fighting common ragweed (Ambrosia artemisiifolia) and other invasive plant species in Geneva state
problems and challenges
Generally speaking for IAS, the biggest challenge is that Geneva is at the lower area of the water basin.
Mountain rivers carry invasive species to Geneva.
To fight the problem, coordination with neighbours in other cantons in Switzerland or in France is of high importance. It is very difficult to bring everyone around the table to fight together, especially because we have neither the same laws nor do we have the required funds available for this. Grand Genève is an organization across the border (http://www.grand-geneve.org/enjeux-strategie/nature-paysage), with French and Swiss participation, that plans activities to take action on both sides of the border. Their mission is to coordinate action for nature conservation and especially for fighting invasive alien species. This is in a beginning phase and will take time to develop.
There is no real strategy to control entry of invasive species in the State of Geneva even if Switzerland disposes of a federal law that should help to control the circulation of IAS (see the annex 2 of the
“Ordonnance sur l’utilisation d’organismes dans l’environnement”). The State of Geneva completed this federal law with a cantonal law, based on a blacklist and a watchlist available on this web site:
http://www.infoflora.ch/fr/flore/neophytes/listes-et-fiches.html.
At the airport, customs monitoring should take place if someone carries plants on the list. However, it is difficult with seeds to have good control. The difficulty to ensure IAS entry control is the lack of customs staff to have effective control at the borders.
scope and size of impact
No precise data is available on the scope and size of the impacts of invasive species. In nature reserves it is not so bad, no valuable ecosystems have been lost because of invasive species.
In cultivation for example, the fields should not have more than a certain % of Solidago or Senecio per hectare. Farmers have to fight it. In the legislation this has been included in 2010. However, the legislation is not that effective for the moment, colleagues of the agriculture office cannot watch every year the results, as they cannot check every field. The monitoring is not possible at the moment because of limited human resources.
Only one impact has been measured, namely the economic impact of Ambrosia artemisiifolia for health care. An evaluation in France (Région Rhône Alpes) estimates it between 14 and 19 million Euros. This
includes allergens, medical consultations, specific tests, asthma attack treatment or short sick leave.
approach and activities
Education on the problem of invasive species is limited due to financial constraints and a lack of human resources. It is difficult to provide information directly to the key actors concerned. We spend some days every year with groups that take voluntary action against invasive species.
Concretely, the state of Geneva is not able to develop efficient prevention measures, because of the lack of human resources.
constraints and obstacles
It is most difficult to maintain funds in place, as it requires explaining to politicians that funds are needed every year without ending. For Ambrosia, the wind dissemination continues. Action has to be taken every year, even though the result is good now, the pollen will spread. Also with our partners, citizens, colleagues in other offices it remains difficult to explain that continuous efforts are needed.
For the moment there is a fixed fund for IAS
eradication in nature reserves. It is for fighting against the invasive species solidago, reynoutria, buddleia or ambrosia for example. If we try to develop new projects it is hard to justify the increase of the costs (especially for reynoutria, because the costs are very high). The main aim at the moment is to keep the actual quality of the nature reserves in place.
In addition, as mentioned before, another difficulty is to have human resources to work on this (border control, control of the plants sale in garden centers, communication and education, etc.).
social dimension
To fight invasive species, the role of nature
associations is very important. They are our partners and help us to communicate the issue and raise public awareness. The biggest one is Pro Natura.
La Libellule, is an NGO working on nature education and also talks about this topic. They are helping us in working with citizens. We should be more present to connect with persons who have a garden. That is missing at the moment.
In addition, associations of house owners also contribute to the information dissemination. They are especially helpful with garden owners.
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results and lessons learned
The lesson learned is to take action at the moment when we have the suspicion of a species that looks invasive. We have many botanic experts in Geneva.
If they see invasives they inform us. We should take measures at the beginning and do not give invasive species the time to spread. Always keep an eye on what is happening. Don’t think twice about taking action. As an example, Ludwigia grandiflora appeared in a natural pond, and the State took action as soon as they knew about its existence. This IAS is now eradicated.
On the other hand, we had discovered a moss species with our specialists and we decided to keep it as an experiment to see how it reacts and how fast it develops. This was an exception. The species was located on a stone and does not disseminate quickly.
That is a test but under strong control measures.
additional information
• The website of the state of Geneva: http://etat.
geneve.ch/dt/nature/neophytes-274-2001-12193.
html
• The federal law (http://www.admin.
ch/opc/fr/classified-compilati
on/20062651/201206010000/814.911.pdf)
• The cantonal law (http://www.geneve.ch/
legislation/rsg/f/s/rsg_L4_05p11.html)
• The website of the Grand Geneve http://www.
grand-geneve.org/
• Etat de Genève (2013), stratégie de lute contre les planters exotiques envahissantes 2012-2023.
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