Invasive species

Question 1

What is biotic homogenisation and why does it occur?

Answer 1

Biotic homogenisation is the combined effect of habitat homogenisation (e.g. towards urban and agriculture) and the human-led movement of species around the globe, leading to less diverse and less random species compositions (in terms of species, phylogenies and functionality) as areas become human-dominated. It is forecast to result in the loss of at least 50% of all species.

Question 2

Which traits allow non-native species to be invasive?

Answer 2

Invasive species are most commonly (but not always) r-selected, highly variable, generalist and capable of rapid dispersal. High levels of introduction effort (i.e. number of times the species has been imported) can also increase the chance of a species becoming invasive. Generalist predators and pathogens are most likely to cause extinctions.

Question 3

What kind of areas are particularly vulnerable to the effects of invasive species?

Answer 3

Areas of isolated islands are particularly vulnerable to invasive species, especially predators, due to having endemic species which largely evolved in the absence of predators e.g. rats. Highly disturbed environments with low community diversity are also most likely to be affected by invasive species.