Casual Alien Research Articles

Novedades Para La Flora De La Argentina

Novelties for the Flora of Argentina. On the occasion of preparing the Flora of Cordoba, new records for the Argentinean flora have been registered as a result of intensive field trips and the revision of the main herbaria collections of the country. In this paper, three new records for the native flora and 17 for the introduced flora (casual aliens and naturalized species) of Argentina are presented. Descriptions, illustrations and a lectotypification are done. Furthermore, the presence of 10 introduced species is formally documented for the first time

A critical conspectus of Italian Lycopodiaceae

As a result of our work on the Lycopodiaceae account for the Critical Flora of Italy, a new, synonymic inventory of Italian taxa is presented, based on herbarium studies and critical re-examination of extant literature. Three genera with eight species are accepted: Huperzia (1 species), Lycopodiella (1), and Lycopodium (6). An additional, ninth species (Lycopodiella cernua) is listed as a casual alien. The genus Diphasiastrum, accepted in several recent works, is treated at sectional level within Lycopodium (three species and their three hybrids). Lycopodium lagopus ( = L. clavatum subsp. monostachyon) is a recent addition to the Italian flora. Images of five types and Internet URI of other six types are supplied. Dot distribution maps and a dichotomous key to Italian species are provided. It is shown that the family name Urostachyaceae (a family here not separated from Lycopodiaceae) was validly published and has priority over Huperziaceae, for which the oldest name, however, would be Phylloglossaceae.

A casual alien plant new to Mediterranean Europe: <em>Ceiba speciosa</em> (Malvaceae) in the suburban area of Palermo (NW Sicily, Italy)

Pasta, S., La Mantia, T. & Badalamenti, E. 2014. A casual alien plant new to Mediterranean Europe: Ceiba speciosa (Malvaceae) in the suburban area of Palermo (NW Sicily, Italy). Anales Jard. Bot. Madrid 71(2): e010. The abiotic and biotic characteristics of the first sites where floss silk tree behaves as a casual alien plant in the Mediterranean Europe are described. The species was probably first planted in botanical gardens of southern France few decades before mid XIX century. It was introduced in Palermo in 1896, a city which appears to match very well its climatic requirements. According to the available information on its biology and ecology in both its original and secondary range, the floss silk tree should not become an invasive alien plant in the Mediterranean. Nevertheless, several gaps need to be filled in order to increase our understanding of future trends of Ceiba speciosa in southern Europe, in particular, the eventual role of pollinators and seed dispersers outside the species’ natural range.

Zavlečené a invazní druhy hmyzu v České republice a jejich ekonomický a ekologický význam (Insecta)

A total of 383 alien insect species were registered in the Czech Republic, which represents 1.4% of local fauna. The most numerous taxonomic groups are Homoptera (116 species, 30.3%), Coleoptera (110; 28.7%) and Lepidoptera (37; 9.7%). The occurrence of 200 species (52.2%) are limited to closed heated spaces, casual aliens (28; 7.3%) infiltrate the outdoor environment for a short term only, 36 (9.4%) naturalized non-invasive species do not spread from the location of introduction, 50 (13.1%) species are post-invasive and 69 (18.0%) invasive. From the species registered, 61 (15.9%) are stored product pests (especially Coleoptera 36 species, Psocoptera 11, and Lepidoptera 9), 50 (13.1%) are plant pests indoors (especially Coccinea 33 species, Aphidinea 7, and Thysanoptera 6), 25 (i.e. 6.5% of aliens) are pests in agriculture, forestry, and in ornamental cultures, 15 species (3.9%) are important animal parasites, and 5 species (1.3%) can affect biodiversity. Of the remaining 227 species (59.3%), no economic or ecological effects were found. The origin of most of the species living eusynanthropically is in the tropics and subtropics; of the 155 naturalized (non-invasive, post-invasive, and invasive) species, 42 (27.1%) originate from the Mediterranean, 36 (23.2%) from North America, 28 (18.1%) from Central to Southwest Asia, 14 (9.0%) from East Asia, 13 (8.4%) from South and Southeast Asia, with the remaining 22 species (14.2%) coming from other areas.

Alien flora of the Garden Route National Park, South Africa

Invasive alien plants (IAPs) are regarded as the leading ecological threat to the recently established Garden Route National Park (GRNP) along the Cape south coast of South Africa. The extensive and long-standing presence of commercial forestry in the region has contributed substantially to the current load of IAPs in the area. The GRNP's fragmented, linear configuration and a multitude of anthropogenic and ecological disturbances in the landscape contribute to its susceptibility to alien plant invasion. In compiling a checklist of alien flora for the park, we recorded 244 species of alien plants in 77 families, of which 58% (141 species) have not been recorded for the region by the Southern African Plant Invaders Atlas. Of the GRNP alien plant species, 9% are casual aliens, 27% naturalised, 59% invasive, and 5% transformers. Among South African National Parks, the GRNP ranks second in terms of alien plant species richness and has the largest proportion of invasives and transformers for those parks where invasion status was recorded. Transformer species in the GRNP are almost exclusively tree species introduced from Australasia >100years ago for forestry purposes or sand stabilisation. Natural habitat within the park that is most threatened by IAPs is fynbos shrublands and riparian habitat. Our analysis indicates that the pressure of IAPs in the GRNP is escalating. Substantial and sustained management actions will be required to mitigate impacts from alien plant invasions in the GRNP. We identified species posing emerging or escalating threats that require improved control or regulation.

Alien Species of Lepidium in the Flora of Romania: Invasion History and Habitat Preference

The history of spread and habitat preferences during invasion of four alien species of Lepidium in Romania, namely L. densiflorum, L. oblongum, L. sativum, and L. virginicum are presented in this paper. The floristic records of these species, collected between 1816 and 2013, were used in the study. L. sativum was sporadically mentioned by earlier botanic references, as a casual alien plant in ruderal places. L. oblongum was reported from a single locality, but it may be considered a potential invader of ruderal habitats from southern regions. For L. densiflorum and L. virginicum, distribution maps were made in the Universal Transverse Mercator system, and exponential regression models were fitted to the cumulative number of records against time. Both L. densiflorum and L. virginicum are invasive in Romania, and their spread was initiated at the middle of last century. The slope of invasion curves, which was used as a measure of the invasion rate, did not differ significantly between the two invasive species. Although both L. densiflorum and L. virginicum were first reported in the North-West of the country, they followed different paths of migration in Romania. Ruderal habitats associated with railways played an important role in the invasion process of both species, but invaded habitats became more diversified over the time. Among the four species, only L. densiflorum tends to invade agricultural crops.

A New Polish Record of Dracocephalum Thymiflorum

Abstract Pliszko A., 2014: A new Polish record of Dracocephalum thymiflorum [Nauja Dracocephalum thymiflorum radvietė Lenkijoje]. - Both. Lith., 20(1): 64-66. The paper presents a new record of a rare casual alien Dracocephalum thymiflorum L. (Lamiaceae) in Poland. A small population consisting of 42 generative individuals of this species was found in May 2013 on railway embankment in Okuniowiec village near the northeastern boundary of the town of Suwałki in the Polish part of the Lithuanian Lakeland. The current distribution (according to the ATPOL cartogram grid) is given, and introduction pathways via railway transport and contaminated crop seed are recognized

Invasion status and risk assessment for Salvia tiliifolia, a recently recognised introduction to China

SummaryThis study corrected the misidentification of an alien species, Salvia tiliifolia, which had been incorrectly identified as S. dugesii (a synonym of S. melissodora) in China. The distribution of S. tiliifolia in China was surveyed and it was inferred that it was probably introduced into Kunming, Yunnan in the 1990s and then spread to adjacent counties of Yunnan and south‐western Sichuan Province. The Australian weed risk assessment (WRA) was used to evaluate its invasive status. To determine the validity of Australian WRA in China, another 25 exotics representing casual alien plants, naturalised plants and invasive plants were tested. The Australian WRA was validated as a legitimate approach in China. Salvia tiliifolia scored 14, falling into the category of invasive plants. While the distribution of S. tiliifolia is currently restricted to Yunnan and a small part of Sichuan and the species has not displayed an adverse impact on local environments yet, the WRA results indicated that the species was a high risk plant. It was recommended that local land managers should monitor this species and take measures to stop its continuing expansion or eradicate it if possible.

A new locality of Solidago ×niederederi Khek (Asteraceae) in Poland

Abstract Solidago ×niederederi is a natural hybrid between S. canadensis and S. virgaurea, which occurs sporadically in synanthropic habitats together with the parental species. The hybrid was reported from seven countries in Central and Northern Europe and its presence emphasizes the invasive character of S. canadensis. A new locality of the hybrid was found in Mieruniszki village in the Zachodniosuwalskie Lakeland in NE Poland in 2011 (ATPOL square: FB06). Solidago ×niederederi grew on fallow land, at the edge of planted birchen shrubbery and its population comprised two small clumps. Current data suggest that the hybrid is a casual alien in the Polish flora, however, it has the potential to become established by clonal growth or restricted sexual reproduction.

The casual, naturalised and invasive alien flora of Zimbabwe based on herbarium and literature records

Zimbabwe’s casual, naturalised and invasive alien plant species were analysed with regard to their habit, origin, mode or purpose of introduction and their invasion status in the country. This alien flora of 391 taxa belonged to 239 genera and 73 families, corresponding to 6.6% of the total flora of Zimbabwe. Of these, 153 (39.1%) plant species were casual aliens, 154 (39.4%) were naturalised and 84 (21.5%) were invasive species. Most invasions in terms of numbers of alien species were in the central and eastern parts of the country. Asteraceae (53 species), Poaceae (48 species) and Fabaceae sensu lato (49 species) families were prominent in all the floristic regions of the country. Annual and perennial herbaceous species formed the majority of life forms of the casual, naturalised and invasive alien flora of Zimbabwe. Genera with the highest number of alien species were Ipomoea with nine species, Acacia and Euphorbia with eight species each, Chenopodium and Senna with seven species each, Eucalyptus with six species, Oenothera, Physalis and Solanum with five species each. More than 49.6% of the alien plants in Zimbabwe originated primarily from South, Central and North America, followed by Europe (24.6%), Asia (23.8%), Africa (10.5%) and Australasia (5.9%).Conservation implications: This research provides baseline information and historical invasion patterns of casual, naturalised and invasive alien flora in Zimbabwe. This inventory is a crucial starting point in trying to understand and initiate the management of biological invasions. This is also important for monitoring new introductions and management of existing alien plants in Zimbabwe.

Impact of climate and land use type on the distribution of Finnish casual arable weeds in Europe

Hyvönen T, Glemnitz M, Radics L & Hoffmann J (2011). Impact of climate and land use type on the distribution of Finnish casual arable weeds in Europe. Weed Research51, 201–208.SummaryThe aim of the study was to explore the impact of climate and land use type on species richness and abundance of arable weeds found as casual aliens in Finland. We used an empirical data set collected along a European climate gradient, from which 163 plants were selected for the analyses. Using generalised linear modelling (GLMM) and redundancy analysis (RDA), we compared species richness and abundance of all species and three functional groups (dicotyledons and grasses, C3 and C4 species, alien and native species to Europe), as well as occurrence of the 13 most common individual species between three land use types (fallow, low‐input and conventionally cultivated) and six regions. In general, fallowing and low‐input cultivation, as well as warmer climate, supported greater weed species richness and abundance. Temperature was found to be a more important factor for weed abundance than land use. The only exception was C4 species richness, which did not respond to either factor. The impact of land use was independent of climate for all variables, except C4 species abundance. Non‐cultivated fallows had more weeds than cultivated fields, in most cases. No difference was found in the species richness and abundance of grasses or in the occurrence of individual species between low‐input and conventionally cultivated fields. It was evident that climate and land use affect the distribution of arable weed species currently found as casual aliens in Finland. This suggests that climate warming will increase the risk of the population establishment of new weed species in northern regions.

Contrasting response of native and alien plant species richness to environmental energy and human impact along alpine elevation gradients

ABSTRACTAim We tested whether the species–energy and species–human relationships vary between native and both naturalized and casual alien species richness when other environmental variables had been taken into account.Location Trento Province, a region (c. 6200 km2) on the southern border of the European Alps (Italy), subdivided into 156 contiguous (c. 37.5 km2) cells and ranging in elevation from 66 to 3769 m.Methods Data were separated into three subsets, representing richness of natives, naturalized aliens and casual aliens and separately related to temperature, human population and various environmental correlates of plant species diversity. We applied ordinary least squares and simultaneous autoregressive regressions to identify potential contrasting responses of the three plant status subsets and hierarchical partitioning to evaluate the relative importance of the predictor variables.Results Variation in alien plant species richness along the region was almost entirely explained by temperature and human population density. The relationships were positive but strongly curvilinear. Native species richness was less strongly related to either factor but was positively related to the presence of calcareous bedrock. Native species richness had a decelerating positive relationship with temperature (R2= 55%), whereas naturalized and casual aliens had a positive accelerating relationship explaining 86% and 62% of the variation in richness, respectively. Native species richness had a positive decelerating relationship with population density (R2= 42%), whilst both alien subsets had a positive accelerating relationship.Main conclusions Alien species richness was higher in areas with the most rich and diverse assemblages of native species. Areas at high altitudes are not especially prone to alien invasion due to energy constraints, low propagule pressure and disturbance, even considering a potential increased in temperature. Thus, if we consider future environmental change, we should expect a stronger response of aliens than natives in the currently warm, urbanized, low‐altitude areas than in cold, high‐altitude areas where human population density is low.

An Assessment of Stakeholder Perceptions and Management of Noxious Alien Plants in Spain

Despite biological invasions being a worldwide phenomenon causing significant ecological, economic, and human welfare impacts, there is limited understanding regarding how environmental managers perceive the problem and subsequently manage alien species. Spanish environmental managers were surveyed using questionnaires to (1) analyze the extent to which they perceive plant invasions as a problem; (2) identify the status, occurrence, and impacts of noxious alien plant species; (3) assess current effort and expenditure targeting alien plant management; and, finally, (4) identify the criteria they use to set priorities for management. In comparison to other environmental concerns, plant invasions are perceived as only moderately problematic and mechanical control is the most valued and frequently used strategy to cope with plant invasions in Spain. Based on 70 questionnaires received, 193 species are considered noxious, 109 of which have been the subject of management activities. More than 90% of species are found in at least one protected area. According to respondents, the most frequently managed species are the most widespread across administrative regions and the ones perceived as causing the highest impacts. The perception of impact seems to be independent of their invasion status, since only half of the species identified as noxious are believed to be invasive in Spain, while 43% of species thought to only be casual aliens are causing a high impact. Records of management costs are poor and the few data indicate that the total actual expenditure amounted to 50,492,437 euros in the last decade. The majority of respondents stated that management measures are insufficient to control alien plants due to limited economic resources, lack of public awareness and support, and an absence of coordination among different public administrations. Managers also expressed their concern about the fact that much scientific research is concerned with the ecology of alien plants rather than with specific cost-efficient strategies to manage alien species.

Alien species in the Finnish weed flora

The present study aimed at assessing the invasion of alien weed species in Finland based on a review of their occurrence in the Finnish weed flora. The evaluation was conducted for the three phases of the invasion process, i.e. introduction, naturalization and invasion. The literature review revealed that 815 alien weed species occur in Finland of which 314 are regarded as naturalized. Based on their occurrence in different climate zones, the risk of naturalization of new harmful alien weed species was deemed low for those species not currently found in Finland, but higher for species occurring as casual aliens in Finland. In the latter group, 10 species of concern were detected. Exploration of the distribution patterns of naturalized species within Finland revealed species occupancy to be dependent on the residence time of the species. Established neophytes can be expected to extend their ranges and to increase occupation of agricultural habitats in the future.;

Invasive, naturalized and casual alien plants in southern Africa: a sum­mary based on the Southern African Plant Invaders Atlas (SAPIA)

The primary objective of this publication is to provide an overview of the species identity, invasion status, geographical extent, and abundance of alien plants in South Africa, Swaziland and Lesotho, based on field records from 1979 to the end of 2000. The dataset is all the species records for the study area in the Southern African Plant Invaders Atlas (SAPIA) database during this time period. A total of 548 naturalized and casual alien plant species were catalogued and invasion was recorded almost throughout the study area. Most invasion, in terms of both species numbers and total species abundance, was recorded along the southern, southwestern and eastern coastal belts and in the adjacent interior. This area includes the whole of the Fynbos and Forest Biomes, and the moister eastern parts of the Grassland and Savanna Biomes. This study reinforces previous studies that the Fynbos Biome is the most extensively invaded vegetation type in South Africa but it also shows that parts of Savanna and Grassland are as heavily invaded as parts of the Fynbos. The Fabaceae is prominent in all biomes and Acacia with 17 listed species, accounts for a very large proportion of all invasion. Acacia mearmii was by far the most prominent invasive species in the study area, followed by A. saligna, Lantana camara, A. cyclops, Opuntia ficus-indica. Solarium mauritianum, Populus alba/xcanescens, Melia azedarach, A. dealbata and species of Prosopis.

Comparison of native and alien plant traits in Mediterranean coastal dunes

This study is part of a general project to analyse the biological and ecological mechanisms that influence the invasion of Mediterranean sand dune ecosystems by alien plants. In this paper we analyse the morphological and functional traits of coastal dune wild species (natives and aliens) based mainly on information from the literature. The most common 130 wild species occurring on the recent (Holocenic) coastal dunes were included considering the invasive status of alien plants. A comparative analysis of functional groups was performed through ordination techniques (PCoA using the Gower index). This reveals four functional groups related to the most important plant communities in coastal vegetation zonation. Alien plants were found in all functional groups and no trait or set of traits was specifically related to them. This indicates that aliens show similar traits to those natives growing in different communities of the coastal dune zonation, from the small beach annuals to the evergreen taller shrubs of the Mediterranean macchia. When the invasive status of alien species was taken into account, however, some differences emerged: a) casual aliens were found in almost all groups but their traits were not interpreted as being due to any particular adaptive strategy; b) naturalised aliens were only found in the less fluctuating habitats of the inner coastal zones; c) invasive alien species were connected with two major plant strategies: annual invasive aliens (quick-to-mature low grasses and herbs) and perennial invasive aliens (taller and often strongly clonal).

Predicting invasions by woody species in a temperate zone: a test of three risk assessment schemes in the Czech Republic (Central Europe)

ABSTRACTTo assess the validity of previously developed risk assessment schemes in the conditions of Central Europe, we tested (1) Australian weed risk assessment scheme (WRA; Pheloung et al. 1999); (2) WRA with additional analysis by Daehler et al. (2004); and (3) decision tree scheme of Reichard and Hamilton (1997) developed in North America, on a data set of 180 alien woody species commonly planted in the Czech Republic. This list included 17 invasive species, 9 naturalized but non‐invasive, 31 casual aliens, and 123 species not reported to escape from cultivation. The WRA model with additional analysis provided best results, rejecting 100% of invasive species, accepting 83.8% of non‐invasive, and recommending further 13.0% for additional analysis. Overall accuracy of the WRA model with additional analysis was 85.5%, higher than that of the basic WRA scheme (67.9%) and the Reichard–Hamilton model (61.6%). Only the Reichard–Hamilton scheme accepted some invaders. The probability that an accepted species will become an invader was zero for both WRA models and 3.2% for the Reichard–Hamilton model. The probability that a rejected species would have been an invader was 77.3% for both WRA models and 24.0% for the Reichard–Hamilton model. It is concluded that the WRA model, especially with additional analysis, appears to be a promising template for building a widely applicable system for screening out invasive plant introductions.

The alien flowering plants of Mexico

ABSTRACTA list of 618 species of alien flowering plants recorded for Mexico is presented; they are distributed in 355 genera and 87 families. The families with the largest number of species are Poaceae (171), Fabaceae sensu lato (57), Asteraceae (56), and Brassicaceae (45). The representation of most families with alien species in Mexico agrees with the average distribution frequencies estimated by Pysek (1998) for 26 floras throughout the World. Exceptions are an under‐representation of Asteraceae and an over‐representation of Poaceae. Most alien species (78.9%) in Mexico have their origin in the Old World; South America ranks second with 9.6%. As defined by Richardson et al. (2000), 19.8% of the alien species could be considered casual aliens and 80.2% of them naturalized. The proportion of alien species relative to the 22,968 native flowering plant species recorded for Mexico is 2.7%.

New Infrageneric Taxa and Combinations in Chenopodium L. (Chenopodiaceae)

New Infrageneric Taxa and Combinations in Chenopodium L. (Chenopodiaceae)