Characteristics of Invasive Species

1. Characteristics of Invasive Species

2. Who is likely to be successful? • Abundance in native land • Widespread distribution • Great dispersal or migratory tendencies • r-selected-high seed production or dispersal abilities • Early maturation • Large body size • Small body size • Essential symbiont already present • Edge species • Affinity with humans • Capacity for asexual reproduction • Frequency of propagule pressure-how often released • History of invading elsewhere

3. Who is likely to be successful? • Abundance in native land • Widespread distribution • Great dispersal or migratory tendencies • r-selected-high seed production or dispersal abilities • Early maturation • Large body size • Small body size • Essential symbiont already present • Edge species • Affinity with humans • Capacity for asexual reproduction • Frequency of propagule pressure-how often released • History of invading elsewhere

4. In other words…. WEEDY species.

6. Seeds with hooks…Burdock

7. Enchanter’s Nightshade Desmodium Bidens, Beggars Ticks Beggars Ticks

9. Galapagos: a case study for invasion • volcanic archipelago-never connected to S. America • about 3-5 million years old • ~600 miles due west of Ecuador

10. Galapagos plants: how did they get there? Mostly from South America-nearest large source • Ocean drift 9% • Birds (total of 60%) • sticky seeds 38% • In mud 9 • Internal 7 • Hooked seeds 5 • Air/wind 31 Only need to add one species every 8,000 years to account for the current flora.

11. Farthest Known Ocean Crossings

14. Hawaii (1000 miles long, 2000 miles from continent) has NO native • freshwater fish • amphibians • reptiles • land mammals • 21 orders of insects are absent

15. What happens when you get there? • Failure • Predators • Find habitat • Live long enough to reproduce • Pregnant? Obligately sexual? • Success • Lag period