Non-native Populations Research Articles

Aquatic species shows asymmetric distribution range shifts in native and non-native areas

IntroductionClimate change is reshaping the geographical distribution of species across the globe. In marine ecosystems, climate change creates novel challenges to an environment impacted by numerous anthropogenic stressors. Forecasting shifts in species distribution, including the expansion of non-indigenous species under climate change scenarios, is a management challenge for today’s world.MethodsWe applied Bayesian Additive Regression Tree (BART) models to investigate the environmental factors modulating the occurrence and habitat preferences of the Atlantic blue crab Callinectes sapidus Rathbun, 1896 in native and non-native areas. With BART models, we also aimed to predict its current and future distributions under two climate change scenarios (RCPs 4.5 and 8.5). BART models were performed using global occurrences of the Atlantic blue crab – recorded from 1830 to 2022 – and several environmental covariates (i.e., water temperature, salinity, current velocity, and rugosity). Model accuracy was assessed with the Area Under the Curve (AUC) and True Skill Statistics (TSS) criteria. Cross-validation experiments were made to balance accuracy prediction and uncertainty model prediction intervals.Results and discussionAUC and TSS values indicated that data validation was successful for the BART model. Water temperature was the most critical variable affecting the presence probability of the Atlantic blue crab. The BART model predicts asymmetric distribution range shifts on both sides of the Atlantic Ocean. The non-native populations will experience broader shifts in their distribution range than in the native range, and the RCP 8.5 scenario model outputs predict a wider distribution range by the end of the century. Overall, we anticipate significant ecological changes in native and non-native areas. The range expansion in native areas is often equivalent to the ecological shifts induced by invasive species, so lessons learned by ecologists and managers in non-native areas will provide actionable insights to managers in native areas.

Patterns of genetic variation in native and non-native populations of European catfish Silurus glanis across Europe

Patterns of genetic variation in native and non-native populations of European catfish Silurus glanis across Europe

Genetic diversity and population structure among native, naturalized, and invasive populations of the common yellow monkeyflower, Mimulus guttatus (Phrymaceae).

An ongoing controversy in invasion biology is the prevalence of colonizing plant populations that are able to establish and spread, while maintaining limited amounts of genetic variation. Invasive populations can be established through several routes including from a single source or from multiple introductions. The aim of this study was to examine genetic diversity in populations of Mimulus guttatus in the United Kingdom, where the species is considered invasive, and compare this diversity to that in native populations on the west coast of North America. Additionally, we looked at diversity in non-native populations that have not yet become invasive (naturalized populations) in eastern North America. We investigated population structure among populations in these three regions and attempted to uncover the sources for populations that have established in the naturalized and invasive regions. We found that genetic diversity was, on average, relatively high in populations from the invasive UK region and comparable to native populations. Contrastingly, two naturalized M. guttatus populations were low in both genetic and genotypic diversity, indicating a history of asexual reproduction and self-fertilization. A third naturalized population was found to be a polyploid Mimulus hybrid of unknown origin. Our results demonstrate that M. guttatus has likely achieved colonization success outside of its native western North America distribution by a variety of establishment pathways, including those with genetic and demographic benefits resulting from multiple introductions in the UK, reproductive assurance through selfing, and asexual reproduction in eastern North America, and possible polyploidization in one Canadian population.

Dried Blood Spot Sampling to Assess Rifampicin Exposure and Treatment Outcomes among Native and Non-Native Tuberculosis Patients in Paraguay: An Exploratory Study.

The aim of this study was to evaluate the difference in drug exposure of rifampicin in native versus non-native Paraguayan populations using dried blood spots (DBS) samples collected utilizing a limited sampling strategy. This was a prospective pharmacokinetic study that enrolled hospitalized tuberculosis (TB) patients from both native and non-native populations receiving oral rifampicin 10 mg/kg once-daily dosing. Steady-state DBS samples were collected at 2, 4, and 6 h after intake of rifampicin. The area under the time concentration curve 0-24 h (AUC0-24) was calculated using a Bayesian population PK model. Rifampicin AUC0-24 < 38.7 mg*h/L was considered as low. The probability of target attainment (PTA) was calculated using AUC0-24/MIC > 271 as a target and estimated MIC values of 0.125 and 0.25 mg/L. In total, 50 patients were included. Native patients (n = 30) showed comparable drug exposure to the non-natives (n = 20), median AUC0-24 24.7 (17.1-29.5 IQR) and 21.6 (15.0-35.4 IQR) mg*h/L (p = 0.66), respectively. Among total patients, only 16% (n = 8) had a rifampicin AUC0-24 > 38.7 mg*h/L. Furthermore, PTA analysis showed that only 12 (24%) of the patients met a target AUC0-24 /MIC ≥ 271, assuming an MIC of 0.125 mg/L, which plummeted to 0% at a wild-type MIC of 0.25 mg/L. We successfully used DBS and limited sampling for the AUC0-24 estimation of rifampicin. Currently, our group, the EUSAT-RCS consortium, is preparing a prospective multinational, multicenter phase IIb clinical trial evaluating the safety and efficacy of high-dose rifampicin (35 mg/kg) in adult subjects using the DBS technique for AUC0-24 estimation.

Concerning the different pronunciations of “our,” how does the pronunciation affect people of generational and foreign language background differences?

The younger generation’s dialect has changed rapidly due to the increased consumption of media from different backgrounds. Changing dialect affects the way we communicate with each other. The research question I curated concerned the different pronunciations of “our,” and how the difference in pronunciation affects people of generational and foreign language backgrounds. The methods of the study included a short sequence of questionnaires to provide interest, statistical information, as well as availability information for myself (the interviewer) to find a time at which I may interview the participant. The takeaway from the research was originally to research more on the topic of the generational differences of dialects. However, upon further inspection of my participant pool, another observation of the variables was needed to encompass the entire population. Thus, it can be concluded that dialect changes among people with the competing dialects of the older and younger generations affect the non-native population. The hypothesis suggests there is a relationship between dialect used by both younger and older generations, which impacts L2 English speakers and their pronunciation of “our.” The results were calculated by hand from data collected on Google Sheets. It can be assumed that the [‘aʊɚ] to [‘ar] pronunciation dialect change affected most of the older and younger populations. 42.86% of the total participants used the pronunciation of “our” as [‘aʊɚ], meaning that less than half of the population used the “proper” pronunciation of “our.” The following results are deemed inconclusive due to the number of variables that were present.

New Records of the Alien Chinese Ricefish (Oryzias sinensis) and Its Dispersal History across Eurasia

The diversity of biota in different parts of the planet has demonstrated dramatic changes within the last several decades due to the extinction of native taxa and the appearance of invasive taxa. The correct taxonomic identification of non-native species is important for understanding their dispersal abilities, especially when potential invaders may be of closely related species. Information on the species identity of ricefish (Oryzias spp.), which have formed self-sustainable populations in some parts of Eurasia, is contradictory. In this paper, we studied samples from non-native populations of Oryzias from several Eurasian regions. The results of our mtDNA COI partial sequence study confirm that the individuals we studied belong to the species Chinese ricefish, O. sinensis. Analyses of the literature and our own data suggest that all known alien populations of Oryzias in continental Eurasia belong to the same species, O. sinensis. A recent finding of O. sinensis in the Don delta suggests that one of the species’ secondary dispersal pathways could run from the Kuban region through the lower part of the Don basin to the Cis-Azov area.

Detection of Endoparasites in Non-Native Raccoons from Central Italy.

The raccoon (Procyon lotor) is a carnivore native to North and Central America, gradually introduced into Asia and Europe, including Italy. It is an important carrier of multiple endoparasites, both Protozoa and Helminths, some of them being zoonotic. The aim of this study was to investigate the endoparasites of the non-native raccoon population of Central Italy. Sixty-two raccoons were collected by local competent authorities (sixty trapped and euthanized, two found dead) and subjected to necroscopic examination. Carcasses underwent a broad parasitological investigation, including coprological techniques (macroscopic examination of the gastrointestinal tract, lungs, trachea, and heart, Flotac®, Baermann test, and immunofluorescence for Giardia duodenalis and Cryptosporidium spp.), research on respiratory/urinary capillariosis and artificial digestion for Trichinella spp. larvae, and a histopathological examination of the ileum. Ascarid parasites were further identified at the species level using a next-generation sequencing-based amplicon sequencing approach. The results showed the presence of different Protozoa and Nematodes: Baylisascaris procyonis (26/62; 41.9%), Pearsonema sp. (6/62; 9.6%), Capillariidae (6/62; 9.6%), Eimeria sp. (2/62; 3.2%), Cryptosporidium sp. (2/62; 3.2%), and Ancylostomatidae (2/62; 3.2%). B. procyonis is an emerging helminthic zoonotic agent considered a serious concern for public and animal health, given the possibility of its transmission to paratenic hosts, including humans and pets. The demonstrated role of the raccoon as a multi-parasite carrier should be an incentive to continuing the eradication/control of this alien species, and supports the need to implement related disease surveillance programs.

Decreased Vitamin D Levels and Altered Placental Vitamin D Gene Expression at High Altitude: Role of Genetic Ancestry.

High-altitude hypoxia challenges reproduction; particularly in non-native populations. Although high-altitude residence is associated with vitamin D deficiency, the homeostasis and metabolism of vitamin D in natives and migrants remain unknown. We report that high altitude (3600 m residence) negatively impacted vitamin D levels, with the high-altitude Andeans having the lowest 25-OH-D levels and the high-altitude Europeans having the lowest 1α,25-(OH)2-D levels. There was a significant interaction of genetic ancestry with altitude in the ratio of 1α,25-(OH)2-D to 25-OH-D; with the ratio being significantly lower in Europeans compared to Andeans living at high altitude. Placental gene expression accounted for as much as 50% of circulating vitamin D levels, with CYP2R1 (25-hydroxylase), CYP27B1 (1α-hydroxylase), CYP24A1 (24-hydroxylase), and LRP2 (megalin) as the major determinants of vitamin D levels. High-altitude residents had a greater correlation between circulating vitamin D levels and placental gene expression than low-altitude residents. Placental 7-dehydrocholesterol reductase and vitamin D receptor were upregulated at high altitude in both genetic-ancestry groups, while megalin and 24-hydroxylase were upregulated only in Europeans. Given that vitamin D deficiency and decreased 1α,25-(OH)2-D to 25-OH-D ratios are associated with pregnancy complications, our data support a role for high-altitude-induced vitamin D dysregulation impacting reproductive outcomes, particularly in migrants.

There and Back Again: The Unexpected Journeys of Metridium de Blainville, 1824 between the Old Oceans and throughout the Modern World.

AbstractMembers of the sea anemone genus Metridium are abundant in temperate rocky habitats and fouling communities. Their biogeographic history is expected to reflect changes in currents and habitats that have influenced benthic communities, such as the climate-influenced changes that occurred during the Last Glacial Maximum. More recently, however, anthropogenic influences such as shipping transportation and the creation of artificial habitat have altered and affected the composition of modern-day marine communities. Here we use sequence-capture data to examine the genetic structure of Metridium across its shallow-water distribution to (1) evaluate species boundaries within Metridium, (2) elucidate the dispersal history of Metridium between and among oceans, and (3) assess the influence of anthropogenic movement on modern-day populations. We find strong evidence for two species within Metridium: M. farcimen and M. senile. Dispersal from the Pacific to the Atlantic included a subsequent isolation of a small population in or above the Bering Sea, which has presumably moved southward. Within the native range of M. senile, admixture is prevalent even between oceans as a result of anthropogenic activities. The nonnative populations in Chile and the Falkland Islands came from at least two distinct introduction events originating from both coasts of the United States in the North Pacific and North Atlantic Oceans. Hybridization between M. senile and M. farcimen is documented as occurring in anthropogenically influenced habitats. The heavy influence from anthropogenic activities will continue to impact our understanding of marine organisms, particularly within the native range and for those that are easily transported across long distances.

Establishment of the Smooth-scaled Tegulet (Gymnophthalmus underwoodi) and the Common House Gecko (Hemidactylus frenatus) on St. Eustatius

Within the northern Lesser Antilles, the island of Saint Martin, including the Dutch part (St. Maarten, a constituent country of The Netherlands) and the French part (the Collectivity of Saint Martin), is considered the main hub for established non-native reptiles, currently numbering ten species (Table 1) (Dewynter et al. 2022; Thorpe 2022). The islands of Saba and St. Eustatius are special municipalities of The Netherlands and frequently trade with St. Maarten. During the last five years, several new non-native reptile species have been reported on Saba and St. Eustatius, which originate from the non-native populations already present on Saint Martin: the Green Iguana, Iguana iguana (van den Burg et al. 2018, 2022) on St. Eustatius, and the Brahminy Blindsnake, Indotyphlops braminus (van den Burg et al. 2021) and Smooth-scaled Tegulet, Gymnophthalmus underwoodi on Saba (van den Burg et al. 2021). It is believed that these newly established populations have been facilitated by poor biosecurity between the islands. Here, we describe the establishment of two species, G. underwoodi and the Common House Gecko, Hemidactylus frenatus, on St. Eustatius.

Evaluation of roost culling as a management strategy for reducing invasive rose-ringed parakeet (Psittacula krameri) populations

Rose-ringed parakeets (Psittacula krameri) are one of the most widespread invasive avian species worldwide. This species was introduced to the island of Kaua‘i, Hawai‘i, USA, in the 1960s. The rapidly increasing population has caused substantial economic losses in the agricultural and tourism industries. We evaluated the efficacy of a roost culling program conducted by an independent contractor from March 2020 to March 2021. We estimated island-wide minimum abundance was 10,512 parakeets in January 2020 and 7,372 in April 2021. Over 30 nights of culling at four roost sites, approximately 6,030 parakeets were removed via air rifles with 4,415 (73%) confirmed via carcasses retrieval. An estimated average of 45 parakeets were removed per hour of shooter effort. The proportion of adult females removed in 2020 was 1.9 × greater when culled outside of the estimated nesting season. Of the four roosts where culling occurred, the parakeets fully abandoned three and partially abandoned one site. Of the three fully abandoned roosts, an estimated average of 29.6% of birds were culled prior to roost abandonment. The roost culling effort was conducted during the COVID-19 pandemic, when tourist numbers and foot traffic were greatly reduced. It is unknown how public perception of roost culling in public areas may impact future efforts. Findings suggest roost culling can be utilized for management of nonnative rose-ringed parakeet populations when roost size is small enough and staff size large enough to cull entire roosts in no greater than two consecutive nights (e.g., if two shooters are available for three hours per night, roost culling should only be attempted on a roost with ≤ 540 rose-ringed parakeets).

Water transfer determines the regional spread dynamics of non-native fish species

Interbasin water transfer projects (IBWT's) have emerged as dispersal corridors for aquatic species. However, little is known about how water transfer affects regional spread dynamics, or shapes the genetic diversity patterns of non-native populations. Shimofuri Goby Tridentiger bifasciatus is a globally introduced fish species with many well-established populations in IBWT's. Here, we used nuclear microsatellites to assess the genetic diversity and population structure of the Shimofuri Goby in its native and introduced sites belonging to two IBWT's in China. Our objectives were to (1) reveal the genetic diversity patterns of the Shimofuri Goby during regional spread, and (2) identify its mode of spreading in water transfer systems. We observed (1) a high level of genetic diversity in non-native populations without evidence of bottleneck effects, (2) that non-native populations with a longer water transfer times had a higher private allele richness, and (3) that non-native populations showed a highly mixed genetic structure, low level of genetic differentiation, and no significant relationship between geographical and genetic distances. Our results indicate that the genetic patterns of diversity of non-native populations are mainly shaped by a linear cascade spread processes due to long-distance movement of larvae, and are probably related to propagule pressure caused by the construction of water transfer. To manage the non-native populations of T. bifasciatus, preventive actions and physical removal should be implemented in IBWT's.

The parasites of a successful invader: monogeneans of the Asian topmouth gudgeon Pseudorasbora parva, with description of a new species of Gyrodactylus.

Monogenean parasites are often co-introduced with their fish hosts into novel areas. This study confirmed co-introduction of two dactylogyrids, Dactylogyrus squameus Gusev, 1955 and Bivaginogyrus obscurus (Gusev, 1955), and a newly described gyrodactylid species, Gyrodactylus pseudorasborae n. sp. into Europe along with their fish host, the invasive topmouth gudgeon Pseudorasbora parva (Temminck & Schlegel) from East Asia. All three species were observed in the lower Dnieper and middle Danube basin regions and had slightly larger haptoral hard parts than the same parasites in their native range. While dactylogyrids occurred sporadically, we recorded regular infection by G. pseudorasborae n. sp. at relatively high prevalence and abundance. This latter species was observed in both the native and non-native range of topmouth gudgeon, and resembles Gyrodactylus parvae You et al., 2008 recently described from P. parva in China. Both species were distinguished based on genetic analysis of their ITS rDNA sequence (6.6% difference), and morphometric differences in the marginal hooks and male copulatory organ. Phylogenetic analysis of dactylogyrid monogeneans showed that B. obscurus clustered with Dactylogyrus species parasitising Gobionidae and Xenocyprididae, including D. squameus, supporting recent suggestions of a paraphyletic origin of the Dactylogyrus genus. In addition to co-introduced parasites, topmouth gudgeon was infected with a local generalist, G. prostae Ergens, 1964, increasing the number of monogeneans acquired in Europe to three species. Nevertheless, monogenean infections were generally lower in non-native host populations, potentially giving an advantage to invading topmouth gudgeon.

Invasive alien insects represent a clear but variable threat to biodiversity

Invasive alien insects are an important yet understudied component of the general threat that biological invasions pose to biodiversity. We quantified the breadth and level of this threat by performing environmental impact assessments using a modified version of the Environmental Impact Assessment for Alien Taxa (EICAT) framework. This represents the largest effort to date on quantify the environmental impacts of invasive alien insects. Using a relatively large and taxonomically representative set of insect species that have established non-native populations around the globe, we tested hypotheses on: (1) socioeconomic and (2) taxonomic biases, (3) relationship between range size and impact severity and (4) island susceptibility. Socioeconomic pests had marginally more environmental impact information than non-pests and, as expected, impact information was geographically and taxonomically skewed. Species with larger introduced ranges were more likely, on average, to have the most severe local environmental impacts (i.e. a global maximum impact severity of ‘Major’). The island susceptibility hypothesis found no support, and both island and mainland systems experience similar numbers of high severity impacts. These results demonstrate the high variability, both within and across species, in the ways and extents to which invasive insects impact biodiversity, even within the highest profile invaders. However, the environmental impact knowledge base requires greater taxonomic and geographic coverage, so that hypotheses about invasion impact can be developed towards identifying generalities in the biogeography of invasion impacts.

Toward a ‘Migrant Trap’? Local Development, Urban Sustainability, Sociodemographic Inequalities, and the Economic Decline in a Mediterranean Metropolis

After years following the breakdown of the Great Recession in Europe, crisis-driven urban shrinkage can be adequately investigated considering changes over time in selected demographic indicators, with a specific focus on migration. Using official statistics and a literature review, the present study documents the inherent demographic decline in metropolitan Athens (Greece) as a response to economic stagnation after a long-lasting expansion. The empirical results of our study delineate metropolitan shrinkage in Southern Europe as a process associated with complex socioeconomic conditions leading to (possibly counterintuitive) demographic outcomes as far as migration trends are concerned. Recession has determined unsustainable economic conditions especially for non-native population segments, promoting both class and ethnic segregation. The negative migration balance in the 2010s led to an intense population decline hitting settlements made already demographically fragile because of low fertility and aging. Athens became a sort of ‘migrant trap’, being progressively unattractive for incoming migration flows—both internal and international—and losing an increasingly high number of non-native residents settling in the area, especially during the ‘gold’ decade of the 2004 Olympics. A sudden reduction in immigration rates reflected both economic (recession) and non-economic (population aging, fertility reduction, and childbearing postponement) factors, causing an incipient shrinkage after secular urban growth. The empirical results of our study add to the traditional literature on ‘industrial cities shrinkage’ in Europe and contribute to (re)formulate short- and medium-term development scenarios in large agglomerations, shedding further light on the role of migration in crisis-driven processes of urban decline in Mediterranean Europe.

Phylogeography of the Atlantic Blue Crab Callinectes sapidus (Brachyura: Portunidae) in the Americas versus the Mediterranean Sea: Determining Origins and Genetic Connectivity of a Large-Scale Invasion.

The American blue crab Callinectes sapidus is a particularly successful invader in estuarine ecosystems worldwide. Despite increasing awareness of its potential harm, the invasion history and underlying genetic diversity of this species within the Mediterranean Sea remain unknown. This study constitutes the first large-scale approach to study phylogeographic patterns of C. sapidus in Europe, facilitated by the first comparison of all currently available COI sequence data. For this investigation, 71 individuals of C. sapidus were newly analyzed and the entire COI gene was sequenced and used for a comparative phylogeographic analyses. For the first time, two separately used adjacent regions of this gene were combined in a single dataset. This allowed emphasizing the prevalence of three geographically defined lineages within the native range: (1) eastern North America, including the Gulf of Mexico, (2) the Caribbean, and (3) Brazil. New data from the Mediterranean reveal that non-native populations of C. sapidus are characterized by a conspicuously low genetic diversity (except for Turkey, where stocking took place), and that there is surprisingly low connectivity among established populations. The occurrence of strong genetic bottlenecks suggests few founder individuals. This confirms that, even under a scenario of restricted large-scale gene flow, a very limited number of invasive individuals is sufficient for a massive impact.

Population genetic structure, parasite infection and somatic condition of pumpkinseed Lepomis gibbosus (Actinopterygii: Centrarchidae) in the Oder river basin.

In Poland, distribution of non-native pumpkinseed Lepomis gibbosus (Centrarchidae) is strictly limited to the Oder river basin, where it was introduced in the early 20th century. Recently, several populations have been found in waterbodies adjacent to the Oder, particularly in its lower reaches. In this study, we compare the genetic relatedness of populations in the Oder basin with other European populations using nuclear (microsatellite) and mitochondrial (partial cytochrome c oxidase subunit I; cox1) markers. Microsatellite analysis indicated that four populations in the lower Oder form a separate cluster, while one in the middle Oder clustered with Danubian populations, from where probably having been introduced. Microsatellite data suggested that the lower Oder populations differ from other non-native European populations, making it impossible to estimate the source of introduction. Nevertheless, analysis of cox1 indicated that Oder pumpkinseeds belong to the same haplotype as the vast majority of European populations. Parasitological examination confirmed the presence of two North American species, the monogenean Onchocleidus dispar and trematode Posthodiplostomum centrarchi, in the lower Oder, both previously unknown in the region. Fifteen other parasite species were acquired, including glochidia of invasive Sinanodonta woodiana. In the middle Oder, parasite infection was more limited. Fish from the Gryfino Canal, considered one of the most invasive populations in Europe, showed the highest parasite abundance and diversity, and the highest somatic condition and growth rate due to warm water released from the Dolna Odra power plant. Our results highlight significant differences in somatic condition and parasite infection in long-established non-native pumpkinseed populations in the same river system, reflecting mainly environmental conditions.

Establishment of the non-native horned-face bee Osmia cornifrons and the taurus mason bee Osmia taurus (Hymenoptera: Megachilidae) in Canada.

Established populations of the non-native horned-face bee, Osmia cornifrons (Radoszkowski, 1887), and the taurus mason bee, Osmia taurus Smith, 1873 (Hymenoptera: Megachilidae), have been identified from Canada for the first time. In the US, the importation of O. cornifrons, beginning in the 1970s, led to its release for agricultural crop pollination and spread across the country. In this article, we report on O. cornifrons captured while sampling wild bees in Toronto, Ontario using hand nets, bug vacuums, and vane traps, as well as established populations in trap nests, from 2017-2020. The morphologically similar O. taurus, which was accidentally introduced to the US with shipments of imported O. cornifrons, was also recorded in our samples. Recently, a few individual O. taurus specimens have been identified from Ontario and Quebec; however, the extent of our sampling included nests, indicating it is also established in Canada. Others have shown its population growth to have been associated with concordant declines in abundances of native mason bee species in the US, and similar impacts are possible in Canada if action is not taken. We propose three non-mutually exclusive possible pathways for the arrival of O. cornifrons, as well as O. taurus, in Canada: (1) natural migration northward from non-native populations in the US, (2) international importation in the 1980s-2000s to support agricultural research programs, and (3) unintentional release of mason bee cocoons purchased from non-local vendors. We argue that a focus on enhancing populations of locally occurring native bees and stronger policy on the importation and sale of non-native bees are needed.

Apparent Hybridization of Nonnative Rhamnus Populations in Central New York and Connecticut, U.S.A.

The Eurasian Rhamnus cathartica is widespread, common, and naturalized in parts of the northeastern United States. Other nonnative buckthorn species are also present but underreported because intraspecific leaf polymorphisms, hybridization, and imprecise literature descriptions confuse identifications. A study of Rhamnus populations in Tompkins and Onondaga counties in New York and Hartford County in Connecticut provided an opportunity to revisit the literature and to propose identification aids based on infrequently reported fruit stone number and mature fruit pulp color. These characters facilitate inferences of ancestry of apparent hybrids involving R. cathartica, R. davurica, and R. utilis.

Limited evidence for phenological differences between non-native and native species

Although many species shift their phenology with climate change, species vary significantly in the direction and magnitude of these responses (i.e., phenological sensitivity). Studies increasingly detect early phenology or high phenological sensitivity to climate in non-native species, which may favor non-native species over natives in warming climates. Yet relatively few studies explicitly compare phenological responses to climate between native vs. non-native species or between non-native populations in the native vs. introduced range, limiting our ability to quantify the role of phenology in invasion success. Here, we review the empirical evidence for and against differences in phenology and phenological sensitivity to climate in both native vs. non-native species and native and introduced populations of non-native species. Contrary to common assumptions, native and non-native plant species did not consistently differ in mean phenology or phenological sensitivity. However, non-native plant species were often either just as or more sensitive, but rarely less sensitive, to climate as natives. Introduced populations of non-native plant species often show earlier reproduction than native populations of the same species, but there was mixed evidence for differences in phenological sensitivity between introduced and native plant populations. We found very few studies comparing native vs. invasive animal phenology. Future work should characterize phenological sensitivity to climate in native vs. non-native plant and animal species, in native vs. introduced populations of non-native species, and across different stages of invasion, and should carefully consider how differences in phenology might promote invasion success or disadvantage native species under climate change.