Stampa Layout 1 - IUCN Invasive Species Specialist Group

horizontalis, Rhododendron ponticum, Rosa rugosa,
Spiraea alba and Spiraea douglasii) are included
in the Belgian black list, being invasive in
very specific site conditions such as dune ecosystems,
heathlands or dry grasslands.
The socio-economic survey also included some
questions to perceive how a code of conduct would
be welcomed by the horticultural sector. Interestingly,
a large proportion of surveyed horticulture
professionals had a strong willingness to change
their attitude and take concrete action to reduce the
dissemination of IOP in the environment. 54% of
nurserymen would agree to stop selling IOP and
more than 65% of private and public green managers
agreed not to plant them in the future. 86%
of gardeners claimed they would prefer to buy
their plants in nurseries which do not sell invasive
plants (e.g. in nurseries engaged in codes of conduct).
Towards a Belgian code of conduct
Round table discussions were conducted at the initiative
of the AlterIAS team to identify workable
measures to reduce trade and use of IOP in Belgium
and develop a sectorial code of conduct taking
into account both the environmental impact
and the economic value of IOP. A code working
group was established in October 2010 gathering
representatives of the Belgian Forum on Invasive
Species and of the main horticulture federations
active in the country.
Two target groups were consulted, i.e. ornamental
plant producers and sellers (nurseries and garden
centers) and ornamental plant users (public
green managers, landscape architects, garden
contractors and representatives of botanical gardens).
Five main preventive measures were identified
by the working group: to know the list of
IOP, to disseminate information on IOP and alternatives
to customers, to stop selling or planting
IOP, to promote the use of non invasive (alternative)
ornamental plants and to participate in early
detection of new invaders.
The key measure of the code is the limitation of
IOP use.
As a ban on the production and the planting of all
the black and watch list species would not be immediately
accepted by some of the working group
participants (i.e. plant producers), it was decided
to develop a code with two main engagements depending
on the plant species.
The first corresponds to a commitment to stop selling
or planting species (including cultivars and varieties)
from a consensus list including 28 terrestrial
and aquatic IOP, which represents 67% of the
black list species and 30% of the watch list species
(figure 2).
Fig. 2 Relationship between the willingness of code representatives
to include IOP species in the consensus list
and their economic value
The second refers to a commitment to inform gardeners
and citizens about potential threats linked to
the used of other black and watch list species. The
willingness of sector representatives to include IOP
species in the consensus list was directly linked to
their economic value: no agreement was found to
include plant species with a high economic importance
in this list (figure 3).
On top of that, species that only invade very specific
habitats were hardly perceived as detrimental
by horticulturists because of their limited distribution.
It should be noted that another preventive measure
that is often cited in codes of conduct on IOP is the
adoption of labelling practices mentioning invasiveness
peculiarities (e.g. ability to escape, ecosystems
at risk, etc.).
This measure was however considered as poorly applicable
by the working group participants as it is
costly, time consuming and detrimental to the green
image of the sector.
They preferred to choose a system where detrimental
species are not distributed anymore when a
strong environmental impact has been demonstrated.
This code is nearly finalised and its implementation
is expected to start in June 2011. As with other codes
of conduct, it will be a voluntary tool based on the
principle of self-regulation. This instrument allows
more flexibility than legally binding measures and
is well adapted to the specificity of horticultural
trade.
Similar or equally appealing non-invasive plants can
often be used as alternatives and moreover, the high
public visibility of the horticulture trade increases
the potential for self-regulation within this industry
wishing to project an environmentally friendly image
(Baskin 2002, Harrington et al. 2003, Heywood
& Brunel 2008).
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