which can be replicated elsewhere in the world.


2021 ◽  
Author(s):  
Sonja Stutz ◽  
Hariet Hinz ◽  
Chris Parker

Abstract L. latifolium is an erect, branching perennial native to southern Europe and western Asia. It was accidentally introduced into countries outside of its native range as a contaminant of seeds such as Beta vulgaris. L. latifolium exhibits a wide ecological adaptation to different environmental factors, tolerating a range of soil moisture and salinity conditions, which has allowed it to spread explosively in recent years in wetlands and riparian areas especially in the western USA. L. latifolium thrives in many lowland ecosystems and is extremely competitive, forming monospecific stands that can crowd out desirable native species and a number of threatened and endangered species. L. latifolium alters the ecosystem in which it grows, acting as a 'salt pump' which takes salt ions from deep in the soil profile and deposits them near the surface, thereby shifting plant composition and altering diversity.


Oecologia ◽  
2020 ◽  
Vol 194 (1-2) ◽  
pp. 237-250
Author(s):  
Rutger A. Wilschut ◽  
Kim J. H. Magnée ◽  
S. Geisen ◽  
W. H. van der Putten ◽  
O. Kostenko

Abstract Climate change causes species range expansions to higher latitudes and altitudes. It is expected that, due to differences in dispersal abilities between plants and soil biota, range-expanding plant species will become associated with a partly new belowground community in their expanded range. Theory on biological invasions predicts that outside their native range, range-expanding plant species may be released from specialist natural enemies, leading to the evolution of enhanced defence against generalist enemies. Here we tested the hypothesis that expanded range populations of the range-expanding plant species Centaurea stoebe accumulate fewer root-feeding nematodes than populations from the original range. Moreover, we examined whether Centaurea stoebe accumulates fewer root-feeding nematodes in expanded range soil than in original range soil. We grew plants from three expanded range and three original range populations of C. stoebe in soil from the original and from the new range. We compared nematode communities of C. stoebe with those of C. jacea, a congeneric species native to both ranges. Our results show that expanded range populations of C. stoebe did not accumulate fewer root-feeding nematodes than populations from the original range, but that C. stoebe, unlike C. jacea, accumulated fewest root-feeding nematodes in expanded range soil. Moreover, when we examined other nematode feeding groups, we found intra-specific plant population effects on all these groups. We conclude that range-expanding plant populations from the expanded range were not better defended against root-feeding nematodes than populations from the original range, but that C. stoebe might experience partial belowground enemy release.


Author(s):  
James A. Strong ◽  
Christine A. Maggs ◽  
Mark P. Johnson

The overall biotic pressure on a newly introduced species may be less than that experienced within its native range, facilitating invasion. The brown algaSargassum muticum(Yendo) Fensholt is a conspicuous and successful invasive species originally from Japan and China. We comparedS. muticumand native macroalgae with respect to the biotic pressures of mesoherbivore grazing and ectocarpoid fouling. In Strangford Lough, Northern Ireland,S. muticumthalli were as heavily overgrown with seasonal blooms of epiphytic algae as native macroalgal species were. The herbivorous amphipodDexamine spinosawas much more abundant onS. muticumthan on any native macroalga. When cultured with this amphipod,S. muticumlost more tissue than three native macroalgae,Saccharina latissima(Linnaeus) Laneet al.,Halidrys siliquosa(Linnaeus) Lyngbye andFucus serratusLinnaeus.Sargassum muticumcultured with both ectocarpoid fouling and amphipods showed a severe impact, consistent with our previous findings of large declines in the density ofS. muticumobserved in the field during the peak of fouling. Despite being a recent introduction into the macroalgal community in Strangford Lough,S. muticumappears to be under biotic pressure at least equal to that on native species, suggesting that release from grazing and epiphytism does not contribute to the invasiveness of this species in Strangford Lough.


2020 ◽  
Vol 16 (8) ◽  
pp. 20200474 ◽  
Author(s):  
Christian L. Cox ◽  
Sean Alexander ◽  
Brianna Casement ◽  
Albert K. Chung ◽  
John David Curlis ◽  
...  

Introduced species can become invasive, damaging ecosystems and disrupting economies through explosive population growth. One mechanism underlying population expansion in invasive populations is ‘enemy release’, whereby the invader experiences relaxation of agonistic interactions with other species, including parasites. However, direct observational evidence of release from parasitism during invasion is rare. We mimicked the early stages of invasion by experimentally translocating populations of mite-parasitized slender anole lizards ( Anolis apletophallus ) to islands that varied in the number of native anoles. Two islands were anole-free prior to the introduction, whereas a third island had a resident population of Gaige's anole ( Anolis gaigei ). We then characterized changes in trombiculid mite parasitism over multiple generations post-introduction. We found that mites rapidly went extinct on one-species islands, but that lizards introduced to the two-species island retained mites. After three generations, the two-species island had the highest total density and biomass of lizards, but the lowest density of the introduced species, implying that the ‘invasion’ had been less successful. This field-transplant study suggests that native species can be ‘enemy reservoirs’ that facilitate co-colonization of ectoparasites with the invasive host. Broadly, these results indicate that the presence of intact and diverse native communities may help to curb invasiveness.


Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 773
Author(s):  
Marie Zakardjian ◽  
Benoît Geslin ◽  
Valentin Mitran ◽  
Evelyne Franquet ◽  
Hervé Jourdan

Land-use changes through urbanization and biological invasions both threaten plant-pollinator networks. Urban areas host modified bee communities and are characterized by high proportions of exotic plants. Exotic species, either animals or plants, may compete with native species and disrupt plant–pollinator interactions. These threats are heightened in insular systems of the Southwest Pacific, where the bee fauna is generally poor and ecological networks are simplified. However, the impacts of these factors have seldom been studied in tropical contexts. To explore those questions, we installed experimental exotic plant communities in urban and natural contexts in New Caledonia, a plant diversity hotspot. For four weeks, we observed plant–pollinator interactions between local pollinators and our experimental exotic plant communities. We found a significantly higher foraging activity of exotic wild bees within the city, together with a strong plant–pollinator association between two exotic species. However, contrary to our expectations, the landscape context (urban vs. natural) had no effect on the activity of native bees. These results raise issues concerning how species introduced in plant–pollinator networks will impact the reproductive success of both native and exotic plants. Furthermore, the urban system could act as a springboard for alien species to disperse in natural systems and even invade them, leading to conservation concerns.


2019 ◽  
Vol 13 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Jialiang Zhang ◽  
Evan Siemann ◽  
Baoliang Tian ◽  
Wei Huang ◽  
Jianqing Ding

Abstract Aims Seeds of many invasive plants germinate more quickly than those of native species, likely facilitating invasion success. Assessing the germination traits and seed properties simultaneously for introduced and native populations of an invasive plant is essential to understanding biological invasions. Here, we used Triadica sebifera as a study organism to examine intraspecific differences in seed germination together with seed characteristics. Methods We measured physical (volume, mass, coat hardness and coat thickness of seeds) and chemical (crude fat, soluble protein, sugar, gibberellins [GA] and abscisic acid [ABA] of kernels) properties of T. sebifera seeds collected in 2017 from 12 introduced (United States) populations and 12 native (China) populations and tested their germination rates and timing in a greenhouse experiment in China. Furthermore, we conducted an extra experiment in the United States using seeds collected in 2016 and 2017 to compare the effects of study sites (China vs. United States) and seed collection time (2016 vs. 2017) on seed germination. Important Findings Seeds from the introduced range germinated faster than those from the native range. Physical and chemical measurements showed that seeds from the introduced range were larger, had higher GA concentrations and GA:ABA ratio, but lower crude fat concentrations compared to those from the native range. There were no significant differences in seed mass, coat hardness and coat thickness or kernel ABA, soluble protein or sugar concentrations between seeds from introduced vs. native ranges. Germination rates were correlated between United States and China greenhouses but germination rates for populations varied between collection years. Our results suggest that larger seeds and higher GA likely contribute to faster germination, potentially facilitating T. sebifera invasion in the introduced range.


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.


2019 ◽  
Vol 50 (1) ◽  
pp. 169-190 ◽  
Author(s):  
James C. Russell ◽  
Christopher N. Kaiser-Bunbury

The rate of non-native species introductions continues to increase, with directionality from continents to islands. It is no longer single species but entire networks of coevolved and newly interacting continental species that are establishing on islands. The consequences of multispecies introductions on the population dynamics and interactions of native and introduced species will depend on the form of trophic limitation on island ecosystems. Freed from biotic constraints in their native range, species introduced to islands no longer experience top-down limitation, instead becoming limited by and disrupting bottom-up processes that dominate on resource-limited islands. This framing of the ecological and evolutionary relationships among introduced species with one another and their ecosystem has important consequences for conservation. Whereas on continents the focus of conservation is on restoring native apex species and top-down limitation, on islands the focus must instead be on removing introduced animal and plant species to restore bottom-up limitation.


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