Latest Articles from NeoBiota Latest 15 Articles from NeoBiota https://neobiota.pensoft.net/ Fri, 29 Mar 2024 12:03:57 +0200 Pensoft FeedCreator https://neobiota.pensoft.net/i/logo.jpg Latest Articles from NeoBiota https://neobiota.pensoft.net/ Tracing the origins and tracking the movements of invasive rubber vines (Cryptostegia spp., Apocynaceae) https://neobiota.pensoft.net/article/109180/ NeoBiota 89: 95-133

DOI: 10.3897/neobiota.89.109180

Authors: Marion K. Seier, Alessandro Rapini, Kate M. Pollard, Robert W. Barreto, Harry C. Evans

Abstract: Cryptostegia grandiflora and C. madagascariensis (Apocynaceae) are the only two species of this Madagascan plant genus. Both have been transported around the world as ornamentals due to their attractive flowers and based on a perceived potential as sources of rubber – hence, the common name rubber vine – because of their copious latex, which also contains toxic cardiac glycosides. As a result of their vigorous growth and ability to climb over and smother vegetation, both species have become invasive, posing an actual or potential threat to native ecosystems in many tropical and sub-tropical countries, as well as to human and animal health. Classical biological control (CBC), or the introduction of co-evolved natural enemies to control an invasive alien species in its exotic range, has successfully been used to tackle C. grandiflora in northern Queensland, Australia. This strategy is currently being evaluated for its suitability to manage C. madagascariensis in north-eastern Brazil using the same Madagascan rust fungus, Maravalia cryptostegiae, released as a CBC agent in Australia. For CBC to be successful, it is critical to understand the taxonomy of the invader as well as the origin(s) of its weedy biotype(s) in order to select the best-matched co-evolved natural enemies. Based on an exhaustive search in published and unpublished sources, we summarise the taxonomy and uses of these rubber vines, follow their historical movements and track their earliest records and current weed status in more than 80 countries and territories around the world.

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Review Article Wed, 8 Nov 2023 16:48:27 +0200
Escape from the garden: spreading, effects and traits of a new risky invasive ornamental plant (Gaillardia aristata Pursh) https://neobiota.pensoft.net/article/97325/ NeoBiota 83: 43-69

DOI: 10.3897/neobiota.83.97325

Authors: Gabriella Süle, Zsombor Miholcsa, Csaba Molnár, Anikó Kovács-Hostyánszki, Annamária Fenesi, Norbert Bauer, Viktor Szigeti

Abstract: Ornamental plants constitute a major source of invasive species. Gaillardia aristata (great blanketflower) is planted worldwide and its escape has been reported in several European countries without ecological impact assessment on the invasive potential. As there is a markedly spreading population with invasive behaviour in Hungary, we aimed to reveal the distribution, impacts and traits of G. aristata. We gathered occurrence data outside the gardens in Hungary, based on literature, unpublished observations by experts and our own records. We investigated the impacts of an extended population, where the species invaded sandy old-fields within a 25 km2 area. Here, we compared the species richness, diversity, community composition and height of invaded and uninvaded vegetation. Furthermore, we evaluated the traits potentially associated with the invasiveness of G. aristata in comparison with other herbaceous invasive species in the region. We found that G. aristata occurred mostly by casual escapes, but naturalised and invasive populations were also detected in considerable numbers. G. aristata usually appeared close to gardens and ruderal habitats, but also in semi-natural and natural grasslands and tended to spread better in sandy soils. We found lower plant species richness and Shannon diversity in the invaded sites and the invasion of G. aristata significantly influenced the composition of the plant community. The trait analyses revealed that the invasive potential of G. aristata is backed by a wide germination niche breadth, extremely long flowering period, small shoot-root ratio (large absorption and gripping surface), large seeds (longer persistence) and dispersal by epizoochory of grazing livestock (mostly by sheep), probably helping the species’ survival and spreading in the disturbed, species-poor, sandy, open habitats. These functional traits, as well as the ornamental utilisation, may act together with the aridisation of the climate and the changing land-use practices (e.g. abandoned, disturbed sites) in the success of G. aristata. We raise awareness of the rapid transition of G. aristata from ornamental plant to casual alien and then to invasive species in certain environmental conditions (i.e. sandy soils, species-poor communities, human disturbances), although it seems to be not a strong ecosystem transformer so far. Nonetheless, banning it from seed mixtures, developing eradication strategy and long-term monitoring of this species would be important to halt its spreading in time.

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Research Article Thu, 23 Mar 2023 18:14:07 +0200
Spreading of the cup plant (Silphium perfoliatum) in northern Bavaria (Germany) from bioenergy crops https://neobiota.pensoft.net/article/94283/ NeoBiota 79: 87-105

DOI: 10.3897/neobiota.79.94283

Authors: L. Marie Ende, Marianne Lauerer

Abstract: Invasive species can be the cause of severe problems for biodiversity, economy and human health. The cup plant (Silphium perfoliatum) is native to eastern North America and is increasingly cultivated in Germany as a new bioenergy crop. Its growth characteristics and autecology do not exclude a possible invasive potential. However, there are hardly any studies on this to date. In this study, habitat requirements for spontaneous colonization and establishment of the cup plant were investigated. Therefore, a 15 m radius around eleven cup plant fields in northern Bavaria (Germany) was examined. Data on cup plant colonization, habitat type, vegetation structure, ground cover, and further site conditions using the Ellenberg indicator values were collected and analyzed by logistic regression models. Spontaneously colonized cup plants were found in a wide range of habitats. Open habitats and human settlement areas were particularly suitable, especially field margins and agricultural paths. A portion of open soil of about 25% was preferentially colonized. Cup plants occurred predominantly within the first few meters of the field margin and increasingly around cup plant fields that have existed for a longer period. Favorable for the development of stems and thus for flowering, fruiting and establishing are warmer sites with a high herb layer. Individual plants that had developed a stem persist for several years and increased their stem number over time. The number of stem-developing individuals also increased over time. Thus, there exist an enormous potential for spread in the future. However, an invasive potential could not be confirmed based on the present study, because a threat of biodiversity was not proven.

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Research Article Fri, 23 Dec 2022 13:53:01 +0200
The distribution and impact of an invasive plant species (Senecio inaequidens) on a dune building engineer (Calamagrostis arenaria) https://neobiota.pensoft.net/article/78511/ NeoBiota 72: 1-23

DOI: 10.3897/neobiota.72.78511

Authors: Ruben Van De Walle, François Massol, Martijn L. Vandegehuchte, Dries Bonte

Abstract: Disturbance is thought to enhance the probability of invasive species establishment, a prerequisite for naturalisation. Coastal dunes are characterised by disturbance in the form of sand dynamics. We studied the effect of this disturbance on the establishment and spread of an invasive plant species (Senecio inaequidens) in European coastal dunes. Local sand dynamics dictate the spatial configuration of marram grass (Calamagrostis arenaria). Therefore, marram grass configuration was used as a reliable proxy for disturbance. Since marram grass plays a crucial role in natural dune formation, we evaluated the possible effects S. inaequidens could have on this process, if it is able to naturalise in European coastal dunes. We expected the highest probability of S. inaequidens establishment at intermediate marram grass cover because too low cover would increase sand burial, whereas high cover would increase competition. However, our results indicate that S. inaequidens is quite capable of handling higher levels of sand burial. Thus, the probability of S. inaequidens establishment was high under low marram cover but slightly lowered when marram cover was high, hinting at the importance of competition. We expected a negative impact of Senecio-altered soils on marram grass growth mediated by soil biota. However, marram grass grew better in sand gathered underneath Senecio plants due to abiotic soil modifications. This enhanced growth may be caused by Senecio leaf litter elevating nutrient concentrations in an otherwise nutrient-poor substrate. If such increased plant growth is a general phenomenon, further expansion of S. inaequidens could accelerate natural succession in European coastal dunes.

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Research Article Fri, 4 Mar 2022 16:29:26 +0200
Competitive ability of native and alien plants: effects of residence time and invasion status https://neobiota.pensoft.net/article/63179/ NeoBiota 65: 47-69

DOI: 10.3897/neobiota.65.63179

Authors: Christine S. Sheppard, Marco R. Brendel

Abstract: Competition is commonly thought to underlie the impact of plant invasions. However, competitive effects of aliens and competitive response of natives may also change over time. Indeed, as with time, the novelty of an invader decreases, the accumulated eco-evolutionary experience of resident species may eventually limit invasion success. We aimed to gain insights on whether directional changes in biotic interactions over time or more general differences between natives and aliens, for instance, resulting from an introduction bias, are relevant in determining competitive ability. We conducted a pairwise competition experiment in a target-neighbour design, using 47 Asteraceae species with residence times between 8 years-12,000 years in Germany. We first tested whether there are differences in performance in intraspecific competition amongst invasion status groups, that is casual and established neophytes, archaeophytes or native species. We then evaluated whether competitive response and effects depend on residence time or invasion status. Lastly, we assessed whether competitive effects influence range sizes. We found only limited evidence that native target species tolerate neighbours with longer potential co-existence times better, whereas differences in competitive ability were mostly better explained by invasion status than residence time. Although casual neophytes produced most biomass in intraspecific competition, they had the weakest per-capita competitive effects on natives. Notably, we did not find differences between established neophytes and natives, both of which ranked highest in interspecific competitive ability. This lack of differences might be explained by a biased selection of highly invasive or rare native species in previous studies or because invasion success may result from mechanisms other than interspecific competitive superiority. Accordingly, interspecific per-capita competitive effects did not influence range sizes. Further studies across a broader range of environmental conditions, involving other biotic interactions that indirectly influence plant-plant interactions, may clarify when eco-evolutionary adaptations to new invaders are a relevant mechanism.

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Research Article Tue, 25 May 2021 09:28:00 +0300
Long term monitoring of recruitment dynamics determines eradication feasibility for an introduced coastal weed https://neobiota.pensoft.net/article/35070/ NeoBiota 50: 31-53

DOI: 10.3897/neobiota.50.35070

Authors: John K. Scott, Kathryn L. Batchelor, Bruce L. Webber

Abstract: Bitou bush (Chrysanthemoides monilifera subsp. rotundata) is a Weed of National Significance in Australia and has impacted a significant portion of the eastern coastline. Its discovery in Western Australia was, therefore, a cause for concern. Assessment and control of the isolated and well-defined population began in 2012. To assess the feasibility of eradication in Western Australia as a management outcome for bitou bush, we applied a rigorous data-driven quantification and prediction process to the control program. Between 2012 and 2018 we surveyed over 253 ha of land and removed 1766 bitou bush plants. Approximately 97 person-days were spent over the six years of survey. We measured the seed bank viability for five years starting in 2013, with the 2017 survey results indicating a decline of mean viable seeds/m2 from 39.3 ± 11.4 to 5.7 ± 2.2. In 2018 we found only ten plants and no newly recruited seedlings in the population. No spread to other areas has been recorded. Soil core studies indicate that the soil seed bank is unlikely to persist beyond eight years. Eradication of the population in Western Australia, defined as five years without plants being detected, therefore remains a realistic management goal. The information generated from the documentation of this eradication program provides invaluable insight for weed eradication attempts more generally: novel detection methods can be effective in making surveys more efficient, all survey methods are not entirely accurate and large plants can escape detection, bitou bush seeds persist in the soil but become effectively undetectable at low densities, and migration of seed was unquantifiable, possibly compromising delimitation. Continued monitoring of the Western Australian population will determine how much of a risk these factors represent to eradication as the outcome of this management program.

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Research Article Mon, 2 Sep 2019 15:07:40 +0300
Time to cut: population models reveal how to mow invasive common ragweed cost-effectively https://neobiota.pensoft.net/article/23398/ NeoBiota 39: 53-78

DOI: 10.3897/neobiota.39.23398

Authors: Suzanne T. E. Lommen, Eelke Jongejans, Melinda Leitsch-Vitalos, Barbara Tokarska-Guzik, Mihály Zalai, Heinz Müller-Schärer, Gerhard Karrer

Abstract: Roadsides are an important habitat for invasive common ragweed, Ambrosia artemisiifolia L., by facilitating seed dispersal. Reducing the size of roadside populations is therefore essential for confining this highly allergenic species. Here, we aim to determine the cost-effectiveness of mowing regimes varying in frequency and timing, by analysing population-level effects and underlying demographic processes. We constructed population models of A. artemisiifolia parameterised by demographic data for four unmanaged reference populations across Europe in two years. We integrated the effects of four experimental mowing regimes along Austrian road sides on plant performance traits of five years and experimental data on seed viability after cutting. All four experimental regimes reduced the projected intrinsic population growth rates (r) compared to the unmanaged controls by reducing plant height and seed viability, thereby counteracting increased size-dependent fecundity. The prevailing 2-cut regime in Austria (cutting during vegetative growth, here in June and just before seed ripening, here in September) performed least well and the reduction in r was mainly due to reduced seed viability after the second cut. The efficacy of the two best experimental regimes (alternative schemes for 2 or 3 cuts) was mainly due to cutting just before female flowering (here in August) by decreasing final adult plant height dramatically and thereby reducing seed numbers. Patterns were consistent across reference populations and years. Whether regimes reduced r below replacement level, however, varied per population, year and the survival rate of the seeds in the soil bank. Our model allowed projecting effects of five theoretical mowing regimes with untested combinations of cuts on r. By plotting r-cost relationships for all regimes, we identified the most cost-effective schemes for each cutting frequency (1–3 cuts). They all included the cut just before female flowering, highlighting the importance of cutting at this moment (here in August). Our work features i) the suitability of a modelling approach for the demography of an annual species with a seed bank, ii) the importance of seed viability in assessing mowing effects, iii) the use of population models in designing cost-effective mowing regimes.

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Research Article Wed, 27 Jun 2018 14:13:46 +0300
Biotic constraints on the establishment and performance of native, naturalized, and invasive plants in Pacific Northwest (USA) steppe and forest https://neobiota.pensoft.net/article/10820/ NeoBiota 34: 21-40

DOI: 10.3897/neobiota.34.10820

Authors: Brian M. Connolly, Jennifer Powers, Richard N. Mack

Abstract: Factors that cause differential establishment among naturalized, invasive, and native species are inadequately documented, much less often quantified among different communities. We evaluated the effects of seed addition and disturbance (i.e., understory canopy removal) on the establishment and seedling biomass among two naturalized, two invasive, and two native species (1 forb, 1 grass in each group) within steppe and low elevation forest communities in eastern Washington, USA. Establishment within each plant immigrant class was enhanced by seed addition: naturalized species showed the greatest difference in establishment between seed addition and no seed addition plots, native and invasive species establishment also increased following seed addition but not to the same magnitude as naturalized species. Within seed addition plots, understory canopy disturbance resulted in significant increases in plant establishment (regardless of plant immigration class) relative to undisturbed plots and the magnitude of this effect was comparable between steppe and adjacent forest. However, regardless of disturbance treatment fewer invasive plants established in the forest than in the steppe, whereas native and naturalized plant establishment did not differ between the habitats. Individual biomass of naturalized species were consistently greater in disturbed (canopy removed) versus undisturbed control plots and naturalized species were also larger in the steppe than in the forest at the time of harvest. Similar trends in plant size were observed for the native and invasive species, but the differences in biomass for these two immigration classes between disturbance treatments and between habitats were not significant. We found that strong limitations of non-native species is correlated with intact canopy cover within the forest understory, likely driven by the direct or indirect consequences of low light transmittance through the arboreal and understory canopy. Considered collectively, our results demonstrate how seed limitation and intact plant ground cover can limit the abundance and performance of naturalized species in Pacific Northwest steppe and low elevation forest, suggesting that local disturbance in both habitats creates microsites for these species to establish and survive. Future studies evaluating interactions between multiple barriers to establishment using more representatives from each immigration class will further reveal how biotic interactions ultimately influence the demography and distribution of non-native plants within these communities.

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Research Article Thu, 23 Feb 2017 10:55:53 +0200
Factors influencing the local scale colonisation and change in density of a widespread invasive plant species, Lantana camara, in South India https://neobiota.pensoft.net/article/5064/ NeoBiota 25: 27-46

DOI: 10.3897/neobiota.25.8354

Authors: Bharath Sundaram, Ankila J. Hiremath, Jagdish Krishnaswamy

Abstract: Identifying factors that underlie invasive species colonisation and change in density could provide valuable insights into the mechanisms of biological invasions and for invasive species management. We examined a suite of factors potentially influencing the landscape-level invasion of Lantana camara L., one of the most ubiquitous invasive species in South Asia. These factors included disturbance factors like forest fires, historical habitat modification, and edge effects, in addition to factors like propagule pressure and habitat suitability. We examined the relative importance of these factors on the colonisation and change in density of L. camara in the Biligiri Rangaswamy Temple Tiger Reserve, Western Ghats, India. We used extensive (1997–2008) datasets tracking the presence and abundance of L. camara and combined these with corresponding data on disturbances, propagule pressure, and habitat suitability. We used an information-theoretic model selection approach to determine the relative importance of each factor on the colonisation and change in density of L. camara. Colonisation was mainly a function of proximity to already established populations (i.e. propagule pressure), whereas increase in L. camara density appeared to be constrained by high fire frequency. Research and management efforts need to recognize the multi-dimensional nature of mechanisms underlying L. camara’s success during different invasion phases when strategizing interventions to mitigate its effects.

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Research Article Tue, 14 Apr 2015 00:00:00 +0300
Lantana camara L. (sensu lato): an enigmatic complex https://neobiota.pensoft.net/article/5061/ NeoBiota 25: 15-26

DOI: 10.3897/neobiota.25.8205

Authors: Neha Goyal, Gyan Prakash Sharma

Abstract: Lantana camara L., considered among the world’s worst invaders is in identity crisis and contentiously referred as Lantana camara L. (sensu lato). Taxonomic ambiguity in L. camara L. (sensu lato), a species complex is one of the grim caveats behind incompetence of its management efforts. Recognizing the extent of variability within the complex, we aim to highlight the need to circumscribe its composition to bring effective management and control efforts into practice. There is a need for clear terminology to examine weedy, naturalized and/or invasive complex constituents that have been placed under the contentious umbrella of ‘L. camara L. (sensu lato)’. The time is ripe for invasion ecologists, cytogeneticists and conservationists to collaboratively focus on disentangling the complex and integrate their knowledge and expertise into management and control programs.

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Research Article Tue, 14 Apr 2015 00:00:00 +0300
Aliens in Transylvania: risk maps of invasive alien plant species in Central Romania https://neobiota.pensoft.net/article/4527/ NeoBiota 24: 55-65

DOI: 10.3897/neobiota.24.7772

Authors: Heike Zimmermann, Jacqueline Loos, Henrik von Wehrden, Joern Fischer

Abstract: Using the MAXENT algorithm, we developed risk maps for eight invasive plant species in southern Transylvania, Romania, a region undergoing drastic land-use changes. Our findings show that invasion risk increased with landscape heterogeneity. Roads and agricultural areas were most prone to invasion, whereas forests were least at risk.

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Short Communication Fri, 16 Jan 2015 00:00:00 +0200
The effect of insect herbivory on the growth and fitness of introduced Verbascum thapsus L https://neobiota.pensoft.net/article/1262/ NeoBiota 19: 21-44

DOI: 10.3897/neobiota.19.5123

Authors: Hannah Wilbur, Christina Alba, Andrew Norton, Ruth Hufbauer

Abstract: A majority of the plant species that are introduced into new ranges either do not become established, or become naturalized yet do not attain high densities and are thus considered ecologically and economically unproblematic. The factors that limit these relatively “benign” species are not well studied. The biotic resistance hypothesis predicts that herbivores, pathogens and competition reduce growth and reproduction of individual plants and so suppress population growth of non-native species. We explored the effect of insect herbivory and surrounding vegetation on growth and fitness of the non-native biennial plant Verbascum thapsus (common mullein) in Colorado, USA. Mullein is widespread in its introduced North American range, yet is infrequently considered a management concern because populations are often ephemeral and restricted to disturbed sites. To evaluate the impact of insect herbivores on mullein performance, we reduced herbivory using an insecticide treatment and compared sprayed plants to those exposed to ambient levels of herbivory. Reducing herbivory increased survival from rosette to reproduction by 7%, from 70–77%. Of plants that survived, reducing herbivory increased plant area in the first year and plant height, the length of the reproductive spike, and seed set during the second year. Reducing herbivory also had a marked effect on plant fitness, increasing seed set by 50%, from about 48,000 seeds per plant under ambient herbivory to about 98,000 per plant under reduced herbivory. Our findings also highlight that the relationship between herbivory and performance is complex. Among plants exposed to ambient herbivory, we observed a positive relationship between damage and performance, suggesting that, as predicted by the plant vigor hypothesis, insect herbivores choose the largest plants for feeding when their choice is not restricted by insecticide treatment. In contrast to the strong effects of experimentally reduced herbivory, we found that cover of other plants surrounding our focal plants explained relatively little variation in performance outcomes. Overall, we found that herbivore-induced impacts on individual plant performance and seed set are substantial, and thus may help prevent this naturalized species from becoming dominant in undisturbed recipient communities.

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Research Article Fri, 11 Oct 2013 00:00:00 +0300
A review of the influence of root-associating fungi and root exudates on the success of invasive plants https://neobiota.pensoft.net/article/1231/ NeoBiota 14: 21-45

DOI: 10.3897/neobiota.14.2927

Authors: Cindy Bongard

Abstract: Plant-fungal interactions are essential for understanding the distribution and abundance of plants species. Recently, arbuscular mycorrhizal fungal (AMF) partners of non-indigenous invasive plants have been hypothesized to be a critical factor influencing the invasion processes. AMF are known to improve nutrient and moisture uptake, as well as disrupt parasitic and pathogenic microbes in the host plant. Such benefits may enable invaders to establish significant and persistent populations in environments previously dominated by natives. Coupling these findings with studies on invader pathogen-disrupting root exudates is not well documented in the literature describing plant invasion strategies. The interaction effects of altered AMF associations and the impact of invader root exudates would be more relevant than understanding the AMF dynamics or the phytochemistry of successful invaders in isolation, particularly given that AMF and root exudates can have a similar role in pathogen control but function quite differently. One means to achieve this goal is to assess these strategies concurrently by characterizing both the general (mostly pathogens or commensals) and AM-specific fungal colonization patterns found in field collected root samples of successful invaders, native plants growing within dense patches of invaders, and native plants growing separately from invaders. In this review I examine the emerging evidence of the ways in which AMF-plant interactions and the production of defensive root exudates provide pathways to invasive plant establishment and expansion, and conclude that interaction studies must be pursued to achieve a more comprehensive understanding of successful plant invasion.

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Review Article Wed, 22 Aug 2012 00:00:00 +0300
Plant pathogens as biocontrol agents for Cirsium arvense – an answer to Müller and Nentwig https://neobiota.pensoft.net/article/1226/ NeoBiota 13: 31-39

DOI: 10.3897/neobiota.13.3137

Authors: Michael Cripps, Graeme Bourdot, Karen Bailey

Abstract: /none/

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Letter To The Editor Wed, 16 May 2012 00:00:00 +0300
Ploidy levels and reproductive behaviour in invasive Hieracium pilosella in Patagonia https://neobiota.pensoft.net/article/1218/ NeoBiota 11: 25-31

DOI: 10.3897/neobiota.11.1349

Authors: František Krahulec, Anna Krahulcova

Abstract: Within a population of invasive Hieracium pilosella in Chilean Patagonia we found two ploidy levels, pentaploid and hexaploid. Each ploidy level was represented by one clone. Their reproductive system was apomictic (and thus replicating the maternal genome), with a low degree of residual sexuality. It is necessary to prevent the evolution of new biotypes via hybridisation with different clones of H. pilosella or other Hieracium species introduced into Patagonia.

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Research Article Wed, 30 Nov 2011 00:00:00 +0200