scholarly journals Decline of six native mason bee species following the arrival of an exotic congener

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kathryn A. LeCroy ◽  
Grace Savoy-Burke ◽  
David E. Carr ◽  
Deborah A. Delaney ◽  
T’ai H. Roulston
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Niche Overlap ◽  
Enemy Release ◽  
Native Bees ◽  
Pollinator Species ◽  
Insect Pollinators ◽  
Natural Range ◽  
Nesting Resources ◽  
Pollinator Declines

Abstract A potential driver of pollinator declines that has been hypothesized but seldom documented is the introduction of exotic pollinator species. International trade often involves movement of many insect pollinators, especially bees, beyond their natural range. For agricultural purposes or by inadvertent cargo shipment, bee species successfully establishing in new ranges could compete with native bees for food and nesting resources. In the Mid-Atlantic United States, two Asian species of mason bee (Osmia taurus and O. cornifrons) have become recently established. Using pan-trap records from the Mid-Atlantic US, we examined catch abundance of two exotic and six native Osmia species over the span of fifteen years (2003–2017) to estimate abundance changes. All native species showed substantial annual declines, resulting in cumulative catch losses ranging 76–91% since 2003. Exotic species fared much better, with O. cornifrons stable and O. taurus increasing by 800% since 2003. We characterize the areas of niche overlap that may lead to competition between native and exotic species of Osmia, and we discuss how disease spillover and enemy release in this system may result in the patterns we document.

scholarly journals Isotopic niches of sympatric native and exotic fish species in a Neotropical floodplain

2015 ◽  
Vol 87 (2) ◽  
pp. 825-833 ◽  
Author(s):  
Juliana S. Philippsen ◽  
Marília Hauser ◽  
Evanilde Benedito
Keyword(s):  
Exotic Species ◽  
Fish Species ◽  
Intraspecific Competition ◽  
Native Species ◽  
Niche Overlap ◽  
Food Resources ◽  
Foraging Strategies ◽  
Isotopic Niche ◽  
Exotic Fish ◽  
Niche Concept

This study investigated the isotopic niches of two fish species, one exotic and one native. It was hypothesized that these species would show little or no isotopic niche overlap. This hypothesis was tested with the isotopic niche concept and the trophic Layman's metrics. A considerable isotopic niche overlap was observed between the species, mainly for the exotic that showed the greater percentage of overlapping, indicating an interspecific competition for food resources. Layman's metrics also showed this species probably exploits a more specific array of food resources when compared with the native species. The native species probably has the ability to exploit a wider array of resources, highlighted by the higher values given for the Layman's metrics. The juveniles and adults of native species showed minor overlapping between the isotopic niches. This indicates that they have probably adopted different foraging strategies, minimizing intraspecific competition. Evidences that the exotic species explores a narrower range of resources and that the native species has a greater isotopic niche and possibly suffer less intraspecific competition, indicates that the native species can tolerate the presence of the exotic species and promote survival and maintenance of its population even under possible competition effects imposed by the exotic species.

scholarly journals Exotic species enhance response diversity to land-use change but modify functional composition

2017 ◽  
Vol 284 (1860) ◽  
pp. 20170788 ◽  
Author(s):  
Jamie R. Stavert ◽  
David E. Pattemore ◽  
Anne C. Gaskett ◽  
Jacqueline R. Beggs ◽  
Ignasi Bartomeus
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Biodiversity Loss ◽  
Functional Redundancy ◽  
Ecosystem Functions ◽  
Functional Composition ◽  
Response Diversity ◽  
Pollinator Species ◽  
Pollinator Community ◽  
Multiple Species

Two main mechanisms may buffer ecosystem functions despite biodiversity loss. First, multiple species could share similar ecological roles, thus providing functional redundancy. Second, species may respond differently to environmental change (response diversity). However, ecosystem function would be best protected when functionally redundant species also show response diversity. This linkage has not been studied directly, so we investigated whether native and exotic pollinator species with similar traits (functional redundancy) differed in abundance (response diversity) across an agricultural intensification gradient. Exotic pollinator species contributed most positive responses, which partially stabilized overall abundance of the pollinator community. However, although some functionally redundant species exhibited response diversity, this was not consistent across functional groups and aggregate abundances within each functional group were rarely stabilized. This shows functional redundancy and response diversity do not always operate in concert. Hence, despite exotic species becoming increasingly dominant in human-modified systems, they cannot replace the functional composition of native species.

An eco-evolutionary rationale to distinguish alien and native status: why the dingo is a native species on mainland Australia

2021 ◽  
Vol 41 (3) ◽  
pp. 358-366
Author(s):  
Peter B. Banks
Keyword(s):  
Alien Species ◽  
Introduced Species ◽  
Native Species ◽  
Genetic Basis ◽  
Evolutionary Approach ◽  
Range Transport ◽  
The Status ◽  
Local Species ◽  
Natural Range ◽  
Native Status

Distinguishing between whether a species is alien or native can be problematic, especially for introduced species that are long-established in new areas outside of their natural range. Transport by humans is the criterion for alien status used by many definitions, whereas arbitrary time since arrival to a location is often used to define native status. Here I propose an eco-evolutionary approach to distinguish between alien and native status and use this to resolve uncertainty in the status of the dingo in Australia. Dingoes were transported to mainland Australia by humans, but more than 4000 years ago, and dingoes now interbreed with feral domestic dogs. Legally, this mix of events has the dingo classified as native in some jurisdictions and alien in others. I suggest that native status for introduced species should be based on (1) whether the species has evolved in their new environment; (2) whether local species recognise and respond to them as they do towards deep endemic native species, and; (3) whether their impacts benchmark against those of a native species or are exaggerated like those of other alien species. Dingoes are behaviourally, reproductively and morphologically different to close ancestors from south-east Asia, and this difference has a genetic basis indicative of evolution in Australia. There is abundant evidence that native prey species on mainland Australia recognise and respond to them as a dangerous predator, which they are. But there is strong evidence that dingo impacts on prey are not exaggerated, with effect sizes from mensurative experiments similar to those of experiments on native predators rather than alien predators. These three lines of evidence suggest dingoes should be considered native to mainland Australia. I suggest this eco-evolutionary approach to defining native status can be helpful in resolving the often-heated debates about when an alien species becomes native.

scholarly journals Alien Species vs. Native Species: From Community Ecology to Eco-Evolutionary Dynamics

2019 ◽  
Author(s):  
Andersonn Silveira Prestes
Keyword(s):  
Alien Species ◽  
Exotic Species ◽  
Native Species ◽  
Evolutionary Dynamics ◽  
Evolutionary Processes ◽  
Native Communities ◽  
Individualized Approach ◽  
History Of ◽  
Relationship Of ◽  
The Relationship

The establishment and spread of exotic species is a contemporary major concern. Alien species may become invasive in their new habitat, leading to both/either environmental and/or economic impacts. I briefly reviewed the literature in the last decade about the relationship of exotic species and native communities. I identified that professionals usually approach the subject in two main points of view: (1) researchers tend to point out the impacts of alien species on entire communities, evaluating if the relationship is positive, negative or neutral; (2) they focus on the eco-evolutionary processes involved in the introductions, the dynamics of invasion, and individual study cases. When evaluating the response of introductions to entire communities, evidence seems to be ambiguous and may support positive, negative or neutral relationship, especially depending on the scale approached. The unique eco-evolutionary pathways of each introduction may be a great shortcoming in the searching for generalities. On the other hand, advances have been made in understanding the dynamics of invasion on different lineages through a more selective/individualized approach. I suggest that the dynamics of invasion might be studied through a perspective in which different eco-evolutionary processes, levels of organization (from gene to entire communities), the history of the organism(s) and time are taken into account. Individual cases might be compared in attempt to understand how the relationship exotic and native works and in the search for generalities.

scholarly journals Intrinsic Prey Preference and Selection of the Giant Gartersnake: A Threatened Predator in a Nonnative Prey-Dominated Community

2020 ◽  
Vol 11 (1) ◽  
pp. 164-173
Author(s):  
Julia S.M. Ersan ◽  
Brian J. Halstead ◽  
Erica L. Wildy ◽  
Michael L. Casazza ◽  
Glenn D. Wylie
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Prey Selection ◽  
Central Valley ◽  
Prey Preference ◽  
Live Prey ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Behavioral Trials ◽  
Selection Of

Abstract The introduction of exotic species into an environment can introduce great change in the trophic dynamics of native species. This is of even greater concern if the native species is of conservation concern. The giant gartersnake, Thamnophis gigas, an endemic predator of the Central Valley of California and a species of conservation concern at the state and federal levels, has declined as a result of conversion of its once vast wetland habitat to agriculture. Another anthropogenic factor contributing to this snake's changing ecology is the introduction of nonnative prey into the species' habitats. These introductions have resulted in a prey community that is almost completely composed of exotic species and have potential for considerable effects. In order to assess prey preference and selection we performed three sets of behavioral trials on naïve neonates. We examined 1) neonate prey preference in response to olfactory cues of prepared prey extracts, 2) neonate consumption of different live prey items presented simultaneously; and 3) terrestrial feeding behavior and/or latency to successful attack. Results from the olfactory study suggest that native Sierran treefrogs, Pseudacris sierra, are preferred by neonates. Results from consumption trials suggest that neonates are more likely to select frog species than fish species. This is the first study that we are aware of that examines prey selection of this threatened species and serves to inform its conservation and management.

scholarly journals Monitoring the influx of new species through citizen science: the first introduced ant in Denmark

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8850
Author(s):  
Julie K. Sheard ◽  
Nathan J. Sanders ◽  
Carsten Gundlach ◽  
Sämi Schär ◽  
Rasmus Stenbak Larsen
Keyword(s):  
Exotic Species ◽  
Citizen Science ◽  
Niche Overlap ◽  
Botanical Garden ◽  
Sampling Effort ◽  
Niche Modelling ◽  
Climatic Niche ◽  
History Museum ◽  
Geographic Space ◽  
Citizen Science Project

Climate change and invasive species threaten biodiversity, yet rigorous monitoring of their impact can be costly. Citizen science is increasingly used as a tool for monitoring exotic species, because citizens are geographically and temporally dispersed, whereas scientists tend to cluster in museums and at universities. Here we report on the establishment of the first exotic ant taxon (Tetramorium immigrans) in Denmark, which was discovered by children participating in The Ant Hunt. The Ant Hunt is a citizen science project for children that we ran in 2017 and 2018, with a pilot study in 2015. T. immigrans was discovered in the Botanical Garden of the Natural History Museum of Denmark in 2015 and confirmed as established in 2018. This finding extends the northern range boundary of T. immigrans by almost 460 km. Using climatic niche modelling, we compared the climatic niche of T. immigrans in Europe with that of T. caespitum based on confirmed observations from 2006 to 2019. T. immigrans and T. caespitum had a 13% niche overlap, with T. immigrans showing stronger occurrence in warmer and drier areas compared to T. caespitum. Mapping the environmental niches onto geographic space identified several, currently uninhabited, areas as climatically suitable for the establishment of T. immigrans. Tetramorium immigrans was sampled almost three times as often in areas with artificial surfaces compared to T. caespitum, suggesting that T. immigrans may not be native to all of Europe and is being accidentally introduced by humans. Overall, citizen scientists collected data on ants closer to cities and harbours than scientists did and had a stronger bias towards areas of human disturbance. This increased sampling effort in areas of likely introduction of exotic species naturally increases the likelihood of discovering species sooner, making citizen science an excellent tool for exotic species monitoring, as long as trained scientists are involved in the identification process.

scholarly journals Niche Models Differentiate Potential Impacts of Two Aquatic Invasive Plant Species on Native Macrophytes

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 162
Author(s):  
Michael R. Verhoeven ◽  
Wesley J. Glisson ◽  
Daniel J. Larkin
Keyword(s):  
Native Species ◽  
Invasive Plant ◽  
Environmental Gradients ◽  
Myriophyllum Spicatum ◽  
Light Availability ◽  
Niche Overlap ◽  
Growth Cycle ◽  
Potamogeton Crispus ◽  
Starting Point ◽  
Niche Models

Potamogeton crispus (curlyleaf pondweed) and Myriophyllum spicatum (Eurasian watermilfoil) are widely thought to competitively displace native macrophytes in North America. However, their perceived competitive superiority has not been comprehensively evaluated. Coexistence theory suggests that invader displacement of native species through competitive exclusion is most likely where high niche overlap results in competition for limiting resources. Thus, evaluation of niche similarity can serve as a starting point for predicting the likelihood of invaders having direct competitive impacts on resident species. Across two environmental gradients structuring macrophyte communities—water depth and light availability—both P. crispus and M. spicatum are thought to occupy broad niches. For a third dimension, phenology, the annual growth cycle of M. spicatum is typical of other species, whereas the winter-ephemeral phenology of P. crispus may impart greater niche differentiation and thus lower risk of native species being competitively excluded. Using an unprecedented dataset comprising 3404 plant surveys from Minnesota collected using a common protocol, we modeled niches of 34 species using a probabilistic niche framework. Across each niche dimension, P. crispus had lower overlap with native species than did M. spicatum; this was driven in particular by its distinct phenology. These results suggest that patterns of dominance seen in P. crispus and M. spicatum have likely arisen through different mechanisms, and that direct competition with native species is less likely for P. crispus than M. spicatum. This research highlights the utility of fine-scale, abundance-based niche models for predicting invader impacts.

scholarly journals Ectoparasite extinction in simplified lizard assemblages during experimental island invasion

2020 ◽  
Vol 16 (8) ◽  
pp. 20200474 ◽  
Author(s):  
Christian L. Cox ◽  
Sean Alexander ◽  
Brianna Casement ◽  
Albert K. Chung ◽  
John David Curlis ◽  
...  
Keyword(s):  
Introduced Species ◽  
Native Species ◽  
Population Expansion ◽  
Enemy Release ◽  
Total Density ◽  
Agonistic Interactions ◽  
Native Communities ◽  
Trombiculid Mite ◽  
Density And Biomass ◽  
Field Transplant

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.

U.S. State's View and Regulations on Fish Introductions

1991 ◽  
Vol 48 (S1) ◽  
pp. 167-170 ◽  
Author(s):  
Paul J. Wingate
Keyword(s):  
Exotic Species ◽  
Fish Species ◽  
Native Species ◽  
Good Thing ◽  
Political Pressure ◽  
Fish Introductions ◽  
Genetic Strains

A survey of the poiicy of 50 U.S. states on transplanted fish introductions and stocking fish of different genetic strains indicates that all 39 responding states control exotic introductions. While 67% of the responding states restrict in-state movement of fish species, more attention is being given to restricting in-state strain movement. More needs to be done. Native species are stocked on top of reproducing populations and moved among watersheds; exotic species are introduced. In some cases, these stockings have appeared to benefit all interested parties, while in other circumstances exotics have totally disrupted ecosystems and become pests. These introductions and stockings are a combination of the fish being available, misunderstanding by managers of possible effects, and strong political pressure to satisfy anglers in more and more waters. Many times, little attention is given to the effect of these introductions on the native biota and fauna as it is perceived that stocking fish is a good thing. It is not until problems develop or anglers want another species added that the wisdom or success of these stockings is questioned. Minnesota's policy is that fish are not moved between watersheds until genetic similarities of the various species in the different watersheds are demonstrated.

The loss of native terrestrial small mammals in large urban reserves in the Australian Capital Territory

2010 ◽  
Vol 16 (1) ◽  
pp. 36 ◽  
Author(s):  
A. J. Buckmaster ◽  
W. S. Osborne ◽  
N. Webb
Keyword(s):  
Species Composition ◽  
Exotic Species ◽  
Native Species ◽  
Indirect Detection ◽  
Urban Landscapes ◽  
Australian Capital Territory ◽  
Mammal Species ◽  
Detection Techniques ◽  
Australian Capital ◽  
Terrestrial Mammals

Urban development can alter species composition and diversity within an area through biotic homogenization, the introduction of exotic species, and localized extinctions of native species. In this study we examined the composition and diversity of small terrestrial mammals within nature reserves surrounded by urban landscapes and compared this with previous surveys of these reserves and nearby non-urban reserves with similar vegetative and geomorphological characteristics. A combination of live trapping and indirect detection techniques was employed in eight reserves in the Australian Capital Territory and surrounding New South Wales to determine current species composition. Compared with previous studies and the non-urban reserves, the urban reserves appear to have lost two-thirds of their native terrestrial small mammal species in the past 26 years. Exotic species were present in all urban reserves, but were only associated with areas characterized by human-induced disturbance in non-urban reserves. Possible causes of this disparity in native species diversity between urban and non-urban reserves are discussed.

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