10.2 -> 10.3 Flashcards
biodiversity
variety and number of living organisms in particular area
species, genetic and ecosystem diversity
species diversity
number of different species and number of individuals of each species within any one community
genetic diversity
variety of genes possessed by individuals that make up population of a species
ecosystem diversity
range of different habitats from small local habitat to whole of earth
species richness
number of different species in particular area(community) at a given time
index of diversity
N(N-1)/Σn(n-1)
N= total number of organisms of all species
n = total number of organisms of each species
stable ecosystem
high species diversity index
less affected by change
7 agricultural practices that have reduced species diversity
- removal of hedgerows and grubbing out woodland
- creating monocultures
- filling in ponds, draining marsh and wetland
- over-grazing land- preventing regeneration
- use of pesticides and inorganic fertilisers
- escape of effluent from silage stores and slurry tanks into water courses
- absence of crop rotation and lack of intercropping or underslowing
Agricultural ecosystem
controlled by humans
farmers select species for particular quantities that make them more productive
- reduce genetic variety
12 conservation techniques
- maintain existing hedgerows at beneficial height and shape
- plant hedges rather than fences as field boundaries
- maintain existing ponds and create new ones
- leave wet corners of fields- don’t drain
- plant native trees on land with low species diversity
- reduce pesticide use- biological control or use genetically modified organisms resistant to pests
- use organic fertilisers
- use crop rotation that includes nitrogen-fixing crop to improve soil fertility
- use intercropping rather than herbicides to control weeds and pests
- create natural meadows and use hay not grass for silage
- leave cutting of verges and field edges until after flowering and when seeds have dispersed
- introduce conservation headlands
