Biodiversity within a community Flashcards
What is species richness?
- measure of the number of different species in a community.
What does the index of diversity describe?
- relationship between the number of species in a community and the number of individuals in each species
What does N represent in the index of diversity formula?
- total number of organisms of all species
What does n represent in the index of diversity formula?
- total number of organisms of each species
What is species abundance?
- Total number of individuals of a given species within a given area
Why maintain biodiversity?
- For future generations
- Medicinal purposes
- Undiscovered plants
- Allow production of oxygen
- Spiritual and culture reasons
What is loss of biodiversity due to?
- Loss of habitat - Industrial development
(roads, houses being built) - Deforestation – palm oil production
- Competition from introduced species
- Over hunting (fishing)
- Pollution - Methane (landfill), carbon
dioxide - Drainage of wetland
What human activities affect species diversity?
- Climate change- ice melts causing rising sea even, affects wether and animal migrations
- Deforestation- loss of habitat and species
- Over exploitation- overfishing, hunting causes extinction of species and can affect food webs
- Invasive species- introduction of non native species affect food webs
- Pollution- air pollution, acid rain affects water and soil, plastic pollution
How does increase in food demand impact agriculture?
- Selective breeding
- Use of fertilizers/pesticides
- Larger farms
Why is the impact of agriculture on biodiversity?
- Farming can reduce biodiversity as farmers plant monoculture, use pesticides and fertilisers
What are the problems of agriculture?
- Creating monocultures
- Overgrazing of land
- Removal of hedgerows
- Eutrophication as a result of using fertilisers
- Filling in ponds/draining marsh and other wetland
- Use of pesticides
What is the solution for creating monocultures?
- crop rotation
- intercropping
What are the benefits of intercropping?
- weeds reduced
- reduced chemical fertilisers
What is the solution to removal of hedgerows?
- maintain existing hedgerows or plant hedges rather than using fences as field boundaries
What is the solution to eutrophication as a result of using fertilisers?
- Limit use of fertilisers (especially near water
bodies or use organic fertilisers instead of inorganic ones
Advantage of organic fertiliser
- Nutrients in concentrated form and can therefore be applied in smaller amounts, i.e. cost effective
- Nutrients released slowly into the soil
- Easy to apply to fields
- Add structure in the form of humus to the soil
Disadvantage of organic fertiliser
- Offensive smells
- May be difficult to spread
- Mineral release slow
Advantage of inorganic fertiliser
- Provide a steady supply of nutrients to plants and contain both macro and micro nutrients
Disadvantage of inorganic fertilisers
- Readily leached from the soil
- Increased risk of eutrophication
- Expensive to manufacture/buy
- Risk of fertiliser spray
What is the solution to use of pesticides?
- Use biological control (natural predators)
to control weeds and pests where possible
What are some other solutions to agricultural problems/increase species diversity
- Plant trees on land with a low species diversity rather than species-rich areas
- Create natural meadows
- Introduce conservation headland
What does index of diversity measure?
- species diversity
- measures the relationship between the number of species in a community and the number of individuals in each species
What does a greater value of index of diversity indicate?
- greater the species diversity
