10.3 Species diversity and human activities

Question 1

Describe an agricultural ecosystem.

Answer 1

• controlled by humans to have a large number of a productive species
• possess alleles limited to desirable characteristics
• economically, there should be a large number of desirable organisms, especially with the pressure of an increasing population

Question 2

Why are agricultural ecosystems damaging?

Answer 2

• an area can only support a certain amount of biomass
• if desirable species take up most of this, there isn’t much room for other species
• they must then compete for resources and space
• pesticides kill competing species
• thus, the index of species diversity is low

Question 3

Why has UK food production doubled in 40 years?

Answer 3

• improved genetic varieties of plants and animals
• more fertilizers and pesticides
• more biotechnology
• changed farming practices
  This has led to fewer habitats and ecosystems, and lower species diversity.

Question 4

How does agriculture directly remove habitats?

Answer 4

• removal of hedgerows
• creating monocultures
• filling in ponds and draining wetlands
• over-grazing land

Question 5

How does agriculture have an indirect effect?

Answer 5

• pesticides and inorganic fertilizers
• escape of efluent from silage stores into water
• no crop rotation and under cropping

Question 6

Which management techniques increase biodiversity without decreasing yield or profit?

Answer 6

• Maintaining hedgerows
• planting hedges rather than fences
• maintaining and putting in ponds
• not draining wet areas
• planting trees in areas of low species diversity
• reduced pesticide usage
• use of organic fertilizers
• crop rotation with a nitrogen-fixing crop
• intercropping
• creating natural meadows and using hay rather than grass for silage
• leave cutting of verges until after seed dispersal
• introduce conservation headlands