Mapping invasive plants with citizen science. A case study from Trieste (NE Italy)

Abstract

A citizen science initiative was launched in the province of Trieste, aimed at mapping the distribution of Ailanthus altissima, Ambrosia artemisiifolia and Senecio inaequidens. The reliability of citizen data was tested against control data obtained by trained personnel with a stratified random sampling. In spite of the lack of a strict sampling strategy, citizen data were highly correlated with control data. This was mainly due to: 1) the easy identification of the species and 2) the instructions given to citizens for selecting their observation areas and for avoiding duplicate records. The three species tend to be most frequent in disturbed areas; Ailanthus is highly concentrated in the urban area, Senecio is widely distributed but avoids the city centre, with the highest frequency in the industrial area and along the railways, Ambrosia has a similar pattern, but is most frequent in areas with calcareous substrata. The interpretation of the distribution patterns in terms of land use and ecological factors proved to be quite easy when the three species are considered together (higher frequency in disturbed areas), less so when they are considered separately, most probably because of historical and sociological factors, such as incomplete migration into the survey area, and “gentrification effects”.

Keywords:

• Ailanthus altissima
• alien species
• Ambrosia artemisiifolia
• distribution patterns
• Friuli Venezia Giulia
• Senecio inaequidens

Acknowledgments

This study was financed by the Interreg project SiiT (School-oriented Interactive Identification Tools: exploring biodiversity in a cross-border area), funded under the Interreg program Italy-Slovenia 2007-2013, the European Regional Development Fund and national funds, and by the CSMON-LIFE project (LIFE13 ENV/IT/842), funded in the framework of the LIFE + Programme. We are also grateful to citizens and botany students involved in data collection, and to dr. Paola Ganis for technical support.

Disclosure statement

No potential conflict of interest was reported by the authors.