1. Biotic Resistance What can stop invasive species? Liz Schultheis April 21, 2011

2. Do you know of any invasive species?

3. Why do some invaders succeed? Open habitat – places to grow Available food/resources Can grow better than native species Nothing eats them! No enemies

4. Why do some invaders fail? Diversity – lots of competition – no space or resources left Enemies – diseases, predators, herbivores

5. Native Blue Crab Likes soft sandy areas Lives in shallow water Prefers ocean water that’s not too salty Invasive Green Crab Introduced from Europe Likes the same areas that the Blue Crab likes Catherine E. deRivera & others 2005

6. Native Blue Crab Range Invasive Green Crab Range

7. SOUTH NORTH LOCATIONS # Blue Crabs # Green Crabs SOUTH NORTH

8. Winner!

10. N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N = invader resource

11. N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N P P P P P P PP P P P P P P P P PP P P P P P P P P PP P P P P P P P P PP P P P P P P P P PP P P N = invader resource P = native species resource

12. N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P Diversity = 1 N = invader resource P = native species resource

13. N N N P P P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P Diversity = 3 P P P N N N = invader resource P = native species resource

14. N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P Diversity = 3, Fertilized N = invader resource P = native species resource

15. N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P N N N N N N N P P P P P P PP P P Diversity = 3, Disturbance N = invader resource P = native species resource