Nonnative Species In Aquatic Ecosystems

25 July 2022
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question
Which of the following is an example of chemical control of nonnative species? a. mowing b. herbicides c. net barriers d. inspections
answer
b. herbicides
question
Why might it be beneficial for governments to restrict the types of plants and animals that individuals can keep as pets in a particular environment?
answer
For many exotic pet species, if they escape or are released into the environment they have the potential to become invasive and do extensive damage to the local environment. In order to preserve the local environment for everyone, it may therefore be beneficial to restrict individuals' rights to own exotic species.
question
Based on California's experience with Caulerpa, the killer algae, explain why it is important to regulate the pet and aquarium trade.
answer
Even species that are kept as pets and in aquariums should be regulated and tracked because their accidental release can have serious negative environmental impacts. Some owners and aquarium keepers intentionally release these species into the wild rather than destroy them, and accidental release is always a risk. Therefore, if a potentially destructive species is going to be kept as a pet or in an aquarium they should be regulated so proper safety precautions can be taken.
question
What factor determines when a species is considered invasive? a. It has positive environmental impacts. b. It is environmentally damaging. c. It spreads outside its native range. d. It spreads within its natural range.
answer
b. It is environmentally damaging.
question
Which of the following is not a reason that nonnative species are reared outside their native ecosystems? a. They are commercially important. b. They are used to replace native species. c. They are used for restocking programs. d. None of the above
answer
d. None of the above
question
Explain why the fact that invasive species did not co-evolve with the native species unbalances an ecosystem.
answer
Because invasive species did not co-evolve with the other species of an ecosystem, they lack controls on their population, such as predators, that native species possess. As a result the population of an invasive species can grow uncontrolled and will eventually unbalance an ecosystem.
question
Explain why the cane toad was a failure as a biological control method in Australia.
answer
The cane toad was introduced into Australia to control the population of sugarcane beetles. However, upon introduction, the toads did not eat the beetle, but instead began damaging local ecosystems by preying upon other organisms and poisoning most animals that tried to prey on them.
question
Nonnative species disrupt ecosystems by _______. a. increasing biodiversity b. preventing the spread of disease c. disrupting food chains d. increasing the populations of native species
answer
c. disrupting food chains
question
As a vector for the introduction of nonnative species, why is hull fouling particularly difficult to combat?
answer
Recreational boating and commercial shipping are an immense source of revenue and commerce around the world. Therefore, the need to protect the environment must be balanced against the needs of individuals and communities to earn a living. People who financially benefit from these industries do not want too many obstacles erected in the way of such businesses.
question
Since invasive species did not co-evolve with the other species in the ecosystem where they were introduced _______. a. they can unbalance the ecosystem b. they are considered a serious environmental problem c. they lack natural predators to help control their population d. all of the above
answer
d. all of the above
question
The rusty crayfish is harmful to native species of crayfish because it clear cuts the bottom of waterways leaving native species without a food supply.
answer
TRUE
question
Why does the aquarium trade contribute to the introduction of nonnative species? a. Exotic species can escape or be released into local ecosystems. b. Aquarium owners do not always understand how ecosystems interact. c. Nonnative fish are shipped worldwide for aquariums. d. All of the above
answer
NOT B
question
Ships that use ballast water are not in danger of introducing invasive species into aquatic habitats.
answer
FALSE
question
Nonnative species are only introduced unintentionally.
answer
FALSE
question
Which of the following is true concerning hull fouling from commercial shipping and recreational boating? a. It constitutes less than half of all nonnative species introductions. b. The revenue brought in from these industries is relatively small. c. It is difficult to prevent since ship hulls begin, conduct, and end voyages in water. d. It is best combated by chemical treatments.
answer
c. It is difficult to prevent since ship hulls begin, conduct, and end voyages in water.
question
Hull fouling is a(n) _______ introduction of nonnative species. a. unintentional b. intentional c. unimportant d. land-based
answer
a. unintentional
question
Cane toads are highly successful as an invasive species in Australia because there is only one species that is believed to be able to prey on them.
answer
TRUE
question
All of the following are true of the Zebra mussels found in the Great Lakes EXCEPT: a. Zebra mussels are having are having a negative impact on the native population of mussels in the region. b. They were unintentionally introduced to the Great Lakes by humans. c. Zebra mussels have caused a great deal of environmental damage to the area. d. People of the Great Lake region are benefitting from the economic advantages of having zebra mussels in the region.
answer
d. People of the Great Lake region are benefitting from the economic advantages of having zebra mussels in the region.
question
Which of the following is not true about nonnative species? a. They can have positive impacts on an ecosystem. b. They can have negative impacts on an ecosystem. c. They can be introduced within their natural range. d. A nonnative species can be an invasive species.
answer
c. They can be introduced within their natural range.
question
Introducing invasive species to an ecosystem results in an increase in biodiversity.
answer
FALSE