The Multiple Meanings of the Cameraria ohridella Biological Invasion in Paris's Green Areas

Abstract

The article presents a study of the various meanings given by different actors to the biological invasion of Cameraria ohridella in Paris's green spaces. This insect of unknown origin has spread throughout Europe, mining the leaves of horse chestnut (Aesculus hippocastanum), a tree species widely distributed in European capital cities. The elaboration of a map of actors allowed the identification of the stages in the bioinvasion management. The research shows that: i) despite the existence of specialized regional and international species monitoring organizations, the key alert networks were of an informal nature; ii) Paris's Green Areas Directorate assessed and treated the invasive species with a rationale that did not include other sectors of society; iii) the effectiveness of the adopted measures was undermined by the fact that the Green Areas Directorate does not control all the parks or gardens within the city. Owners/managers acted independently, so allowing the development of new sources of infestation. The article concludes that the invasiveness of an ecosystem is not only shaped by its ecological traits but also by social organizations and policies.

Key Words:

• Alert networks
• Cameraria ohridella
• Aesculus hippocastanum
• urban green areas
• invasiveness
• management strategies

Acknowledgements

The ICTA–UAB group on the socio-economics of biological invasions is funded by FP 6 Integrated Project ‘ALARM’ (GOCE-CT-2003-506675). We would also like to extend particular thanks to Beatriz Rodríguez-Labajos, Iliana Monterroso, Laura Maxims, Sylvie Augustin, Joan Martinez Alier, Nicolas Kosoy, Jorge Walter and Alicia Novick for their valuable contributions. Moreover, we are particularly grateful to the different stakeholders that actively collaborated in the research process.

Notes

1. Île-de-France is one of the 22 administrative regions of France, composed mostly of the Paris metropolitan area.

2. Paris gardeners' inability to identify the impact was also observed at the national level in 2001. The INRA, in cooperation with the PHPS, which is part of a network of parks and gardens directors in France, sent to all members of the network a questionnaire on the impact of C. ohridella and a grid to aid recognition of the level of infestation. There was a very low rate of response (around 10%), and positive answers were mainly provided by those districts already suffering a strong impact.

3. Interview with M.B., technician of the Sustainable Planning Area, Green Areas and Environment Directorate of Paris. Paris, 7 December 2007.

4. Interview with C.L., head of the Technical Studies Area, Green Areas and Environment Directorate of Paris. Paris, 7 December 2007.

5. Interviews conducted with neighbouring municipalities and technicians from other jurisdictions. J.G., head of the Studies Area, Green Areas and Landscape Directorate of Val-de-Marne, 24 October 2007. S.A., researcher and C. ohridella expert from the National Institute for Agricultural Research (INRA), Orléans, 17 October 2007.

6. Interview with C.L., head of the Technical Studies Area, Green Areas and Environment Directorate of Paris. Paris, 7 December 2007.