1. Harmonising the invasiveness concept The EPPO prioritization scheme as a tool to identify the most invasive plant species in Europe
Etienne Branquart, Mark Hill, Cathy Maguire,
Uwe Starfinger, Johan van Valkenburg & Sarah Brunel
Les abords des cours d'eau constituent des milieux très propices aux invasions biologiques (i) parce qu'il s'agit de milieux régulièrement perturbés par les crues, favorables à l'établissement d'espèces pionnières et (ii) parce que l'eau véhicule facilement les diaspores, facilitant ainsi la dispersion.

2. ?
Apparent dichotomy between scientific questions and societal and motivational issues (see e.g. Richardson et al. 2000, Davis & Thomson 2001, Larson 2007 & Colautti & Richardson 2009);
Impact often perceived by scientists as not clearly associated to any specific ecological process and linked to subjective intepretation!
Des mesures préventives contre les espèces invasives

3. Standardization of terminology The stage-based approach of Colautti & McIsaac (2004)
SPREAD filter
Stage III
(localized
+ numerically rare)
ENVI filter
Stage IVa
(widespread
+ numerically rare)
EARLY
WARNING
Stage IVb
(localized
+ dominant)
Stage V
(widespread
+ dominant)
DISP = local dispersal
ENVI = environment and community suitability
ENVI filter
DISP filter
Des mesures préventives contre les espèces invasives

4. Standardization of the impact definition Loss in native species through competitive interactions
at the stand scale
at the landscape scale
Data : Hejda et al. 2009, Journal of Ecology 97:
Des mesures préventives contre les espèces invasives

5. Standardization of the impact definition Species loss is density dependent
Data : Hejda et al. 2009, Journal of Ecology 97:
Des mesures préventives contre les espèces invasives

6. Three main questions Harmonising the invasiveness concept
To compare the invasiveness status of non-native plant species based on national definitions and a standardized terminology inspired by the stage-based approach of Colautti & McIsaac (local spread potential + plant capacity to dominate native vegetation);
To see if the use of this standardized terminology allows to reduce subjective interpretation and to define plant invasiveness in an unambiguous way;
To look how the use of standardized terminology may help in the development of early warning systems.
Des mesures préventives contre les espèces invasives

7. 1. The EPPO prioritization process
2. Testing the EPPO process
3. Early warning outcomes
4. Conclusion & perspectives
Des mesures préventives contre les espèces invasives

8. The EPPO proritization process for IAP General principles
The process is designed:
to produce a reference list of Invasive Alien Plants (IAP) that are established or could potentially establish in the EPPO region,
to determine which IAP have the highest priority for an EPPO pest risk analysis (= screening tool to identify quarantine organisms).
Plant species invasiveness:
(potential for establishment),
local spread capacity,
environmental impact
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9. Category Dispersion distances Dispersion agents
Local spread capacity Natural dispersion + unintentional human assistance
Assessed through a combination of plant life-history traits and field dispersion data.
Category Dispersion distances Dispersion agents
Low < a few meters/year
Medium < 100 meters/year ants
High >> 100 meters/year wind, water vertebrates.
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10. Non-native species dominance
Environmental impact Dominance & colonization of semi-natural habitats
Proxy = plant species dominance. Ability to make large, dense and persistent populations. Cover > 80 %. Exclusion of native plant species.
Species occurrence in semi-natural habitats is also taken into account.
Non-native species dominance
Low High
Habitats
Man-made habitats
Natural habitats
Low Medium
Medium High
Des mesures préventives contre les espèces invasives

11. Invasiveness categories Combination of spread and impact data
High
Medium
Low
Impact (dominance)
Low Medium High
Spread capacity
Des mesures préventives contre les espèces invasives

12. Invasiveness categories Combination of spread and impact data
High
Medium
Low
Invasiveness
Impact (dominance)
High (V)
Medium
Low
Low Medium High
Spread capacity
Des mesures préventives contre les espèces invasives

13. 1. The EPPO prioritization process
2. Testing the EPPO process
3. Early warning outcomes
4. Conclusion & perspectives
Des mesures préventives contre les espèces invasives

14. EPPO vs national definitions The European Atlantic region
set of 27 non-native plant species established in Europe before 1950;
independent assessments using the EPPO process by experts of 5 countries within the European Atlantic region: BE, DE, GB, IE and NL;
comparison of plant invasiveness status based on national and EPPO definitions.
Des mesures préventives contre les espèces invasives

15. EPPO vs national definitions National invasiveness categories
Protocol Assessor Spread Impact BE DE GB IE NL
ISEIA E. Branquart * ***
GABLIS U. Starfinger ns ***
ISEIA M. Hill ns ***
ISI C. Maguire ns ***
J. van Valkenburg *** *
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16. National definitions Mean stdev Invasiveness 0.58 High Medium Low
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17. EPPO definition Mean stdev Invasiveness 0.31 High Medium Low
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18. EPPO vs national definitions EPPO invasiveness categories / high
Medium
Low
Crassula helmsii
Fallopia japonica
Heracleum mantegazzianum
Impatiens glandulifera
Ludwigia grandiflora
Prunus serotina
Rosa rugosa
Impact (dominance)
Low Medium High
Spread capacity
Des mesures préventives contre les espèces invasives

19. EPPO vs national definitions EPPO invasiveness categories / medium
High
Medium
Low
Impact (dominance)
Cornus sericea
Lysichiton americanus
Robinia pseudacacia
Spiraea spp.
Low Medium High
Spread capacity
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20. EPPO vs national definitions EPPO invasiveness categories / medium
High
Medium
Low
Impact (dominance)
Buddleja davidii
Mimulus guttatus
Oenothera spp.
Senecio inaequidens
Low Medium High
Spread capacity
Des mesures préventives contre les espèces invasives

21. EPPO vs national definitions EPPO invasiveness categories / medium
High
Medium
Low
Impact (dominance)
Duchesnea indica
Quercus rubra
Low Medium High
Spread capacity
Des mesures préventives contre les espèces invasives

22. 1. The EPPO prioritization process
2. Testing the EPPO process
3. Early warning outcomes
4. Conclusion & perspectives
Des mesures préventives contre les espèces invasives

23. Sounding the early warning bell Relevant EPPO invasiveness categories?
High
Medium
Low
Impact (dominance)
Low Medium High
Spread capacity
Des mesures préventives contre les espèces invasives

24. Sounding the early warning bell 1
Sounding the early warning bell 1. Crossing of the environmental barrier (nat. habitats)
Country Habitat
Amelanchier lamarkii
Cornus sericea
Cotoneaster horizontalis
Helianthus tuberosus
Lupinus polyphyllus
Lysichiton americanus
Rhododendron ponticum
Spiraea spp.
NL Heathlands
BE, IE Damp woodlands
BE Chalk grasslands
BE, DE River banks
DE Acidic grasslands
DE Damp woodlands
GB, IE Heaths and woodlands
BE Riparian areas
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25. Spread capacity: medium
Cornus sericea
Spread capacity: medium
Dominance: high

26. Cotoneaster spp.
Spread capacity: high
Dominance: high

27. Rhododendron ponticum
Spread capacity: medium to high
Dominance: high

28. Sounding the early warning bell 2. New detrimental incomers
Giant Rhubarb Purple Dewplant Redvein Maple
Gunnera tinctoria Disphyma crassifolium Acer rufinerve
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29. Gunnera tinctoria
Spread capacity: high
Dominance: high

30. Disphyma crassifolium
Spread capacity: high
Dominance: high

31. Dominance: medium to high
Acer rufinerve
Spread capacity: high
Dominance: medium to high

32. 1. The EPPO prioritization process
2. Testing the EPPO process
3. Early warning outcomes
4. Conclusion & perspectives
Des mesures préventives contre les espèces invasives

33. Three main questions Harmonising the invasiveness concept
To compare the invasiveness status of non-native plant species based on national definitions and a standardized terminology inspired by the stage-based approach of Colautti & McIsaac >>> strong differences between national and standardized terminologies (national defintions are often impact-oriented)
To see if the use of this standardized terminology allows to define plant invasiveness in an unambiguous way >>> strong reduction of data heterogeneity and improvement of the repeatability within a biogeographic region
To look how the use of standardzed terminology may help in the development of early warning systems >>> provides an objective framework to document detrimental effects of newcomers and to detect behavioural shifts of established populations of non-native plant species.
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34. Data integration for early warning based on standardized definitions and protocols
Data integration at a regional level
(regional consensus under the umbrella of a European organization)
Data integration at national level
(national consensus)
Independent assessments
by national experts
Country 1
Country 2
Country 3
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35. Monitoring by Member States Field data needed to assess spread and impacts
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