10.3- SPECIES DIVERSITY AND HUMAN ACTIVITIES Flashcards
As natural ecosystems develop over time, what do they become?
complex communities with many individuals of a large number of different species
What is the index of diversity like for natural ecosystems that develop into complex communities like?
high index of diversity
What does farmers selecting species for particular qualities that make them more productive lead to?
number of species + genetic variety of alleles reduced to few that exhibit the desired features
What follows if most of an area is taken up by one species that a farmer considers desirable?
there’s smaller area available for all the other species
What happens to other species when there is a smaller area available for them?
compete for little spaces + resources available- many will not survive this competition
Why are pesticides used to exclude unwanted species?
as they compete for light, mineral ions, water + food required by farmed species
What is the index of species diversity like in agricultural ecosystems?
index of species diversity low
What has helped increase food production in the UK?
improved genetic varieties of plant + animal species, greater use of chemical fertilisers + pesticides, greater use of biotechnology + changes in farm practices, leading to larger farms + conversion of land supporting natural communities into farmland
Examples of practices that have directly removed habitats and reduced species diversity? (4)
removal of hedgerows + grubbing out woodland
creating monocultures, e.g. replacing natural meadows with cereal crops or grass for silage
filling in ponds + draining marsh/ wetland
over-grazing land- preventing regeneration of woodland
Examples of practices that have a more indirect effect on reduced species diversity? (3)
use of pesticides + inorganic fertilisers
escape of effluent from silage stores + slurry tanks into water courses
absence of crop rotation + lack of intercropping or undersowing
Conservation techniques- maintaining hedgerows at most beneficial height + shape
A-shape provides better habitats than rectangular one
Conservation techniques- plant hedges
plant hedges rather than erect fences as field boundaries
Conservation techniques- ponds
maintaining ponds + create new ones
Conservation techniques- wet corners of fields
leaving wet corners of fields and not draining them out
Conservation techniques- planting native trees
plant native trees with low species diversity rather than in species-rich areas
Conservation techniques- reducing use of pesticides
use biological control where possible or genetically modified organisms that are resistant to pests
Conservation techniques- type of fertiliser
use organic, rather than inorganic, fertilisers
Conservation techniques- alternative to improving soil fertility
use crop rotation that includes nitrogen-fixing crop, rather than fertilisers, to improve soil fertility
Conservation techniques- controlling weeds + other pests
use intercropping rather than herbicides to control weeds + other pests
Conservation techniques- alternative to grass for silage
create natural meadows + use hay rather than grasses for silage
Conservation techniques- when to cut verges + field edges?
leave cutting of verges + field edges until after flowering + when seeds have dispersed
Conservation techniques- introducing conservation headlands
areas at edge of fields where pesticides used restrictively so wild flowers + insects can breed
What can these conservation practices lead to?
food being slightly more expensive to produce
What is in place as the conservation techniques will make food slightly more expensive to produce?
number of financial incentives from DEFRA + European Union
Why is maintaining biodiversity important?
if biodiversity reduced, global living system becomes increasingly unstable + we all rely on global system for food + other resources
