Plant invasions, cause and effect of global change : focus on two emerging Ambrosia species

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1 Plant invasions, cause and effect of global change : focus on two emerging Ambrosia species Arnaud Monty Biodiversité et Paysage, Gembloux Agro-Bio Tech, Université de Liège, Belgique Xavier Tassus Laboratoire de la santé des végétaux, Anses, Angers, France

2 «Invasive species»?

3 «Invasive species»? An invasive species (espèce exotique envahissante (EEE) ou espèce invasive) is: An exotic species, moved by human activities outside of its natural occurrence range

4 «Invasive species»? An invasive species (espèce exotique envahissante (EEE) ou espèce invasive) is: An exotic species, moved by human activities outside of its natural occurrence range naturalized in the new range A species is considered «naturalized» when it forms stable populations and is able of reproduction without any human intervention.

5 «Invasive species»? An invasive species (espèce exotique envahissante (EEE) ou espèce invasive) is: An exotic species, moved by human activities outside of its natural occurrence range naturalized in the new range and showing an expansion dynamics Mark Easton, BBC

6 «Invasive species»? An invasive species (espèce exotique envahissante (EEE) ou espèce invasive) is: An exotic species, moved by human activities outside of its natural occurrence range naturalized in the new range and showing an expansion dynamics

7 «Invasive species»? An invasive species (espèce exotique envahissante (EEE) ou espèce invasive) is: An exotic species, moved by human activities outside of its natural occurrence range naturalized in the new range and showing an expansion dynamics [ AND having a significant impact on ecosystems ]

8 Impacts of plant invasions Invasive plants can have different types of impacts: - Global homogenization of the flora

9 Impacts of plant invasions Invasive plants can have different types of impacts: - Global homogenization of the flora - Competition with native species

10 Impacts of plant invasions Invasive plants can have different types of impacts: - Global homogenization of the flora - Competition with native species - Long-term alteration of ecosystem functioning and ecosystem services

11 Impacts of plant invasions Invasive plants can have different types of impacts: - Global homogenization of the flora - Competition with native species - Long-term alteration of ecosystem functioning and ecosystem services - Genetic effects (hybridization)

12 Impacts of plant invasions Invasive plants can have different types of impacts: - Global homogenization of the flora - Competition with native species - Long-term alteration of ecosystem functioning and ecosystem services - Genetic effects (hybridization) - Nuisance for humans: Pests Damage to infrastructures Change in land use

13 Impacts of plant invasions Invasive plants can have different types of impacts: - Global homogenization of the flora - Competition with native species - Long-term alteration of ecosystem functioning and ecosystem services - Genetic effects (hybridization) - Nuisance for humans: Pests Damage to infrastructures Change in land use Health risks

14 Impacts of plant invasions Invasive plants can have different types of impacts: - Global homogenization of the flora - Competition with native species - Long-term alteration of ecosystem functioning and ecosystem services - Genetic effects (hybridization) - Nuisance for humans: Pests Damage to infrastructures Change in land use Health risks Plant invasions are an important component of global change!

15 Plant invasions: cause or effect of global change?

16 Plant invasions: cause or effect of global change?

17 Plant invasions: cause or effect of global change? Senecio inaequidens

18 Plant invasions: cause or effect of global change? «Passenger» of environmental change

19 Plant invasions: cause or effect of global change? «Passenger» of environmental change

20 Plant invasions: cause or effect of global change? Impatiens glandulifera

21 Plant invasions: cause or effect of global change? «Passenger» of environmental change «Driver» of environmental change

22 Plant invasions: cause or effect of global change? «Passenger» of environmental change «Driver» of environmental change

23 Plant invasions: cause or effect of global change? Bromus tectorum

24 Plant invasions: cause or effect of global change? «Passenger» of environmental change «Back-seat driver» of environmental change «Driver» of environmental change

25 Plant invasions: cause or effect of global change? «Passenger» of environmental change «Back-seat driver» of environmental change «Driver» of environmental change

26 Focus on two emerging Ambrosia species What is the problem? - Potential similarity with the noxious weed Ambrosia artemisiifolia - Agricultural pests - Allergenic pollen

27 Focus on two emerging Ambrosia species Ambrosia trifida Ambrosia psilostachya

28 Focus on two emerging Ambrosia species What is the problem? - Potential similarity with the noxious weed Ambrosia artemisiifolia - Agricultural pests - Allergenic pollen Risk assessment needed to setup and prioritize management strategies

29 Focus on two emerging Ambrosia species Ambrosia psilostachya DC. Ambrosia trifida L. Small perennial plant (<1 m) Mainly vegetative reproduction (suckers) Tall annual plant (3 m) Exclusively sexual reproduction (seeds)

30 Focus on two emerging Ambrosia species Ambrosia psilostachya DC. Ambrosia trifida L. Small perennial plant (<1 m) Mainly vegetative reproduction (suckers) Ruderal areas, overgrazed pastures, sandy areas, etc. Tall annual plant (3 m) Exclusively sexual reproduction (seeds) Ruderal areas, crop fields, moist areas, etc.

31 Focus on two emerging Ambrosia species Ambrosia psilostachya DC. Ambrosia trifida L. Both are from North America Both are already present in Europe

32 Focus on two emerging Ambrosia species Ambrosia psilostachya DC. Ambrosia trifida L. Both are from North America Both are already present in Europe Both have a clear expansion potential in Europe

33 Focus on two emerging Ambrosia species Ambrosia psilostachya DC. Ambrosia trifida L. Both are from North America Both are already present in Europe Both have a clear expansion potential in Europe Both can cause allergy problems

34 Focus on two emerging Ambrosia species Ambrosia psilostachya DC. Ambrosia trifida L. Entry - + Establishment Natural dispersal - + Human-induced dispersal Socio-economic impact Environmental impact - +

35 Focus on two emerging Ambrosia species Ambrosia psilostachya DC.

36 Focus on two emerging Ambrosia species Ambrosia psilostachya DC. x x

37 Focus on two emerging Ambrosia species Ambrosia trifida L.

38 Focus on two emerging Ambrosia species Ambrosia trifida L. x x x

39 Conclusions Not clear drivers of environmental changes Mainly socio-economic issues potentially important! Different recommendations for the two species:

40 Conclusions Not clear drivers of environmental changes Mainly socio-economic issues potentially important! Different recommendations for the two species: acceptable risk for Ambrosia psilostachya

41 Conclusions Not clear drivers of environmental changes Mainly socio-economic issues potentially important! Different recommendations for the two species: acceptable risk for Ambrosia psilostachya unacceptable risk for Ambrosia trifida

42 Conclusions Not clear drivers of environmental changes Mainly socio-economic issues potentially important! Different recommendations for the two species: acceptable risk for Ambrosia psilostachya unacceptable risk for Ambrosia trifida Measured proposed by the experts: Control of imported seed lots Use of certified seeds Surveillance and eradication of new populations Containment of existing populations

43 This work was made in collaboration with Bruno Chauvel, Guillaume Fried, Jean-Pierre Rossi and Thomas Le Bourgeois Thank you for your attention!