10.3 Species diversity and human activities Flashcards
What impact has human action had on biodiversity
It has decreased biodiversity as humans are trying to provide enough food to sustain the population at a low cost.
This has negatively affected ecosystems
Why is biodiversity different between natural ecosystems and agricultural ecosystems
As natural ecosystems develop over time, they become complex communities as there are many individuals of a large number of different species
However, with agricultural ecosystems they are controlled by humans and are different. Eg farmers often select species for particular qualities that make them more productive.
What impact does agricultural farming have on the biodiversity
As farmers choose certain species for particular qualities eg size,
the number of different species and the genetic variety of alleles they possess is reduced to the few that exhibit the desired features.
So farmers may take up most of the space with one species they deem as desirable so there is a small amount of space left for other species, where they will compete for the few nutrients and sunlight.
Many won’t survive this competition so die, and even species that have adapted to the conditions, the population will be reduced.
How do pesticides affect biodiversity
. Pesticides kill any unwanted species growing near the desired one as they compete for light, water, ions with them.
They also may kill harmless bugs.
The overall affect is the reduction in species diversity.
How has food production doubled in the UK in the last 40 years
. Improved genetic varieties of plants
. More chemical fertilisers and pesticides
. More biotechnology
. Changes in farm practices eg larger farms
However all of this has diminished the variety of habitats in ecosystems and so reduce species diversity
Name 4 practices that have a direct effect on reduced species diversity
. Removing hedgerows and grubbing out woodland (less space for insects to live)
. Creating monocultures eg replace meadows with wheat
. Filling in ponds and draining marsh or wetlands
. Over grazing land by cows or sheep so no more crops can grow
Name 3 practices that have an indirect effect on species diversity
- Using pesticides and inorganic fertilisers
- Escape of effluent from silage stores and tanks into rivers
- Absence of crop rotation and lack of intercropping
What are some conservation techniques to improve species diversity
Eg hedgerows, draining fields, ponds, trees
. Maintain existing hedgerows at a beneficial height and shape
. Plant hedges as field boundaries rather than fences
. Maintain existing ponds or make new ones
. Leave wet corners on fields rather than draining them
. Replant native trees to the area with low species diversity
What are some conservation techniques to improve species diversity
pesticides and fertilisers, conservation spots
- Reduce use of pesticides and use biological control where possible=e, or genetically modified crops that are resistant to pests
- Use organic fertilisers
- Areas at edges of fields can be dedicated with no pesticides, for wild flowers and insects
What is intercropping
What is crop rotation
How do they conserve and improve species diversity
Intercropping: Where different species of crop are grown in alternating rows so there is more crop diversity making it difficult for weeds to survive.
Crop rotation is where you split field into 4 and each season swap around what crop grows in what field.
Always leave one quarter of the field blank.
This improves soil health, and conserves nutrients
What is a problem with conservation techniques
They will make the food more expensive to produce
