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Abstract

Attempts to predict which species will become invaders and those which will not, represent one of the main areas of interest in the study of biological invasions. At present, however, only very limited generalizations are available, based on plant physiology, genetics, demography, species behaviour in other countries, or behaviour of congeneric species. Here I report that invasiveness of pines (genus Pinus) and, very likely, other woody species of seed plants in disturbed landscapes, is predictable on the basis of a small number of attributes: small mean seed mass, short juvenile period, and short mean interval between large seed crops. Moreover, vertebrate dispersal is responsible for success of many woody invaders in disturbed as well as 'undisturbed' habitats. As for herbaceous species, their primary (native) latitudinal range seems to be the best predictor of invasiveness, at least for species introduced from Eurasia to North America.

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... Les chercheurs (Cronk et Cet intérêt a fait l'objet de plusieurs définitions caractérisant le statut ou encore le niveau d'invasion de l'espèce. Les définitions attribuées aux espèces invasives varient à l'échelle mondiale selon les auteurs (Muller, 2004 ;Pyšek, 1995 ;Pyšek, et al., 2004 ;Cronk & Fuller, 1995 ; Williamson & Fitter, 1996a, b). Elles font l'objet de nombreuses controverses (Menozzii, 2010) dans la littérature (articles, revues, dictionnaires), dans la communauté scientifique, mais également au niveau de la population. ...
... Les auteurs européens décrivent l'indigénat en fonction de deux critères. Ce statut est attribué à des taxa selon leur date d'introduction sur un territoire donné (avant ou après 1 500 ans après J.C.) et/ou une période d'observation de l'espèce dans une même station sur ce territoire (supérieure ou égale à 10 ans d'observations) (Pyšek, 1995 ;Rejmànek, 1995 ;Binggeli, 1994 ;Prach & Wade, 1992). ...
... Le critère d'indigénat repose essentiellement sur la notion de situation géographique d'un taxon. Cette appartenance à la région ou à la surface donnée [avant le début de la période néolithique (Heywood & Brunel, 2009 ;Pyšek, 1995 ;Webb, 1985)], lui est totalement naturelle, sans l'intervention de l'homme. Ces espèces font référence à des taxa ou à des cortèges floristiques natifs d'un territoire biogéographique ou d'espèces indigènes (ou autochtones) de territoires voisins qui se situent dans la région donnée ou ont migré dans cette zone sans l'intervention de l'Homme (Levy, et al., 2015 ;Cordier, et al., 2010 ;Brun, 2007 Il s'agit de plantes qui se développent hors de leurs aires naturelles grâce à l'activité humaine. ...
Thesis
Le développement économique (industrialisation, échanges commerciaux) et social (accroissement des besoins humains) représente une menace importante pour la biodiversité. Il a conduit à l’introduction d’espèces végétales dans de nouveaux territoires. En franchissant les barrières écosystémiques (environnementale, reproductive et de dispersion), certaines d’entre elles parviennent à devenir invasives. Les invasions biologiques sont la cause de l’extinction d’un grand nombre d’espèces végétales (indigènes et/ou endémiques). En Martinique, les forêts font l’objet d’une grande anthropisation qui facilitent l’installation d’espèces introduites dont certaines deviennent potentiellement invasives. Afin de déceler les éventuels impacts de ces espèces potentiellement invasives sur les populations de taxa indigènes, une campagne d’inventaires floristiques a été menée en Martinique. L’objectif principal était de les identifier et d’évaluer leur état d’évolution sur l’île. Dans le cadre de cette thèse, les recherches bibliographiques (revues scientifiques, rapports, thèses, flores) et les nombreux relevés de terrain menés, nous avons permis de définir leur profil écologique. Les données recueillies ont également été analysées à l’aide d’indices écologiques. Les zones où les espèces potentiellement invasives seraient les plus virulentes ont été déterminées à partir de leurs affinités écologiques en s’appuyant sur des cartes SIG (Système d’Information Géographique). Cette analyse nous a permis de déterminer la chorologie des espèces potentiellement invasives. Ce taxa colonisent aussi bien les formations végétales naturelles ou non et leur essor dépend fortement de l’activité anthropique. Ils se développent dans tous les étages bioclimatiques (inférieur, moyen et supérieur) et à différents stades d’évolution.
... A principios del siglo XX se acumularon conocimientos del proceso de invasión de especies y éstos se consideraron como parte de una subdisciplina de la ecología, pero en el último cuarto de siglo, la ecología de la invasión se convirtió en una de las ramas de esta ciencia, desarrollándose rápidamente (Pysek, 1995(Pysek, , 1998(Pysek, , 2003Williamson, 1996Williamson, , 2002. Como la invasión de las especies exóticas es un fenómeno global que ocasiona graves consecuencias ecológicas, económicas y sociales (David et al., 2000) se creó un Programa Internacional coordinado por SCOPE (Drake et al., 1989) y el Programa Global de Especies Invasoras (GISP; Mooney, 1999;Mooney y Hobbs, 2000;McNeeley et al., 2001). ...
... A principios del siglo XX se acumularon conocimientos del proceso de invasión de especies y éstos se consideraron como parte de una subdisciplina de la ecología, pero en el último cuarto de siglo, la ecología de la invasión se convirtió en una de las ramas de esta ciencia, desarrollándose rápidamente (Pysek, 1995(Pysek, , 1998(Pysek, , 2003Williamson, 1996Williamson, , 2002. Como la invasión de las especies exóticas es un fenómeno global que ocasiona graves consecuencias ecológicas, económicas y sociales (David et al., 2000) se creó un Programa Internacional coordinado por SCOPE (Drake et al., 1989) y el Programa Global de Especies Invasoras (GISP; Mooney, 1999;Mooney y Hobbs, 2000;McNeeley et al., 2001). ...
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The intense anthropic activities in cattle grasslands in the Reserva de Biosfera-Sierra del Rosario‖ (Biosphere Reserve-Sierra del Rosario‖) cause strong disturbance and therefore typical plant communities including alien species establish themselves readily. In order to acknowledge the degree of invasion of these foreign species five grasslands in the southern region of the Biosphere having different uses (traditional sensu lato and traditional with extraction of spiny, toxic and/or poisoning species , culture practices, introduction of foreign species and fertilization with cattle manure) were selected. A correlation analysis using 59 biological and ecological variables was performed as well as a simple linear regression for elucidating the trends of independence relations among species. Results show that the variables allowing invasion capacity of alien species are: palatability, absolute abundance of species, frequency, production of seeds, growth of individuals, reproductive effort and defense, reproductive and vegetative potentials.
... Parmi les espèces du genre Pinus, le pin maritime (P. pinaster) est particulièrement préoccupant (Tassin et al., 2009 ;Pyšek et al., 1995). Il est classé parmi les cinq pins les plus invasifs dans le monde (Pyšek et al., 1995). ...
... pinaster) est particulièrement préoccupant (Tassin et al., 2009 ;Pyšek et al., 1995). Il est classé parmi les cinq pins les plus invasifs dans le monde (Pyšek et al., 1995). Nos résultats démontrent le lien entre incendie et invasion par le pin maritime (figure 6) ainsi que sa capacité à s'accommoder des conditions du milieu de plus en plus contraignantes dans ce contexte de changement climatique, ce qui confirme son grand potentiel invasif que ce soit dans son aire naturelle ou ailleurs. ...
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Plusieurs subéraies du Nord-Est algérien sont sujettes à une invasion par le pin maritime. Cette dynamique forestière qui a débuté dans les années 1980 est souvent citée parmi les facteurs de dégradation des subéraies algériennes mais n’a encore jamais fait l’objet de recherche. L’objectif de notre étude, qui porte sur le cas de la subéraie de Haddada (wilaya d’El-Tarf), était d’identifier les déterminants de l’invasion par le pin maritime, Pinus pinaster Ait., en recourant à une cartographie chorologique de facteurs tels que la pente, l’exposition et les surfaces incendiées en 1994, ainsi qu’une cartographie de la subéraie avant et après l’invasion. L’élaboration des cartes a suivi une approche géomatique complétée par des enquêtes sur le terrain. La cartographie montre que les parties envahies par le pin maritime sont celles qui ont été le plus touchées par l’incendie de 1994, ce qui correspond aussi aux pentes fortes et très fortes. La faible résilience du chêne-liège, Quercus suber, dans ces conditions a permis au pin maritime de le supplanter. Cette dynamique illustre bien le paradigme patch dynamics dans une forêt méditerranéenne, et nous renseigne aussi sur le potentiel invasif du pin maritime, s’agissant d’une espèce se révélant également invasive ailleurs dans le monde. Le changement climatique risque d’accentuer ces processus d’invasion.
... Parmi les espèces du genre Pinus, le pin maritime (P. pinaster) est particulièrement préoccupant (Tassin et al., 2009 ;Pyšek et al., 1995). Il est classé parmi les cinq pins les plus invasifs dans le monde (Pyšek et al., 1995). ...
... pinaster) est particulièrement préoccupant (Tassin et al., 2009 ;Pyšek et al., 1995). Il est classé parmi les cinq pins les plus invasifs dans le monde (Pyšek et al., 1995). Nos résultats démontrent le lien entre incendie et invasion par le pin maritime (figure 6) ainsi que sa capacité à s'accommoder des conditions du milieu de plus en plus contraignantes dans ce contexte de changement climatique, ce qui confirme son grand potentiel invasif que ce soit dans son aire naturelle ou ailleurs. ...
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A number of cork oak woods in north-eas�tern Algeria are being invaded by mari�time pines. These forest dynamics began in the 1980s and although they are often cited as one of the factors of degradation of Algeria’s cork oak woods, they have never been researched. The aim of our study, on the cork oak woods of Had�dada (wilaya of El-Tarf) was to identify the determinants of invasion by the maritime pine, Pinus pinaster Ait., by chorological mapping of factors such as slopes, expo�sure and areas burned by wildfires in 1994, together with mapping of the cork oak woods before and after the invasion. The maps were produced by applying a geomatics approach supplemented by ground surveys. The maps show that the areas invaded by maritime pine are those that were most affected by the fires of 1994, which are also those on steep and very steep slopes. The low resilience of cork oaks, Quercus suber, in such conditions has allowed maritime pines to supplant them. These dynamics are a good illustration of the “patch dynamics” paradigm in Mediterranean forests and also show the invasive potential of mari�time pine, which has been shown to be equally invasive elsewhere in the world. The invasion process is likely to be accen�tuated by climate change
... Darwin (1859) Adaptação das espécies a partir da modificação de seus traços biológicos por meio de fluxos gênicos e naturalização de genótipos Baker e Stebbins (1965) Invasividade das espécies e invasibilidade dos ambientes Elton (1958) Potencial invasor de espécies não-indígenas na dependência das suas necessidades biológicas Drake et. al., (1989) Susceptibilidade do meio à receptividade de espécies exóticas na dependência do grau de pobreza dos ecossistemas Groves e Di Castri (1991) Conservação biológica: manejo e restauração de áreas invadidas Pyšek et al. (1995) Regra dos 10% (Tens Rule) Williamson (1996) Foi proposta uma regra geral das condições para ser considerado o sucesso da invasão biológica (WILLIAMSON, 1996): ...
... Desde a década de 60 inúmeros modelos teóricos vem sendo desenvolvidos visando a identificação e a análise dos principais problemas encontrados nos territórios invadidos por espécies exóticas, bem como a proposição de alternativas que indiquem caminhos para a construção de um ambiente natural sustentável, contemplando as estratégias propostas pelo SCOPE. São destaque os trabalhos de Charles Darwin, 1859, On The Origin of Species (DARWIN, 1859); de Charles Elton, 1958, The Ecology of Invasions by Animals and Plants (ELTON, 1958); o trabalho de Hebert Baker e Leyard Stebbins (1965), The Genetics of Colonizing Species (BAKER; STEBBINS, 1965); o trabalho de James A. Drake e colaboradores (SCOPE), 1989, Biological Invasions: A Global Perspective (DRAKE et al., 1989); o trabalho de Bill Jordan (WILLIAN R. JORDAN III), de 1990, Restoration and Management Notes (atual Journal of Ecological Restoration), e Restoration Ecology: A Synthetic Approach to Ecological Research (JORDAN III et al., 1990); e a obra de Richard H. Groves e Francesco Di Castri, 1991, Biogeography of Mediterranean Invasions (GROVES; DI CASTRI, 1991).Na ciência da invasão moderna (pós 1990), destaque para os modelos teórico-conceptuais e hipóteses científicas de: NentwigWolfgang (1993), Biological Invasions (WOLFGANG, 1993; PetrPyšek et al. (1995); Plant Invasions. General Aspects and Special Problems (PYŠEK et. ...
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Invasão biológica é um processo de degradação dos ecossistemas causado pela proliferação de espécies exóticas no ambiente. O sucesso desse processo dependerá das características abióticas do ambiente (invasibilidade) e das características biológicas da espécie (invasividade). Em Portugal e no Brasil a preocupação com o assunto é significativamente recente e decisões quanto ao manejo de espécies invasoras têm sido tomadas sem o conhecimento suficiente, gerando impactos. Espécies invasoras têm ampla diversidade funcional, que, associada às condições eco-geográficas dos territórios, parece aumentar a sua capacidade de invadir ambientes naturais. Este trabalho objetiva primordialmente apresentar as bases teóricas e metodológicas que dão suporte a um projeto de pesquisa em andamento sobre invasões biológicas; o projeto em questão tem por objetivos: (i) modelar a distribuição espacial, e (ii) caracterizar a suscetibilidade a invasão por uma espécie exótica invasora comum aos ambientes litorais de Portugal e do Brasil, através da (1) avaliação dos caracterizadores estruturadores dos territórios (uso das terras, condições do relevo, balanço hídrico, contexto socioambiental), e (2) análise dos atributos funcionais da espécie. A australiana Acacia longifolia (Fabaceae), a espécie invasora, é uma árvore leguminosa costeira originária do Sudeste da Austrália, que foi introduzida em Portugal para fins ornamentais e fixação de dunas litorais no início do século XIX, pelo menos um século antes que no Brasil, sendo esperadas diversificações da espécie e do território entre os países. Para caracterizar a diversidade funcional da planta, a metodologia do projeto em epígrafe baseia-se em trabalhos de campo, separadamente em cada país, avaliando-se tipos morfológicos (tipo, tamanho, peso das folhas e dos frutos/vagens, período de floração, e outros). Para modelar a distribuição espacial, será montado um Sistema de Informação Geográfica (SIG), em sistema de posicionamento geográfico (software ArcGIS), a partir do qual serão incorporados dados georreferenciados sobre a presença/abundância das espécies. Esta é uma rara oportunidade para comparar o funcionamento de uma espécie invasora com uma distribuição global em climas mediterrânicos e tropicais, sendo que nos dois países serão estudados os sistemas costeiros litorais.
... Against the ideal of value-free science, the terminology concerning introduced species reflects a conservation bias. Cronk and Fuller (1995) Although many different defintions of the term 'invasive' are in use, most of them include a tendency for the species to expand and this expansion is seen as bearing negative consequences for the native flora and fauna (Pysek 1995). The same is true for the term 'neophyte', which is prevalent in Central Europe. ...
... Elton's term 'invasion' has been criticized as militaristic from the very beginning of the SCOPE programme (Groves and Burdon 1986). Nevertheless, it is still the most common term in articles explicitly dealing with non-indigenous plants (PYSEK 1995 To term a plant species 'invasive', due to this common meaning of the term, evokes the idea that its expansion has to do with aggression and destruction. The ability of an introduced plant to successfully colonize new areas, and outcompete other species, still is characterised as "aggressiveness" in many texts (e.g. ...
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There is a tendency among ecologists to regard biological invasions as obviously negative. To question value-judgements based on 'ecological evidence' I present an analysis of the impact of non-scientific values and norms on the scientific writing about introduced plants. Special concern is given to the suspicion of a xenophobic bias. Scientific terms like 'alien' or 'invasion' bear negative connotations that might influence perception and evaluation. Furthermore, the terminology often reflects a conservation bias. Like the term 'weed' the terms 'invasive' or 'neophyte' denote interference with conservation or management goals. The concept of the plant community also influences assessments. In an organism-like community, intruders necessarily are seen as afflicting the health or integrity of the whole. The concept of disturbance or the hypothesis of natural stability refer to an ideal of nature as a harmonic cosmos. From this perspective, human interventions necessarily are conceived as destructive. Conservationists tend to idealize pristine nature as intrinsically good, harmonic and stable. The opposite image of a nature 'red in teeth and claws' suggests that nature must be controlled and subjected by humans. As spreading introduced plants are neither pristine nor controllable, they are conceived as negative from the perspective of conservation. I claim that the replacement of original vegetation by a new species may not per se be assessed negatively, but needs further reasons. The conservation of biodiversity or endangered species is a reasonable argument, the preference for natives is not.
... The distinctions between them are quite subtle and result from differing viewpoints. According to Rejmanek (1995), weeds interfere with human land use; colonizers are successful at establishing following disturbance; and invaders are species introduced into their non-native habitat. There is substantial overlap among these terms. ...
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This study consolidated our understanding on the weeds of Bhadrak district, Odisha, India based on both bibliographic sources and field studies. A total of 277species of weed taxa belonging to 198 genera and 65 families are reported from the study area. About 95.7% of these weed taxa are distributed across six major superorders; the Lamids and Malvids constitute 43.3% with 60 species each, followed by Commenilids (56 species), Fabids (48 species), Companulids (23 species) and Monocots (18 species). Asteraceae, Poaceae, and Fabaceae are best represented. Forbs are the most represented (50.5%), followed by shrubs (15.2%), climber (11.2%), grasses (10.8%), sedges (6.5%) and legumes (5.8%). Annuals comprised about 57.5% and the remaining are perennials. As per Raunkiaer classification, the therophytes is the most dominant class with 135 plant species (48.7%).The use of weed for different purposes as indicated by local people is also discussed. This study provides a comprehensive and updated checklist of the weed speciesof Bhadrak district which will serve as a tool for conservation of the local biodiversity. Bangladesh J. Plant Taxon. 27(1): 85-101, 2020 (June)
... На сьогодні методологічна база дослідження інвазій є надзвичайно потужною, розробленою і апробованою для усіх етапів досліджень від визначення понять (Pyšek et al., 1995;Protopopova, et al., 2006;Richardson, et al., , 2012), інвентаризації (A comparative…, 2011), складання списків (Бурда et al., 2015; Баранский et al., 2016; Зав'ялова, 2017 та ін.) та виявлення трансформерів (Протопопова et al., 2009Tokaryuk et al., 2012;Dvirna, 2015;Kucher, 2015;Зав'ялова, 2017) до встановлення упливу (Lockwood et al., 2007;Vilà et al., 2009;McGeoch et al., 2010;Foxcroft et al., 2013) і прогнозування ризиків втрат природного біорізноманіття (Andreu et al., 2009;A comparative…, 2011;Дідух, 2014;, моделювання поширення (Вихор, 2015 та ін.), створення баз даних (DAISIE; EPPO; NOBANIS тощо) та розробки заходів по контролю і попередженню інвазій із залученням їх у загальний менеджмент заповідних об'єктів De Poorter et al., 2007). Адаптація і впровадження напрацьованого світового досвіду з вивчення фітоінвазій -крок до їхнього попередження в Україні. ...
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Distribution of the gilthead seabream, Sparus aurata Linnaeus, 1758 (Perciformes) in waters of Ukraine. — L. G. Manilo, K. A. Redinov. — The gilthead seabream (Sparus aurata Linnaeus, 1758) is distributed in the East Atlantics from the British Isles to Senegal, the Canary Islands, and Cape Verde being also common in the Mediterranean Basin. In the Black Sea, the species was 楦rst recorded in 1933 along the shore near Romania. Currently, the species occurs here in coastal waters of Ukraine, Turkey, Bulgaria, Romania and Georgia. In waters of Ukraine, the gilthead seabream was first recorded in 1999 at the mouth of Balaklava Bay. In the northwest part of the Black Sea, the species was first recorded in 2004 in the Dnipro-Bug Estuary. The species was recorded the most frequently in coastal waters of the southern part of the Crimean Peninsula, from Sevastopol to Cape Aya, and in Yahorlyk and Tendra Bays in the northern part of the Black Sea. According to the fish collection of the National Museum of Natural History, NAS of Ukraine and literature sources, the gilthead seabream also occurs in the seaside along the Danube Delta (mouth Skhidne), in the southeast part of the Sea of Azov, and in the Dnipro-Bug Estuary. The specimen caught on 8.10.2008 near mouth Skhidne and a female caught in the Dnipro-Bug Estuary on 23.11.2018 are deposited in the fish collection of NMNH NAS of Ukraine (No. 8741 and No. 10435, respectively). A brief morphological description of the latter specimen is presented, including 6 meristic and 20 plastic characters, colouration, and physiological state. The gilthead seabream can be considered as partly acclimatized species of the Black Sea, although data on its spawning here are absent. The increase in the number of the species in the Azov–Black Sea Basin might indicate that the gilthead seabream entered the Black Sea independently through the Bosporus (process of “mediterranezation”), although simultaneous accidental release of specimens into the sea when cultivated as an object of mariculture cannot be excluded. In particular, the gilthead seabream is cultivated in coastal waters of Turkey.
... Of the approximately 130 non-native species known in Teton County, 26.9% were recorded in this study. Non-native species may be displacing or eliminating native and rare species in these riparian habitats, the net result being reduction in overall species diversity and a simplified ecosystem (Beerling 1995;Crawley 1987;Ferreira and Moreira 1995;Randall1996;Rejmanek 1995). ...
Article
Non-native species invasions in national parks directly interfere with the major management goal of protecting native biota. The status of species richness and non-native invasions was assessed in five riparian vegetation types in Grand Teton National Park, Wyoming, with nested-scale number and frequency vegetation data using a Modified­Whittaker sampling design. In the 20 (1OOO-m2 plots sampled, non-native species represented 11.9% (35) of the total 294 species recorded. Non-native species were found in small populations either widely dispersed across the five vegetation types or appearing to have some level of habitat specificity. Total species richness across the five vegetation types varied from 42 species in the sage community to 96 species in the conifer-broadleaf community. Overall, mean species richness across the five communities was 81.9 species/0.1 ha. A suite of environmental variables such as nutrient availability, flood regime, herbivory as well as successional trends may explain the variability in species richness across communities. Patterns of total species richness across multiple scales were fairly consistent. Patterns of non-native species invasion, however, appeared to be both scale and vegetation type dependent. The highest proportion of non-native species for four of the five vegetation types was recorded at the smaller sampling scales. The alder community was the most invaded at all scales measured and had the most distinct assemblage of non-native species. Some studies suggest that community invasibility may be related to species richness. At the 1-m2 and 1000- m2 scales, total species richness and number of non-native species were significantly and positively correlated. When the alder sites were removed from analysis at the 1000- m2 scale, the positive linear relationship increased, and the total variance explained by the linear models was enhanced by 38%. At all scales sampled, the alder sites were highly and disproportionately invaded, often more than twice the level of other communities. The mechanism of nitrogen fixation may be promoting non-native invasions in the alder community. At the vegetation type scale (combined species lists from four 1OOO-m2 plots in each community), those communities with the most unique non-native assemblages were the most invaded. A significant negative linear relationship between non­native species overlap and percentage of non-native species was observed in the alder sites at each scale sampled. This pattern suggests some relationship between properties of an invading species and properties of the community that it invades. Because the results of this study suggest species rich riparian landscapes are vulnerable to non-native invasions, recommendations are offered to assist managers in responding efficiently and effectively to this conservation priority.
... Parthenium hysterophorus has widened its range to cover threatened mammal populations from urban areas and grasslands to woodland eco-systems and raised its resources to the hardwood forests (Bhusal et al., 2014). Large coverage of Chromolaena odorata diseases could also lead to invasion (Rejmanek 1995). It may be attributed to limited seed quantity, robust development, fast growth, low nuclear DNAs, strong competition capacity for nutrition. ...
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Invasive alien plant species (IAPS) are a significant threat to agriculture, resulting in crop loss and increased production cost. Because of their detrimental effects on floral and faunal organisms and their ecosystems, they pose a significant threat to biodiversity. There are 219 species of alien flowering plants native to Nepal, 26 of which have been reported to be invasive with negative environmental impacts, including agricultural production. Four of them (Lantana camara L., Mikania micrantha Kunth, Chromolaena odorata (L.) King & Robb. and Eichhornia crassipes (Mart.) Solms) are among the 100 of the world’s worst invasive alien species in agroecosystems and range lands. The current status and impacts of invasive alien plant species are discussed in this paper.
... De acordo com Pysek (1995), para melhor compreensão da dinâmica populacional das espécies, alguns conceitos sobre estas merecem ser abordados. Dentre eles destacam-se: espécie nativa -com distribuição natural em seu local de ocorrência; espécie exótica (EE) -está inserida em um ambiente diferente do seu local de ocorrência natural; espécie exótica casual (EEC) -é encontrada fora do seu local de ocorrência natural, mas não forma população persistente; espécie exótica naturalizada (EEN) -é distribuída em um ambiente fora do seu local de origem e que consegue formar população persistente e conviver com as espécies nativas sem causar desequilíbrio; espécie exótica invasora (EEI) -é encontrada em um Res., Soc. ...
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The growing increase in the human population has been causing biodiversity to be reduced. Processes such as habitat loss and fragmentation, excessive exploitation of plant and animal species and the introduction of exotic species contribute to this loss. In this context, this study aimed to carry out a survey on the occurrence of exotic species of fauna and flora in the federal and state conservation units of the state of Rio de Janeiro. Initially, there was a consultation of the management plans of the units through the sites of the Chico Mendes Institute for Biodiversity Conservation (ICMBio) and the State Institute of Environment (INEA). In order to systate the analyzed data, four categories were created referring to the management plans, Category 1: without management plan; Category 2: Without management plan, but which have a decree published in the Official Gazette of the Union, which establishes the elaboration of official document; Category 3: With management plan, but no type of exotic species is cited; Category 4: With management plan, where exotic species are cited. Among the animal species, the most common to these UCs was the star-white-tufed Tamarin (Callithrix jacchus Linnaeus, 1758), found in 10 UCs and among the plant species, the most common was the Jaqueira (Artocarpus heterophyllus Linnaeus, 1753), found in 11 UCs. This study provided information and a report on the distribution pattern, in the federal and state UCs of the state of Rio de Janeiro, of species that has the ability to cause imbalance in different ecosystems.
... H. gardnerianum inhibits the regeneration of native vegetation whilst facilitating the colonisation and replacement of native ecosystem by alien species [1]. The invasion by H. gardnerianum occurs by high seed production, quick seed dispersion by birds, fast growth and the ability to spread through rhizomes compared to native species [8,9,[13][14][15][16] (Figure 1). This plant species outcompetes native plant species for nutrients, water and sunlight, thus replacing indigenous forests [17]. ...
... For analysing the flora the following species attributes were considered: (1) the immigration status of the species (according to Pyšek 1995;Terpó et al. 1999;Balogh et al. 2004): native species-those present in the local flora before the Neolithic times or immigrated there without direct or indirect human intervention, archaeophytesintroduced before the discovery of America, approx. 1500 A. D-and neophytes-introduced after that date, (2) the status of legal protection (according to Magyar Közlöny 2015), and (3) in the case of the most widespread species the dispersal types (anemo-, hydro-, endozoo-and autochorous species), life forms (annual and biennial species, perennial herbaceous species, shrubs and trees) and chorological types (adventive, cosmopolitan, European, continental, Mediterranean, boreal and mountain, and endemic species) according to Soó (1964Soó ( , 1966Soó ( , 1968Soó ( , 1971Soó ( , 1973Soó ( , 1980, Horváth et al. (1995) and Terpó et al. (1999). ...
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Urbanization is one of the major causes of species loss and the homogenization of the world's flora. Our coarse-scale floristic mapping project of the largest south Transdanubian city, Pécs, is the first grid-based urban study in Hungary that reveals the current pattern of the vascular flora. Beyond the general description of the project, the species richness, the number of native, archaeophyte, neophyte and legally protected taxa are presented in the scale of the grid units (2.2 km2) and according to the residential area of the city. Relationships between the number and proportion of natives, archaeophytes, neophytes, protected species versus the proportion of built-up areas, forest coverage and elevation are estimated by linear regression models. Among the 1458 spontaneous or subspontaneous vascular plant species of the study area 131 are legally protected. The average number of species per grid unit is 338. Regression models show that the number of aliens decreases with forest coverage and increases with the rate of built-up areas, while number of natives shows opposite trends as a function of the same variables. These opposite trends lead to the conclusion that in the case of the vascular flora of Pécs the “poor get richer” theory is supported. Among the most frequent species hemicryptophytes, widespread, native and zoochorous plants are dominant. The most widespread four invasive taxa are native to North America.
... Regarding invasion or invaders, the terms are generally used without explicit definition. Focusing on the term invasive, it is not used only in a biogeographical sense (referring to alien species) but also in an ecological way, introducing community colonizations and species migrations (Pysek 1995). In this sense, Wacquant (1990) pointed out the interesting history of Dittrichia viscosa, a species native to the Mediterranean basin that is extending its geographical range by entering man-made habitats. ...
... My sought was to find hints at non-scientific influences on the scientific writing. I used specific papers about species that are considered problematic in Central Europe context (Schwabe and Kratochwil 1991;Hartmann et al. 1994;De Waal et al. 1994;Pysek et al. 1995;Cronk and Fuller 1995), as well as more general and international publications, especially the results of the SCOPE-Programme on Biological Invasions (Groves and Burdon 1986;Kornberg and Williamson 1986;MacDonald et al. 1986;Mooney and Drake 1986;Joenje 1987;Drake et al. 1989;Mooney and Drake 1989;Di Castri et al. 1990). ...
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There is a tendency among environmentalists to mistake the role of ecology. To question value-judgements based on 'ecology', I present an analysis of values involved in the assessment of introduced plants. Special concern is given to the relation of ecology and values. I show that the common use of the terms 'neophyte' or 'invader' reveals a conservation bias. I describe, how organismic concepts of the community, the concept of disturbance or the hypothesis of natural stability refer to an idealized nature as an harmonic cosmos. Conservationists also tend to idealize pristine nature as intrinsically good, harmonic and stable. They neglect the opposite image of a 'wild' nature that must be controlled and subjected by humans. Nature conservation is then interpreted as a need for "Heimat", a place that guarantees stability, identity and safety. I claim, that the replacement of original vegetation by a new species is not an 'ecological' damage but requires a comparative norm that is not the result of natural laws but of human decisions. This comparative norm often is the idea of Heimat. Concluding I point out the relevance of my results for nature conservation and environmental ethics.
... Although dispersal capabilities, life-history traits, and competitive abilities are some of the main attributes related to the success of invasive species in relation to native species (Rejmánek, 1995;Callaway and Ridenour, 2004), thermal physiology may also play a fundamental role in the establishment of invasive species in novel areas and in their interaction with native species (Kelley, 2014). The thermal environment is particularly important for ectothermic animals, as they rely on environmental temperature to behaviorally thermoregulate and thus sustain basic biological functions, such as metabolism, growth, and lo comotion (Huey, 1982). ...
Article
For ectotherms, thermal physiology plays a fundamental role in the establishment and success of invasive species in novel areas and, ultimately, in their ecological interactions with native species. Invasive species are assumed to have a greater ability to exploit the thermal environment, higher acclimation capacities, a wider thermal tolerance range, and better relative performance under a range of thermal conditions. Here we compare the thermal ecophysiology of two species that occur in sympatry in a tropical dry forest of the Pacific coast of Mexico, the microendemic species Benedetti's Leaf-toed Gecko (Phyllodactylus benedettii) and the invasive Common House Gecko (Hemidactylus frenatus). We characterized their patterns of thermoregulation, thermoregulatory efficiency, thermal tolerances, and thermal sensitivity of locomotor performance. In addition, we included morphological variables and an index of body condition to evaluate their effects on the thermal sensitivity of locomotor performance in these species. Although the two species had similar selected temperatures and thermal tolerances, they contrasted in their thermoregulatory strategies and thermal sensitivity of locomotor performance. Hemidactylus frenatus had a higher performance than the native species, P. benedettii, which would represent an ecological advantage for the former species. Nevertheless, we suggest that given the spatial and temporal limitations in habitat use of the two species, the probability of agonistic interactions between them is reduced. We recommend exploring additional biotic attributes, such as competition, behavior and niche overlap in order assess the role of alternative factors favoring the success of invasive species.
... Compared to their native counterparts, many nonnative species have broad climatic tolerances and large geographic ranges, short generation times, rapid growth, high fecundity, strong dispersal ability, and independence from (specific) mutualists, all of which may affect their responses to climate change (Py sek et al., 1995;Rejm anek & Richardson, 1996;Goodwin et al., 1999;Qian & Ricklefs, 2006;Bradley et al., 2010;Park & Potter, 2015). Thus, we might expect that climate-change responses of nonnative invaders can differ from native taxa. ...
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Though substantial effort has gone into predicting how global climate change will impact biodiversity patterns, the scarcity of taxon‐specific information has hampered the efficacy of these endeavors. Further, most studies analyzing spatiotemporal patterns of biodiversity focus narrowly on species richness. We apply machine learning approaches to a comprehensive vascular plant database for the United States and generate predictive models of regional plant taxonomic and phylogenetic diversity in response to a wide range of environmental variables. We demonstrate differences in predicted patterns and potential drivers of native versus non‐native biodiversity. In particular, native phylogenetic diversity is likely to decrease over the next half century despite increases in species richness. We also identify that patterns of taxonomic diversity can be incongruent with those of phylogenetic diversity. The combination of macro‐environmental factors that determine diversity likely vary at continental scales; thus, as climate change alters the combinations of these factors across the landscape, the collective effect on regional diversity will also vary. Our study represents one of the most comprehensive examination of plant diversity patterns to date and demonstrates that our ability to predict future diversity may benefit tremendously from the application of machine learning.
... Discussion concerning invasion requires deliberate and precise language given the dubious and often political nature of the term (Pyšek 1995;Larson 2005Larson , 2007. Here, we define invasive as non-native species whose introductions are linked to anthropogenic activity and which have negative effects on local ecosystems. ...
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The rapid expansion of urban land across the globe presents new and numerous opportunities for invasive species to spread and flourish. Ecologists historically rejected urban ecosystems as important environments for ecology and evolution research but are beginning to recognize the importance of these systems in shaping the biology of invasion. Urbanization can aid the introduction, establishment, and spread of invaders, and these processes have substantial consequences on native species and ecosystems. Therefore, it is valuable to understand how urban areas influence populations at all stages in the invasion process. Population genetic tools are essential to explore the driving forces of invasive species dispersal, connectivity, and adaptation within cities. In this review, we synthesize current research about the influence of urban landscapes on invasion genetics dynamics. We conclude that urban areas are not only points of entry for many invasive species, they also facilitate population establishment, are pools for genetic diversity, and provide corridors for further spread both within and out of cities. We recommend the continued use of genetic studies to inform invasive species management and to understand the underlying ecological and evolutionary processes governing successful invasion.
... Only then did P. judaica start to establish large populations in the city centre, thus becoming Table 5 Range of pollen production values (minima and maxima) for a north-and a south-facing population of P. judaica in spring and autumn at the level of flower, shoot, and area; average values are also given for number of pollen grains per shoot (± standard error) and number of shoots per square metre Min 0.44 × 10 9 0.61 × 10 9 0.72 × 10 9 0.24 × 10 9 Max 5.4×10 9 2.3×10 9 1.13×10 9 0.87×10 9 Fig. 9 Average proportion of viable pollen (± standard error) from P. judaica plants collected from stations in and around the city of Thessaloniki that differ in traffic intensity; means followed by the same letters are not significantly different at P<0.05. See Table 3 and Fig. 1 for information on sampling sites and their locations, respectively; -a and -s in the sampling-site codes indicate autumn and spring sampling, respectively an expansive man-accompanying native plant (for this terminology, see Krigas and Dardiotis 2008;Pyšek 1995;Pyšek et al. 2004) in the metropolitan area of the city. According to Bass and Bass (1990), the rate of spread of P. judaica is dependent on its dispersal ability and on the availability of suitable disturbed sites. ...
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Parietaria judaica (wall pellitory) is a wind pollinated, ruderal species. It invades urban environments and has highly allergenic pollen. Given its occurrence and impacts on human health, it is important to know the species flowering phenology and pollen productivity patterns. We studied two populations of the species in Thessaloniki, the second largest city of Greece, where P. judaica is widely distributed forming dense stands. The populations examined differ in exposure - southern and northern. P. judaica flowers both in spring and autumn. We followed progression of flowering in three sampling areas of 0.5 m2 in each population, on a 5-day basis, during both flowering periods; we divided sampling areas into five equal-sized sub-units, sampled 3 shoots from each (45, in total) and estimated the percentage of open flowers that they carried. In both flowering seasons, we collected 30 shoots from each population, measured their length and counted the number of flowers present. We further counted the number of pollen grains bore by the anthers in three indehiscent flowers from each of the 30 shoots, and we also measured corolla width in the autumn sampling. Flowering started at least one week earlier in the population of southern-exposure, in spring, but no difference was observed in autumn. In the spring period, peak of flowering occurred in mid-April, whereas in the autumn period, it occurred in mid-October. Plants in the population of southern exposure were higher and bearing more flowers; there was no difference regarding the flower size. Corolla width was found to be positively correlated with the pollen content. To examine the influence of temperature on flowering phenology, we performed multiple regression analyses. Progression of flowering was more related with minimum rather than with average or maximum temperature for both populations. Given the dependence of pollen amount from temperature and of allergenic incidents from pollen amount, it is very likely that wall pellitory-related allergy will be more frequently and/or severely manifested in response to global warming.
... Only then did P. judaica start to establish large populations in the city centre, thus becoming Table 5 Range of pollen production values (minima and maxima) for a north-and a south-facing population of P. judaica in spring and autumn at the level of flower, shoot, and area; average values are also given for number of pollen grains per shoot (± standard error) and number of shoots per square metre Min 0.44 × 10 9 0.61 × 10 9 0.72 × 10 9 0.24 × 10 9 Max 5.4×10 9 2.3×10 9 1.13×10 9 0.87×10 9 Fig. 9 Average proportion of viable pollen (± standard error) from P. judaica plants collected from stations in and around the city of Thessaloniki that differ in traffic intensity; means followed by the same letters are not significantly different at P<0.05. See Table 3 and Fig. 1 for information on sampling sites and their locations, respectively; -a and -s in the sampling-site codes indicate autumn and spring sampling, respectively an expansive man-accompanying native plant (for this terminology, see Krigas and Dardiotis 2008;Pyšek 1995;Pyšek et al. 2004) in the metropolitan area of the city. According to Bass and Bass (1990), the rate of spread of P. judaica is dependent on its dispersal ability and on the availability of suitable disturbed sites. ...
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Parietaria judaica (Urticaceae) pollen is renowned for its high allergenic potency. Given the species’ impact on human health and its prevalence in urban areas of the Mediterranean basin, we kept records of its air-borne pollen in Thessaloniki, Greece, by use of a Burkard trap, and we studied pollen production in two populations differing in exposure (southern and northern), in the centre of the city. Effectively, we studied the pollen circulation characteristics of the whole Urticaceae family, since further distinction was not feasible under the optical microscope. We monitored the two populations at regular time intervals throughout the year. We found the species to have two flowering periods, in spring and autumn; during these periods we kept records of the ratio of open hermaphrodite flowers in 45 shoots from each population, every 5 days. In both flowering periods and populations, we estimated the pollen amount carried by 90 indehiscent hermaphrodite flowers. Flowering started nearly one week earlier in the population of southern exposure in spring, but not in autumn. The southern exposure population produced more pollen per flower and also more flowers per shoot in spring, but there was no difference in pollen production per flower between the two populations, in autumn. Pollen production per flower differed between flowering periods; in spring, it was more than double that in autumn. Peak of flowering of P. judaica fairly coincided with the pollen load peak of the whole Urticaceae family. Even though this widely-distributed species displayed a second flowering period in autumn, very low to negligible amounts of Urticaceae pollen were then trapped. It derives, therefore, that species-flowering periods and pollen seasons do not necessarily coincide.
... The checklist covers alien flora to Algeria that correspond to all plant taxa whose presence in Algeria is due to "intentional or accidental introduction as a result of human activity" (Richardson et al. 2000). To be included in the checklist, taxa should i) have been introduced (or presumed to be introduced) through activities related to humans or their domestic animals, whether intentionally or not, and ii) have been found in the wild (Webb 1985;Pyšek 1995;Krigas and Kokkini 2004;Campos et al. 2004;Lambinon 2005). Therefore, alien species exclusively cultivated or planted without clear evidence of escape or naturalization (Kowarik 1995;Wade 1997;Starfinger 1998;Richardson et al. 2000;Celesti Grapow et al. 2001;Vilà et al. 2001;Krigas and Kokkini 2004;Paradis et al. 2008) are not considered, even those cultivated on a large scale. ...
Article
Biological invasions are permanent threat to biodiversity hotspots such as the Mediterranean Basin. However, research effort on alien species has been uneven so far and most countries of North Africa such as Algeria has not yet been the subject of a comprehensive inventory of introduced, naturalized and invasive species. Thus, the present study was undertaken in order to improve our knowledge and to propose a first checklist of alien plants present in Algeria, including invasive and potentially invasive plants. This work aims to make an inventory of all available data on the alien flora present in Algeria, and to carry out preliminary quantitative and qualitative analyses (number of taxa, taxonomic composition, life forms, geographical origins, types of habitats colonized, degree of naturalization). The present review provides a global list of 211 vascular species of alien plants, belonging to 151 genera and 51 families. Most of them originated from North America (31.3%) and the Mediterranean Basin (19.4%). Nearly half (43%) of alien species are therophytes and most of them occur in highly disturbed biotopes (62%), such as arable fields (44.5%) or ruderal habitats, including rubble (17.5%). Introduced plants for ornamental purposes account for almost half (43.6%) of the alien flora. A large proportion (51.2%) of alien species is naturalized in Algeria, with about 16% considered as invasive or potentially invasive. However, the actual impact of these alien species on plant communities and ecosystems deserves urgent assessment with specific studies on impact at the community and the ecosystem levels.
... In vascular plants, for example, these characteristics are often related to rapid growth and reproduction, reproductive systems that combine sexual and asexual modes, and abundant production of flowers and seeds (Noble 1989). Additional traits are recognized in seed dispersal (e.g., seed size, dispersal mode), the ability to fix nitrogen, and the biogeographic origin or latitudinal band that invasive species occupy in their original range (Rejmánek 1995;Rejmánek and Richardson 1996). Some of these attributes are phylogenetically associated with certain lineages, so that these lineages have intrinsic characteristics that make them more likely to naturalize once they have been relocated (Pyšek 1998). ...
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The propagules that have survived the primary dispersion barrier are able to found a colony, initially of reduced population size. From that point on, the newly arrived species may be called exotic (see Fig. 1.7). The colony will be successful if it persists and expands, occupying a larger area in the recipient region. In a broad sense, the persistence or population establishment of an exotic species in the introductory habitat is called naturalization. This concept (Table 1.1) can be defined as the process in which the individuals that make up the population are able to complete their life cycle, reproduce, and leave fertile offspring, thereby allowing population growth or at least avoiding extinction. Thus, naturalized species correspond to those exotic species whose populations have been established in population terms in the recipient area (Table 1.1), as opposed to non-naturalized exotic species whose fate is either extinction or persistence through human aid (Heywood 1989; Richardson et al. 2000b; Pyšek and Prach 2003).
... Firstly, we have classified the plants as alien or native. Alien plants may be archaeophytes, introduced before 1500, or neophytes, introduced later ( Korn as 1990;Py sek 1995); in this area alien plants have been introduced especially since the 15th century, so almost all are neophytes. Alien plants can be introduced voluntarily (sowing or planting) or involuntarily, and after the introduction they can naturalize, establishing new self-perpetuating populations ( Richardson et al. 2000) or not. ...
Article
Mediterranean ecosystems have a high diversity of plants, especially in mountain areas; this diversity is especially high in the eastern sector of the Spanish Central Range, where Mediterranean and Eurosiberian species contact. Parts of these plants have been favoured by human activities throughout the last millennia, in an intentional or unintentional way. We have studied the composition of the flora of a valley in the Spanish Central Range to determine the human influence. Although it is a mountainous area, where the presence of synanthropic species should be lower than in territories with a strong human impact, we have identified a minimum of 20.7% of the plants favoured by human action, including alien (6.2%) and strict ruderals (14.5%), which may increase to 39.2% including plants growing both in ruderal and non-ruderal habitats. The entrance of ruderal and alien plants continues currently , especially through roadsides, and probably increases in the future, due to growing tourism and to climate change, which may influence the patterns of colonization and invasion of ruderal and alien plants, and the response of the native flora.
... Le specie aliene si possono quindi considerare francamente sinantropiche, cioè più o meno strettamente legate all'uomo e alle sue attività e a questo proposito, una distinzione che storicamente viene utilizzata riguarda il periodo della loro introduzione (Thellung 1911-12;Kowarik 1990;Trepl 1990;Pyšek 1995): convenzionalmente si stabilisce il 1500 come spartiacque fra archeofite, termine che raggruppa specie aliene introdotte antecedentemente a questa data, e neofite, d'ingresso posteriore. Molte archeofite infatti sono rappresentate da piante introdotte durante il neolitico, in seguito all'affermarsi dell'agricoltura e con la diffusione dei cereali vernini. ...
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Riassunto-Viene presentata la checklist aggiornata delle specie esotiche per il territorio del Friuli Venezia Giulia, comprensiva di indicazioni sullo status delle specie, diffusione nel territorio, dominanza, invasività potenziale e di altri caratteri funzio-nali. Complessivamente la lista annovera 341 specie e 23 sottospecie delle quali 185 possiedono lo status di casuale, 119 di naturalizzata, 30 di invasiva e 7 di trasformatrice. Sono state effettuate alcune elaborazioni relativamente al comportamento delle aliene in base ai caratteri funzionali e alla loro distribuzione in regione. Vengono poi riportate le schede monografiche delle specie aliene trasformatrici e invasive comprensive di mappe distributive. Abstract-The updated checklist of the exotic species of the Friuli Venezia Giulia territory is presented, including indications on the status of the species, diffusion in the territory, dominance, potential invasiveness and other functional traits. The list includes 341 species and 23 subspecies of which 185 have the status of casuals, 119 of naturalized, 30 invasive and 7 of transformers. Some elaborations have been made regarding the behavior of the aliens on the basis of functional traits and their distribution in the region. The monographic sheets of the alien and transformers invasive species including distribution maps are then reported Introduzione Collaboratori La realizzazione di questo lavoro ha potuto contare sul fattivo contributo dei molti collaboratori, ai quali va la nostra gratitudine. Fondamentali per la ricerca sul campo e la consulenza sono stati: Gianfranco Bertani (S. Vito al Tagliamento), Adriano Bruna (Maniago), Antonino Danelutto (Tarcento), Giuliano Mainardis (Venzone), Roberto Pavan (Sacile) e Claudio Peruzovich (Martignacco). Le immagini sono di Elio Polli (Trieste). La flora aliena l problema dell'invasione di specie aliene (dette anche esotiche o neofite) è ormai divenuto straordinariamente attuale, tant' è che a livello europeo è stata varata una normativa (Regolamento [UE] N. 1143/2014) che in-quadra gli aspetti legati al controllo della loro diffusione e alle strategie per evitare ulteriori ingressi nei Paesi del-l'Unione. Nel regolamento vengono fra l'altro elencate le specie di rilevanza unionale, ritenute cioè pericolose a livello UE. In Italia è stato recentemente pubblicato il Decreto legislativo attuativo n. 230/2017 che recepisce la normativa europea e, inoltre, è di recentissima pub-blicazione la checklist delle specie aliene (Galasso et al. 2018), che aggiorna quella precedente di Celesti-Grapow et al. (2010). In sede locale, la Regione Friuli Venezia Giulia ha pubblicato nel 2016 un manuale di riconoscimento delle principali specie aliene invasive, fornendo indicazioni utili al contenimento della loro espansione (Carpanelli & Valecic 2016). Una specie si definisce esotica quando si trova in un territorio differente rispetto alla sua naturale area di di-stribuzione, ossia quando proviene da una diversa area geografica. Le specie possono espandere il proprio area-le distributivo anche naturalmente, ma nel caso delle neofite l'introduzione in un territorio estraneo dipende sempre dall'uomo e può essere volontaria, come nel caso di specie coltivate a scopo ornamentale o alimentare, oppure accidentale, nel caso in cui queste vengano ca-sualmente trasportate attraverso i traffici commerciali o, in generale, tramite qualsiasi spostamento di uomini, merci e mezzi da un Paese all'altro. A questo proposito, le vie di comunicazione principali (linee ferroviarie, autostrade, canali, ecc.) e i diminuiti tempi di percor-renza svolgono un ruolo chiave nella propagazione di queste piante, mentre i vettori di diffusione sulle grandi distanze sono rappresentati più spesso da frutti e/o semi, raramente da propaguli vegetativi. Quando una specie esotica giunge in un nuovo ter-ritorio, o vi si trova già coltivata in parchi, giardini o vivai, può incontrare le condizioni idonee per potersi
... The species were classified according to their immigration status (for details, see Pyšek 1995;Pyšek et al. 2012): ...
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Riparian zones provide many ecosystem services and are a frequently found type of green area in urban ecosystems; these areas increase the aesthetic value of urban landscapes. The aim of this 17-year study was to assess the applicability of passive vegetation restoration of the gravel/sand bars that emerged after a devastating flood along the river in the city of Prague. The number of species and the sum of their coverages rapidly increased for the initial six years. After the twelfth year, the vegetation composition gradually began to stabilize. Species diversity increased for seven years after the beginning of the succession and then remained essentially unchanged. The diversity values were lower on finer substrates with higher proportions of dust and clay particles. The neophytes, i.e. species introduced after the year 1500, established with more successful on substrates with greater soil skeleton proportions. Finer substrates were preferred by graminoids; among them, the invasive Arrhenatherum elatius was the most abundant. The share of invasive species in the total vegetation cover initially fluctuated at approximately 40%; after eight years, it stabilized at approximately 10%. The proportion of naturalized alien species stabilized within the range of 20–30%. The results show that a new type of species-rich vegetation spontaneously emerged on gravel/sand bars. The vegetation consisted mainly of native and naturalized non-invasive alien species. However, attention needs to be given to potential alien plant invasions.
... However, the mechanisms that underlie these associations between species' ecology and naturalization are impossible to tease out without accounting for context-dependent anthropogenic effects, including introduction history and cultivation, that can bias the composition and distribution of traits of introduced species Pyšek et al., 2015). Introduction history involves (a) colonization pressure, that is, the number of species introduced (Diez et al., 2009;Lockwood et al., 2009); (b) residence time since introduction (Rejmánek, 1995); and (c) propagule pressure, that is, the number of propagules introduced (Lockwood et al., 2005;Simberloff, 2009). ...
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Species characteristics and cultivation are both associated with alien plant naturalization and invasiveness. Particular species characteristics are favoured for cultivation, obscuring the relationship between traits and naturalization success. We sought to better understand the drivers of naturalization and invasiveness by analysing relationships with species characteristics and cultivation and by disentangling the direct effects of characteristics from the indirect effects mediated by cultivation. Great Britain. c. 1000–present. Seed plants. We used a comprehensive dataset of 17,396 alien plant taxa introduced to Great Britain before 1850, a country with one of the most well‐documented histories of plant introductions. We integrated this with cultivation data from historical and modern records from botanic gardens and commercial nurseries and with trait data. Accounting for time since introduction, we quantified the influences of cultivation and species characteristics on present‐day naturalization and invasiveness in Great Britain. Larger native range size, earlier flowering, long‐lived herbaceous growth form, and outdoor cultivated habitat were all associated with naturalization. However, these relationships between characteristics and naturalization largely reflected cultivation patterns. The indirect, mediating influence of cultivation on naturalization varied among species characteristics, and was relatively strong for growth form and weak for native range size. Cultivation variables, particularly availability in present‐day nurseries, best explained invasiveness, while species characteristics had weaker associations. Human influence on species introduction and cultivation is associated with increased probability of naturalization and invasiveness, and it has measurable indirect effects by biasing the distribution of species characteristics in the pool of introduced species. Accounting for human cultivation preferences is necessary to make ecological interpretations of the effects of species characteristics on invasion.
... In Baker's view, traits promoting invasiveness include the ability to reproduce both asexually and sexually, rapid growth from seed to sexual maturity and, in particular, high adaptability to environmental stress along with high tolerance to environmental heterogeneity. Later studies on plants have identified other characteristics associated with reproductive potential, vegetative reproduction, dispersal, life-form and competitiveness as essential features of a successful invader (Forcella et al. 1986;Noble 1989;Roy 1990;Pysek et al. 1995;Rejmanek 1995;Thompson et al. 1995;Crawley et al. 1996;Reichard and Hamilton 1997;Pysek and Richardson 2007). ...
Chapter
Biological invasions are one of the worst threats to biodiversity conservation, ecosystem services and functionality, and human health. However, of the high number of organisms that are transported and introduced outside their native range, only a subset of them can survive, establish and spread in the novel area, becoming invasive. What determines the ability of an alien animal species to become invasive? There is an increasing awareness that the answer to this longstanding and crucial question is highly multifactorial, with some factors already well-discerned, and some not yet elucidated. In this book chapter, we focus on developmental plasticity, the permanent change in the developmental trajectory adopted by an organism in response to gene–environment interactions. Developmental plasticity is an important adaptive response to the obvious variability of biotic and abiotic environmental conditions over time. Yet, it can also promote the invasion of novel habitats, by favouring the optimal match between individual phenotypes and the new environment, during the early steps of an invasion. By relying on the available literature and focusing on animal invasions, we analyse the adaptive advantages conferred by developmental plasticity (i) in dealing with the new biotic and abiotic environment during the stage of introduction, (ii) in terms of reproductive rate and population growth, two crucial processes for overcoming the stages of establishment and (iii) in dispersal traits promoting the spread in the new environment. We conclude that, although acknowledged in previous literature, the actual contribution of developmental plasticity to the shaping of the ideal invader might have been underrated.
... Жлезистата слабонога (Impatiens glandulifera Royle) (Balsaminaceae) е силно инвазивен чужд растителен вид, който се разпространява бързо в цяла Европа [1] и Северна Америка [2], вследствие на интродуцирането му от планинските склонове на Хималаите в началото на 19 век. В България видът е регистриран за първи път през 1978 г. ...
... This problem was presented in a particularly interesting way in the work published jointly with Scholz at the end of the 20th century (Sukopp & Scholz 1997). In the context of classi fications proposed by other authors (Kornaś 1968(Kornaś , 1981Jackowiak 1990Jackowiak , 1993Mirek 1991;Pyšek 1995;Pyšek et al. 2004), attention is drawn to the consideration of the group of native species occurring only in natural habitats (Ahemerophytes) and separation of the In digenophyta anthropogena (Anecophytes) group (Fig. 1). The introduction to this classification of native species not adaptable to anthropogenic factors, at the same time, draws attention to the less frequently discussed problem of apophytes. ...
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The changes in plant cover have been the subject of regular geobotanical research for over 150 years. For several decades, one of the most outstanding researchers of this process has been Professor Herbert Sukopp from the Technische Universität Berlin. This paper discusses the main concepts and most important results of his empirical research. Based on the analysis of international scientific information database resources (Scopus, Web of Science, Google Scholar), the worldwide impact of Sukopp’s publications on the development of research in the field of anthropogenic changes in flora and vegetation was illustrated.
... La terminología empleada para designar los diferentes tipos de plantas llegadas recientemente a una zona concreta ha sido revisada por diversos autores (PYSEK, 1995;RICHARDSON & al., 2000). En el presente estudio se ha adoptado la propuesta por SANZ-ELORZA & al. (2001), que llaman alóctonas a aquéllas plantas que han colonizado recientemente un área al amparo de la actividad humana, en contraposición aplican autóctonas a las que son originarias de la zona. ...
Technical Report
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Realizado para el Organismo Autónomo de Parques Nacionales y publicado por la Real Sociedad Española de Historia Natural
... Seeds are produced by mature plants as naturally and genetically unique small organs, which serve as dispersal agents and enable species survival by remaining dormant until the environmental conditions are favorable (Fenner 1985). Smaller seed weight is associated with higher seed number (of similar weight), greater fertility, abundant seed bank (Banovetz and Scheiner 1994), high initial germination, and shorter chilling period needed to overcome dormancy (Westoby 1998;Rejmánek 1995). Small seeds reach distant geographical sites are long-lived (Hodkinson et al. 2002), experience lower predation, and therefore persist in the soil for a longer duration than larger seeds (Graebner et al. ...
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Background To address the lack of evidence supporting invasion by three invasive plant species ( Imperata cylindrica, Lantana camara, and Chromolaena odorata ) in tropical ecosystems, we compared the ecophysiological and leaf anatomical traits of these three invasive alien species with those of species native to Sempu Island, Indonesia. Data on four plant traits were obtained from the TRY Plant Trait Database, and leaf anatomical traits were measured using transverse leaf sections. Results Two ecophysiological traits including specific leaf area (SLA) and seed dry weight showed significant association with plant invasion in the Sempu Island Nature Reserve. Invasive species showed higher SLA and lower seed dry weight than non-invasive species. Moreover, invasive species showed superior leaf anatomical traits including sclerenchymatous tissue thickness, vascular bundle area, chlorophyll content, and bundle sheath area. Principal component analysis (PCA) showed that leaf anatomical traits strongly influenced with cumulative variances (100% in grass and 88.92% in shrubs), where I. cylindrica and C. odorata outperformed non-invasive species in these traits. Conclusions These data suggest that the traits studied are important for plant invasiveness since ecophysiological traits influence of light capture, plant growth, and reproduction while leaf anatomical traits affect herbivory, photosynthetic assimilate transport, and photosynthetic activity.
... Existen discrepancias entre autores a la hora de establecer si una especie es o no alóctona en un país o región, especialmente en el caso de las especies arvenses. Una clasificación ampliamente aceptada divide las plantas alóctonas en arqueófitos, introducidos antes de 1500, y neófitos, introducidos con posterioridad (Kornás 1990;Pyšek 1995); para la Península Ibérica, en los primeros se integran sobre todo especies euroasiáticas y norteafricanas, mientras que en los segundos entran también especies de antiguas colonias europeas posteriores a 1500, entre ellas América. Los neófitos no suelen presentar dificultad de atribución, sobre todo cuando su origen es americano o de regiones remotas, pero los arqueófitos resultan complicados de identificar; el límite entre especies arvenses nativas, y arqueófitos introducidos con los cultivos hace siglos es muy difícil de discernir. ...
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En esta segunda parte del atlas de flora alóctona de Madrid, se incluyen los órdenes Nymphaeales, Magnoliales, Laurales y las Monocotiledóneas. Se han considerado los taxones introducidos fuera de terrenos urbanos, parques o jardines, naturalizados o no. Se analizan 101 taxones y se incluyen referencias a otros 39. De los taxones analizados 58 son alóctonos en Madrid (49 naturalizados, 8 sin constancia de que lo estén y uno sin localidades concretas conocidas) y 9 en localidades próximas (8 naturalizados y 1 sin constancia de estarlo). Otros 11 son alóctonos en Madrid y podrían naturalizarse, pero no hay constancia de ello; 5 aparecen en jardines y en 6 hay sospechas de su posible presencia por usarse en cultivos o siembras extensivas. En 18 taxones hay discrepancias entre autores sobre si son o no alóctonas; en este trabajo se ha considerado que no lo son. Finalmente se propone excluir 5 taxones de la flora alóctona de Madrid. Entre los taxones incluidos Arundo donax está considerada una de las más agresivas invasoras del mundo. Algunos taxones son antiguas introducciones con poblaciones estabilizadas o en regresión. Hay muy pocas referencias a cereales naturalizados, lo que puede deberse a su baja persistencia. Algunas especies son neocolonizadoras, como Limnobium laevigatum, la más recientemente detectada, o Cortaderia selloana, en expansión.
... Alien plants, also known as exotic, adventive, introduced, allochthonous, non-indigenous and non-native are plant species whose presence in a given area is the result of deliberate or unintentional human activity or which have arrived in a given area without human assistance (Pyšek, 1995;Richardson et al., 2000;Pyšek et al., 2004). Alien plants include a large group of plants. ...
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In the urban area of Banja Luka, 77 species of alien plants have been found, most of them neophytes (64.94%) while a smaller percentage are archeophytes (35.06%). Most of the plants originate from America (34), and Asiatic species rank second (17). Most of the alien plants belong to the Compositae family, in terms of life form are therophytes, and intention has been involved in their arrival in this area.The anthropogenic change indicator values have been shown to have a significant anthropogenic impact on the overall flora.
... São consideradas exóticas as espécies transportadas de uma dada região geográica para outra em que não ocorreriam naturalmente, independentemente de seu eventual impacto sobre os ecossistemas naturais, sendo o transporte realizado por ação humana intencional ou acidental (LOCKWOOD et al., 2007). Entre as exóticas, são consideradas invasoras aquelas que colonizam e se expandem em ecossistemas nos quais não ocorreriam naturalmente, não fosse a interferência humana (PYŠEK et al., 1995;WILLIAMSON, 1996;RICHARDSON et al., 2000;AZEVEDO, 2009). No âmbito da Ecologia da Conservação, questão importante é avaliar o impacto das exóticas sobre os ambientes nos quais elas foram introduzidas e, caso necessário, adotar medidas de erradicação e controle . ...
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Espécies invasoras prejudicam as comunidades vegetais autóctones por eliminar diretamente as espécies nativas ou por inibir a sua regeneração. Há evidências de que as palmeiras exóticas Livistona chinensis e Archontophoenix cunninghamiana, que colonizam remanescentes de Floresta Atlântica, ameaçam os processos sucessionais da vegetação natural e, portanto, devem ser controladas. Neste estudo, avaliamos a eficácia do controle químico dessas palmeiras exóticas com o herbicida glifosato. Efetuamos o controle químico por meio da injeção de glifosato (ROUNDUP TRANSORB R 30%) no estipe de 30 indivíduos de cada espécie, em dosagens variáveis de acordo com o porte das palmeiras. Os sinais de senescência foram ilustrados, descritos e acompanhados semanalmente até a morte de todas as palmeiras, que demorou 18 semanas para L. chinensis e 29 semanas para A. cunninghamiana. O glifosato mostrou-se eficaz para ambas as espécies e recomendado para o controle de palmeiras adultas de grande porte, as quais devem ser priorizadas no manejo, a fim de eliminar as matrizes responsáveis pela oferta de propágulos.
... Thus, these species have the potential to spread over a considerable area. PySek (1995) affirms that species can only be regarded as native to a given area if its occurrence is independent of human activities. However, those species that arrived before the beginning of the Neolithic period should also be considered as native, even if introduced by man. ...
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Bamboo has been receiving increased attention as a renewable resource owing to its fast growth, economic value, widespread availability, and physical properties. However, environmental impacts of such intensive bamboo cultivation need to be assessed in order to avoid any negative consequences that could result from this plant’s invasive potential. In this study, we sought to evaluate the possible implications of bamboo growth in diverse ecosystems, as well as its relations with riparian zones and local hydrology. We reviewed studies that have focused on cultivation of bamboo in various areas where they are not always native. Furthermore, we have provided an objective compilation of studies that report possible effects and impacts that bamboo may have in local landscapes where it has been introduced or established. We conclude that, regardless of bamboo being native or exotic in a region, it can become invasive in some ecosystems, even when a bamboo species does not show spreading characteristics. Introduction of bamboo in a new area needs preliminary studies to avoid the species that may become invasive and to minimize the risk of suppression of different stages of ecological succession in local vegetation and of the changes in the forest structure and diversity.
... The controversial term "weed" can be defined, in a broad sense, as those plant species that interfere with human activity because they grow at a time and place where they are unwanted (Holzner 1978, Fryer 1979. From a biogeographical perspective, "weeds" are considered exotic species that are distributed outside their native distribution area due to an unnatural cause (Rejmánek 1995). However, if ecological changes occur under man-made management systems, species of the native flora can expand their range of distribution and invade new habitats (Mortimer 1990). ...
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Currently, in Argentina 368 species of true ferns (i.e. Polypodiopsida class) are distributed throughout the country, however, only four of them have been mentioned until now as weeds and ruderal species. The goal of this work was to generate an update of weedy ferns from Argentina, including morphology, distribution, and type of weed according to their impact on natural habitats and/or human activities. All Argentinian fern species were analyzed based on references, herbarium specimens, and field trips. As a result of our study 25 species were recorded from Argentina and classified as segetal, ecological, or aquatic weeds, and ruderal and/or toxic species. Current taxonomic identity, diagnostic characters, origins, habitats, geographical distribution, common names, and impact and potential risks were indicated by species. In addition, we provide a dichotomous key to species, presence of these species in southern South American countries, as well as and photographs in natural habitat. This work represents the first review on native and exotic ferns from Argentina that cause an impact on human activities or disturbe native habitats. The results provide information for the development of weed management tools and priority areas to implement them.
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100 invasive alien species of vascular plants, the most harmful for phytodiversity on the protected areas of national importance of Ukraine, are given as a brief compendium of three lists: Black (17), Grey (50) and Watch (33). This lists are compiled on the basis of set criteria adapted to the compilation Black, Grey, and Watch (white, alarm, alert) lists, such as invasive status, species’ distribution, known or estimated environmental impact, as well as possible of management options or control measures, etc. For each species the information is provided about the group by the time of immigration, origin, way of introduction, life form, soil humidity requirement, refined types of total range, ecological and coenotic information on the occurrence in certain habitats. The participation of the studied species in the composition of plant communities, which belong to 32 classes of mainly native vegetation, was established as well as their representation in the territory of more than 50 protected areas of Ukraine of different categories and in the European lists of invasive plants. We have found that about a third of the studied species have a significant impact on the species, coenotic and ecosystem levels, and threatening to the native biodiversity of protected areas of Ukraine. The rest is a potential threat. At the same time, some alien species of Grey and Watch lists threaten native biodiversity at local or regional level in some native areas of Ukraine. They are dangerous only for certain types of natural habitats or plant communities of certain vegetation types. All of the studied species of invasive plants appeared on the territory of the studied protected areas being already naturalized and are in the process of expanding secondary range by spontaneous dispersal, the vast majority of them due to the deliberate introduction in Ukraine, it’s certain regions, or directly in the protected sites.
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Se cita por primera vez en la Comunidad Valenciana la presencia de Annona cherimola Mill. (Annonaceae), localizada en los márgenes del río Carraixet a su paso por Alboraya, en la provincia de Valencia (España). Palabras clave: Annona; Annonaceae; flora alóctona; Comunidad Valenciana; España. ABSTRACT. Annona cherimolia Mill. (Annonaceae) first record for the valencian flora (E Spain). A first reference on the presence of Annona cherimola Mill. (Annonaceae) in Valencia Community (Spain) is provided. This species has been located in the Carraixet River in the Valencian province (Spain). Keywords: Annona; Annonaceae; exotic plant; Valencian Community; Spain.
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A LA VENTA en www.JOLUBE.es // Se trata del trabajo más completo sobre la flora y la vegetación de los campos de cultivo, las cunetas, las vías de comunicación, los descampados, los márgenes de campos, etc., de la provincia de Huesca (Aragón, España). Incluye la descripción del paisaje vegetal de la provincia; un completo y exhaustivo catálogo de las flora arvense y ruderal; otro sobre este tipo de vegetación con inventarios fitosociológicos. Le sigue un capítulo dedicado al neofitismo y al xenofitismo. Continua con otro dedicado a la erosión genética de la flora arvense y sobre la sectorización biogeográfica teniendo en cuenta la flora arvense y ruderal. Finaliza con las conclusiones, la bibliografía y el índice de familias y géneros.
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Researches related to invasive plant ecology has recently increased, hence the terminology used in the early studies can later be perused by other researchers. Incorrect use of the term "invasive species" instead of "non-invasive species" may lead to environmental consequences and threatens the biodiversity and life of endangered species. Therefore in this study, terminology and applicability of invasive species that is frequently used by Iranian researchers were compared with those of the international standards. Thirty-three papers of Iranian researchers that had used the term of invasive plants were surveyed. Then chorotype and the origin of each plnt species were studied. Accordingly, we found that 154 native plant species of Iran had erroneously been identified as invasive species. Among them, 34% had used the term invasive species instead of non-palatable species also 24, 18, 27 percent had respectively been used instead of weed, toxic, ephemeral and ruderal plants. All of these species should be classified as native species according to the international standards. Results of this study can be used as a framework for terminology and applicability of invasive plant species in the Iranian literature, and prevent further nomination of native species as the invasive plants. This study broadens the current knowledge of biological invasion in Iran and can be considered as a unified framework for Iranian researchers to prevent the current mistakes.
Article
The research of European urban flora is still based on the study of Western and Central European settlements, while relatively few data are available from the southern and eastern parts of Europe. This paper presents the first grid-based approach that surveyed the spontaneous and sub-spontaneous flora and its temporal changes of a Hungarian city located in this latter region of Europe. The changes during 70 years in the flora of a Hungarian county seat, Pécs were investigated. The contemporary city areas were used as two different study areas in the analyses. Changes in species richness, proportions of dispersal types, life form traits and alien statuses were examined during the mentioned period. With 1641 vascular plant species found at 232.88 km² in the last 70 years, the flora of Pécs represents a diversity hotspot within Europe. In contrast with other European cities we found significant (19.37%) increase in the number of species over the last 70 years. As a result of temporal changes in the city flora, differnces were found only in the case of neophytes’ life forms regardless of the spatial approach. Similar to the other cities globally the number of woody species neophytes and short-lived alien plants increased.
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The Special Issue of the Rendezvous, “Portugal: Territory, Society and Nature”, is the initiative of an interdisciplinary collaboration that is critically examining the research, policy, and practices which currently underpin geography and spatial planning in Portugal. On this theme, this Special Issue has contributions that critically assess the following proposition statements: Concepts that shape how geography is understood and discussed within any society Narratives that shape how the problem of geography is framed and communicated Science that underpins geography, and critical considerations of the role of science in supporting action and change Governance processes of interaction and decision-making Systems, approaches and framings that conceptualize feedbacks and interconnections between social, biophysical, climate, and institutional problems from local to global scales Studies of future scenarios that consider ways of supporting decision-making and implications of long-term future changes We have contributions from several areas of geography research and practice with broader disciplinary perspectives in the social and biophysical sciences and humanities. As a result, this special issue epitomizes results of recent studies and discusses long-standing questions in diverse areas of geography, paying special attention to the interconnectedness of: (1) human geography studies: human modifications and territorial planning, teaching, population and tourism migration; (2) physical geography and developmental ecology constraints, that is, the notion of ‘nature conservation’. The editors have brought together a solid and productive cast of researchers with singular focus, presenting at the same time the diversities and similarities in the approaches to the geography studies. The first part of this special issue is composed of the contributions about the themes: human geography, population, teaching, frontiers and migrations, and tourism in Portugal. Paulo Nuno Nossa seeks to bring a contemporary geographical insight into the study of Portuguese demographics from the early days of census taking to the present, which could reflect on the relationship between migration and the socioeconomic context in the country. Miguel Padeiro focuses on Portugal’s recent demographic ageing process and presents some reliable statistics to show how and why Portugal has been ageing so quickly in comparison with other European countries. Fátima Velez de Castro and Érica Mitelo pursue to offer a reflective summary on the Portuguese immigration scenario, highlighting the volunteer and workflows, from the second half of the 20th century onwards. Luís Mendes develops his paper about recent urban regeneration as a tool in the restructuring of Portuguese cities and the problematic of gentrification, focusing on the case of Lisbon. Manuel Pérez Pintor and João Paulo Candeias Garrinhas discuss the Eurocity Elvas, Badajoz and Campo Maior (EUROBEC) as a socio-economic and territorial reality of a new cross-border governance structure in Portugal. Norberto Santos presents an intriguing reflection about gastronomy and wines in Portugal as fundamental to the development of touristic activity. Miguel Castro’s study based on the schoolbooks used by the Portuguese dictatorial regime, intends to make a brief expedition throughout the twentieth century (until 1975), exploring how Geography was an instrument for the construction of a submissive, obedient, and apolitical population. The second part of this special issue encompasses contributions on the themes such as physical geography, ecology, biological invasions, space planning, and biological conservation. Bruno Martins and Adélia Nunes present the reader with a summarized but an inquisitive vision about physical geography highlighting certain unique aspects of Portuguese territory. Jorge Luis Oliveira-Costa, Rui Ferreira de Figueiredo and Vânia Regina Pivello discuss the role of coastlines in plant invasion dynamics, focusing on the case of Acacia longifolia (Andrews) Willd. in Portugal. Thus, this distinct issue of Rendezvous reaches out in a singular effort to capture the intricacy of the structure, origin, processes, dynamics and mechanisms of Geography, representing a coherent and synthetic framework, attempting convincing clarifications of the solutions to the problems, conflicts and impacts of the different territories.
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In this work we aim to review empirical evidences using data for Acacia longifolia to analyze coastal systems invasibility, under three synthetic steps: (i) explaining the influence of geographic conditions on invasibility levels at large spatial scales; (ii) correlating this knowledge with the dynamics of A. longifolia invasiveness in temperate regions; (iii) seeking to understand the coastline invasibility phenomenon, using the A. longifolia as an empirical example of invasive species. We examine multiple lines of evidence to try to untangle these issues, about how determinant is ecological similarity between different ranges to explain the susceptibility to invasion by A. longifolia.
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The results of studying the participation of invasive plants in the synanthropic plant communities in the Bukovinian Cis-Carpathians (Chernivtsi Region, Ukraine) are presented. 29 invasive species, including 6 tranformers, were noted in 16 associations from 5 classes: Polygono arenastri-Poetea annua, Stellarietea mediae, Artemisietea vulgaris, Galio-Urticetea, and Robinietea.
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Urban water managers, engineers and conservation ecologists in the Western Cape (WC) Province of South Africa are faced with a major environmental and human health challenge, with urbanisation, industrialisation, population growth and agricultural development placing pressure on the limited water and soil resources. In addressing this resource degradation an effective, affordable and sustainable solution is required. The implementation of ‘green infrastructure’ (GI), such as phytoremediation, involves the use of plants to hinder pollutant transport and attenuate runoff flow, protecting the health of the human population and the environment. However, care must be taken when selecting plant species due to possible invasive behaviour, affecting ecosystem dynamics. As a result of the need for resource remediation in both urban and rural areas, the use of non-invasive indigenous species is vital to an efficient and sustainable technology, as urban areas are often the initial sites for introduction from which invasions spread. This paper proposes indigenous WC species for potential use in GI, identified from global bioremediation literature, as an aid to the practicing civil engineer and water manager responsible for the design and management of the phytotechnology. These indigenous species offer potential as phytoremediators in local GI, as well as suggest the types of plants that should be investigated further as alternatives to effective exotics. The investigation returned 56 non-invasive WC plant species likely to aid resource remediation without jeopardising the conservation and biodiversity of the administered area. The selected vegetation is potentially capable of increasing heterogeneity and adjusting to the dynamic biogeographic conditions of the recipient habitat. Thus, distinct species capable of remediating a wide range of environmental contaminants for GI, into the diverse habitats of the WC, at a fraction of the cost of conventional techniques, are promoted.
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O presente dossiê temático, intitulado "Representações da Paisagem: Abordagens Multidisciplinares", publicado numa edição especial da Revista GEOGRAFIA Publicações Avulsas, traz as discussões e resultados estabelecidos durante o 1° International Workshop Landscape Representations (IWLR). Com abordagem interdisciplinar, o Dossiê é composto por 7 contributos que contemplam questões desde a entrada socio-cultural do conceito de PAISAGEM, à questões ligadas a entrada naturalista deste mesmo conceito.
Article
River ports represent a special type of urbanized area. They are considered to be an important driver of biological invasion and biotic homogenization on a global scale, but it remains unclear how and to what degree they serve as a pool of alien species. Data for 54 river ports (16 German, 20 Czech, 7 Hungarian, 3 Slovak, and 8 Austrian ports) on two important Central European waterways (the Elbe-Vltava and Danube waterways) were collected over 40 years. In total, 1056 plant species were found. Of these, 433 were alien, representing 41 % of the total number of species found in all of the studied Elbe, Vltava, and Danube ports. During comparison of floristic data from literary sources significant differences in the percentage of alien species in ports (50 %) and cities (38 %) were found. The number of alien species was closely related to port size, but the proportion of alien species expressed as a percentage of the total number of species did not depend significantly on port area. The proportion of alien species in both studied waterways decreased with distance from the sea and was highest in the Hungarian ports and lowest in the Czech Republic, Austria and Bavaria. Lower levels of shipping towards inland regions due to decreased river flow are likely the reason for this trend. The dissimilarity in the species composition of alien and native flora between individual river ports increased with increasing inter-port distance. Neophytes presented a stronger distance decay pattern than did either native species or archaeophytes of the Danube inland ports, potentially due to the different cargoes of individual ports, which may affect the introduction of different neophytes from different geographic areas. The results show that river ports in Central Europe should be regarded as a type of industrial area and deserve full attention with regard to the distribution and spread of alien plants.
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Williamson and Fitter adopted a statistical approach to study the proportion of imported species achieving different levels of invasion success--introduced, established, and pest. They found a regularity in these proportions and a predictability about deviations.
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Disjunct taxa within genera of herbaceous perennial plants relict to temperate eastern Asia and eastern North America exhibit a significant correlation in area of geographical range. This relationship suggests evolutionary stasis of traits related to ecological distribution over periods of at least 10 million and possibly more than 30 million yr. Because woody taxa lack this pattern but appear to exhibit broader ecological distributions on a local scale than do herbaceous taxa, we suggest that stasis goes hand in hand with ecological specialization; some restricted subsets of ecological conditions to which herbs are specialized may persist within a changing ecological mosaic.
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Nuclear 1C DNA content in haploid megagametophyte tissue of 18 North American and one exotic Pinus species was determined using scanning microspectrophotometry. The nuclear DNA content in root meristematic cells of Zea mays L. ssp. mays, inbred line Va35 (4C = 10.31 pg) was used as a standard. DNA content measured by microspectrophotometry was verified using laser flow cytometry with two additional standards, Hordeum vulgare cv. Sultan (2C = 11.12 pg) and P. eldarica (2C = 47.30 pg). DNA values obtained by both methods were significantly correlated (r = 0.987). The 1C nuclear DNA content ranged from 21 pg to 31 pg. The ratio of DNA content in embryo tissue of P. eldarica to that in megagametophyte tissue was 1.72 by scanning microspectrophotometry and 1.74 by laser flow cytometry. To date, this is the most comprehensive data set available for North American Pinus species. Relationships between genome size of 18 North American Pinus species and climatic factors and indices of growth were investigated using regression and correlation analyses. Positive correlations were observed between nuclear DNA content and growth indices, minimum seed-bearing age, and seed dimensions. Strong negative correlations were observed between nuclear DNA content and two climatic factors, the lowest mean annual and monthly precipitation (excluding January) and the highest mean monthly spring air temperature. These correlations suggest that the large genome size and its variation in Pinus are adapted responses to the habitats of these species.
Chapter
The invasion by alien species of new regions and territories is a phenomenon of paramount importance, particularly in the last four centuries after the ‘Great Discoveries’. Biological invasion is likely to acquire soon an even greater frequency, because of the current transportation systems and the forthcoming global climatic change. ‘Invader’ species have diverse sets of ecological, physiological, genetic and morphological characteristics that make them suitable for wide dispersion, colonization and competition. We refer to their intrinsic aptitude and potential for invasion as their ‘biological necessity’. Nevertheless, no one of the various sets of biological characteristics can fully explain success or failure to invade. It is indispensable for invaders to have caught opportunities to leave and to be transported, and to have found at their arrival open spaces, available resources and ecosystems poorly resistant to invasions. This is their ‘historical chance’. Among new patterns of invasion are those associated to the release of genetically designed organisms. Bioengineered organisms cannot be related to any of the existing biogeographical realms. A new world-wide ‘anthropogenic realm’, with its own peculiar characteristics and trends, is to be considered.
Chapter
A unique attribute of invaders is that they thrive in a country in which they did not evolve. In this chapter, I review the physiological, demographic and genetic attributes of invaders sensu stricto (excluding native weeds or colonists). When compared to similar native species, invaders often have features likely to endow them with higher relative fitness. However, the few available comparisons may constitute a biased sample. Attempts to generalize show that the invasive flora of a country is composed of a large array of plant types and that there are no attributes with which to characterize invaders in general. More specific approaches of invasions, centered on the invaders or the recipient habitats, are reviewed. The need for an approach combining ecolological and evolutionary features of habitats and introduced species is emphasized.
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The Eurasian and North African distributions of several species of Carduus, Centaurea and Onopordum were examined. Species that occur in Australia were significantly more widespread in their native continents than were species not recorded in Australia. Moreover, most species occurring in Australia characteristically co-exist in a limited subset of European countries. Thus, by implication, widespread species not yet known in Australia are more likely to colonize and establish in Australia than are narrowly distributed species, and widespread species that occur in the specified subset of countries have even higher probabilities of successful colonization of Australia. These findings may aid plant quarantine officials in making decisions with respect to the potential of various taxa to become weeds in Australia.-from Authors
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Basic features of weediness and successful worldwide colonists are reviewed with emphasis on genetic processes. Based on a review of breeding system and genetic variation patterns in Echinochloa crus-galli (barnyard grass) and Eichhornia crassipes (water hyacinth), two major aquatic weeds, strong evidence is found for the effects of founder events as well as strong selective pressures during colonization. Information on the genetic structure, reproductive biology, and evolutionary dynamics in the past and present would be helpful in devising effective methods of biological control. For example, there is indirect evidence for greater success in the biological control of asexually reproducing weeds. -from Author
Article
Annual brome grasses reach their highest specific diversity in areas of mediterranean climate, but many species are found under most climatic conditions except for humid-equatorial ones. Most Bromus species are native to Eurasia. Invasions from the Mediterranean Basin to other regions of mediterranean-type climate date back to the second half of the nineteenth century. The invaded regions have received between five (Chile) and 13 (California) of the 24 species native to the Mediterranean Basin. Of the invasions that would be possible if the only condition of success was the climatic similarity between the source and the recipient continents, only 37% can be demonstrated. The climatic width of the native distribution is positively correlated with the number of invaded mediterranean regions. The few species with a wide native climatic distribution, but found currenly only in one or two regions (viz. B. squarrosus, B. arvensis and B. secalinus) are serious potential invaders. -from Authors
Article
Forty nine British annual species were examined for characters or groups of characters that might relate to their ability to behave as weeds. The weediness score of a species was obtained from the opinions of 65 scientists working in a variety of botanical fields. It is often stated that weeds have groups of characters in common, but five different methods demonstrated that there were no characters which reliably distinguished weeds from non-weeds. A more successful approach may be comparison of the characters that differ between pairs of closely related species of which one is a weed, the other not. This approach identified an extended flowering season as being of potential importance. -from Authors
Article
Increment cores from 144 Fremont cottonwoods (Populus fremontii var. wislizeni) were taken at three riparian woodland sites along the Rio Grande in New Mexico. Trees at two study sites averaged 38.8 and 43.2 years old. All trees fewer than 26 years old at those sites were root suckers from older trees whose primary trunks had decayed. The third site, one of few known locations where young trees are present, had 75% of the trees between 5 and 25 years old. Cottonwood recruitment generally (but not always) could be associated with years of overbank flooding. The combination of a paucity of cottonwood regeneration over the last 30 years, the rapid colonization during this century of Russian-olive (Elaeagnus angustifolia) and salt cedar (Tamarix chinensis) into the valley, and current river channel management practices suggests that the Rio Grande riparian woodland will become dominated by the exotic shrubs over the next 50 to 100 years. To assure the continued survival of the cottonwood riparian community along the Rio Grande, resource managers need to implement strategies to enhance cottonwood regeneration and survival and to control the spread of exotics.
Article
Effects of experimental habitat disturbance on seedling establishment of Scotch broom Cytisus scoparius, an alien shrub species now naturalized in California, were examined at two locations (the Sierra Nevada foothills and the northern coastal region). Variation in the species and foraging behaviors of ant dispersers of Scotch broom at the two sites resulted in differences in local seed dispersion at these sites. At the foothill location, soil disturbance significantly promoted seedling establishment. At the coastal site quail and grouse preferentially foraged in disturbed areas. The interaction of seed predators and dispersers modified the abiotic effects of habitat disturbance on seedling establishment, resulting in no significant differences being found among habitat disturbance treatments at the coastal site. Results of this study indicate effects of disturbance on seedling establishment of a given species are not generalizable from one population or habitat to another.
Article
Photosynthetic activity of the cortical tissues of Cytisus scoparius. Link stems were examined in regard to individual biomass production and allocation, structural attributes of stem tissue, chlorophyll content, photosynthetic rates and ability to recover from herbivory. Biomass production and allocation were assessed through growth analysis of plants given one of four treatments: all stems loosely wrapped with aluminium foil; plants defoliated once; plants defoliated repeatedly; and controls. Stem photosynthesis made a significant contribution to growth and biomass production of this mesic species. Cortical stem tissue is structurally very similar to leaf tissue. Chlorophyll content and biomass accumulation of stems, leaves, roots, and nodules changed significantly with simulated herbivory. Apparently, in Cytisus scoparius, stem photosynthesis helps meet different needs, depending on which factor or combination of factors are most critical in any given habitat. For an invasive, weedy perennial like Cytisus scoparius, this flexibility may itself be the most important benefit of having photosynthetic stems. Photosynthetic stems may play an important role in the success of leguminous shrubs in general and in the success of invasive leguminous shrubs in particular.
Article
Data are presented on the amount of DNA in absorption units per nucleus for 43 species of frogs belonging to nine families. Values range from 4.5 au/nucleus in Scaphiopus holbrookii to 26 in Rana catesbeiana. Comparison of amounts of nuclear DNA and of minimum known durations of the larval stages indicates that the species that have the least amounts of nuclear DNA pass through the larval stages most rapidly. Data are also presented on the amount of nuclear DNA of two species of salamanders. It is suggested that a high level of DNA and low rate of development restrict some frogs and salamanders to the vicinity of permanent water while a low level of DNA and rapid rate of development allow other frogs to invade arid environments.
Article
Partial table of contents: Discriminant Analysis in Research. PREDICTION. Basic Ideas of Classification. Multivariate Normal Rules. Classification Results. Hit Rate Estimation. Nonnormal Rules. Reporting Results of a PDA. Applications of PDA. DESCRIPTION. Group Separation. Assessing Effects. Describing Effects. Selecting and Ordering Variables. Reporting Results of a DDA. Applications of DDA. ISSUES AND PROBLEMS. Special Problems. Appendices. Answers to Exercises. References. Index.
Article
Weed status in Australia was associated with being geographically widespread in southern Africa, being found in a wide range of climates in southern Africa, being described as a weed or targeted by herbicides in southern Africa, with early introduction and establishment in Australia, and with weediness in regions other than southern Africa. Multiple logistic regressions were used. The best fitting regressions were for weeds present for a long time in Australia (>140 yr). They utilized three variables, namely weed status, climatic range in southern Africa and the existence of congeneric weeds in southern Africa. The highest level of variation explained (43%) was obtained for agricultural weeds using a single variable, weed status in southern Africa. Being recorded as a weed in Australia was related to climatic range and the existence of congeneric weeds in southern Africa (40% of variation explained). Recently-arrived species which were predicted to become weeds are Acacia karroo (Mimosaceae), Arctotis venustra (Asteraceae), Sisymbrium thellungii (Brassicaceae) and Solanum retroflexum (Solanaceae). Analysis of the residuals of the regressions indicated two long-established species which might prove to be good targets for biological control: Mesembryanthemum crystallinum (Aizoaceae) and Watsonia meriana (Iridaceae). -from Authors
Article
The gross form of the nuclear genome varies greatly among plant species in both anatomy and genetic organization. Chromosome number (ft) ranges from 2 to over 600, and ploidy from 1 to over 20. The amount of DNA in the unreplicated haplophase genome (the 1C value) differs by more than 2500-fold among angiosperms. Although it has been questioned since the 1930s whether such variation is of adaptive significance and whether it is related, perhaps causally, with environmental factors, no direct or causal links have yet been found. However, variation in DNA C-value has far-reaching biological consequences and can be of considerable adaptive and hence ecological significance. Strikingly precise interspecific relationships exist between DNA C-value and many diverse phenotypic characters at the cellular level, and DNA can affect the phenotype in two ways, firstly by expression of its genie content and, secondly, by the biophysical effects of its mass and volume, the latter defined as nucleotypic effects. Nucleotypic variation in DNA C-value sets absolute limits to both the minimum size and mass of the basic unit of plant anatomy (i.e. the cell) and the minumum time needed to produce a similar cell with newly synthesized organic molecules. Moreover, in complex multicellular vascular plants, such effects at successive cell cycles are additive, so that DNA C-value influences many characters, including growth rate, seed weight, minimum generation time and type of life-cycle. Thus, the nucleotype profoundly affects where, when and how plants grow. Selection for a particular genomic form acting on its spatial or temporal consequences may occur at various levels ranging from the cell to the whole organism and may operate throughout the life-cycle or at just one stage. DNA C-value is often indirectly related to environmental factors which determine time-limited environments via selection acting on the temporal phenotypic consequences of nucleotypic variation. However, in the case of radio-sensitivity, selection for a low DNA C-value may act directly on the nucleotype itself, as the size of the nuclear DNA target directly affects the ability of the plant to survive.
Article
Bitter orange (Citrus aurantium), sweet orange (C. sinensis) and an intermediate type became naturalized in eastern Paraguay soon after the introduction of citrus some four centuries ago. Dissemination of the abundant propagules to uncultivated sites is achieved via the gaudy and buoyant fruit by birds, mammals, water and man. Three kinds of factors explain the widespread presence of wild-growing orange. One is the hereditary predisposition of the species to volunteer and, at the same time, to survive in the forest under-story. Another group of factors is the favourable biophysical environment- a humid subtropical climate, stratified arboreal vegetation and a rolling surface-which proved receptive to feral citrus establishment. Human influences in seed dispersal, relieving competition, and grove abandonment favoured the presence of orange in the Paraguayan landscape. The trees have benefited from farming, lumbering and grazing practices and the intermittent use of the fruit, wood and leaves. Additional studies of cultigen behaviour outside of man's control are needed to clarify the general requisites and stages of the volunteering process.
Article
Bitter orange (Ctirus aurantium), sweet orange (C. sinensis) and an intermediate type became naturalized in eastern Paraguay soon after the introduction of citrus some four centuries ago. Dissemination of the abunant propagules to uncultivated sites is achived via the gaudy and buoyant fruit by birds, mammals, water and man. Three kinds of factors explain the widespread presence of wild-growing orange. One is the hereditary predisposition of the species to volunteer and, at the same time, to survive in the forest understory. Another group of factors is the favourable biophysical environment--a humid subtropical climate, stratified arboreal vegetation and a rolling surface--which proved receptive to feral citrus establishment. Human influence in seed dispersal, relieving competition, and grove abandonment favoured the presence of orange in the Paraguayan landscape. The trees have benefited from farming, lumbering, and grazing practices and the intermittent use of the fruit, wood and leaves. Additional studies of cultigen behaviour outside of man's control are needed to clarify the general requisites and stages of the volunteeering process.
Article
Nuclear 1C DNA content in haploid megagametophyte tissue of 18 North American and one exotic Pinus species was determined using scanning microspectrophotometry. The nuclear DNA content in root meristematic cells of Zea mays L. ssp. mays, inbred line Va35 (4C = 10.31 pg) was used as a standard. DNA content measured by microspectrophotometry was verified using laser flow cytometry with two additional standards, Hordeum vulgare cv. Sultan (2C = 11. 12 pg) and P. eldarica (2C = 47.30 pg). DNA values obtained by both methods were significantly correlated (r = 0.987). The 1C nuclear DNA content ranged from 21 pg to 31 pg. The ratio of DNA content in embryo tissue of P. eldarica to that in megagametophyte tissue was 1.72 by scanning microspectrophotometry and 1.74 by laser flow cytometry. To date, this is the most comprehensive data set available for North American Pinus species. Relationships between genome size of 18 North American Pinus species and climatic factors and indices of growth were investigated using regression and correlation analyses. Positive correlations were observed between nuclear DNA content and growth indices, minimum seed-bearing age, and seed dimensions. Strong negative correlations were observed between nuclear DNA content and two climatic factors, the lowest mean annual and monthly precipitation (excluding January) and the highest mean monthly spring air temperature. These correlations suggest that the large genome size and its variation in Pinus are adapted responses to the habitats of these species.
Article
Seed dispersal and seedling establishment of Korean pine (Pinus koraiensis) were studied in Hokkaido, Japan, by means of: (1) observation of seed harvest and seed dispersal by animals; (2) distribution of the offspring (seedlings, saplings and juveniles); and (3) sowing experiments. 1.(1) Red squirrels (Sciurus vulgaris orientis) harvested and transported Korean pine cones away from seed sources and scatterhoarded seeds in clumps of 2–4 seeds under litter on the ground. Other vertebrates could harvest seeds only from the stripped cones left by red squirrels.2.(2) Korean pine offspring ranged up to 1.8 km distant from the nearest seed source, and regenerated intensively in young broad-leaved stands after improvement cutting or wind damage. Seventy-five percent of the clusters of 1-year-old seedlings consisted of 2–4 seedlings.3.(3) The establishment of Korean pine seedlings 5 years after sowing were initially most affected by seed disappearance. The best establishment occurred in the stands where floor vegetation was disturbed by improvement cutting after sowing.It is concluded that almost all of the offspring originated from widely scatterhoarded seeds around seed sources of red squirrels and the distribution of the offspring were ultimately decided by the fate of the scattered seeds.
Article
Potted seedlings of Chinese tallowtree (Sapium sebiferum [L.] Roxb.) and Carolina ash (Fraxinus caroliniana Mill.) were grown in 5%, 20%, 53%, and 100% of full sunlight. Growth and dry mass partitioning at all light levels, differences between leaf photosynthetic systems developed at 20% and 100% light, and crown profiles of net photosynthesis (PN) in 53% of full sunlight were measured. Tallowtree dry mass peaked at 100%, light while ash dry mass peaked at 53% light. Expressed as a proportion of peak dry mass within species, growth of tallowtree exceeded that of ash at all light levels except 53% of full sunlight. In all but 100% light, tallowtree partitioned more dry mass to leaves than did Carolina ash. For plants grown in 100% light, PN was highly variable with low values in some tallowtree and most ash leaves, although highest PN occurred in ash. For plants grown in 20% light, PN was closely related to photosynthetic photon flux density (PPFD), and both species had similar PN Values at any given PPFD. For plants in 53% light, maximum PN occurred at the top of the crown in tallowtree and in the middle of the crown in Carolina ash. Tallowtree seedlings are shade tolerant and yet grow rapidly in full sun. For. Sci. 36(4):851-862.
Article
The reduction of species richness of indigenous plants is one of the major problems associated with the presence of dense stands of invasive alien trees and shrubs in the Fynbos Biome of the Cape Province, South Africa. A synthesis was made of published and unpublished data on plant species richness in fynbos with different levels of invasion and different histories of control. Linear regressions of species richness on the log of quadrat size were significant for both uninvaded fynbos and fynbos under dense stands of alien trees and shrubs. The slopes of the regression equations did not differ significantly between invaded and uninvaded sites, but elevations were significantly different, indicating a marked reduction in richness of indigenous plant species in invaded areas. The linear regression of species richness on quadrat size for cleared areas was not significant, but quadrats at most cleared sites showed species richness values intermediate to those of uninvaded fynbos and dense stands of aliens. Reductions in species richness at the scale of the sample quadrats used in this study (4–256 m) occur once the canopy cover of aliens exceeds about 50% and there is evidence of reduced species richness with increased time of suppression. For this reason, stands should be cleared before canopy closure is achieved.
Article
Many factors interact to determine whether an introduced organism will become invasive. The widespread planting of many Pinus species at various densities and in many habitats at different times in the Southern Hemisphere (well outside their natural range) provides a unique opportunity to identify the determinants of invasive success for a large group of related organisms. At least sixteen pine species have spread from planting sites to invade natural or semi-natural vegetation. Species with adventive populations over fairly large areas are P. contorta Dougl., P. halepensis Mill., P. nigra Arnold, P. patula Schiede & Deppe, P. pinaster Ait., P. ponderosa Laws., P. radiata D. Don and P. sylvestris L. This paper explores the biological profiles of successful invaders, the inherent and induced susceptibility of different vegetation types to invasion, patterns of invasion, the role of disturbance in initiating and sustaining invasions, the role of time, and the various functions of the resident biota in the receiving habitat in mediating the outcome of an introduction. This information, with evidence from contemporary studies of pine dynamics in the Northern Hemisphere and reconstructions of pine migrations in the early Holocene, shows that: (1) Most of the important invaders share a suite of biological traits that facilitate long-distance dispersal by wind, and allow invading populations to persist in habitats subjected to frequent disturbance. (2) The extent of invasion for widely planted species is positively correlated with the residence period. (3) Ground-cover categories can be ranked according to their vulnerability to invasion as follows: forest < shrubland < grassland < < dunes < bare ground. (4) Disturbance regimes and the resident biota have a marked (and complex) influence on invadability. This information is used to predict future trends in pine invasions.
Article
At a site near Armidale, New South Wales, Australia, unplanted individuals of two plant species not native to the region (Grevillea rosmarinifolia and Viola odorata) grow predominantly within 5 m of a nest of the ant Iridomyrmex purpureus, which is situated 40–50 m from planted, parent individuals. Seeds of both species, but not of two other plant species (Dianthus barbatus. Nigella damascena) not growing near the nest, were shown to be attractive to ants. Marked seeds of V. odorata were observed being carried into the I. purpureus nest, and some (with most of the elaiosome removed) were later discarded by ants from the nest. Plant invasion apparently is being facilitated by myrmecochory.
Article
The Brush-tailed possum Trichosurus vulpecula eats the fleshy fruits of the introduced shrub Crataegus monogyna and defaecates intact seeds at least 0–50 m away. Viability of seeds recovered from faeces was >73%. comparable to the viability of fresh seeds (87.6%). Seed dispersal by possums has been largely neglected and may have important implications for invasion by woody weeds in Australasia.
Article
Plant quarantine agencies attempt to regulate the continuing worldwide problem of spread of alien plants, but systems of plant quarantine have not been based entirely on objective criteria. Comparative epidemiological research of known alien weeds may provide such criteria and thereby improve the success of plant quarantine. For this reason biogeographical and ecophysiological data were gathered and analyzed for Echium (Boraginaceae), especially for the three differentially distributed and weedy species in Australia: E. italicum L. (rare), E. vulgare L. (uncommon), and E. plantagineum L. (common). Such data included the following: native distributions in Eurasia and North Africa, historical spread in Australia, seed germination, vegetative growth and propensity to flower. Quantitative plant characteristics which distinguish weedy species of Echium from their innocuous counterparts, and whose values could most easily be determined by plant quarantine officials, are the breadth of native distribution and rapidity of seed germination. Although these results were derived from only a few temperate taxa, they may apply in principle to many species.
Article
South African mountain fynbos has been severely invaded by trees and shrubs introduced from other mediterranean-climate regions. Management of these invasions should involve controlling current invaders and screening future introductions. Invasion windows are described and functional groups are defined for pines based on life history attributes important for invasion in the fire-prone mountain fynbos. The most successful invasive pines here (Pinus halepensis, P. pinaster and P. radiata) are fire-resilient and have small seeds, low seed-wing loadings, short juvenile periods, moderate to high degrees of serotiny and relatively poor fire-tolerance as adults. Other species with these attributes, especially from mediterranean-climate regions, wouldbe high-risk introductions. Taxa in other functional groups have not become major weeds even with widespread man-aided dissemination.
Article
Differences in major selective forces important in early and late successional communities should influence niche breadth and degree of overlap. Early successional species may not experience consistent, strong selection against competition and can be expected to have broader niches with more overlap than later successional species. This paper presents data from 2 early successional winter annuals that show clear niche separation under conditions in which coevolution is unlikely. Lactuca scariola L. and Erigeron annuus (L.) Pers. flower in mid-summer and attract the same insect visitors. Erigeron, the more common species, begins to flower in mid-morning when insect visitors are quite active. Lactuca flowers open earlier in the morning and close just before Erigeron flowers open. The early morning hours are not optimum for Lactuca visitation, as most of the visits occur just before floral closing. Both species can selffertilize without a vector, and Lactuca was introduced from Europe. It is, therefore, not possible that niche separation inflowering time and subsequent time of visit in Erigeron and Lactuca is a result of coevolutionary niche differentiation between the two species. This separation is likely to be a preadaptation resulting from coevolution with other species.
Article
Invaders, weeds and colonizers comprise different but overlapping sets of species. The probability of successful invasion is low. The 10:10 rule state that 10% of introduced speices (those with feral individuals) become established, 10% of established species (those with self-sustaining populations) become pests. The rule gives an adequate fit to British plant data. The rule predicts that invaders will be rarer than natives. This is shown for British Anatidae. There is a continuous spectrum of perceived weediness. Although this spectrum is significantly related to Baker characters, neither those characters or any others can usefully predict which species will be weeds over a wide range of species. Characters tuned to sets of closely related species shown more promise. A study of BritishImpatiens shows that the characters responsible for critical ecological behaviour are still obscure. Small genetic changes can cause large ecological changes. GMOs will have characters entirely new to that species' evolutionary history. While most will have little ecological effect, a few may be ecologically and economically damaging. A sensible programme of field trials and monitoring is justified to minimize the risk.
Article
Sixty-five scientists, from different disciplines and including agriculturalists, ecologists, taxonomists, conservationists and gardeners, were questioned as to the weed status of forty-nine annual species occurring in the United Kingdom. The views held by the different groups were compared. Ecologists, agriculturalists and gardeners considered weedy species to be more weedy than average, whereas conservationists viewed weedy species as being less weedy than average. The month in which flowering ends, the ability to survive gut dispersal, and the ability to germinate in spring differed between the weedy and non-weedy species. The implications for conservation and ecology are discussed.
Article
Myrica faya, an introduced actinorhizal nitrogen fixer, in invading young volcanic sites in Hawaii Volcanoes National Park. We examined the population biology of the invader and ecosystem-level consequences of its invasion in open-canopied forests resulting from volcanic cinder-fall. Although Myrica faya is nominally dioecious, both males and females produce large amounts of fruit that are utilized by a number of exotic and native birds, particularly the exotic Zosterops japonica. In areas of active colonization, Myrica seed rain under perch trees of the dominant native Metrosideros polymorpha ranged from 6 to 60 seeds m⁻² yr⁻¹; no seeds were captured in the open. Planted seeds of Myrica also germinated an established better under isolated individuals of Metrosideros than in the open. Diameter growth of Myrica is > 15-fold greater than that of Metrosideros, and the Myrica population is increasing rapidly. Rates of nitrogen fixation were measured using the acetylene reduction assay calibrated with ¹⁵N. Myrica nodules reduced acetylene at between 5 and 20 μmol g⁻¹ h⁻¹, a rate that extrapolated to nitrogen fixation of 18 kg ha⁻¹ in a densely colonized site. By comparison, all native sources of nitrogen fixation summed to 0.2 kg ha⁻¹ yr⁻¹, and precipitation added < 4 kg ha⁻¹ yr⁻¹. Measurements of litter decomposition and nitrogen release, soil nitrogen mineralization, and plant growth in bioassays all demonstrated that nitrogen fixed by Myrica becomes available to other organisms as well. We conclude that biological invasion by Myrica faya alters ecosystem-level properties in this young volcanic area; at least in this case, the demography and physiology of one species controls characteristics of a whole ecosystem.
Article
Biological invasions by exotic species alter the composition and community structure of invaded areas. There is increasing evidence that they can also alter properties of whole ecosystems, including productivity, nutrient cycling, and hydrology. The exotic actinorrhizal nitrogen-fixer Myrica faya alters primary successional ecosystems in Hawaii Volcanoes National Park by quadrupling inputs of nitrogen, the nutrient limiting to plant growth. Biological invaders change ecosystems by differing from native species in resource acquisition and/or resource use efficiency, by altering the trophic structure of the area invaded, or by altering disturbance frequency and/or intensity. Where exotic species clearly affect ecosystem-level properties, they provide the raw material for integrating the methods and approaches of population and ecosystem ecology. -from Author
Article
Asks 1) what attributes of communities make them more likely to be invaded? and 2) what attributes of individual species make them more likely to be successful invaders? Data are drawn from 1) the large-scale, but unintentional introduction of alien plant species into British plant communities, and 2) the recorded attempts to establish introduced insects for the biological control of weeds. -from Author