# Monitoring and management of populations of four invasive alien plants along the French national road network

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## Arnaud ALBERT¹ and Marine PAULAIS²

1 AFB, French Agency for Biodiversity, Division of Support for Public Policies, 94300 Vincennes, France

2 MTES, French Ministry for an Ecological and Solidary Transition, Directorate of Transport Infrastructures, 92055 La Défense, France
[arnaud.albert@afbiodiversite.fr](mailto:arnaud.albert@afbiodiversite.fr) and [marine.paulais@developpement-durable.gouv.fr](mailto:marine.paulais@developpement-durable.gouv.fr)

AGENCE FRANÇAISE
POUR LA BIODIVERSITÉ
ÉTABLISSEMENT PUBLIC DE L'ÉTAT

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## Context and objective

French Ministry in charge of the Environment (MTES), with the support of the French Agency for Biodiversity (AFB), has the purpose to map, in a comprehensive and harmonized manner, the current distribution of four invasive alien plants, located into the « green dependencies » along the national road network. These occurrence data will enable national authority and its local services to obtain an overview of the invasions, in order to define management objectives for the populations, with the aim of mitigating their adverse impacts, particularly on road safety, biodiversity conservation and public health.

### What?

Distribution of four selected invasive alien plants of national concern:

* Ambrosia artemisiifolia

* Heracleum mantegazzianum

* Ailanthus altissima

* Genus Reynoutria

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### Where?

* All along the 12.000 kilometers of the French national road network, operated and maintained by public authorities

* Green roadside dependencies: ditches, basins, interchanges, abandoned areas, rest areas, etc.

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### When?

* Two years: 2017 and 2018

* Inventory preferentially in July:

* Facilitated identification of species

* Respect of roadside management programs

* Respect of prefectoral orders against common ragweed

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### Who?

Collaboration of two organizations:

* 11 National Botanical Conservatories (CBN)

* 11 Interdepartmental Directorates of Roads (DIR)

Complementarity of scientific and operational staff

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## Materials and methods

* Development of a field protocol with 7 criteria to collect in order to describe, localize and characterize each population

<table><thead><tr><th>Variables</th><th>Modalities</th></tr></thead><tbody><tr><td>Name of the species</td><td>Reynoutria ; ailanthus ; ambrosia ; heracleum</td></tr><tr><td>Location on the network</td><td>Lateral dependency ; central dependency ; basin ; interchange ; service/rest area ; art work</td></tr><tr><td>Location on the dependency</td><td>Central land ; shoulder ; bottom of the ditch ; bank ; particular situation</td></tr><tr><td>Area of the population = length x width</td><td>&lt;1m² ; 1-20m² ; &gt;20m²</td></tr><tr><td>Density of the individuals within the population</td><td>Isolated individuals ; discontinuous patches ; continuous population</td></tr><tr><td>Type of the adjacent plot</td><td>Agricultural ; forested ; urban ; wet/aquatic ; other</td></tr><tr><td>Areas with stakes or risks in the vicinity</td><td>Bridge ; basin ; tunnel ; wall ; house ; dangerous area ; protected area</td></tr></tbody></table>

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Seven survey criteria for each population

* Acquisition of data by 3 agents using a speed-reduced vehicle to survey around 60 kilometers of road network per day

* Possibility of using mobile cameras and smartphone applications ; safety of agents and users is a priority

## Results and challenges

This project reflects the challenge of implementing a common, original, effective and feasible national method, due to territorial variations between organizations.

* Need for flexibility:
  * Tools: positioning systems or road markers?
  * Skills: experienced or trained agents?
  * Circulations: low or high speed?
  * Availabilities: services busy or free?
  * Budgets: full or partial actions?

* Need for preparation:
  * Planning of work
  * Meetings of coordination
  * Recall of the stakes
  * Tests of the method
  * Trainings of the agents

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Adaptability of the field protocol but need for homogeneous data in a national database

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Use of a vehicle and potentially of a camera to survey populations

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## Consequences and decisions

The establishment of a major database, the combination of the values of the survey criteria and the resulting precise maps will provide a decision-making tool to define the management objective for each population, declined into three categories:

* Populations to eradicate

* Populations to contain

* Populations without intervention

Management measures (mowing, etc.) will vary according to species, populations and situations. Phases of data updating are planned every four years to follow the evolution of the invasive populations and the impact of control programs.

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Definition of a management objective for each population after survey

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<figure><img src="image_19.png" /><figcaption>Ambrosia artemisiifolia</figcaption></figure>

<figure><img src="image_20.png" /><figcaption>Heracleum mantegazzianum</figcaption></figure>

<figure><img src="image_21.png" /><figcaption>Ailanthus altissima</figcaption></figure>

<figure><img src="image_22.png" /><figcaption>Genus Reynoutria</figcaption></figure>

State of the current knowledge of the distribution in natural environments (www.siflore.fcbn.fr)

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STRATÉGIE NATIONALE

relative aux espèces exotiques envahissantes

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## French and European frameworks

This program is a concrete case of « active surveillance » (specific, dedicated and organized inventory of invasive alien plants) for the following-up of widely spread terrestrial species, in the context of the obligation of the establishment of a national « surveillance system », for the implementation of the European Regulation on IAS and the associated National Strategy. It also presents a particular process to quickly and easily chase invasive alien plants along roads.

## References

Albert, A. (coord.) 2017. *Protocole d'acquisition de données sur les plantes exotiques envahissantes le long du réseau routier national*. Fédération des Conservatoires botaniques nationaux, Montreuil. 24 p.

Just, A. et al. 2015. SIFlore, a dataset of geographical distribution of vascular plants covering five centuries of knowledge in France: results of a collaborative project coordinated by the Federation of the National Botanical Conservatories. PhytoKeys, 56, 47-60.

European Regulation N° 1143/2014 of the European Parliament and of the Council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species. 21 p.

Ministère de l'Environnement, de l'Energie et de la Mer. *Stratégie nationale relative aux espèces exotiques envahissantes*. 44 p.

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