lecture 31- biological invasions Flashcards
what is a non-native species?
A species introduced to a region outside of its natural (historical) range. In other words, it’s where it evolved.
What is a biological invasion?
The spread and establishment of a species into a region beyond its natural range. In other words, where it forms a self-sustaining population.
What is the process of biological invasion?
1- Introduction
2- Establishment: forming a self-sustaining population
3- Geographic spread: impacts often detected here
What is an invasive species?
A common definition: A species undergoing a population outbreak that causes adverse ecological or economic effects.
Another definition: An introduced (alien) species that spreads rapidly, i.e. a highly successful invader.
What are the 5 facts about biological invasions?
1- Species are being moved long distances to regions that they could never reach without human assistance.
2- Invasions are now occurring at unprecedented rates.
3- Invasive species are a major threat to native biodiversity.
4- Invasions can disrupt ecosystems, often in unpredictable ways.
5- Invasive species are hard to eradicate.
What is an example of an invasion of the past?
The Great American Biotic Exchange.
3 million years ago: North& South America becameconnected by the Panamaland bridge.
- Mammals moved north &south.
- A series of extinctions followed on both continents.
What is an example of a modern invasion?
European mammals to New Zealand
What are the 3 ways that modern (human-facilitated) invasions are occurring?
1- Accidental introductions:
– Hitchhikers (ballast water, brown tree snake)
– Escapees (Asian carp)
2- Deliberate introductions:
– Biological control (Mongoose)
– Live Trade:
* Food (Nile perch)
* Ornamental (Kudzu)
* Pet release (Goldfish)
Why were mongoose introduced? What went wrong?
Why: to control rats in sugar cane fields.
They ate more than just the rats and caused extinctions.
What are the differences between natural (prehistoric) and human-assisted invasions?
1- Frequency of long-distance dispersal events
2- Number of species transported per event
3- Variation in mechanisms & routes of dispersal
4- Frequency of invasions between biogeographic realms
5- Potential for synergies with other stressors
1- natural: very low; human: very high
2- natural: small, except during biotic exchange; human: potentially large
3- natural: small; human: very large
4- natural: rare; human: common
5- natural: low; human: very high
Are native or non-native consumers more damaging to prey populations?
non-native
When are eradications usually successful?
On island or lakes
