Publisher | Instituut voor Natuur- en Bosonderzoek |
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Number of pages | 78 |
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Publication status | Published - 2012 |
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Name | Rapporten van het Instituut voor Natuur- en Bosonderzoek |
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Publisher | Instituut voor Natuur- en Bosonderzoek (INBO): Brussel |
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No. | INBO.R.2012.13 |
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Invasive alien plants are of increasing global concern. These plants potentially harm local
biodiversity, economy, public health and road safety. Therefore, they are being increasingly
counteracted. Before going into action, knowledge is needed on the distribution of invasive
alien species, the desirability of their eradication and control methods.
In accordance with the Upper Scheldt Department of Waterwegen en Zeekanaal NV (W&Z),
INBO has performed an exploratory screening of the distribution of invasieve alien plants
along navigable watercourses in West- and East-Flanders (Belgium). This is a first attempt to
assess the problem of invasive alien species along these watercourses, in order to underpin
options for control.
In 2011 ca. 1250 kilometers were investigated for the presence of invasive alien plants, as
defined by the ISEIA-protocol. 23 invasive alien plant species were recorded, of which 13
belong to the ‘black list’ (species with the highest biological impact). The top 5 consisted of
Impatiens glandulifera, Fallopia japonica, Senecio inaequidens, Robinia pseudoacacia and
Heracleum mantegazzianum. The presence of invasive alien plants spanned 74 kilometers of
river bank (not taking overlap between species into account), 48 kilometers of which were
occupied by black-list species. The distribution of invasive alien plants is not uniform. Three
of the seven investigated districts hold significantly more invasieve alien plants: Ghent,
Upper Scheldt, and Dender and Moervaart. The lowest presence of invasive alien plants was
found along the Yser. Moreover, large differences were found between the districts regarding
the presence of species. E.g., Fallopa japonica and Impatiens glandulifera were prominent in
the District of Ghent, while Heracleum mantegazzianum was most common in the Upper
Scheldt district.
Based on literature, a table is presented in which the degree of potential nuisance is listed
for each observed species. This table supports the decision which species one may want to
control. Furthermore, a table is presented on the feasability to control species, taking into
account local species abundance and the effort needed to achieve success for each species.
This table will be applicable for those species that a manager would like to eradicate (see
nuisance table). Based on a decision tree, it is then possible to prioritize actions. Finally, an
overview is given of common control methods for the observed black-list species. It can be
concluded that current knowledge is still insufficient in order to tell with certitude which
method is best in each case. Knowledge gaps include effectiveness of measures on short and
longer terms, and cost-benefit tradeoffs. Obviously, such knowledge is crucial in deploying a
more efficient counteraction policy.