3.4.6 biodiversity within a community

What is species diversity?

Refers to the number of different species and the number of individuals of each species within one community

Genetic diversity definition?

Refers to the variety of genes possessed by the individuals that make up a population of a species

Ecosystem diversity definition?

Refers to the range of different habitats, from a small local habitats to all of Earth

What is species richness and what is it used to measure?

As a measure of diversity, and it is the number of different species in a particular area at a given time (in a community)

What is the index of diversity equation?

d = N(N-1)/

Σ n(n-1)

d= index of diversity

N=total number of organisms of all species

n=total number of organisms of each species

What does index of diversity describe?

The relationship between the number of species in a community and the number of individuals of each species

What does a higher index of diversity show?

That the species diversity is greater

What makes agricultural ecosystems different from natural ecosystems?

Natural communities have a high index of diversity, however agricultural ecosystems are controlled by humans, and species will often be selected in particular quantities to make them more productive.

What is the impact of agriculture on biodiversity?

Having a reduced number of species reduces the genetic variety of alleles to those that possess the desired features. To be economic there is often a large quantity of a species and because an area can only support a certain biomass other species cannot grow/live. This increases competition and means the populations of other species is reduced. Pesticides exclude species that compete for resources with the desired species. This reduces the species diversity and means index of diversity is low.

How has food production been made greater with technology?

Through use of improved genetic varieties of plant and animal species, greater use of chemical fertilisers and pesticides, greater use of biotechnology and farm practice changes, leading to larger farms and conversion of natural land into farmland.

What impact has greater food production had on ecosystems?

Reduces the variety of habitats within ecosystems and reduces species diversity

List some examples of practices that have directly removed habitats in farming:

• Removal of hedgerows and woodland

• Creating monocultures - replacing meadows with cereal crops

• Filling in ponds, draining marshes

• Over grazing land - eg upland areas with sheep

List some farming practices that have indirectly removed habitats:

• Use of pesticides and inorganic fertilisers

• Escape of effluent from silage and slurry tanks into water courses

• Absence of crop rotation

What are some management techniques to reduce the conflict between intensive food production and conservation?

• Manage hedgerows at a beneficial height and shape

• Plant hedges not fences

• Maintain existing ponds and build new ones

• Plant native trees on land with low species diversity

• Reduce the use of pesticides and use biological control

• Use organic fertiliser

• Use intercropping not herbicides to control weeds and pests

• Create natural meadows, and introduce conservation headlands where wild flowers and insects can breed

What incentives are used to encourage farmers to use practices that increase biodiversity?

Financial incentives from the Department of Environment, Food and Rural Affairs and the EU.