ecosystem dynamics - introduced & invasive species

Question 1

introduced species

Answer 1

-species intentionally or unintentionally moved from native location to new ecological region
-without natural predators, parasites and pathogens which would limit their growth
-this has increased due to advances in human travel
-become invasive species if establish populations in new area; outcompeting natives

Question 2

feral populations

Answer 2

-cause issues because feral populations become pests in WA, causing damage to agriculture & environment
-put pressure on native species, harming native species
-prey on or outcompete native organisms for resources
-contributed to 40% of species extinctions since 1750

Question 3

WA’s invasive species declared pests

Answer 3

-fox
-feral camel
-wild dog
-feral cat
-feral pig
-feral goat
-feral goat
-feral donkey
-rabbit
-cane toad
-rainbow lorikeet
-red-eared slider

Question 4

chemical control

Answer 4

-quick and effective
-however, are ecologically damaging as well as costly
-usually with pesticide or poison, such as bait to control invasive species

Question 5

biological control

Answer 5

-another species is introduced to control the population of a pest species
-biological control agents exploit relationships between organisms
-sometimes an integrated response (2 or more) is used when rapid response is needed in early stages
-four types are general predators, specialised predators, parasites & microbial diseases

Question 6

precautions for biological control

Answer 6

-field trials in isolated areas must be conducted to study unexpected effects, especially to prevent the biological control species from becoming another pest
-only target pest species and not impact other populations
-decrease numbers as the pest species decreases in number
-not compete with native species for a resource

Question 7

biological control species: lady birds

Answer 7

-introduced to battle aphids on citrus trees, reducing costs from using chemical control

Question 8

culling

Answer 8

-under strict regulations invasive organisms are culled
-e.g. red/grey kangaroos outcompete other species for resources. every year 2 million kangaroos are killed, with a small portion of meat being used for human consumption

Question 9

reintroducing populations

Answer 9

-some species are rereleased from breeding programs back into their environment for purpose of building up population
-e.g. galaxias is a genus of native freshwater fish who have suffered due to mosquitofish, and are now reintroduced in uninfested waterways or artificially created ponds