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| Baas, Wim J.; Holverda, Wout J.. |
| In het voorjaarsnummer van 1996 deden wij verslag van het spectaculaire woekeren van de Grote waternavel (Hydrocotyle ranunculoides). Gedurende de zomer en herfst van 1995 veroverde deze drijvende, oorspronkelijk uit Amerika afkomstige waterplant in recordtijd grote delen van vaarten in West- en Midden-Nederland. Zo massaal, dat bijvoorbeeld in Utrecht-Rijnsweerd de watergangen tot 4 maal toe moesten worden vrijgemaakt. Gezien de serieuze problemen die deze plant sinds enkele jaren in Australië oplevert is het van belang te weten of de Grote waternavel ook in onze streken een permanente bedreiging kan vormen. Zeker toen bleek dat de vegetatief groeiende plant onze laatste zachte winters had overleefd. |
| Tipo: Article / Letter to the editor |
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| Ano: 1996 |
URL: http://www.repository.naturalis.nl/record/528084 |
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| Baas, Wim J.; Holverda, Wout J.. |
| The appearance of the alien floating pennywort Hydrocotyle ranunculoides as an invasive weed of an urban waterway in Utrecht (the Netherlands) was the reason to do some research on the possible origin and the distribution of the weed. The plant, propagated in aquatic nurseries, probably escaped as a nuisance weed favoured by two successive abnormally hot summers, with little frost in-between. There are indications that the plant may withstand average Dutch winters. During the autumn of 1995 the species had been recorded on several localities in the Central, Western and Southern part of the Netherlands, one of which in a nature reserve. |
| Tipo: Article / Letter to the editor |
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| Ano: 1996 |
URL: http://www.repository.naturalis.nl/record/526523 |
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| Baas, Wim J.; Duistermaat, Leni (H.). |
| The first local invasion of the alien subtropical aquatic Floating Pennywort (Hydrocotyle ranunculoides) in urban waterways during the hot summer of 1995 seemingly ended due to a combination of mechanical removal of floating and terrestrial plant material and a subsequent severe winter. Recently however the plant proved to be hardy to even severe frost when protected bij natural vegetation. As a result a large area of waterways in and around the city ’s-Hertogenbosch became covered with floating mats of plants which had to be removed at the expense of high costs. This however could not prevent the plant from escaping to the river Meuse, and probably from there to a former tidal nature reserve. Although the species will probably be confined to eutrophic... |
| Tipo: Article / Letter to the editor |
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| Ano: 1999 |
URL: http://www.repository.naturalis.nl/record/526988 |
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