# National management strategy for *Heracleum mantegazzianum*, an example of how France wants to control widely spread IAP

AGENCE FRANÇAISE
POUR LA BIODIVERSITÉ
ÉTABLISSEMENT PUBLIC DE L'ÉTAT

## Madeleine FREUDENREICH<fnref n="1" />, Guillaume FRIED<fnref n="2" />, Emmanuelle SARAT<fnref n="3" /> and Arnaud ALBERT<fnref n="1" />*

Contact e-mail of the corresponding author: *arnaud.albert@afbiodiversite.fr

## Objectives of a national management strategy

For **invasive alien species (IAS)** that are **widespread in France** such as Giant hogweed (*Heracleum mantegazzianum*), national eradication is no longer conceivable, because not all known populations can be managed due to lack of stakes or means. Choices have to be made on **where and how to manage the existing populations**.

In connection with the European IAS Regulation, the National IAS Strategy, the French Environment Code and the French Biodiversity Plan, the AFB is thus developing **national management strategies (NMS)** for these species. Mostly intended for **regional coordinations and local managers**, NMS aim to **provide a decision support tool** to determine gradually **priority regions**, areas, **populations** and interventions.

## Demonstration with Giant hogweed (Heracleum mantegazzianum)

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### The Giant hogweed

Monocarpic
perennial species
of the Apiaceae
family

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### An invasive species

* One single plant can produce between 5 000 and 100 000 seeds

* Seeds spread along roads, railways and watercourses

* The seed bank can persist in the soil for more than 7 years (Diadema, 2018)

* The sap can cause photodermatities

### Distribution in France

Habitats with good resource supplies, high light levels, disturbance or lack of regular management

Ex.: riparian forest, forest edge and clearing, meadows and wasteland (Fried, 2009)

<figure><img src="image_3.png" /></figure>

(FCBN and GBIF, 2019)

## Where to intervene and with which objectives ?

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1. **Prediction of the probability of establishment based on current occurrences (both in the native and introduced ranges) and the level of climatic suitability**

Climatic variables used : temperature, precipitation, seasonality, moisture index, etc.

<figure><img src="image_8.png" /></figure>

2. **Definition of global management objectives for the administrative regions**

Taking in account existing regional management plans and voluntary actions

<table><thead><tr><th rowspan="2">Management objective</th><th colspan="2">Control</th><th colspan="2">Eradication</th></tr><tr><th>I</th><th>IV</th><th>III</th><th>II</th></tr></thead><tbody><tr><td>Zone</td><td></td><td></td><td></td><td></td></tr></tbody></table>

Early detection and rapid response (EDRR) should be applied in zones II and III

## Definition of objectives at the regional level

<figure><img src="image_9.png" /></figure>

2. **Delimitation of different zones according to regional boundaries, based on a cross between population density and establishment risk**

Moderately favorable and moderately invaded zones

Favorable and heavily invaded zones

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Favorable and moderately invaded zones

<figure><img src="image_11.png" /></figure>

Unfavorable and weakly invaded zones

## Definition of objectives at the population level

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

4. **Identification of populations located in areas with high biodiversity stakes**

National and regional nature reserves, regional natural parks, national parks, biotope protection acts, etc.

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5. **Prioritization of populations with the use of a scoring method based on several criterions**

* direct hazard to human health

* threat for local biodiversity

* spread risk

* feasibility

* size of the population

* etc.

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

6. **Definition of local management objectives per population respecting regional management objectives**

Population objective

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

or

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Eradication

Control

## How to intervene ?

### BEFORE

The choice of the intervention method has to be based on :

* defined objective

* site conditions

* technical feasibility

* human resources

* etc.

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

### AFTER

Follow-up measures have to be implemented and **further repeated treatment** may be necessary

Restoration → local native plants

Ultimate waste → landfills

Green waste → composting centres or certified centres for incineration

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

### Overview of the best management practices :

#### Eradication

* manual removal

* cutting below the root collar

* tillage

* glyphosate and triclopyr *

* as a last resort and in accordance with existing regulations

#### Control

* inflorescences removal

* controlled use of grazing animals

* planting competitive native species

* land management practices

### DURING

## Conclusions and perspectives

* NMS will **support and encourage French regions to develop strategies and improve coordination**, at their own level but also amongst each other

* Declination of NMS into **regional management plans (RMP)** by regional coordinators will allow a more precise identification of the priority populations at local scale with tailored objectives

* This model will be **used for each of the widespread IAS** and these NMS will be revised every 5 years to reflect current trends and best IAS management practices

**References** : Fried, G. (2009). Changement d'habitat d'Heracleum mantegazzianum (Apiaceae) au cours de son invasion en France. XIIIème Colloque international sur la Biologie des Mauvaises Herbes. Dijon, France Diadema, K. (2018). La Berce du Caucase (Heracleum mantegazzianum, Sommier & Levier). Evolution de la banque de graines du sol, Secteur la Lane-Andon (Alpes-Maritimes)

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CENTRE DE RESSOURCES
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IUCN | French Committee

<footnote n="1">¹French Biodiversity Agency (AFB), Research, Science-advice and Data Division (Dred), Vincennes, France</footnote>

<footnote n="2">²French Agency for Food, Environmental and Occupational Health and Safety (Anses), Plant Health Laboratory (LSV), Montferrier-sur-Lez, France</footnote>

<footnote n="3">³French Committee of the International Union for Conservation of Nature (IUCN), French Invasive Alien Species Resource Centre (CDR), Orléans, France</footnote>