Global Change and Animal Behaviour Flashcards
What are invasive species? (Name three examples.)
A non-native species that is abundant enough to become a nuisance for humans, or disruptive to a host system.
- European Starling, Nile Perch, Cane Toad
Why are invasive species spreading?
Traditional species boundaries are breaking down due to human movement. Shipping lanes and road networks are a path for invasive species.
Nile Perch in Lake Victoria
Introduced for “better fishing” for colonists. However, they managed to eat up many cichlid species, making them extinct.
This made cichlid based fisheries extinct. And because nile perch were so big, they couldn’t just be fished by individuals, only by professionals with large equipment.
Deforestation, then erosion occurred. This affected the turbidity of the lake, removing vision for the fish remaining in the lake.
How light can affect speciation
At shallow depth, blue light and coloration is favoured. At low depths, red light and red coloration are favoured. These preferences can diverge a population. However, water clarity can change this. Muddy waters cause species barrier breakdown, and many hybrids.
Why are invasive species so successful?
- Generalist foraging
- Wide environmental tolerance
- Short generation time
- High reproductive capacity
- High interspecific aggression
- Tendency to disperse
- Gregariousness (live in high densities with conspecifics)
Sources of Aquatic Contamination
- Urban or Domestic sources (road runoff, sewage)
- Agricultural sources (pesticides, fertilizers)
- Industrial sources (effluents into air or water, direct dumping)
Insecticide and Fish
Found in streams, where fish breed, in BC. Even at low concentrations, it affected fishes’ ability to perceive danger and return to their native stream. Couldn’t smell alarm cues, and homing mechanism was broken; these are both olfactory mechanisms.
Birth Control and Fish
Birth control (active ingredient, EE2) feminized fish in Lake Ontario. Males did not make sperm, and had eggs in their testes. This caused a population crash.
Round Gobies in Hamilton Harbour
An invasive species that hops along the ground. Comes from Asia; taken up by ships, and brought here. Highly aggressive, and outcompetes native species for resources. Spread to all great lakes in the 90s. Oddly, they spread fast though they do not move much (extremely site faithful, small home range).
Pollution: Round goby is vector for increased mobilization of bioaccumulated contaminants. (It eats mussels which have a lot, then other species eat it.)
Balshine and team found that fish from more contaminated sites were smaller, and younger (either they die, or go elsewhere; we can’t be sure). They also have higher contaminant body burdens. They are also feminized, and have fin erosion.
They are slower and less exploratory. They are more likely to be taken by predators. They take longer to sort out dominance and win shelter.
Chronic wastewater exposure reduced survival and dampened aggression.
