Lecture 13: Invasive Species

what is an exotic (introduced) species?

a species introduced by human activities intentionally or accidentally to an area or areas that is not part of its native range

what is a naturalized species?

an introduced species that has established a stable population that reproduces in a new habitat. has little impact on the environment in which it lives, including economic impact

can naturalized species become harmful?

yes, they can become invasive. they can easily adapt to new environments and reproduce quickly, which are good characteristics to become invasive.

what are some examples of naturalized species?

dandelions and monk parakeets

what is an invasive species?

an organism that causes ecological or economic harm in a new environment where it is not native. 1/3 of all invasive species were likely introduced in the last 50 years due to global trade. responsible for loss of biodiversity

what are characteristics of an invasive species?

• adapts to the new area easily

• lacks natural predators/pathogens in the new environment

• reproduces quickly

• outcompetes and harms native species

how can an invasive species be introduced?

• ship ballast water

• importing of product - firewood or plants

• pet trade

• accidentally - spore or seed on shoe

• on purpose - releasing an animal or planting plants

why are invasive species a problem?

• displace and threaten and even result in extinction of native species

• altering habitats significantly

• reduce biodiversity

• agricultural problems

• economic cost

describe the european starling

• introduced by humans on purpose - 100 birds released in central park in 1800s

• aggressive to native birds

• easily adapts to new environments and reproduces well

• now one of the most numerous birds in the US

describe european house sparrows

• introduced by humans on purpose - 1850s

• aggressive to native species

• displace native birds from nests and will even kill babies and/or parents

• easily adapt to new environments and reproduces well.

• one of most numerous birds in US

what is biological control?

the control of a pest species through the introduction of a natural enemy or predator

how do bats play an important role in ecosystems?

• pollinators

• seed dispersal

• understanding disease transmission

• pest control - need to eat a lot of food to sustain energy for flight

what is white-nosed syndrome?

a fungal disease of hibernating bats. caused by an invasive fungus that has killed millions of bats across North America. likely to lead to regional extinctions of bat species including the federally listed Indiana bat and northern long-eared bat. kills 70-90% of bats that are affected by it. causes fungal growth around nose and wings

what is different about the bats that have survived white-nosed disease?

1 in 10 bats seem to be able to survive better = evolution by natural selection. have different genes that are associated with regulating arousal from hibernation, regulating breakdown of fats, ecolocation and communication

describe zebra mussels

• native to Russia and Ukraine - introduced from a ship’s ballast water

• have invaded the great lakes

• highly reproductive and can start reproducing very early

• adapts well to new environments

• can live outside of water for up to a week

• clog and cover pipes, anchors, docks, and anything they land on

• outcompete native species for food and smother them

why are ohio river valley mussels and clams?

• they clean water and pollution

• good ecological indicators

• they are filter feeders - filter particles from water. if there are particles in the water, the particles accumulate in their tissues

• Ohio River Valley has the highest biodiversity of freshwater mussels in clams in the world (almost half of the species found in North America)

how are zebra mussels affecting native species?

• zebra mussels outcompete native mussels species for food and grow on top of them and suffocate them

• zebra mussels have consumed so much of the nutrients and food that the food web relies on that important fish populations have started to decline

• many mussel species require fish to reproduce

• zebra mussels are believed to be the source of avian botulism, which has killed many birds

what can be done to fight back against invasive zebra mussels?

they are spead by boats, paddleboards, buckets, and fishing gear. clean, drain, and dry all equipment. allow equipment to dry for at least 5 days

how have wild hogs affected the US?

• first brought to North America in the 1500s by early explorers as a source of food. later imported for hunting

• most destructive invasive species in the US

• affect native wildlife, especially amphibians and birds through extensive hunting, destroy croplands, and release CO2 into the atmosphere

• common in texas, florida, georgia, and california

how has garlic mustard affected the US?

• imported as an herb for cooking from europe

• spreads easily

• likes disturbed habitats and edges as well and undisturbed habitats (adapts well)

• outcompetes native plants (wildflowers, trees, and shrubs)

how has the asian long-horned beetle (murder hornet) affected the US?

• kills about 50 people per year

• delivers more venom than any other hornet

• they scout out honeybee hives so they can steal baby bees to feed their own young

• kill several thousands of honeybees in a matter of hours

how have burmese pythons affected the US?

• lack natural predators

• compete with native species for food and habitat

• prey on native wildlife of all sizes

• can take out apex predators like alligators

• can reproduce quickly

• have caused a trophic cascade effect

how has the asian carp affected the US?

• four species were imported from asia with support from government and scientific community to help clean up sewage from waterways

• they grow more, reproduce faster, and generally outcompete all other fish in the river

• they escaped the mississippi river system and are now making their way to the great lakes

• have altered food web dynamics