Alien vascular plants in Iceland: Diversity,spatial patterns,temporal trends,and the impact of climate change

The present study provides first comprehensive and up-to-date results on alien plant taxa in Iceland since 1967. We evidenced the presence of 336 alien vascular plant taxa, including 277 casuals and 59 naturalised taxa, two being invasive. The distribution of the alien flora exhibits a clear spatial pattern showing hotspots of occurrence and diversity within areas of major settlement centres. Altitude above sea level and temperature-related variables proved to be the most important factors shaping alien plant distribution in Iceland. Predictive modelling evidenced that arctic areas of Iceland and the Central Highlands are under serious risk of alien plant invasion due to climate change. The results provide crucial information for alien and invasive plant management and contribute data for meta-analyses of invasion processes worldwide.     

The vascular flora of Rome

The aim of this paper is to document plant diversity in the metropolitan area of Rome (Italy) by providing a comprehensive inventory of the present-day vascular flora and an overview of its composition and species diversity. We compiled the floristic catalogue by including all vascular plant entities that occur spontaneously within the administrative boundaries of the Rome municipality. The data, which were gathered from extensive field surveys, from a broad review of the literature and from herbaria records, were updated and integrated in a comprehensive account. The inventory of the flora of metropolitan Rome lists 1649 entities, from 139 families and 677 genera. The flora contains 228 taxa that are non-native to the Italian flora, 81 of which are established in the study area. The overview of flora reveals a remarkable species diversity and outlines the main characteristics of the flora of Rome, which may be summarized as (1) a large number of taxa of high conservation value which occur in remnants of near-natural vegetation, (2) the loss or decline of some species, particularly of native freshwater plants, (3) a remarkably high native species richness within the urban area, which includes many native woody species and (4) a rich ruderal flora, prevalently composed of native species that are well adapted to human disturbance, along with a variety of taxa of non-native or uncertain origin. The large set of data and the overview presented in this paper represent a fundamental framework for future research and for the conservation of plant diversity in metropolitan Rome.     

中国外来植物数据集

搞清楚中国外来植物种类有哪些, 从哪里来, 如何进入中国, 属于什么性质的类群, 它们的生物学特征和生态学特性如何等问题, 是中国外来入侵植物预防和预警机制研究的重要基础。《中国植物志》、Flora of China、各省级植物志书等记载的外来植物信息由于种种原因非常有限, 且目前我国尚没有完整体现中国外来植物信息的数据库。本文通过整合近几年外来植物相关的资料, 并通过文献考证增补外来植物原产地、习性等信息, 利用计算机网络、数据库及大数据分析技术手段, 经信息化处理和分类学校正, 进行分类体系重建, 最终确定中国外来植物的物种名录数据集。该数据集共有数据14,710条, 记载中国外来植物283科3,233属14,710个类群(含13,401原种332杂交种2嵌合体458亚种503变种14变型)。每个类群包括类别、中文科名、科名、中文属名、属名、中文名、别名、学名、命名人、生存状态、生存时间、生活型、原产国家或地区和中国引入省份等基础信息。数据集显示, 外来植物已在中国的植物种类构成中占据了相当大的比例(高达28.19%, 中国境内有维管植物52,177个类群, 其中本土37,464, 外来14,710, 上述数字包含种下等级, 统计截至2021年12月31日); 就生存状态而言, 栽培植物占所有外来植物的比例高达91%, 逃逸植物占7.36%, 归化植物占6.69%, 入侵植物占2.66%; 对于生活型的分析显示, 多年生类群占据了外来植物的绝大多数(13,625种, 约占总数的92.6%), 草本植物(8,937种, 约占总数的60.8%)相较于乔木(2,752种, 约占总数的18.7%)、灌木(4,916种, 约占总数的33.4%)及其他生活型数量要更多; 中国的外来植物大多来自北美洲(4,242种)、非洲(3,707种)、南美洲(3,645种)、亚洲(3,102种), 欧洲(1,690种)和大洋洲(1,305种)相对较少; 而中国具有外来植物最多的前10个省份分别为台湾(6,122种)、北京(5,244种)、福建(3,667种)、广东(3,544种)、云南(3,404种)、上海(2,924种)、江苏(2,183种)、江西(1,789种)、浙江(1,658种)和湖北(973种)。本数据集是第一次对中国外来植物进行全面系统整理, 可供从事外来植物相关研究工作参考, 也可作为植物多样性研究的基础资料, 还可作为农业、林业、草业、园林、草药及自然保护和环境保护人士及高等院校师生的参考数据。     

An updated inventory of the non-native flora of Sardinia (Italy)

We provide an updated inventory of the non-native flora of the Italian island of Sardinia, including accepted names, family, synonyms, biological form, fruit type, introduction pathway and native origin. This inventory was performed by reviewing the available literature and conducting dedicated field surveys across the entire island. The inventory catalogues 931 non-native taxa, including 31 cryptogenic species, 901 species, 14 subspecies, 13 varieties, two forms and one cultivar. We utilised the position on the introduction–invasion continuum concept and meta-population criterion to further label each species. Based on these frameworks, the non-native flora of Sardinia can be divided into 274 casual, 169 naturalised, 19 invasive, 440 exclusively planted and 29 unobserved after 1950. There are 204 archaeophytes and 727 neophytes. The majority of the non-native species (791) were introduced to the island voluntarily, and 140 species were introduced accidentally. The present inventory identifies 72 additional non-native taxa not previously reported in the literature.     

The non-native vascular flora of the Falkland Islands

Summary

Non-native species form a significant, but under-recorded, component of the Falkland Islands vascular flora. With this in mind a comprehensive re vie w of the non-native flora of the Falkland Islands was undertaken for the first time since the publication of the definitive Flora in 1968. We have recorded 175 non-native taxa, from 46 families, from the Falkland Islands which are listed with accompanying notes on habitat, status and distribution. Twenty-nine of these are likely to be commonly encountered, though only Aira praecox, Cerastium fontanum, Rumex acetosella and Sagina procumbens are near ubiquitous throughout. The origins of much of the non-native flora are obscure, however most species seem to be of European descent, and a significant proportion of taxa seem to have become established after introductions for agricultural and horticultural purposes.     

The urban vascular flora of Palermo (Sicily,Italy)

Abstract

This article presents a comprehensive inventory of the urban vascular flora of the town of Palermo. The data were gathered from extensive field collections, from specimens kept in different herbaria, and publications of the last 30?years. The floristic catalogue includes all the vascular plants that occur spontaneously within the urban area. Thirteen taxa are endemic to Sicily and one of these, Clinopodium raimondoi, is exclusive to Palermo’s area. The inventory comprises 1052 taxa belonging to 119 families and 225 genera, and contains 170 taxa non-native to the Italian flora.     

Taxonomic and biogeographic patterns in the native and alien woody flora of Kashmir Himalaya,India

Biodiversity inventories unravel insightful taxonomic and biogeographic patterns that provide valuable inputs in guiding conservation practices and policymaking. Here we present an updated inventory of the native and alien woody flora of the Kashmir Himalaya, India, together with analyses of the patterns of taxonomic composition, geographic distribution, and invasion status of the alien species. The data was assembled from the floristic literature of the last two centuries, supplemented with herbarium records and validated by field surveys over the past decade. In total, the woody flora comprised of 520 species; out of these 322 species were native and 198 alien, yielding a proportion of 38% aliens. Amongst the natives, 16 species are on the IUCN red list 2009. While 37 genera included both native and alien species indicating a potential for hybrid formation, only 15 families were represented by alien species exclusively. Regarding the invasion status, presently 37 alien woody species are naturalized and 7 are invasive in the region. The results show that the Kashmir Himalaya harbours a diverse woody flora. It is concluded that a distinction between the native and the alien flora, as adopted in the present study, is crucial for a meaningful analysis of any biodiversity patterns. We predict that in the near future many alien woody species, presently naturalized in the region, can become serious plant invaders, and therefore need further research efforts and timely management.     

Alien flora of the Korean Peninsula

The Korean Peninsula has been divided into the countries of North and South Korea since 1948. This adoption of different political and socio-economic regimes has significantly changed economic activity and international exchange by those nations, thus affecting the introduction of alien plants. Our study objective was to provide a comprehensive, up-to-date inventory of the alien flora on the Korean Peninsula and to analyse how the partitioning between North and South Korea has influenced the numbers and status of those alien plants. We identified pre-1876 aliens that were brought to the Korean Peninsula before 1876, when Korea opened up to foreign countries, and also determined the post-1876 aliens that were introduced after 1876. Plants in the latter group were further classified into those that arrived before the outbreak of the Korean War in 1950 (1876–1950 aliens) and those introduced since then (post-1950 aliens). We investigated the regions of origin, family compositions, and invasion status of those alien taxa. In total, 504 alien taxa were identified, with 102 taxa being pre-1876 and 117 being 1876–1950 aliens. After the Korean War, the number of alien plants in South Korea more than doubled (276 taxa), whereas the number reported for North Korea was considerably lower (33 taxa). This might be due to enhanced economic activity and a larger human population in South Korea. Climatic differences as well as variations in the recording intensity for alien flora between North and South Korea may also have contributed to the large contrast in numbers of new alien species recorded during the last decades. Coordinated measures between the two nations are necessary if the spread of invasive alien plants onto the Korean Peninsula is to be reduced.     

An updated checklist of the vascular flora alien to Italy

An updated inventory of the vascular flora alien to Italy, providing details on the occurrence at regional level, is presented. The checklist includes 1597 species, subspecies, and hybrids, distributed in 725 genera and 152 families; 2 taxa are lycophytes, 11 ferns and fern allies, 33 gymnosperms, and 1551 angiosperms. 157 taxa are archaeophytes and 1440 neophytes. The alien taxa currently established in Italy are 791 (570 naturalized and 221 invasive), while 705 taxa are casual aliens, 4 are not assessed, 7 are of unknown regional distribution, 47 have not been confirmed in recent times, 3 are considered extinct or possibly extinct in the country, and 40 are doubtfully occurring in Italy. This checklist allows to establish an up-to-date number (9792) of taxa constituting the whole (native and alien) Italian flora.     

Alien and native birds in South Africa: patterns, processes and conservation

The spatial distribution of alien species richness often correlates positively with native species richness, and reflects the role of human density and activity, and primary productivity and habitat heterogeneity, in facilitating the establishment and spread of alien species. Here, we investigate the relationship between the spatial distribution of alien bird species, human density, and anthropogenic and natural environmental conditions. Next, we examined the relationship between the spatial distribution of alien bird species and native bird species richness. We examined alien species richness as a response variable, using correlative analyses that take spatial autocorrelation into account. Further, each alien bird species was examined as a response variable, using logistic regression procedures based on binary presence–absence data. A combination of human density and natural habitat heterogeneity best explained the spatial distribution of alien species richness. This contrasts with the results for individual alien species and with previous studies on other non-native taxa showing the importance of primary productivity and anthropogenic habitat modification as explanatory variables. In general, native species richness is an important correlate of the spatial distribution of alien species richness and individual alien species, with alien species being more similar to common species than to rare species.     

A review of the alien and expansive species of freshwater cyanobacteria and algae in the Czech Republic

The invasion and spread of non-native species of many different kinds of organisms is of increasing interest to researchers. Invasions by microscopic organisms, however, are poorly understood, and their impact on the environment is probably underestimated. We collected available data on non-native and invasive/expansive algae and cyanobacteria in the Czech Republic; we mapped their distribution and assessed their impact on local species and other real or potential risks resulting from their spread. The list of alien species in the Czech Republic contains 10 species of cyanobacteria, 9 species of Bacillariophyceae, 1 species of Dinophyta, 1 species of Ulvophyceae, 2 species of Chlorophyceae, and 1 species complex of Zygnematopyceae. The literature on the worldwide occurrence of these taxa is also reviewed.     

Nurse effect of the native cushion plant Azorella monantha on the invasive non-native Taraxacum officinale in the high-Andes of central Chile

Positive interactions among native plant species are common in alpine habitats, particularly those where one species (nurse plant) generates microclimatic conditions that are more benign than the surrounding environment, facilitating the establishment of other species. Nonetheless, these microclimatic conditions could facilitate the establishment of non-native species as well. A conspicuous component of the alien alpine flora of the central Chilean Andes is the perennial herb Taraxacum officinale agg. (dandelion). In contrast to other alien species that are restricted to human-disturbed sites, T. officinale is frequently observed growing within native plant communities dominated by cushion plants. In this study we evaluated if T. officinale is positively associated with the cushion plant Azorella monantha. Via seedling survival experiments and gas-exchange measurements we also assessed the patterns of facilitation between cushions and dandelions, and explore the potential mechanisms of invasion by dandelions. T. officinale grows spatially positively associated with cushions of A. monantha. Survival of seedlings, as well as their net-photosynthetic rates and stomatal conductance, were higher within cushions than in open areas away from them, suggesting that the microclimatic modifications generated by this native cushion facilitates the establishment and performance of a non-native invasive species. Our results, as well as other recent studies, highlight the role of native communities in facilitating rather than constraining non-native plant invasions, particularly in stressful habitats such as alpine environments.     

Influence of past land use and current human disturbance on non-native plant species on small Italian islands

Biological invasions are regarded as one of the main drivers of habitat degradation in island ecosystems. Mediterranean islands have been subjected to a high degree of land conversion over the past 60 years, resulting in a massive reduction in the amount of rural land and the sprawl of tourist activities. The aims of this paper are to evaluate the current level of invasion of alien plant species in semi-natural vegetation types that have developed after the abandonment of agriculture and to analyze the relationships between non-native species, native flora, and environmental characteristics. Two Italian islands (Ponza and Ventotene) were surveyed using a random-stratified sampling. The occurrence and relative cover of alien plant species were compared and separate analyses were performed for the native flora. Abundance patterns of both native and alien species were then studied in the light of the environmental and anthropogenic features. Although we found that some non-native species are extremely widespread, their relative cover at the plot level is low. Permutational Multivariate Analysis of Variance and Indicator Species Analysis revealed dissimilarities in the native species composition, while Mann–Whitney and Kruskal–Wallis tests showed differences in the ecological requirements (moisture, soil reaction, and nitrogen) of the native species pool. Canonical Correspondence Analysis pointed to the importance of the proximity to agricultural areas, human disturbance, and past land management, particularly residual terraces, in determining the difference between plant communities on the two islands. The results of our study suggest that traditional forms of agriculture may represent a key element for countering the establishment and spread of non-native plants in Mediterranean areas.     

Research into Plant Invasions in a Crossroads Region: History and Focus

The Czech Republic is a central European country whose geographical location, natural conditions, history of human settlement, and present land-use management make it relatively prone to plant invasions, hence it represents a convenient model for their study. Research in plant invasions, which date to the late 19th century, is reviewed in the present paper. A long-term floristic tradition allowed for the accumulation of a large body of floristic data on alien plants. During the 1960s–1970s, the main research focus was on their distribution. In this period, attempts were also made to predict potential invasiveness of weeds of arable land. The success rate of this prediction was about 39%. Considerable effort was put into a detailed classification of human-accompanying plants and the terminology associated with the issue. There is a high level of taxonomic research conducted in the country, and the new Flora of the Czech Republic treats the immigration status of taxa with reasonable care and detail. A complete, serious catalogue of the alien plants of the country has been published recently: there are currently 1378 alien plants (33.4% of the total flora). The core of present research in plant invasions is in ecological, biological, and biogeographical studies, focussed on (i) the history of invasion of particular species since their introduction, (ii) the role and importance of alien species in vegetation, including their participation in succession, and (iii) the major invasive species of the Czech flora and comparison of congeners. Reynoutria spp., Heracleum mantegazzianum, Oenothera spp., Pinus strobus, and Bidens frondosa are among the taxa most intensively studied in recent time. A complete list of 69 invasive plants in the Czech flora introduced after the year 1500 [following the definition of Richardson et al. (2000a) Diversity and Distributions 6: 93–107] is given. The available legal instruments relevant to the issue are reviewed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Atmospheric invasion of non-native pollen in the Mediterranean region

Most research on the impacts of plant invasion focuses on native plant performance, community structure, and ecosystem functioning. Some non-native species can also pose a risk to human health. One such risk is the allergenic nature of the pollen of some introduced plants. We examined whether patterns of airborne pollen differed between non-native and native taxa by summarizing data from seven Spanish Mediterranean localities monitored over 13 yr. The pollen spectra contained 27 native pollen taxa and 18 non-native taxa. Even though pollen from native taxa were more diverse and were present longer in the atmosphere than the non-native, in some years neither the prevalence of the two nor their weekly maximum pollen values differed significantly. However, maximum values for non-native taxa were found earlier in the season than for native pollen. A small percentage of non-native pollen includes pollen from introduced taxa that have not invaded natural habitats (e.g., ornamental plants). Non-native pollen has a larger proportion of allergenic pollen than native pollen. Therefore, the results reveal that the presence of non-native airborne pollen from naturalized and non-naturalized plant species increases the total amount of airborne allergenic pollen grains and the period of allergenic susceptibility.     

A review of phytoplankton composition within Chesapeake Bay and its tidal estuaries

Based on a continuous 20-year data base of monthly samplingin Chesapeake Bay and tidal regions of its major tributaries,1454 phytoplankton taxa have been identified in these waters.They represent a diverse assemblage of species with a dominantdiatom flora throughout the year, in addition to large seasonalrepresentation by chlorophytes, cyanobacteria, cryptophytesand dinoflagellates. Included among this flora were 34 potentialharmful or toxin producing species. The phytoplankton compositionsassociated with the seasonal successional patterns are discussed,in addition to characterizing the dominant floral relationships,with comparison to early composition records within the Bay.Several of the present day most common taxa were similar tothose reported in sediment cores from the Bay dating to periodsprior to European settlement. Comparison with collections made8 decades ago (1916–1922) within Chesapeake Bay indicatedseveral of the same dominant flora remain dominant today; however,their cell concentrations are now significantly greater alongwith an increased diversity of species compared with these earlierstudies.     

Non-native fishes and native species diversity in freshwater fish assemblages across the United States

The proliferation of non-native species in North American freshwater ecosystems is considered a primary threat to the integrity of native community structure. However, a general understanding of consistent and predictable impacts of non-native species on native freshwater diversity is limited, in part, because of a lack of broad-scale studies including data from numerous localities across multiple drainages. This study uses data from 751 localities collected during the United States Geological Survey (USGS) National Water Quality Assessment (NAWQA) program to examine the influence of non-native fish species on native freshwater fish assemblages across the United States. In general, no significant differences in native fish richness and diversity measures were detected between sites with only native species and sites containing non-native species. However, at sites with non-native species, the number of non-native species present was negatively correlated with native species richness and Shannon diversity and positively correlated with native evenness. Non-native piscivores were negatively correlated with native species richness and Shannon diversity and positively correlated with native evenness. Native piscivores were positively correlated with native richness and diversity and negatively correlated with native evenness at sites with only native species. Our results suggest that from a superficial perspective, native species richness and diversity are not different among sites with and without non-native species. However, when patterns of native species richness and diversity are examined at sites containing non-native species, correlations between non-native and native species richness and diversity imply the expected negative effect of invasive taxa. Additionally, non-native piscivores appear to have a significant negative effect on native taxa and possibly represent a novel selective force on naive native prey.     

Alien invasive neophytes of the Southeastern part of the Pannonian Plain

Floristic diversity in the Pannonian Plain is the result of mosaic habitat composition, characterized by steppes, saline meadows, and lowland forests along major rivers. In the last few centuries, the flora has become enriched by species introduced by human activities, such as colonization and industrialization. Presently it consists of nearly 1800 species. As a result of 30 years of field research as well as herbarium and literature searches, a list of invasive alien neophytes has been compiled and is presented here. The list includes 152 species, classified as either naturalized, casual, or unknown. One of the species is listed in Red Book of Serbian Flora. Eighty species are naturalized, and 61 are casual species. The majority of the introduced flora originates from North America (66) and the Old World (43). Most alien invasive species of the Southeastern part of the Pannonian Plain, were introduced accidentally by seed material or deliberately by nursery saplings. The annual and perennial herbaceous plants, which flower in the summer and summer-autumn periods, are represented in the greatest numbers. The alien flora was further analyzed with respect to taxonomy, life forms, pollination, and seed dispersal mode. The greatest number of alien species appears in anthropogenic and semi-natural habitats (59). In natural habitats, 45 invasive taxa were recorded, representing a conservation threat to biodiversity.     

An Extensive Alien Plant Inventory from the Inhabited Areas of Galapagos

Background

Plant invasions are causing habitat degradation in Galapagos. Problems are concentrated on the four inhabited islands. Plants introduced to rural areas in the humid highlands and urban areas on the arid coast act as foci for invasion of the surrounding Galapagos National Park.

Methodology/Principal Findings

Here we present results of the most comprehensive inventory to date of alien vascular plants in the inhabited areas of Galapagos. The survey was conducted between 2002 and 2007, in 6031 properties (97% of the total) on Floreana, Isabela, San Cristobal and Santa Cruz Islands. In total 754 alien vascular plant taxa were recorded, representing 468 genera in 123 families. Dicotyledons represented 554 taxa, monocotyledons 183, there were 7 gymnosperms and 10 pteridophytes. Almost half (363) of the taxa were herbaceous. The most represented families were Fabaceae (sensu lato), Asteraceae and Poaceae. The three most recorded species in the humid rural areas were Psidium guajava, Passiflora edulis and Bryophyllum pinnatum, and in the dry urban areas, Aloe vera, Portulaca oleracea and Carica papaya. In total, 264 (35%) taxa were recorded as naturalized. The most common use for taxa was ornamental (52%).

Conclusions/Significance

This extensive survey has increased the known alien vascular flora of Galapagos by 257 species, giving a ratio of alien to native taxa of 1.57∶1. It provides a crucial baseline for plant invasion management in the archipelago and contributes data for meta analyses of invasion processes worldwide. A repeat of the survey in the future would act as an effective early detection tool to help avoid further invasion of the Galapagos National Park.     

Alien flora in Calabria (Southern Italy): an updated checklist

Biological Invasions - An updated checklist of the Calabrian alien vascular flora is presented. By way of field, bibliographic, and herbarium research, we recorded 382 alien taxa (representing...