# What about the discoveries of new introduced alien plants in metropolitan France since 2012 ?

Arnaud Albert, Laetitia Guillard

► To cite this version:

Arnaud Albert, Laetitia Guillard. What about the discoveries of new introduced alien plants in metropolitan France since 2012?. 12th International Conference on Biological Invasions, Sep 2022, Tartu, Estonia. . hal-04914112

HAL Id: hal-04914112

https://ofb.hal.science/hal-04914112v1

Submitted on 27 Jan 2025

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# What about the discoveries of new introduced alien plants in metropolitan France since 2012 ?

## Arnaud ALBERT and Laëtitia GUILLARD

French Biodiversity Agency (OFB), Research and Scientific Support Division (DRAS), Species at Stake Service (SCGEE), Vincennes (94300), France
[arnaud.albert@ofb.gouv.fr](mailto:arnaud.albert@ofb.gouv.fr) and [laetitia.guillard@obf.gouv.fr](mailto:laetitia.guillard@obf.gouv.fr)

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RÉPUBLIQUE
FRANÇAISE

Liberté
Egalité
Fraternité

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OFB
OFFICE FRANÇAIS
DE LA BIODIVERSITÉ

## Context and objectives

Alien plants (APs) account for more than half of all introductions of alien species into metropolitan France and these introductions are increasing. To limit some future invasions of these, it is therefore necessary to act as upstream as possible in the invasion stages, particularly shortly after their introductions into the environment of these potentially invasive APs, according to **the principle of early detection and rapid response**.

To this end, a project to **identify new introduced APs** and to **determine their invasion risk** has been initiated at a national scale in France. The overall objective of the project is to draw up a **list of « alerts »**. This census also allows to **study the species traits related to the introduction success**.

## Results

### 1. What are the new introduced alien plants ?

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /><figcaption>Lysichiton americanus</figcaption></figure>

© Jérôme DAO, Conservatoire botanique national Pyrénées et Midi-Pyrénées

<caption>Myriophyllum heterophyllum</caption>

© Alexis LEBRETON, Office français de la biodiversité

<caption>Salvinia molesta</caption>

© Jérôme DAO, Conservatoire botanique national Pyrénées et Midi-Pyrénées

## Materials and methods

**Data sources :**

* TaxRef : database listing the taxa present in France, with the selection of casual introduced taxa, naturalized introduced taxa and invasive introduced taxa

* OpenObs : database gathering taxa occurrences in France, with the selection of the first record of the selected taxa into the environment

* Collaboration with the network of national botanical conservatories (CBN) and other relevant botanists to validate the census

**Approach :**

* Only mainland France (with Corse) in the last 10 years (since 2012)

* Creation of a **census table** of new introduced APs

* Study of the **introduction success** and of the **invasion risk**

<figure><img src="image_6.png" /><figcaption>Plant strata</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Habitat types</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>Location of the 124 new introduced APs in mainland France since 2012</figcaption></figure>

Source : OpenStreetMap - OpenObs, data transmitted by the INPN-national platform of the SINP, 20/04/2022 - TaxRef V15.0, taxonomic reference system for France, 16/12/2021

0 100 200 km

### 2. Which species traits contribute to the introduction success ?

<figure><img src="image_9.png" /><figcaption>Geographical origins</figcaption></figure>

<figure><img src="image_10.png" /><figcaption>Botanical families</figcaption></figure>

<figure><img src="image_11.png" /><figcaption>Life cycles</figcaption></figure>

<figure><img src="image_12.png" /></figure>

* Biological types : hemicryptophytes, geophytes and phanerophytes are the most concerned by introductions

<figure><img src="image_13.png" /></figure>

* Colonized habitats : "continental surface water", "artificial zone" and "cultivated zone" are the most concerned by introductions

## Discussion and implications

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* 124 new introduced APs have been discovered in metropolitan France since 2012 (this census will be regularly updated in the future)

Most of these species are terrestrial herbaceous plants and are introduced throughout the territory

<figure><img src="image_15.png" /></figure>

* The introduction success may be explained by (other characteristics have to be studied : uses, introduction pathways, reproduction modes, dispersal modes, etc.) :

* geographical origins : international trade with some continents favours introductions

* botanical families, life cycles and biological types : some groups of plants are more represented than others in the world, that increase the introduction success for these groups

* colonized habitats : mostly disturbed environments favour the arrival of species

These results will be related, in another project, to the introduction pressure and the introduction failure of alien cultivated plants

These results will also help producers and sellers of alien cultivated plants to pay attention to some risky profiles

<figure><img src="image_16.png" /></figure>

* The next steps of this project :

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<figure><img src="image_18.png" /></figure>

<figure><img src="image_19.png" /></figure>