Ecological Footprint

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Exotic and Invasive Species

Which of the following species is native to North America?

House Mouse Dandelion

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Honeybee

Pigeon (Rock Dove)

Starling

Which of the following species is native to North America?

None of these species are native to

North America.

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Communities can be disrupted by exotic species.

Communities can be disrupted by exotic species.

•  species introduced by humans to communities in which they were not previously found.

Communities can be disrupted by exotic species.

•  species introduced by humans to communities in which they were not previously found.

•  introduction can be intentional or unintentional.

Communities can be disrupted by exotic species.

•  have affected virtually all communities, but especially problematic in disrupted habitats.

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Communities can be disrupted by exotic species.

•  have affected virtually all communities, but especially problematic in disrupted habitats.

•  exotics often invasive.

European Starling – Introduced Species

William Shakespeare’s Birds Central Park NYC, 1896

Spread of the

Starling

1896

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Spread of the

Starling

1904

Spread of the

Starling

1908

Spread of the

Starling

1910

Spread of the

Starling

1912

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Spread of the

Starling

1916

Spread of the

Starling

1918

Spread of the

Starling

1920

Spread of the

Starling

1922

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Spread of the

Starling

1924

Spread of the

Starling

1926

Starling – Current Distribution Great Lakes

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Great Lakes – Rate of Invasions

Woolly Adelgid – Invasive Species

32

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33

Honeysuckle – Invasive Species

Cost of Invasives •  More than 4,500 foreign species have

gained a permanent foothold or taken root in the U.S. during the past century.

•  Invasive species contribute to the decline of 46% of the imperiled or endangered species in the U.S.

•  Invasive species are estimated to cost a total of $137 billion annually in losses to agriculture, forestry, fisheries and the maintenance of open waterways in the U.S.

Characteristics of Invasives

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Characteristics of Invasives

•  Rapid Population Growth.

Characteristics of Invasives

•  Rapid Population Growth. •  Displace or Kill Native Species.

Characteristics of Invasives

•  Rapid Population Growth. •  Displace or Kill Native Species. •  No natural population regulation.

– No predators. – No pathogens.

Characteristics of Invasives

•  Rapid Population Growth. •  Displace or Kill Native Species. •  No natural population regulation.

– No predators. – No pathogens.

•  High Dispersal Rates.

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Communities can be disrupted by exotic species.

•  have affected virtually all communities, but especially problematic in disrupted habitats.

•  exotics often invasive •  native species affected negatively.

Communities can be disrupted by exotic species.

•  have affected virtually all communities, but especially problematic in disrupted habitats.

•  exotics often invasive . •  native species affected negatively. •  at least 30,000 exotic species in U.S. alone.

Exotic species, example

•  Hawaiian land snails – before human contact, more than 1000 species.

Exotic species, example

•  Hawaiian land snails. – before human contact, more than 1000 species.

•  compare to 719 in all of U.S. and Canada.

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Exotic species, example

•  Hawaiian land snails. – before human contact, more than 1000 species .

•  compare to 719 in all of U.S. and Canada. – just after European arrival, ~930 species.

Exotic species, example

•  Hawaiian land snails. – before human contact, more than 1000 species.

•  compare to 719 in all of U.S. and Canada. – just after European arrival, ~930 species. – 1950s, ~500 species.

Hawaiian snails

•  1950s — Giant African snails. – imported for food.

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Hawaiian snails

•  1950s — Giant African snails. – imported for food. – escaped, became agricultural pest. – tried to control with poison, didn’t work.

Hawaiian snails

•  1950s — Giant African snails. – imported for food. – escaped, became agricultural pest. – tried to control with poison, didn’t work.

•  imported carnivorous Rosy Wolfsnails.

Hawaiian snails

•  1950s — Giant African snails. – imported for food. – escaped, became agricultural pest. – tried to control with poison, didn’t work.

•  imported carnivorous Rosy Wolfsnails. – didn’t eat Giant African snails. – did eat native snails.

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Hawaiian snails •  1950s — Giant African snails.

– imported for food. – escaped, became agricultural pest. – tried to control with poison, didn’t work.

•  Imported carnivorous Rosy . – Did eat native snails.

•  now, 75% native species extinct, almost all others endangered.

Exotic species, zebra mussel

•  Native to Black Sea and Caspian Sea.

Exotic species, zebra mussel

•  Native to Black Sea and Caspian Sea. •  1985 – ship discharged ballast (fresh water) in Lake St. Clair.

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Exotic species, zebra mussel

•  Native to Black Sea and Caspian Sea. •  1985 – ship discharged ballast (fresh water) in Lake St. Clair.

•  Zebra mussels now in: –  all Great Lakes. –  Mississippi and Ohio drainages. –  increasing number of other eastern waterways.

Exotic species, zebra mussel

•  Native to Black Sea and Caspian Sea. •  1985 – ship discharged ballast (fresh water) in Lake St. Clair.

•  Zebra mussels now in: –  all Great Lakes. –  Mississippi and Ohio drainages. –  increasing number of other eastern waterways. –  catastrophic decline of native mussel species.

Exotic species, zebra mussel

•  Native to Black Sea and Caspian Sea. •  1985 – ship discharged ballast (fresh water) in Lake St. Clair.

•  Zebra mussels now in: –  all Great Lakes. –  Mississippi and Ohio drainages. –  increasing number of other eastern waterways. –  catastrophic decline of native mussel species. –  encrustation troublesome to humans.

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Why are exotics such strong competitors?

•  Study of European plant (473) and animal (26) species that have invaded U.S.

Why are exotics such strong competitors?

•  Study of European plant (473) and animal (26) species that have invaded U.S.

•  Compared parasites in both locales.

Why are exotics such strong competitors?

•  Study of European plant (473) and animal (26) species that have invaded U.S.

•  Compared parasites in both locales. – 84% drop in fungal infections (plants). – 24% drop in viral infections. – Overall 77% lower disease rate.