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
Distance (miles)
Group
2000+ miles
Bats, land birds, insects, spiders, land mollusks
~1000
Lizards
~500
Tortoise, rodents, amphibian
~200
Small carnivores, conifers
~25
Large mammals
~20
Freshwater fish

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