1. MODULE 1 Introduction to Invasive Alien Species

2. Introduction Invasive alien species harm: –the environment –the economy –people

3. Definition Introduction –The movement by human action of a species outside its native range. This movement can be either within or between countries.

4. Definition Alien species –A species that has been intentionally or unintentionally introduced to a location, area, or region where it does not occur naturally

5. Definition Invasive alien species –An alien species that causes, or has the potential to cause, harm to the environment, economies, or human health

6. Key Point An alien species will be considered invasive only if it has adverse effects on: –the environment, –the economy, or –human health

7. Invasive Species are found in ALL taxonomic groups Plants Fish Mammals Invertebrates Fungi Amphibians Viruses Reptiles Birds

8. Types of introductions Alien Species Introductions IntentionalUnintentional Legal Directly released into the wildIntroduced into captivity Unauthorised Escaped or intentionally released

9. Indian House Crow Accidental introduction Competes with native birds Disease vector A nuisance in urban areas

10. Salvinia molesta A serious aquatic weed Forms thick mats Prevents boat traffic Ruins fish habitat

11. Intentional introductions Legal –directly released into the wild –introduced into captivity Illegal / Unauthorised –smuggling

12. Unintentional introductions ‘Hitchhikers’ and stowaways Trade Travel Transport

13. Most of the known invasive invertebrates have been introduced unintentionally Key Point

14. Natural dispersal tends to play a major role in the subsequent regional spreading once a species has been introduced into a country or region Key Point

15. Process of invasion 1. Introduction 2. Establishment 3. Spread

16. Process of invasion Population size Time Carrying capacity Lag phase Explosion phase

17. Can we predict species invasiveness? Difficult to identify invasive from harmless species Some characteristics: –invasive elsewhere –adaptable –lack of predators

18. Every alien species must be considered invasive until proven otherwise Precautionary approach Key Point

19. Human alteration of the environment increases the likelihood of IAS establishing Key Point

20. Land-use changes IAS thrive in disturbed areas

21. Globalisation Increasing trade, travel & transport = increasing IAS introductions World shipping routes

22. Summary IAS affect the environment, economy and human health Species invasiveness cannot be easily predicted IAS thrive in disturbed areas The rate of IAS introductions is increasing