Invasive species (class 13)

Question 1

How many organisms have invaded the Antarctic continent in the last 200 years? Why/how?

Answer 1

About 200 plants, animals, inverts, and microbes. Human assisted species dispersal!!!

Question 2

Give an example of an invasive species to the Antarctic and why it can survive there?

Answer 2

The king crab can survive in the Antarctic because of warming water temperatues

Question 3

What did the study by Chown in 2012 of Antarctic visitors upon vacuuming their belongings?

Answer 3

People carried seeds on their clothes or gear. Scaled to everyone, there is 7,000 seeds being brought in anually

Question 4

What percentage of the foreign plant material that reaches Antarctica are cold adapted species that can withstand & colonize in extreme conditions?

Answer 4

49-61%

Question 5

Define “exotic species”

Answer 5

species occuring outside of their natural ranges because of human activity

Question 6

Why do most exotic species not become established?

Answer 6

The environment is not suitable of they have not arrived in sufficient numbers

Question 7

Define “invasive species”

Answer 7

species that become established outside their natural range and spread and increase in abundance rapidly

Question 8

What is the risk of invasive species?

Answer 8

They may displace native species through competition or prey on native species to the point of extinction

Question 9

Introduction of a new species occurs via: (4 ways)

Answer 9

1. European colonization
2. Agriculture, horticulture and aquaculture
3. accidental transport
4. biological control

Question 10

Describe introduction via European colonization

Answer 10

settlers released 100s of species of bird and mammals to make countryside more familiar and to provide game for hunting

Question 11

Describe introduction via agriculture, horticulture and aquaculture

Answer 11

species introduced as ornamentals, for agriculture, pasture grasses, or soil stabilizers. They can escape cultivation and become invasive.

Question 12

Describe introduction via accidental transport

Answer 12

• weed seeds harvested along with commercial seeds and sown in new locations
• rats, snakes, insects stow away in ships and airplanes
• pathogenic organisms travel with their hosts (fungus, seeds, microorganisms, marine organisms)

Question 13

Describe introduction via biological control

Answer 13

To control an invasive species, an animal from their original range may be released. Sometimes successful, sometimes becomes invasive and harmful themselves

Question 14

Name one invasive species in North America

Answer 14

EARTHWORMS! They outcompete native species. They change the physical and chemical properties of the soil

Question 15

What are domestic cats a major predator of?

Answer 15

Birds and small animals (in areas occupied by humans)

Question 16

What does the invasive fire ant compete with?

Answer 16

Nestling bobwhites and fire ants compete for insect prey

Question 17

Do many island plants produce bad-tasting tough vegetation that discourages herbivores?

Answer 17

No lol

Question 18

What kind of plants have better defenses against introduced predators?

Answer 18

Exotic plants

Question 19

What kind of plants take over islands following herbivore introductions?

Answer 19

Exotic plants

Question 20

What makes some groups of island birds vulnerable to introduced predators?

Answer 20

Some island birds have lost flight and make their nests on the ground

Question 21

What makes island organisms more susceptible to mainland diseases?

Answer 21

They lack natural immunity carried to the diseases carried by introduced hosts

Question 22

Give an example of an island bird with their nest on the ground and name the introduced predator.

Answer 22

Cape Barren goose, Maria Island in Tasmania. Tasmanian devils were introduced to the island to create a disease-free pop., but have eaten all the goose nests

Question 23

How are freshwater systems similar to oceanic islands?

Answer 23

They are both isolated with many endemic species

Question 24

Are invading fish more or less aggressive than the native species?

Answer 24

MORE aggressive native species

Question 25

How do most fish introductions into marine environments happen?

Answer 25

Through transport of ballast water and introductions for aquaculture

Question 26

Why were lionfish introduced to California in 2000 and what happened after this?

Answer 26

Introduced through aquarium trade. Removed by divers locally, but difficult to control at a broad scale

Question 27

What was introduced to Lake Erie in 1988?

Answer 27

Zebra mussels, which reproduce and reach high densities rapidly

Question 28

What percentage of species are capable or surviving outside of native range AND spreading? (aka becoming invasive)

Answer 28

Fewer than 1%

Question 29

Reasons invaders spread so rapidly:

Answer 29

• absence of natural predators and parasites

- often well suited to disturbed conditions (climate change will increase this vulnerability)

Question 30

Why do some native species “dramatically flourish” within their home range?

Answer 30

Because of the ways in which humans have altered the environment- this can make them as much of a concern as exotic invasive species

Question 31

What are 3 reasons generalist predators have increased?

Answer 31

• forest fragmentation
• suburban development
• easy access to garbage

Question 32

Define genetic swamping

Answer 32

occurs when invasive species is closely related to native species and hybridized with the native variaties, resulting in loss of unique genotypes from local populations

Question 33

What does genetic swamping cause?

Answer 33

taxonomic boundaries that are obscure

Question 34

Give an example of genetic swamping

Answer 34

Cutthroat trout hybridize with introduced rainbow trout. Hybrid individuals are more vigorous than native species (identity of species blurred)

Question 35

What is a challenge of controlling invasive species (relevant to the public)

Answer 35

Public resistance to control of introduced mammals that overgraze native plant communities. OR to invasive predator control (cats, deer, wild horses)

Question 36

Give examples of mammals damaging ecosystems:

Answer 36

• Brumbies damage Australian grassland

- Canadian beavers in Chile and Patagonia

Question 37

Explain the main control strategy of invasive species

Answer 37

• enforcement of laws restricting transport and introduction of exotic species at international borders and checkpoints

Question 38

What is the BEST (cheapest) control strategy for invasive species

Answer 38

PREVENTION (it is much easier and cheaper than eradication)

- train citizens and staff to recognize invasive species and implement control measures

Question 39

What is a tool for early detection of invasive species?

Answer 39

Environmental DNA

Question 40

Once established, invasive species can be controlled through:

Answer 40

• changing land-use practices (in a way that favours native species)
• physical removal, trapping, poisoning
• biological control with predator from the original range

Question 41

3 general steps to minimize the impact of invasive species

Answer 41

1. prevention
2. detection and early intervention
3. long-term management

Question 42

Name the 4 places where we can control invasive species

Answer 42

• place of origin (source)
• in transit
• at place of new infestation
• the places it might be spread to

Question 43

How can invasive species be beneficial?

Answer 43

• invasive plants can stabilize eroding lands, provide nectar for native insects, supply nesting sites for animals
• non-native bees provide pollination
• value in “novel ecosystems”

Question 44

What is a novel ecosystem?

Answer 44

an ecosystem with a mixture of native and nonnative species that is best suited to the new conditions created by human activities