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Plant species used in urban horticulture are frequently non-native despite evidence that urban areas are regular points of introduction, often leading to invasions and negative impacts on biodiversity. Many horticulturalists assert that non-native plants are more successful and provide equal or greater habitat and ecosystem services than native plants. However, little research has compared native and non-native plants in urban systems. We present here a systematic literature review, using the PRISMA methodology, to assess three questions: (1) Is there a difference between native and non-native plants in their ability to support faunal biodiversity in urban green spaces? (2) Is there a difference between native and non-native plants in their provisioning of urban ecosystem services? 3)Do non-native species outperform natives in urban environments in terms of survival, growth, and fitness? We extracted data from 165 total papers. One hundred and twenty studies found that native plants outperform non-native plants on the response metric evaluated in the study, 57 demonstrated mixed impacts, 56 demonstrated no differences among plant origin, and 26 found non-native plants outperformed native plants. We found overwhelming evidence that native plants support higher faunal abundance and diversity than non-native plants in urban landscapes. Relatively few studies examined ecosystem services and plant performance, but we found that native plants support higher levels and diversity of ecosystem services and that many native plants can be used for horticulture, that is, they will survive and thrive in urban conditions. Native plants provide multiple ecosystem functions in urban greenspaces, supporting urban biodiversity and provisioning ecosystem services than non-native plant species and should be prioritized in urban horticulture activities. [ABSTRACT FROM AUTHOR]

Understanding the responses of non‐native plants to climate change while accounting for biotic interactions is key to predicting and mitigating future invasion risks. Non‐native invasive plants may benefit from or decline in the face of climate change, relative to native competitors. Non‐native plants might also suffer less than native plants from natural enemies such as herbivores, which could give non‐natives a competitive advantage. However, we lack an understanding of how non‐native plants will compete with native plants in a warming climate, while accounting for the effects of herbivore pressure. To test the potential interactions between warming, herbivore pressure and competition, we set up a common‐garden experiment in Trondheim, Norway, using five non‐native plants growing either alone or in competition with a native plant community. These plants were subjected to herbivore exclusion and artificial warming treatments, using open‐top chambers. We found that under warming, three non‐native species had greater biomass and all five species were taller than when grown without warming. Competition with native species reduced the biomass of three non‐native species and herbivore exclusion resulted in taller plants for three non‐native species. Native community biomass was not affected by either warming or herbivore exclusion. Furthermore, the native community was not affected by competition with any non‐native plant except Centaurea montana, which resulted in lower native community biomass, suggesting that C. montana is likely to be the most detrimental of these non‐native species to native communities. Competition with natives reduced the positive effects of warming on biomass for only one species, Alchemilla mollis. Our study strongly suggests that a warming climate may benefit invasive plants more than native plants, but for some species these effects will be mediated by biotic interactions in idiosyncratic ways, depending on the identity of both native and non‐native species. This will present a challenge to predicting plant invasion success under climate change while accounting for biotic interactions. [ABSTRACT FROM AUTHOR]

Non‐native annual grasses can dramatically alter fire frequency and reduce forage quality and biodiversity in the ecosystems they invade. Effective management techniques are needed to reduce these undesirable invasive species and maintain ecosystem services. Well‐timed management strategies, such as grazing, that are applied when invasive grasses are active prior to native plants can control invasive species spread and reduce their impact; however, anticipating the timing of key phenological stages that are susceptible to management over vast landscapes is difficult, as the phenology of these species can vary greatly over time and space. To address this challenge, we created range‐wide phenology forecasts for two problematic invasive annual grasses: cheatgrass (Bromus tectorum), and red brome (Bromus rubens). We tested a suite of 18 mechanistic phenology models using observations from monitoring experiments, volunteer science, herbarium records, timelapse camera imagery, and downscaled gridded climate data to identify the models that best predicted the dates of flowering and senescence of the two invasive grass species. We found that the timing of flowering and senescence of cheatgrass and red brome were best predicted by photothermal time models that had been adjusted for topography using gridded continuous heat‐insolation load index values. Phenology forecasts based on these models can help managers make decisions about when to schedule management actions such as grazing to reduce undesirable invasive grasses and promote forage production, quality, and biodiversity in grasslands; to predict the timing of greatest fire risk after annual grasses dry out; and to select remote sensing imagery to accurately map invasive grasses across topographic and latitudinal gradients. These phenology models also have the potential to be operationalized for within‐season or within‐year decision support. [ABSTRACT FROM AUTHOR]

The spatial pattern of leaf stoichiometry is critical in predicting plant palatability and ecosystem productivity and nutrient cycling rates and thus is a major focus of community ecological research. Coastal wetlands as vital blue carbon ecosystems, with high possibility to be vulnerable to plant invasion, studies focused on stoichiometry and its pattern are important to unveil the elements cycling process. However, previous studies have mainly focused on stoichiometry in terrestrial ecosystems, there are few studies conducted on coastal wetland ecosystems, especially the studies that compare leaf stoichiometry between native and non-native plants in coastal wetlands. In this study, we compared the latitudinal patterns of leaf nutrient contents and their stoichiometric ratios between native and non-native plant species across coastal wetland ecosystems and investigated whether leaf stoichiometric patterns were driven by climatic factors. We used a compiled global data set of 954 records to conduct a systematic meta-analysis. The results showed that there were significant differences in latitudinal patterns of leaf carbon (C) and nitrogen (N) contents and C:N ratio between native and non-native species, as well as significant differences in leaf C, N, and phosphorus (P) contents. For native species, we found significant latitudinal patterns in leaf C, N, and P contents and C:N and C:P ratios, whereas for non-native species, we found significant latitudinal patterns in leaf N content and C:P and N:P ratios. Mean annual temperature of the data collection site was a significant predictor of leaf stoichiometry of native plants but only of leaf N content and C:P ratio of nonnative plants. Thus, we demonstrated spatial heterogeneity in leaf stoichiometries between native and non-native plants in coastal wetlands, indicating that such differences should be emphasized in future biogeochemical models and plant-herbivore interaction studies owing to the important role of wetland plants in global C, N, and P cycles. Our findings increase understanding of plant-related nutrient and elements cycling in coastal wetlands, as well as improve predictions of plant growth rates and vegetation productivity across large scales under plant invasion scenarios. [ABSTRACT FROM AUTHOR]

Biodiversity is declining at unprecedented rates worldwide due largely to land use change and abnormal disturbance events. The high species diversity and endemicity found in California's coastal sage scrub (CSS) are especially at risk from urban development and ongoing disturbance. However, several CSS plant species have disturbance adaptations which may allow them to serve as vital resources for insect pollinators when native plant diversity is threatened. Common fiddleneck (Boraginaceae; Amsinckia menziesii var. intermedia) is one of the first annual forbs to germinate in CSS and as a result, it occurs in high density patches in early spring which temporarily creates a near monoculture. Although fiddleneck is a prominent CSS plant, particularly in areas that have experienced a disturbance event, its larger ecological role is not well explored. Therefore, we monitored ten sites across a disturbance gradient for two spring seasons to assess the composition of plant-pollinator networks in fiddleneck-dominated plots. We found fiddleneck supported a diverse pollinator community with 68% of recorded taxa visiting fiddleneck. The plants most frequently visited included two native annual forbs (common fiddleneck and Phacelia distans) and two invasive annual forbs (Erodium cicutarium and Brassica tournefortii). Increased mean precipitation resulted in increased plant abundance but decreased native pollinator diversity. Additionally, plant-pollinator networks changed over time; the number of links per species increased throughout the season but did not differ among disturbance types. Despite the numerical dominance of fiddleneck, CSS supported a diversity of pollinator taxa and exhibited complex plant-pollinator networks across the disturbance gradient. [ABSTRACT FROM AUTHOR]

To serve human needs, non-native species are selected based on an array of functional traits, which generally confer competitive advantages to these species in their recipient environments. Identifying non-obvious functional traits that indirectly inform human selection of non-natives to introduce into urban greenspaces is not yet part of common discussions in invasion biology. We tested whether functional traits integrated within a phylogenetic framework, may reveal those subtle criteria underlying the introduction of non-native plants into urban greenspaces. We found no differences in terms of functional traits between natives and non-natives. We also found no evidence that functional traits predict nectar production, irrespective of how nectar production was measured. Finally, we found that the mean sugar concentration of nectar per flower is evolutionarily shared both within closely related non-native plants as well as within close native plants. However, phylogenetically close species share similar intraspecific variation in mass of nectar sugar per flower, but this is true only for non-native plants, thus revealing a non-obvious selection criteria of non-native plants for urban greenspaces. Our results indicate that the phylogenetic patterns of intraspecific variation in mass of nectar sugar per flower is the major criterion distinguishing non-natives from native plants in urban greenspaces in Southern England. [ABSTRACT FROM AUTHOR]

Several studies have shown that invasive plant species respond more negatively to drought than native plant species, but little remains understood of how and whether drought‐rewetting events may affect growth of invasive and co‐occurring native plant species both directly and indirectly through soil microorganisms.In a fully crossed factorial design, we grew individuals of four congeneric pairs of invasive and native plant species in 2.5 L pots that contained live or sterilized field soil under one of three drought treatments: no‐drought, drought, drought‐rewetting.Results show that drought caused a significantly greater decline in total biomass of invasive plant species than that of native plant species regardless of the presence of live soil microorganisms. However, total biomass of the invasive plant species exhibited a greater recovery from drought following rewetting than did that of the native plant species. Moreover, recovery from drought in invasive plant species tended to be stronger in live soil than in sterilized soil, while for the native plant species, recovery from drought was stronger in sterilized soil than in live soil.Overall, these results suggest that in ecosystems that experience cycles of drought and rewetting, invasive plant species may grow larger than co‐occurring native plant species. Moreover, soil microorganisms may facilitate greater recovery from drought in invasive plant species than in co‐occurring native plant species. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

To serve human needs, non-native species are selected based on an array of functional traits, which generally confer competitive advantages to these species in their recipient environments. Identifying non-obvious functional traits that indirectly inform human selection of non-natives to introduce into urban greenspaces is not yet part of common discussions in invasion biology. We tested whether functional traits integrated within a phylogenetic framework, may reveal those subtle criteria underlying the introduction of non-native plants into urban greenspaces. We found no differences in terms of functional traits between natives and non-natives. We also found no evidence that functional traits predict nectar production, irrespective of how nectar production was measured. Finally, we found that the mean sugar concentration of nectar per flower is evolutionarily shared both within closely related non-native plants as well as within close native plants. However, phylogenetically close species share similar intraspecific variation in mass of nectar sugar per flower, but this is true only for non-native plants, thus revealing a non-obvious selection criteria of non-native plants for urban greenspaces. Our results indicate that the phylogenetic patterns of intraspecific variation in mass of nectar sugar per flower is the major criterion distinguishing non-natives from native plants in urban greenspaces in Southern England.

1. With evidence of significant global insect declines mounting, urgent calls to mitigate such declines are also increasing. Efforts to reverse insect declines will only succeed, however, if we correctly identify and address their major causes. 2. One potential cause that has received little mention is the global spread of non‐native plants as invasive species, agroforestry products, and ornamental plants. 3. Here we (a) review the theory predicting that most insect herbivores are evolutionarily constrained to use a fraction of available plant lineages; (b) document the extent to which nonnative plants have displaced native plant communities around the globe; (c) examine the evidence that non‐native plants reduce insect abundance and diversity; and (d) suggest guidelines for measuring the impact of non‐native plants on insect populations. 4. We conclude that host range expansions to non‐natives do occur among many insect herbivores but not at the frequency required to prevent insect declines when non‐native plants replace native plant communities. Accordingly, we suggest that curbing the spread and use of non‐ native plants at local, national, and international scales will be a necessary and effective way to reduce some insect declines. [ABSTRACT FROM AUTHOR]

Ecosystem property and function can be considerably altered by changes in agricultural land use. Despite the expansion of abandoned fields in temperate humid areas worldwide, little is known about how ecosystem C stock and its partitioning change with secondary succession, especially under the invasion of non-native, fast-growing plants. Using a paired-plot approach, we investigated how plant community type (native vs. non-native, the latter represented by Solidago altissima) influences temporal changes in ecosystem C pools in abandoned paddy fields. Thirty-seven plots of control (paddy) and abandoned (2–37 years of succession) pair having similar soil types under the humid temperate climate of Japan were selected for this study. We detected a net loss of ecosystem C in the first 15.2 years, followed by a gradual C gain. Apparent maximal C gain (up to 10 Mg C ha−1) was observed approximately 30 years after abandonment, based on a smooth spline model. The initial C loss was largely attributed to decomposition in mineral-associated soil C, owing presumably to the rapid decay of the C accumulated under temporally anaerobic paddy. While no detectable difference was found in the ecosystem C stock between plots dominated by S. altissima and native plants, the S. altissima-dominated plots showed significantly lower litter C stock. We therefore conclude that, despite the rapid growth and high aboveground biomass of S. altissima, its invasion did not increase ecosystem C storage in the studied region; these findings highlight the absence of ecological benefits associated with S. altissima invasion. [ABSTRACT FROM AUTHOR]

Seed dispersal by vertebrate animals is important for the establishment of many fleshy-fruited plant species. Different frugivorous species can provide different seed dispersal services according to their specific dietary preferences as well as behaviour and body traits (e.g. body size and beak size of birds). Our aim was to study redundancies and complementarities in seed dispersal and germination between the two main native seed disperser birds and the introduced silver pheasant Lophura nycthemera in the temperate Patagonian forests. For this, we collected fresh droppings from the studied species and analyzed seed content. We conducted germination trials for four plant species common in bird droppings; two native species (Aristotelia chilensis and Rhaphithamnus spinosus) and two invasive non-native species (Rubus ulmifolius and Rosa rubiginosa). Both native frugivorous birds and the silver pheasant dispersed fruits of non- native fleshy-fruited plants, but their roles were non-redundant in terms of species dispersed and effect on seed germination. The silver pheasant dispersed a proportionally high number of non-native seeds, while native birds dispersed a high number of native seeds. In addition, the effect of gut treatment in seed germination differed between seed dispersers. Native birds promoted the germination for the two native plant species studied, while the silver pheasant promoted the germination of one non-native plant. This suggests that seed dispersal by the silver pheasant may contribute to the spread of some invasive fleshy-fruited plants in the ecosystems that otherwise would not be dispersed by any other bird. The understanding of redundancies and complementarities on seed dispersal and germination between native and introduced birds will allow improving the management of fleshy-fruited non-native plants. [ABSTRACT FROM AUTHOR]

Questions: In the assessment of a soil seed bank at invaded sites, do sampling at different microsite types and use of different assessment methods yield different results, which may influence interpretation of management effectiveness and potential for native plant restoration? Location: Saguaro National Park, Arizona, United States. Methods: Seed bank samples were collected from two microsite types (below‐shrub canopies and interspaces between perennial plants) at plots within Pennisetum ciliare‐invaded and untreated sites, non‐invaded sites and sites with five frequencies of Pennisetum‐removal treatments. Seed bank samples were characterized by seedling emergence and seed extraction methods. Results: Assay method influenced whether we detected a significant Pennisetum‐removal treatment response on Pennisetum detected in the seed bank. A treatment response was not observed using the emergence method. Using the extraction method, we found that untreated Pennisetum plots contained significantly more Pennisetum seed than removal treatments. Treatments did not affect detection of native seed banks using either method. Microsite type only had an effect on seed detected using the emergence method, where more perennial species and seed densities were detected below shrubs. Native species richness and estimated seed densities using extraction were correlated with emergence results (r = 0.52, N = 42, p < 0.001 and r = 0.56; N = 42, p < 0.001, respectively). Conclusions: Results highlight several considerations for how different seed bank methods can influence interpretation of management treatments. Along with vegetation surveys, seed bank observations indicate that removal treatments successfully reduced Pennisetum in soil seed banks at invaded sites relative to invaded untreated sites. Natives were a significant proportion of seed banks, showing potential for native plants to establish after treatments of non‐native plants. Results suggest potential to calibrate seed bank methods with each other to reconcile differences. Because viability of extracted seed was uncertain, further analysis may be necessary to test which assay method best predicts future vegetation. Seed bank assays are often used to assess vegetation dynamics and conservation activities. We found that seedling emergence and seed extraction results differed for detection of the non‐native perennial grass Pennisetum ciliare (L.) Link (buffelgrass) along a removal treatment gradient. Results suggest that assay methods selected to assess seed banks can influence the interpretation of non‐native plant removal treatments. [ABSTRACT FROM AUTHOR]

[Display omitted] • Non-native plants mainly shifted upward, while native plants shifted downward. • The upper limit of both native and non-native plants showed different trends. • Non-native plants expanded their elevational range size, native plants shrank. • The climate suitability and change in upper/lower limits influence species' shifts. Species are changing their elevational distributions in response to climate change, leading to biodiversity loss and changes in community structure. Yet whether native and non-native species have consistent elevational shifts remains to be evaluated. Subtropical mountains are rich in biodiversity, sensitive to climate change, and are experiencing high risks of biological invasion. Hence exploring the changes in species elevational distributions induced by climate change in subtropical mountains is an urgent need. Here, we explored the impact of climate change on the elevational distribution of seed plant species in Jinfo Mountain (Mt. Jinfo), a subtropical mountain in China with rich plant diversity. Notably, we compared the elevational redistributions of native and non-native plants in response to climate change. The results showed that the elevational centroids of native plant species moved downhill, while those of non-native plants shifted upward on average. The upper limit of native plants shifted downward, while the upper limit of non-native plants shifted upward on average. The elevational shifts of non-native plants were dominated by changes in the upper range limits, while those of native plants were affected by the lower limits. These opposite elevational shifts of native vs non-native species led to the increase in the elevational range size of the non-native plants, but decrease in the elevational range size of native plants, especially in high altitudes. The differences in the directions and magnitudes of elevational shifts between the native and non-native plants are mainly due to differences in their climate adaptation. Changes in temperature and precipitation influenced the elevational range shifts of native plants but not of non-native ones. This study provides a new perspective for understanding the elevational redistribution of native and non-native plant species in subtropical mountains, and suggests that climate change has stronger influence on native than non-native species. [ABSTRACT FROM AUTHOR]

• There was stronger acceptance for native (98.5%) and cultivated (95.6%) plants. • Non-native and spontaneous plants were generally accepted by inquired professionals. • Information about NUE increased acceptance of non-native and spontaneous plants. • Design and management actions can improve NUE according to social expectations. • Landscape design/management professionals considered NUE relevant to climate change. [ABSTRACT FROM AUTHOR]

Aim Efforts to evaluate the impact of non-native plants on ecosystems rarely consider the role of such plants in sustaining local food webs of arthropods, or whether the effect is similar across arthropod feeding guilds and life stages. We assess this response by comparing arthropod herbivores on native plants (species with evolutionary histories within local food webs) and non-native plants (species without such histories). We further compare the impact of non-native plants that are congeners of local native species with those of non-natives with no close local relatives. Location Suburban landscapes, Mid-Atlantic United States (Delaware, Pennsylvania). Methods We manipulated the composition of the first trophic level by planting four large common gardens of 50 woody plant species replicated in time and space. After an establishment year, we sampled herbivorous arthropods supported by each plant species and classified them by herbivore species, feeding guild and life stage. Results We found that (1) native plants support larger and more diverse herbivore communities, (2) arthropods with chewing mouthparts and immature herbivores were more sensitive to plant origin than arthropods with piercing-sucking mouthparts and adult herbivores, (3) arthropods laid more eggs on native plants, (4) internal feeders were rare on all non-native plants and (5) the reduction in herbivore populations on non-native plants was smaller, but still significant, if species had a close native relative. Main conclusions Novel ecosystems comprised of plant species with no evolutionary history with local members of higher trophic levels may reduce the diversity and complexity of local food webs. Given the rate at which novel ecosystems are replacing coevolved plant communities worldwide, this result has global implications for the conservation of biodiversity. Using more native plants within human-dominated landscapes may help maintain the integrity of arthropod communities, as well as the populations of animals that consume arthropods. [ABSTRACT FROM AUTHOR]

Questions Most rivers in the Western Cape Province of South Africa are heavily invaded by alien trees, often resulting in profound changes in biodiversity and ecosystem functioning. Although large-scale management operations are underway to clear invasive trees and restore ecosystem function, little is known regarding native species recovery after alien clearing. Has Eucalyptus invasion along the Berg River altered the distribution and composition of native vegetation? How does the removal of invasive trees through complete clearing and thinning facilitate the recovery of native vegetation? Location Berg River, Western Cape, South Africa. Methods We assessed the recovery of native vegetation after 4 yr of complete clearing of the invasive tree Eucalyptus camaldulensis (100% alien cover removal) and thinning (40-50% alien cover removal) along the Berg River in the Western Cape, South Africa. Native and alien plant cover, species richness and diversity were recorded on completely cleared and thinned sites and compared to natural (non-invaded control sites) and E. camaldulensis invaded sites. Results Species richness and diversity were significantly higher in both completely cleared and thinned sites compared to natural and invaded sites. Increases in species richness and diversity in completely cleared and thinned sites were a result of re-invasion by alien herbaceous and graminoid species, which have the potential to hinder native species recovery. Cover of native trees and shrubs was higher in both completely cleared and thinned sites compared to invaded sites. Species composition (relative cover) in completely cleared and thinned sites was similar to species composition in natural sites. Conclusions Both complete clearing and thinning methods promote indigenous vegetation recovery and a positive trajectory towards recovery of ecosystem structure and composition can be expected in future. To improve management operations, a four-stage thinning process that has the potential to facilitate native species recovery is suggested. [ABSTRACT FROM AUTHOR]

Managed landscapes in which non-native ornamental plants are favored over native vegetation now dominate the United States, particularly east of the Mississippi River. We measured how landscaping with native plants affects the avian and lepidopteran communities on 6 pairs of suburban properties in southeastern Pennsylvania. One property in each pair was landscaped entirely with native plants and the other exhibited a more conventional suburban mixture of plants—a native canopy with non-native groundcover and shrubs. Vegetation sampling confirmed that total plant cover and plant diversity did not differ between treatments, but non-native plant cover was greater on the conventional sites and native plant cover was greater on the native sites. Several avian (abundance, species richness, biomass, and breeding-bird abundance) and larval lepidopteran (abundance and species richness) community parameters were measured from June 2006 to August 2006. Native properties supported significantly more caterpillars and caterpillar species and significantly greater bird abundance, diversity, species richness, biomass, and breeding pairs of native species. Of particular importance is that bird species of regional conservation concern were 8 times more abundant and significantly more diverse on native properties. In our study area, native landscaping positively influenced the avian and lepidopteran carrying capacity of suburbia and provided a mechanism for reducing biodiversity losses in human-dominated landscapes. [ABSTRACT FROM AUTHOR]

The Hawaiian Islands have lost nearly all their native seed dispersers, but have gained many frugivorous birds and fleshy-fruited plants through introductions. Introduced birds may not only aid invasions of exotic plants but also may be the sole dispersers of native plants. We assessed seed dispersal at the ecotone between native- and exotic-dominated forests and quantified bird diets, seed rain from defecated seeds, and plant distributions. Introduced birds were the primary dispersers of native seeds into exotic-dominated forests, which may have enabled six native understory plant species to become reestablished. Some native plant species are now as common in exotic forest understory as they are in native forest. Introduced birds also dispersed seeds of two exotic plants into native forest, but dispersal was localized or establishment minimal. Seed rain of bird-dispersed seeds was extensive in both forests, totaling 724 seeds of 9 native species and 2 exotics with over 85% of the seeds coming from native plants. Without suitable native dispersers, most common understory plants in Hawaiian rainforests now depend on introduced birds for dispersal, and these introduced species may actually facilitate perpetuation, and perhaps in some cases restoration, of native forests. We emphasize, however, that restoration of native forests by seed dispersal from introduced birds, as seen in this study, depends on the existence of native forests to provide a source of seeds and protection from the effects of ungulates. Our results further suggest that aggressive control of patches of non-native plants within otherwise native-dominated forests may be an important and effective conservation strategy. [ABSTRACT FROM AUTHOR]