4. Biodiversity farming and deforestation

Question 1

Deforestation

Answer 1

Reduces number of trees and sometimes tree species
Destroys habitats for animals
Some animal species lose the variety of their food sources
Some animal species lose their shelter
These species may die or have to migrate to another suitable area

Question 2

Agriculture

Answer 2

Woodland clearance- reduces diversity the same as deforestation
Hedgerow removal – reduces diversity the same as deforestation
Pesticides- reduces diversity by directly killing pests and removing food source of some organisms
Herbicides- reduces plant diversity and the number of organisms that feed on weeds
Monoculture – only grow one type of plant which will support fewer species of animals and so reduce diversity
Competition – eg wheat better at competing for resources than other plants so these die, reducing species diversity

Question 3

Risks and Benefits of Agriculture and Deforestation

Answer 3

Question 4

You have to able to discuss ways in which society uses science to inform decision making relating to biodiversity
Fewer hedgerows reduces diversity.

Answer 4

The UK government offers farmers money to encourage them to plant hedgerows, and to cover the cost of not growing crops on these areas.

Question 5

You have to able to discuss ways in which society uses science to inform decision making relating to biodiversity
Deforestation reduces diversity.

Answer 5

Some governments encourage sustainable logging (a few trees are taken from lots of different areas and young trees are planted to replace them).

Question 6

You have to able to discuss ways in which society uses science to inform decision making relating to biodiversity
Human development reduces diversity.

Answer 6

Many governments are setting up protected areas (e.g. national parks) where human development is restricted to conserve diversity.

Question 7

You have to able to discuss ways in which society uses science to inform decision making relating to biodiversity
Some species are facing extinction.

Answer 7

Breeding programmes in zoos help to increase the numbers of endangered species in a safe environment before reintroducing them to the wild.

Question 8

On the intensive farms, the farmers had removed hedges to increase land for grazing. This resulted in a decrease in the diversity of birds on these farms.
Explain why the removal of hedges caused a decrease in the diversity of birds.(3)

Answer 8

1. Removes species/types of plant/insect;
   Accept: decrease in plant/insect diversity.
2. Fewer food sources;
   Ignore: less food.
   Accept: less variety of food.
   Accept: removes a food source.
3. Fewer habitats/niches;
   Accept: loss/removal/destruction/ of a habitat.
   Accept: no habitat.
   Ignore: homes/shelters.

Question 9

There are ethical and economic arguments for maintaining biodiversity.

Answer 9

We should maintain biodiversity to)
Prevent extinction / loss of populations / reduction in populations / loss of habitats / save organisms for future generations (idea of);

Question 10

Some practices have directly removed habitats and reduced species diversity

Answer 10

Removal of hedgerows
Creating monocultures – single crops
Draining wetlands
Overgrazing eg sheep in upland areas
Fragmentation of habitats. Isolating animals.
Others have had a more indirect effect:
Increased use of pesticides and fertilizer
Contamination of water
Lack of crop rotation

Question 11

A number of management strategies have been developed to increase species and habitat diversity:

Answer 11

Maintain and plant hedgerows
Maintain and create ponds
Leave wet corners of field rather than draining them
Plant native trees on land with low biodiversity.
Use organic rather than inorganic fertilisers
Use biological control of pests rather than chemical pesticides – this has to be very carefully managed and there have been many examples of disasters
Use crop rotation that includes a nitrogen fixing crop
Use intercropping rather than herbicides to control weeds.
Leave cutting verges and field edges until after flowering and seed dispersal
Introduce conservation headlands.
Some of these measure will make food more expensive but grants from government departments such as DEFRA encourage farmers to use them to maintain biodiversity.
If biodiversity is reduced across the globe the security of our food supply becomes increasingly unstable.