1. Invasive Species Lecture Objectives:
Be introduced to biological invasions
Know several examples of invasive species
Learn what you can do to stop the spread of invasive species

2. Definitions: Introduced (non-native, exotic)
- species introduced deliberately or accidentally from
somewhere else
Domestic/Feral (released pets, livestock and game animals)
- can spread disease, compete with native species
Human commensal or subsidized (out of control natives)
- native species that benefit from our land use
(disturbance)
Invasive species
- species that spread subsequent to establishment
usually at some cost.

3. Invasive Species
Some introduced deliberately:
naturalization societies
Shakespeare fans
game animals
domestic animals
Some accidental:
ballasts of ships
unprocessed wood
fruit shipments
by-pass natural barriers

4. Vectors of invasion into ecosystems
Intentional Release of Target Species into Containment:
- Escapes from Zoos and Botanical Gardens
- Farmed Species
- Aquaculture
- Research

5. Vectors of invasion into ecosystems
Intentional Release of Target Species into the Environment:
- Plants for Agriculture
- Plants for Forestry
- Plants for Soil Improvements
- fire suppression, erosion control
- Ornamental Plants
- Birds and Mammals for Hunting
- Biological Control
- Released Pets and Pet Trade

6. Vectors of invasion into ecosystems
Release of Non-Target Species (AKA “Accidental” Releases):
Contaminants or Hitchhikers with Produce
Contaminants or Hitchhikers with Ornamental Plants
Contaminants or Hitchhikers with Aquaculture
Timber
Contaminants of Seed Stock
Cars
Planes
Hitchhikers with Packing Material, Cargo
Ballast in ships
Hull Fouling
Tourists, Luggage
Canals

7. Ballast Tanks

9. Movement of/ increased exposure to exotic species includes pathogens!!
Emerging Infectious Disease – never known before or absent for 20 years
Schistosomiasis, AIDS, SARS, etc.

10. “Forecast and control of epidemics in a globalized world
“Forecast and control of epidemics in a globalized world.” Hufnagel et al. PNAS 2004

11. In 1999, there were more than 50,000 exotic species in the USA

12. Why study biological invasions?
Consequences
threaten biodiversity
costly
widespread
Unique opportunities for basic research
community ecology
animal behavior
evolution

13. Estimated annual costs associated with non-native species:
Group costs (in millions)
Plants (purple loosestrife, weeds) 34,000
Mammals (feral pigs, rats) 37,000
Birds (pigeons, starlings) 2,000
Fishes ,000
Arthropods (ants, termites, other pests) 19,000
Mollusks (zebra mussel, asian clam) 1,200
Microbes (plant pathogens, animal disease) 41,000
All organisms over $136 billion per year
Source: Pimentel et al BioScience

14. Percentage of threatened or endangered species imperiled by:
Habitat degradation and loss - 85%
Invasive species - 49%
Pollution - 24%
Overexploitation - 17%
Disease - 3%
Source: Wilcove et al.1998 BioScience

15. Hypotheses for the success of introduced species:
Escape from natural enemies
predators, parasites, disease
Increased competitive ability
outcompete native species
Pre-adapted to disturbed environments

16. Characteristics of invasive species
general diet and habitat requirements
high abundance
small body size
high reproductive potential (r-strategy)
good competitors
social / gregarious
Generalities would be nice!
Make invasion biology a more predictive science.

17. (different characteristics may be important at different stages)
Stages of invasion
1. Opportunity (transport)
2. Establishment
3. Spread
(different characteristics may be important at different stages)

18. What makes certain ecosystems more vulnerable?
Diverse, undisturbed communities have few invaders
Disturbed habitats: full of invaders
Human residential areas: many European species that are commensal with humans
Islands: little history with competitors, predators, parasites, or diseases

19. Birds
Mute swan
European starling
Monk Parakeet

20. European Starling
First successful introduction was 60 European starlings released in Central Park, NY. in 1890, by fans of Shakespeare
competes with bluebirds, woodpeckers
slippery sidewalks

21. The House Sparrow was introduced into Brooklyn, New York, in 1851.
Competition from the House Sparrow for cavity nests can cause decline of some native species.

22. Insects In 1956, African Honey Bees were imported into Brazil
Africanized Bees
In 1957, 26 African queens escaped
Reached US in 1990
More aggressive than European Honey Bees, have killed 1,000 people
Impact honey and pollination industries

23. Insects Crop pests boll weevil, corn borer Culex mosquitos
carry avian malaria and pox
driven 20 Hawaiian bird species extinct
Adult boll weevil

24. Insects Asian Long-horned Beetle attacks and kills many native trees
Found in Chicago in 1998

25. Insects Gypsy moth Introduced in 1860s
Originally brought to the US for silk production
now defoliates entire forests

26. Reptiles and Amphibians
Cane toad – native to Central and South America
Introduced world-wide to control insects
milky secretions are highly toxic. Kill dogs, cats and small native animals

27. Reptiles and Amphibians
Brown Tree Snake
Introduced to Guam via cargo transported by U.S. military ships during World War II
On Guam wiped out 9 of 13 indigenous bird species

28. Mammals Goats and pigs in Hawaii wiped out native plants
Horses in Grand Canyon
causing erosion
Game animals
“Texotics”
“Texotics” Oryx
Photo: Dr Mike Hill

29. Plants
Kudzu
Introduced into the U.S. in 1876 at the Philadelphia Centennial Exposition
promoted as a forage crop and an ornamental plant until 1953
kills other plants by smothering them under a solid blanket of leaves

30. Plants
Garlic mustard
poses a severe threat to native plants and animals
garlic mustard outcompetes native plants by monopolizing light, moisture, nutrients, soil and space.
Buckthorn
Not as good food for herbivores as many native species

31. Giant snakehead (Channa micropeltes) found in Wisconsin in 2003
Fish
Northern Snakehead
(Channa argus)
Found in Maryland in 2002
Giant snakehead (Channa micropeltes) found in Wisconsin in 2003

32. Laurentian Great Lakes
www1.ncdc.noaa.gov/pub/data/images/ great-lakes-ice-avhrr.gi
Superior
Mills et al. 1993
Over 140 exotic species
Huron
Many fish species were (and continue to be) released intentionally
Michigan
Ontario
Erie
Many other exotics have entered the lake accidentally:
Canals
Escape from captivity
Ballast water
Bait buckets, live wells and gear

33. 19 locks, filled and emptied by gravity

34. Welland Canal
Niagara Falls was the major obstacle to an uninterrupted waterway
Begun in 1829

35. Sea Lamprey
(Petromyzon marinus)
Invaded the Great Lakes after the opening of the Welland Canal
Devastated native fish stocks, especially lake trout

36. Other fish (>25 species)
Round goby (1990)
(Neogobius melanostomus)
Ballast water
Alewife (1873)
(Alosa pseudoharengus)
Canals
Chinook salmon (1873)
(Oncorhynchuys tshawytscha)
Deliberate release
Coho salmon (1933)
(Oncorhynchus kisutch)
Deliberate release

37. Exotic Crustaceans (>6 species)
Bythotrephes cederstromi (1984)
Ballast water
Cercopagis pengoi (1998)
Ballast water

38. Exotic mollusks (> 14 species)
Quagga mussel (1990s)
(Dreissena bugensis)
Ballast water
Asiatic clam (1980)
(Corbicula fluminea)
Aquarium release

39. ZEBRA MUSSEL — Dreissena polymorpha
Found in 1988 in Lake St. Clair (Lake between Huron and Erie, just off of Detroit, MI).
Up to 70,000 individuals per m2
Likely came to North America in ballast water

40. One of the most expensive exotic species
Will biofoul and restrict the flow of water through intake pipes (drinking, cooling, processing and irrigating water)
Also attaches to boat hulls, docks, locks, breakwaters and navigation aids, increasing maintenance costs and impeding waterborne transport.

41. Can attach to hard surfaces
Characteristics of zebra mussels:
Can attach to hard surfaces
They have a free-living planktonic larval stage— veliger
Females can produce 40,000 veligers
These are typical characteristic of marine species

42. Veligers are easily transported in bait buckets and livewells and anywhere else water collects
Adults can attach to hulls and survive outside of water for several days.
Cover most hard surfaces

43. Negative effects on native clams
Zebra mussels cover them and prevent them from feeding and moving

44. Plants (> 59 species) Purple Loosestrife (early 1800s)
Lythrum salicaria
Eurasian Watermilfoil (1881)
Myriophyllum spicatum

45. Never dump bait buckets!!
How to prevent the spread of aquatic nuisance species?
Never dump bait buckets!!
Before leaving site, inspect gear, boats and trailers for exotics
Empty all water before leaving site
Rinse your boat and equipment with high pressure hot water, especially if moored for more than a day
Let equipment dry for several days (does not work for species with resting eggs)