Harvesting from a Natural Ecosystem

Humans have a huge impact on the planet.

This includes intensive farming, selective breeding and pesticides/fertilisers

Impacts of Monoculture:

• 1. Genetic diversity is reduced, crops susceptible to disease
• 2. Fertilisers pollute groundwater
• 3. Pesticides pollute groundwater
• 4. Species diversity is reduced
• 5. Countryside less attractive

Crop rotation: breaks pests’ life cycles, improves soil texture and can increase soil nitrogen

Hedgerows have been diminishing due to human need for barren land

Benefits of hedgerows to ecosystem:

• 1. Provide habitats
• 2. Animals use them to move safely between woodlands
• 3. Shelter predators of pests
• 4. Windbreaks, shelter, reduce soil erosion
• 5. Provide habitats for pollinating insects

Importance is now being recognised and farmers are receiving grants to plant hedgerows

Inorganic fertilisers are most common but affect the environment

Benefits of organic fertilisers to ecosystem:

• Compounds decompose slowly and prevent leaching
• They are cheap
• Can be disposed of on fields and not only in landfill sites
• Improves soil structure and improves drainage and aeration

But… bulky and less concentrated than inorganic ones, highly odorous and can contain weed seeds etc.

Fishing:

Unsustainability: the using up of resources faster than they are produced so that they will not continue in the future e.g. North Sea Cod are over-fished so are reproducing slower than are being caught.

Effect > population is heavily declining

Forestry:

Humans burn wood or clear land for farming > deforestation:

• 1) destroys habitats
• 2) causes soil erosion > barren land and flooding
• 3) causes pollution from combustion
• 4) increased levels of carbon dioxide as loss of photosynthesis