Invasive Species Flashcards
1
Q
What is an invasive species?
A
- species that occur outside of their natural range due to human activities
2
Q
Why do most introduced exotic species not become invasive?
A
- unsuitable habitat, too low numbers to become established, ecological controls in place in new habitat to prevent this
3
Q
What is ecological release?
A
- when a species expands its niche within its own habitat into a new habitat where there is little competition for resources, which remain abundant
- sp introduced to islands also experience competitive release
4
Q
What are the four main causes of introductions?
A
- European Colonization
L> settlers released various bird, mammal and fish sp - Agriculture, horticulture, aquaculture
L> ornamentals, agricultural crops, pasture grass, soil stabilizers - Accidental transport
L> ballast water, planes etc - Biological control
L> species introduced to control invasive
5
Q
What are some examples of invasive sp?
A
- zebra mussel in great lakes
- round goby in great lakes
- yellow crazy any on Christmas island
6
Q
What are the impacts of aquaculture on native species?
A
- water pollution
L> via food, drugs/chemicals used to treat fish, fish waste etc - risk of pathogen /parasite transmission between farmed and wild populations
- fish predators can become entangled in nets
- escaped fish , adapted for life in farm, can breed with locals, leading to increases in maladapted genes in wild populations
7
Q
Explain the example of biocontrol for water fen.
A
- introduced to australia from Brazil
- deliberately released weevils to bring moelstra levels down at Lake Moon Darra (looked completely green from overgrowth)
- within one year fen biomass went down to 1 metric ton (use to be 50,000)
8
Q
Provide an example of how native sp can benefit from disturbance.
A
- coyotes
- spreading via human activity
L> creation of acceptable habitat
L> removal of competitors (wolves)
9
Q
Explain genetic swamping within an invasive species concept
A
- genetic swamping is the loss of unique haplotypes within native species through hybridization with closely related introduced species
10
Q
Give an example of genetic swamping
A
- northern crested newt
- threatened
- hybrids with invasive T.carnifex = genetic pollution
- mixed populations now and few that are pure
11
Q
Explain how cats are invasive on islands
A
- feral cat colonizes introduced to many islands
- large impact one endemic species esp birds
- humans often responded to loss of endemics by trying ti kill feral cat colonies with some success
- BUT sometimes this results in indirect effects resulting in a loss of wildlife via species interactions
12
Q
Relationship between rats and cats on islands and indirect species effects?
A
- where cats have been introduced so have rats
- cats will preferentially eat rats
- rats both compete with, and prey on, local wildlife
- reducing feral cat colonies can cause rat populations to increase, which causes larger crash in wildlife than if cats were still present
13
Q
Explain how controlling invasive species occurs and troubles associated.
A
- typically requires altering habitats to favour natives
- customs restrictions prohibiting transport and introduction of exotics
- inspected plants, animal soils, other bio materials being transported to prevent pest and pathogen transmission
- potential biological control programs -> resulted from carefully testing
- controlling typically is costly and difficult
14
Q
Are all invasive sp bad?
A
- no
- context dependent
- european honey bees for ex
- invasive plants that provide for other sp in disturbed habitat etc
15
Q
Explain the situation of climate change in Mount Loa, Hawaii
A
- human activities (burning fossil fuels, deforestation) increase atmospheric CO2
- higher atmospheric CO2 has been linked to past global warming events
- Mount Loa observatory set up to measure CO2 in atmosphere
- Seasonal CO2 variations - effects of PS (spring/summer) and decay (fall) of plants / leaves (largely plants in North)
