Question of the Day:
1. Are humans an invasive species? Give an
example of why or why not.
2. Name two invasive species affecting the
Great Lakes.
3. What negative impacts are invasive species
having on the Great Lakes ecosystem?
Bioinvasion
• Species introduced to a new area
• Due to either direct or indirect human actions
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Non-native Species
• Species that are introduced to areas beyond
their historic natural range
– Alien
– Exotic
– Foreign
– Introduced
– Non-indigenous
Invasive Species
•
•
•
•
Aggressive
Spread over large areas
Disrupt natural ecosystems
Interfere with human activities
Invasive Species
• After destruction of habitat by human
activities, invasive species are the worst threat
to endangered species and biodiversity
Starlings
• European starling imported from England in
1890
• Intentionally released in Central Park
– Literary societies believed America should have all
birds mentioned in Shakespeare
• Now most common bird
Source: Ross Sea Info
Starlings
• Congregate in large flocks
• Drive native birds from nesting grounds
• Compete with native birds for food
– Omnivores – insects as well as farm crops
• Droppings contain fungus that causes
histoplasmosis – a respiratory disease in
humans
Exotic Newcastle disease
• Fatal viral disease that affects ALL birds
• Believed to have been introduced to US by
parrots from South America
– 1971 outbreak affected 12 million birds, all had to
be destroyed
– Cost $56 million
• Except for 3 years, detected every year since
1974
Problems with Importing Birds
• Big demand for parrots in North America,
Europe, and Japan
• Combined with habitat loss, taking of birds
resulting in population declines
• Illegally imported birds can also carry diseases
without seeming sick
– Affect poultry and native birds
Plants
• Hundreds of plants brought to US intentionally
– Food
– Medicine
– Ornamental
• Others brought accidentally in grain, straw, or
soil
• Changes landscape
Purple Loosestrife
• Introduced to US in 1800s
• Valued for medicinal and
ornamental purposes
• Still widely used for ornamental
reasons
Source: National Park Service
Purple Loosestrife
• Can produce millions of seeds a year
• Also reproduces with rapid growth of
underground stems
• Eliminated native plants from 1.5 million acres
of wetlands
• Displaces food supply of many wild animals
• Few animals feed on it
Purple Loosestrife
• Several states prohibit growing, selling, and
transport
• US Dept. of Agriculture authorized
introduction of two insects that only eat
loosestrife for biological control
Problem with Ballast Water
• Water taken in by ships for stability
– Necessary in commercial shipping
• Often dumped when ship reaches destination
• 1981 study of ballast water
– Ballast water of 30 ships examined
– Found living organisms in every tank
Zebra Mussel
• Native to Caspian Sea
• Made way to Western Europe by Industrial
Revolution
Source: Minnesota Sea Grant
Zebra Mussel
• 1988 – spotted in Lake St. Clair (between Lake
Huron and Lake Erie)
– Came from European freighter
• Mature female can produce 30,000 – 40,000
eggs a year
– Population explosion
• Spread into all of the Great Lakes and
connected bodies of water
Zebra Mussel
• May damage fishing industry
– Completely cover surfaces fish use for spawning
• Filter algae and other microscopic organisms
from water
• Have improved water quality
– More light penetrates deeper in water, more plant
growth
– Removed some chemical pollutants
Zebra Mussel
• Huge expense for cities and industry that use
water from Great Lakes
– Clog water intake pipes of industrial and power
plants
Source: EPA
Chestnut Blight
• First seen in 1904 in New York Zoological Park
• Came from trees imported from Asia
Source: Oregon State Government
Chestnut Blight
• Fungus that grows beneath bark
– Cuts off flow of nutrients and water
– Doesn’t kill roots
– Infects new sprouts
• Spores spread by wind and carried by insects
and birds
• By 1950 had spread throughout chestnut’s
natural range
Dutch Elm Disease
• First reported in Ohio in 1931
• 90% of trees lining streets of some towns
were elms
• Came from France with elm logs
sent to Ohio
Source: Wichita State
Dutch Elm Disease
• Fungus that produces a poison that clogs sapcarrying tubes of American elm
• Carried by European elm bark beetle
• Tree surgeons trying to save remaining elms
– Injecting fungicide into tree and soil
– Removing dead branches to prevent beetle from
breeding in soft wood
Gypsy Moth
• Brought from France to Massachusetts in
1860s
– Hope to breed better silk-producing insects
• Larvae escaped
Source: Michigan Nature Association
Gypsy Moth
• By 1902 spread through New England
• Continue to spread south and west at rate of
13 miles a year
• Have been spotted in California, Utah, Oregon
– Transported by tourists
• Federal law requires movers to check for
moths before moving outdoor equipment
Gypsy Moth
• Larvae feed on as many as 500 species of
plants
• Larger trees die because they don’t have
leaves
– Forest canopy opens
– More light, low-growing plants increase
– Cover for rabbits, turkey, grouse
– Food shortage for squirrels – no acorns or other
nuts
– Deer have more food
Gypsy Moth
• Millions of acres have been sprayed with
pesticides
• Some animals have learned to eat them
Africanized Bees
• 1956 – geneticist imported African queen bee
to Brazil
– Hoped to produce a more productive bee better
suited to tropics
• 26 Africanized bees escaped
– Began to extend northwards at rate
of 200 miles a year
– Arrived in Texas in 1990
Source: USGS
Africanized Bees
• Slightly smaller than European honeybee
• Not the “killer bee” that people think
• More defensive than European bee
– React more quickly
– Many more respond
– Follow intruder 8-10 time further
– Sting 8-10 times more often
Africanized Bees
• Africanized bees’ behavior make it more
difficult for beekeepers to manage hives
• Use more of the honey they produce than
European honeybees
• European honeybees (most bees in US) were
introduced 400 years ago
Mediterranean Fruit Fly (Medfly)
• Native of tropical Africa
• Serious pest in Mediterranean area and other
countries
• Attacks more than 250
varieties of fruits, vegetables
and nuts
APHIS
• US Dept of Agriculture restricts items brought
to mainland US from other countries as well
as Hawaii, Puerto Rico, and the Virgin Islands
• Animal and Plant Health Inspection Service
(APHIS) responsible for guarding against
foreign plants and animals
APHIS
• Required to declare meats, fruits, vegetables,
plants, animals, and plant and animal
products brought to the country
• Potted plants and soil not allowed to be
imported – soil might have pests and disease
• Fruit and lumber go through inspection and
testing procedures in quarantine
Know Before You Go
• You should know import/export restrictions
for countries you are visiting as well as the US
• USDA has publication “Know before you go”
listing US regulations
Know Before You Go
• Until recently, taking a dog to England
required a six month quarantine to ensure it
didn’t have rabies
– England doesn’t have rabies
• New regulations now require pets to have
passport that certifies pet has a microchip to
ensure identity, vaccination against rabies, and
treatments for ticks and tapeworms