3.8 Threats to Biodiversity

Question 1

describe ‘habitat loss and fragmentation’

Answer 1

Human activities, such as the clearing of habitats, has led to habitat fragmentation.

As the fragments suffer edge degradation, that habitat fragment gets smaller.

Question 2

what effect will habitat loss and fragmentation have on interspecific competition within each fragment and will this effect species diversity ?

Answer 2

Interspecific competition will increase as habitat fragments get smaller. This may result in a decrease in species diversity as less dominant species are outcompeted by more dominant ones.

Question 3

describe ‘habitat corridors’

Answer 3

they allow the movement of animals between fragments increasing access to food and choice of mate

Question 4

explain ‘why habitat corridors could help maintain biodiversity under conditions of climate change’

Answer 4

they allow for the recolonisation for small fragments after local extinctions, and allows organisms to move away from unfavourable conditions instead of becoming extinct

Question 5

why might humans choose to introduce non-native species to an ecosystem?

Answer 5

• the food source in agriculture
• biological control
• ornamentation

Question 6

describe ‘introduced, naturalised and invasive species’

Answer 6

Non-native species often become invasive because their new location lacks the limiting factors, such as predators, parasites, pathogens and competitors that would normally keep their population in check.

In addition, they may be larger and breed more rapidly than native species and so out compete native species for space and resources or hybridise with them.

Introduced species can also carry diseases to which the native species are not resistant.