Introduction Flashcards
What is a non-native species?
a species introduced to an area outside of it’s natural / historical range
**also called : non-indigenous species, alien species, exotic species, invasive species
Legal definition of an invasive species?
non-indigenous and strong undesirable impacts
**impact and spread do not have a strong correlation
Describe biological invasion
the spread and ESTABLISHMENT of a species into a region beyond it’s natural range.
aka the process of a species getting over a geographic barrier and becoming established in a new region
Define establishment
forming a self sustaining population that persists year after year. Sometimes a sp can establish well and others can disappear. Most introduced sp actually fail to establish
Define a native range
where it initially evolved
Example of a biological invasion (think piranha)
- red belly piranha
- sold in pet stores, people dumped them in Ontario lake. No evidence that they can reproduce in this lake outside of heated areas from a owe plant potentially 4000km from the area it naturally should be existing .
Briefly what are the stages in an invasion process?
- Introduction
- Establishment (form a self sustaining population) - occurs if the environment is biologically, physically suitble and if the invasive sp arrives in sufficient numbers.
- Population expansion (most impacts are often detected here BUT impact can happen immediately on introduction)
- Geographic spread (feeds back into introduction via natural or human dispersal vectors
What is a common definition of invasive species?
a species undergoing a population outbreak that causes adverse ecological or economic effects.
** prof doesn’t like this definition, this def could actually be applied to a native species via talking ability to spread AND also a species can be invasive in some regions and not others, context dependent.
What is the profs definition of an invasive species? (a more scientific def)
a non native species that spreads rapidly, i.e. a highly successful invader.
**invasive is relative (used to compare species); most introduced species are not invasive; a species may spread at different rates in different regions.
How can invaders have both ecological and socioeconomic impacts?
- Biodiversity
- Human and animal health
- technological systems
Ecosystem functioning ( contaminant cycling , nutrient cycling and ecosystem services); physical habitat
Impact on biodiversity via invasion?
- can have a strong negative impact on biodiversity and also positive.
- ex: Salvation Jane plant and it’s other name – one was seen as bad for cattle but the other is good for bees. THIS viewed overall as alarming bc it is inducing change
- BUT most invasions are not studied well enough to know their impact
Briefly describe the proportion of modern animal extinctions in which invasions were a causal factor.
- Global animal extinctions= 54-63%
- Global fish extinctions 48%
- Global mammal extinctions 48-69%
- Global bird extinctions 50-60%
- Global reptile extinctions 57%
- *in these cases it is bc the invader is driver of biological change or is it a passenger. In many cases they are drivers, sometimes passengers and sometimes they are passengers that become drivers.
Discuss the white nose syndrome and brown bats in NA.
- 6 million bats killed over the course of 6 years
- this decline in population is bad bc bats can wipe out 1.5 million pest insects from agricultural sites each year. With the bats dying out, yield will decrease, tax will go up
- pathogenic fungi ar eon the rise (via climate change + us moving them)
Describe the introduction of a chytrid fungus and it’s impact on Western Palearctic salamanders.
- caused declines globally
- initially the pathogen originated in Asia and due to globalization and lack of biosecurity it has vectored into naive European amphibian populations.
Describe the emerging biosecurity threat with the wheat stem rust fungus (Ug99 strain)
*Also discuss countries with federal agencies dealing in biosecurity
- native to east Africa and is dispersed by spores which destroys entire wheat fields
- considered a threat to global food security
- Aus, Africa and others have federal agencies that deal in biosecurity but western countries do not.
