Non-native Vascular Plant Species Research Articles

Plant succession on glacial moraines in the Arctic Brooks Range along a >125,000-year glacial chronosequence/toposequence

ABSTRACT Widespread glacial retreat is now occurring in many arctic mountain ranges, yet little is known about primary succession following deglaciation in these settings. Newly created habitats could provide refugia for flora and fauna whose ranges are threatened elsewhere by rapid warming. To assess vegetation responses to glacial retreat in an arctic–alpine setting, we first describe plant community development on two recently deglaciated moraines in the Brooks Range. We then compare these recent communities with communities developed along a moraine chronosequence that spans >125,000 years and ranges in altitude between 800 and 1,700 m.a.s.l. Results show that (1) within twenty-two to thirty-six years following deglaciation, primary succession begins with the assembly of small communities of eight to thirteen vascular and nonvascular plant species; (2) species turnover is low, with many pioneer taxa, particularly lichens, persisting at the oldest sites and across all altitudes; and (3) overall, succession is directional and slow, with species richness increasing for up to 25,000 years, and percentage vegetation cover reaching >100 percent on the oldest glacial deposits. This is the first vegetation study on primary succession in the high central Brooks Range, and it supplies a previously missing alpine element within a vegetation transect across northern Alaska’s bioclimatic gradient.

Chlamydomonas reinhardtii exhibits stress memory in the accumulation of triacylglycerols induced by nitrogen deprivation.

Stress memory is a phenomenon whereby exposure to initial stress event influences a response to subsequent stress exposures. Studying stress memory is important to understand the cellular behavior in dynamic environment, especially nowadays, in times with growing environmental instability. Stress memory has been characterized in vascular plants but its occurrence in nonvascular plant species has been rarely investigated. We hypothesized that stress memory occurs in nonvascular plants in relation to metabolic stress. We sought to test it using accumulation of lipids (triacylglycerols) in model green alga Chlamydomonas reinhardtii subjected to nitrogen deprivation stress as a model system. Here, we established stress memory protocol on C. reinhardtii cells. Using a blend of microscopy and gas chromatography methods, we showed that the cells exposed to recurrent stress show differential accumulation of triacylglycerols on the quantitative level without qualitative changes in lipid composition, comparing to single stress controls. Overall, our results suggest that metabolic stress memory does occur in nonvascular plant C. reinhardtii and provides a starting point to characterize mechanistic principles of metabolic stress memory. Due to the commercial potential of algae, our findings are relevant for basic science, as well as industrial production of algae-derived compounds.

Three Non-Native Vascular Plant Species New to the Flora of Alabama

Three species of non-native vascular plants are reported here as new to Alabama. Persicaria capitata (Buch.-Ham. ex D. Don) H. Gross, Pistacia chinensis Bunge, and Sedum diffusum S. Watson are all species cultivated as ornamentals, and likely represent escapes from nearby plantings. Recent collections of three non-native species in Alabama represent the first documented examples of these taxa as naturalized elements of the state's flora. In each case, the taxon was not included in the most recent statewide comprehensive publications including the Annotated Checklist of the Vascular Plants of Alabama (Kral et al. 2011) and the Alabama Plant Atlas (Keener et al. 2021). Additionally, Weakley (2020) did not include Alabama within the known distributions for each of them, and searches of BONAP (Kartesz 2020) and SERNEC (2021) failed to locate any additional non-cultivated specimens from Alabama.

EA Study of Non-native Vascular Plant Species at Hutcheson Memorial Forest Somerset County, New Jersey, USA

EA Study of Non-native Vascular Plant Species at Hutcheson Memorial Forest Somerset County, New Jersey, USA

A Floral Checklist for Wheaton Regional Park, Montgomery County, Maryland

Wheaton Regional Park is a suburban 500-acre park in Montgomery County, Maryland, on the northern edge of the Washington, D.C., metropolitan area. Early floristic surveys of the park, conducted between 1961–1964 when the park was founded, showed the park to be diverse, with 443 taxa of vascular plants. Our research team conducted a second round of floristic surveys between 2014–2019 to update the checklist of plants in the park. Here, we present a comprehensive checklist of all species collected in the park over the past 50 years, discuss recent plant introductions, and share a platform for a digital flora of the park through the Mid-Atlantic Megalopolis online portal. We documented 393 vascular plant species from the 1960s, as part of a comprehensive review of those collections. The 2010s collections recorded 293 vascular plant species, and an additional 16 species of bryophytes. In total, 554 species of plants (vascular and non-vascular) in 326 genera and 118 families have been recorded in Wheaton Regional Park over the past 50 years. We found that the surveys in the 2010s identified a substantial number of vascular plant species that were not recorded in the 1960s surveys. Additionally, we were able to recover less than half of the vascular plants recorded in the 1960s. The proportion of non-native vascular plant species increased from 22.1% in the 1960s to 34.5% in the 2010s. We offer recommendations for preserving the extant diversity of native plants in the park.

Noteworthy Collections of Four Non-native Vascular Plant Species New to the Flora of Alabama and One Species Rediscovered After 125 Years

Noteworthy Collections of Four Non-native Vascular Plant Species New to the Flora of Alabama and One Species Rediscovered After 125 Years

First bryophyte records from Diego Ramírez Archipelago: Changing lenses in long-term socio-ecological research at the southernmost island of the Americas

Long-term socio-ecological research requires comprehensive assessments of biodiversity that overcome historical taxonomic biases, such as the strong focus on the vascular flora. This is particularly relevant at high latitudes where the richness of non-vascular plant species exceeds that of vascular species. Additionally, with respect to geographical regions, there is also a marked bias towards ecological and conservation research in the northern hemisphere. In contrast, few studies have investigated patterns of non-vascular species richness in relation to conservation priorities at sub-Antarctic latitudes, particularly in the sub-Antarctic Magellanic ecoregion. In this work, we contribute to overcome such taxonomic, geographical and ecoregional biases by moving outside these limits, and therefore “changing the lenses” that are commonly used to assess and conserve biodiversity. We implemented these new “biocultural lenses” by including, for the first time, bryophytes in the floristic inventory of the southernmost island of the American continent: Gonzalo Island (56°31’16.8’’S; 68°42’53.5’’W) in the Diego Ramirez Archipelago, Chile. The first bryological exploration of the Diego Ramirez archipelago, SW of Cape Horn, revealed a bryophyte flora composed of 14 species, eight liverworts and six mosses. This number of non-vascular plant species almost doubles the eight vascular plants present on the island. Consequently, with our study, we aim to fill a critical gap in the knowledge of the flora of the Diego Ramirez archipelago, and establish an integral floristic characterization for the long-term socioecological research and conservation of the southernmost archipelago of South America. Based on the field material collected, the new nomenclatural combination Chiloscyphus secundifolius (Hook. f. & Taylor) J.J. Engel is proposed. The moss flora comprises Amblystegium serpens, a widespread moss, yet hitherto unknown for sub-Antarctic Chile. The bryoflora of Diego Ramirez has its greatest affinities with that of the sub-Antarctic Magellanic ecoregion and Maritime Antarctica. None of the liverworts present on Gonzalo Island occurs on continental Antarctica; in contrast, four of the six mosses are shared between these two areas.

Evaluating Sphagnum traits in the context of resource economics and optimal partitioning theories

Tradeoffs between key aspects of plant performance such as resource acquisition and allocation underpin several trait‐based theories that have been derived for vascular plants. However, due to difficulty in quantifying traits in nonvascular plants, our theoretical understanding of how traits govern the physiological and ecological preferences of nonvascular plant species is quite limited. Here, we used the resource economics theory (RET) and optimal partitioning theory (OPT) to evaluate functional traits in mosses. We evaluated aspects of these theories in two common but ecologically different Sphagnum moss species. We used a suite of morpho‐physiological traits across a range of environmental treatments to test whether Sphagnum is capable of functional tissue partitioning and whether the two Sphagnum species studied conform to a fast or slow strategy often observed in vascular plants. Consistent with the predictions of RET, the fast‐growing species maintained a faster growth rate and low biomass across treatments. However, some of the traits responded contrary to predictions for respiration and photosynthetic rates. Consistent with OPT, Sphagnum diverted biomass from branch to capitulum to connect with the primary source of moisture when under drought stress. Overall, this study showed that moss traits could be used to test ecological theories that were developed primarily for vascular plants.

Increasing impacts by Antarctica’s most widespread invasive plant species as result of direct competition with native vascular plants

Biological invasions represent significant economic and conservation challenges, though it is widely acknowledged that their impacts are often poorly documented and difficult to predict. In the Antarctic, one non-native vascular plant species is widespread and studies have shown negative impacts on native flora. Using field “common garden” experiments, we evaluate the competitive impact of the increasingly widespread invasive grass Poa annua on the only two native vascular species of Antarctica, the forb Colobanthus quitensis and the grass Deschampsia antarctica. We focus on interactions between these three plant species under current and a future, wetter, climate scenario, in terms of density of individuals. Our analysis demonstrates Poa annua has the potential to have negative impacts on the survival and growth of the native Antarctic vascular species. Under predicted future wetter conditions, C. quitensis communities will become more resistant to invasion, while those dominated by D. antarctica will become less resistant. Under a recently developed unified scheme for non-native species impacts, P. annua can be considered a species that can cause potentially moderate to major impacts in Antarctica. If current patterns of increased human pressure and regional climate change persist and mitigation action is not taken (i.e. reduction of propagule pressure and eradication or control measures), P. annua is likely to spread in Antarctica, especially in the Antarctic Peninsula region, with significant negative consequences for some of the most remote and pristine ecosystems worldwide. Tighter biosecurity across all operators in the region, improved surveillance for the species, and prompt, effective control actions will reduce these risks.

Plant community development following reclamation of oil sands mines using four cover soil types in northern Alberta

Understanding the effects of reclamation treatments on plant community development is an important step in setting realistic indicators and targets for reclamation of upland oil sands sites to forest ecosystems. We examine trends in cover, richness, evenness, and community composition for four cover soil types (clay over overburden, clay over tailings sand, peat‐mineral mix over overburden, and peat‐mineral mix over tailings sand) and natural boreal forests over a 20 year period in the mineable oil sands region of northern Alberta, Canada. Tree, shrub, and nonvascular plant species cover showed similar increases over time for all reclamation treatments, with corresponding declines in forb and graminoid cover with time. These trends resemble those in the natural boreal forests of the region and the trajectory of community development for the reclamation treatments appears to follow typical early successional trends for boreal forests. Species richness and diversity of natural forest differed significantly from reclamation treatments. Nonmetric multidimensional scaling ordination and multi‐response permutation procedure revealed that species composition was not affected by reclamation treatment but clearly differed from natural forest. Analysis of species co‐occurrence indicated random plant community assembly following reclamation, in contrast to a higher proportion of nonrandom plant community assembly in natural forests. Thus, reclaimed plant communities appear to be unstructured through year 20 and assembly is still in progress on these reclaimed sites.

Edge influence of low-impact seismic lines for oil exploration on upland forest vegetation in northern Alberta (Canada)

Low-impact seismic (LIS) techniques were developed to reduce the environmental footprint of oil exploration. Though relatively narrow (∼2–3m) and constructed with light-weight equipment, these lines cause forest fragmentation, and with their high density and potential edge influence extending into adjacent forest, their impact may be considerably underestimated. We assessed the effects of 3- to 4-year-old LIS lines in upland coniferous sub-boreal forests in northwestern Alberta (Canada) by investigating the distance of influence from the LIS line centre, through the edge and into the adjacent forest on vascular and non-vascular plant species diversity and cover and on several environmental factors. We also assessed whether cardinal orientation of the edge affects influence on plants and environmental factors. Edge orientation had no effect on extent of edge influence on plants or environmental variables, but distance from seismic line edge did. Species diversity of herbaceous plants was lowest from the seismic line edge up to 15m into the adjacent forest, when compared to mid- (25m) and far-interior (75m) forest. In contrast, cover was lower 5m from the seismic line edge in comparison to far-interior forest, but conditions on the seismic lines did not differ from the seismic line edge or any sampled distance up to 75m from the edge. Non-vascular species had lower diversity and cover on the seismic lines and along the edges in comparison to any distance away from the edge. There was no effect of distance from the seismic line edge on live woody plants, but deadwood was more frequently encountered near the seismic line edges in comparison to interior forest. Soil temperature was higher on the seismic lines and along the line edges whereas soil moisture on the seismic lines was about twice as high as at the edges and adjacent forest. Seismic lines and edges also received more light than the forest near the edge, but not more than the far-interior forest. With edge influence detectable up to 15m from edge 3 to 4years post-construction, long-term and regular monitoring of LIS lines is recommended, as active management and remedial reclamation actions might be required to bring the recovery of these disturbances on the right trajectory.

Settlements as a source for the spread of non-native plants into Central European suburban forests

Urbanization is considered as a major driver for biotic homogenization. Urbanization also promotes the dispersal of non-native species. This study examined the roles of suburban settlements and of the surrounding landscape composition for the spread of non-native plant species into adjacent mixed deciduous forests in Southern and Northwestern Switzerland. The number and abundance of native and non-native vascular plant species in both the ground vegetation and shrub layer were recorded in 15 forest sites situated adjacent to settlements and 15 control sites far from settlements. Various site and landscape characteristics were assessed in the surroundings (100 m radius) of the study sites. In both regions we found a higher number and larger abundance of non-native plant species in forest sites adjacent to settlements than in control forest sites. Furthermore, non-native plants were more frequently recorded close to roads and in sites surrounded by a large percentage cover of garden. All these effects were more pronounced in Southern Switzerland, a region with milder winter climate, than in Northwestern Switzerland. Our study showed that settlements are a source for the spread of non-native plant species into Central European suburban forests, and that the composition of the surrounding landscape matrix (e.g. traffic infrastructure, percentage cover of gardens) also affects the establishment of non-native plants.

Square-stalked St. John’s-wort, <i>Hypericum tetrapterum</i>, in Peel Region, Ontario: a New Non-native Vascular Plant Species for Eastern North America

The Eurasian Square-stalked St. John’s-wort (Hypericum tetrapterum Fr.: Hypericaceae) was found growing in an open Eastern White Cedar (Thuja occidentalis L.) swamp in Caledon, Regional Municipality of Peel, Ontario. This is the first record for eastern North America; previous North American occurrences have been on the Pacific coast in Vancouver, British Columbia, Canada (1991), and in Wahkiakum County, Washington State, USA (2003).

Non-native species in the vascular flora of the national park «Samarsky Bir»

Results of non-native flora surveys on Samara Dniprovska River valley within the designed National Park «Samarsky Bir» were analyzed in the paper. Scientific justification on first stage creation of the national-level National Park «Samarsky Bir» was prepared in 2012. Its area included the main park area with floodplain, arena and gully landscapes of the rivers Samara and Oril interstream. List of vascular plant species on floodplain, arena and gully habitats of Prisamar'ya counted 887 species. They are classified as 5 divisions, 6 classes, 108 families, 429 genera. This article presents a list of non-native flora fraction with bioecological characteristic of the plant species. The surveys were conducted by conventional methods on vascular flora studying. Analysis of the main plant ecomorphs was carried out by A. L. Belgard ecomorph system (1950). Invasion of plant species in the steppe zone of Ukraine has a long history complicated by significant anthropogenic transformation of the territory. We investigated the status of non-native plants, their ecomorphs, and tendency to invasiveness on the territory of National Park «Samarsky Bir» designed. Presence of 195 adventitious vascular plant species belonging to 48 families was determined. Of them, 7 families with the greatest abundance of non-native species contained 113 taxa (58 % of the total); 20 families were represented with 2–7 advents, and 20 families contained only 1 non-native species. Thus, today the share of non-native species in the vascular flora of the region accounted for nearly 22 %. Most of adventitious species are mesoxerophytes and xeromesophytes. In a cenomorphic relationship, vegetation being ruderal on the territory of Ukraine is dominated in composition of non-native flora. Within the total number of adventitious species, archaeophytes amount up 44 %, whereas neophytes come up to 56 %. The greatest abundance of adventitious species has been found in Brassicaceae, Asterasea and Poaceae families (15 %, 12 %, and 11 % of the total, respectively). 119 non-native vascular plant species were found in the steppe cenoses, 79 species in the gully and watershed forests, 90 species in floodplain forests, and 52 species on the territory of the sandy terrace. Among all the non-native species, 28 species have been identified as invasive, and there was a trend to increased invasiveness of some species in recent years. Among heterogenous species 12 of them were identified as invasive, and there was a tendency to increase theinvasiveness of some species in recent years. The analysis provided on non-native flora in the National Park evidences significant anthropogenic transformation of the territory; that requires establishment of appropriate regime on protection of this important ecological object.

Non-native species in the vascular flora of highlands and mountains of Iceland.

The highlands and mountains of Iceland are one of the largest remaining wilderness areas in Europe. This study aimed to provide comprehensive and up-to-date data on non-native plant species in these areas and to answer the following questions: (1) How many non-native vascular plant species inhabit highland and mountainous environments in Iceland? (2) Do temporal trends in the immigration of alien species to Iceland differ between highland and lowland areas? (3) Does the incidence of alien species in the disturbed and undisturbed areas within Icelandic highlands differ? (4) Does the spread of non-native species in Iceland proceed from lowlands to highlands? and (5) Can we detect hot-spots in the distribution of non-native taxa within the highlands? Overall, 16 non-native vascular plant species were detected, including 11 casuals and 5 naturalized taxa (1 invasive). Results showed that temporal trends in alien species immigration to highland and lowland areas are similar, but it is clear that the process of colonization of highland areas is still in its initial phase. Non-native plants tended to occur close to man-made infrastructure and buildings including huts, shelters, roads etc. Analysis of spatio-temporal patterns showed that the spread within highland areas is a second step in non-native plant colonization in Iceland. Several statically significant hot spots of alien plant occurrences were identified using the Getis-Ord Gi* statistic and these were linked to human disturbance. This research suggests that human-mediated dispersal is the main driving force increasing the risk of invasion in Iceland’s highlands and mountain areas.

Phylogeny of Plant Calcium and Calmodulin-Dependent Protein Kinases (CCaMKs) and Functional Analyses of Tomato CCaMK in Disease Resistance.

Calcium and calmodulin-dependent protein kinase (CCaMK) is a member of calcium/calmodulin-dependent protein kinase superfamily and is essential to microbe- plant symbiosis. To date, the distribution of CCaMK gene in plants has not yet been completely understood, and its function in plant disease resistance remains unclear. In this study, we systemically identified the CCaMK genes in genomes of 44 plant species in Phytozome and analyzed the function of tomato CCaMK (SlCCaMK) in resistance to various pathogens. CCaMKs in 18 additional plant species were identified, yet the absence of CCaMK gene in green algae and cruciferous species was confirmed. Sequence analysis of full-length CCaMK proteins from 44 plant species demonstrated that plant CCaMKs are highly conserved across all domains. Most of the important regulatory amino acids are conserved throughout all sequences, with the only notable exception being observed in N-terminal autophosphorylation site corresponding to Ser 9 in the Medicago truncatula CCaMK. CCaMK gene structures are similar, mostly containing six introns with a phase profile of 200200 and the exception was only noticed at the first exons. Phylogenetic analysis demonstrated that CCaMK lineage is likely to have diverged early from a calcium-dependent protein kinase (CDPK) gene in the ancestor of all nonvascular plant species. The SlCCaMK gene was widely and differently responsive to diverse pathogenic stimuli. Furthermore, knock-down of SlCCaMK reduced tomato resistance to Sclerotinia sclerotiorum and Pseudomonas syringae pv. tomato (Pst) DC3000 and decreased H2O2 accumulation in response to Pst DC3000 inoculation. Our results reveal that SlCCaMK positively regulates disease resistance in tomato via promoting H2O2 accumulation. SlCCaMK is the first CCaMK gene proved to function in plant disease resistance.

Inertia in an ombrotrophic bog ecosystem in response to 9 years' realistic perturbation by wet deposition of nitrogen, separated by form

Wet deposition of nitrogen (N) occurs in oxidized (nitrate) and reduced (ammonium) forms. Whether one form drives vegetation change more than the other is widely debated, as field evidence has been lacking. We are manipulating N form in wet deposition to an ombrotrophic bog, Whim (Scottish Borders), and here report nine years of results. Ammonium and nitrate were provided in rainwater spray as NH4 Cl or NaNO3 at 8, 24 or 56kgNha(-1) yr(-1) , plus a rainwater only control, via an automated system coupled to site meteorology. Detrimental N effects were observed in sensitive nonvascular plant species, with higher cumulative N loads leading to more damage at lower annual doses. Cover responses to N addition, both in relation to form and dose, were species specific and mostly dependent on N dose. Some species were generally indifferent to N form and dose, while others were dose sensitive. Calluna vulgaris showed a preference for higher N doses as ammonium N and Hypnum jutlandicum for nitrate N. However, after 9years, the magnitude of change from wet deposited N on overall species cover is small, indicating only a slow decline in key species. Nitrogen treatment effects on soil N availability were likewise small and rarely correlated with species cover. Ammonium caused most N accumulation and damage to sensitive species at lower N loads, but toxic effects also occurred with nitrate. However, because different species respond differently to N form, setting of ecosystem level critical loads by N form is challenging. We recommend implementing the lowest value of the critical load range where communities include sensitive nonvascular plants and where ammonium dominates wet deposition chemistry. In the context of parallel assessment at the same site, N treatments for wet deposition showed overall much smaller effects than corresponding inputs of dry deposition as ammonia.

Dimension reduction and data sharpening of high-dimensional vegetation data: An application to Swiss mire monitoring

In an era of the availability of very large databases, the problem of efficient methods to analyze such datasets remains. In large scale forest and landscape monitoring projects for instance, appropriate data mining techniques that can summarize the overall status of landscapes are necessary for planning and implementing follow-up management strategies. We consider a vegetation data set consisting of species data from more than 120 mires spread across Switzerland with a total of 20,134 plots on 2658 vascular and non-vascular plant species. Using species indicator values as proxy for site conditions, we propose some simple strategies for data mining involving multidimensional scaling and nonparametric probability density function estimation, both of which are known in the classical statistical literature. We show how commonly known techniques can be adapted in a novel and effective approach for the specific purpose of analyzing plant species occurrence in the plots to identify site conditions that influence species configurations and species diversity, thus providing important information concerning aspects of large scale vegetation structure. Our results indicate high variations among the mires with respect to site conditions that affect species assemblage and species diversity. While species indicator values continue to be popular as well as subject of much debate and research in the ecological community, our experience shows that careful methods of analysis at large landscape scales can reveal some powerful results, which can be taken up as the starting point for the next level of investigation.

Effects of canopy gaps on forest floor vascular and non-vascular plant species composition and diversity in an uneven-agedNothofagus betuloidesforest in Tierra del Fuego, Chile

Canopy gaps modify the environmental conditions available for plant growth in forests. Small canopy gaps are frequent in Nothofagus betuloides forests of Tierra del Fuego. Our objective was to study whether the forest floor vascular and non-vascular plant species composition and diversity are influenced by the occurrence of small-scale disturbances due to changes in the below-canopy solar radiation transmittances and forest floor heterogeneity (cover of litter, bare soil and fallen woody debris classed in three decay stages) in a N. betuloides forest located in south western Tierra del Fuego (53°59’S, 69 58’W). The vegetation was sampled in and around 13 canopy gaps (47 m2 on average). Following a light gradient, 65 plots (2 x 2 m) were established. The cover of all plant species was recorded using Londo’s scale. Species richness and total cover were calculated for each of the following taxonomical groups: spermatophyta (monocotyledons, dicotyledons), pteridophyta, bryophyta, marchantiophyta, anthocerotophyta and lichens. There were 63 species found on the forest floor. Marchantiophyta was the most diverse group with the highest species richness (6.6 species per plot). The vegetation on the forest floor was very homogeneous in species composition, richness and species diversity. The ordination analysis (NMS) showed that the community composition was weakly influenced by the patterns of below-canopy solar radiation transmittances and substrate heterogeneity. MRPP analysis of the community composition did not reveal differences in plant species assemblages between positions along transects running from areas beneath closed canopy to the open centres of canopy gaps. The marchantiophyte Chiloscyphus magellanicus was the only species which can be considered to be an indicator species; it was more likely to occur in gap centres (more open conditions). We conclude that these small canopy gaps do not very much modify the forest floor communities and the communities can be considered relatively stable.

Origin matters: widely distributed native and non‐native species benefit from different functional traits

Recently, ecologists debated whether distinguishing native from non-native species is sensible or not. One argument is that widespread and less widespread species are functionally different, whether or not they are native. An opposing statement points out ecologically relevant differences between native and non-native species. We studied the functional traits that drive native and non-native vascular plant species frequency in Germany by explaining species grid-cell frequency using traits and their interaction with status. Native and non-native species frequency was equally driven by life span, ploidy type and self-compatibility. Non-native species frequency rose with later flowering cessation date, whereas this relationship was absent for native species. Native and non-native species differed in storage organs and in the number of environmental conditions they tolerate. We infer that environmental filters drive trait convergence of native and non-native species, whereas competition drives trait divergence. Meanwhile, introduction pathways functionally bias the frequency of non-native species.