Species Diversity And Human Activities Flashcards
What is an agricultural ecosystem
They are controlled by humans, farmers often select species for particular qualities that make them more productive. As a result the number of species, and the genetic variety of alleles they posses, is reduced to the few that exhibit the desired features
How are pesticides used to exclude these species
As they compete for the light mineral ions, water and food required by the farmed species. Leading to a reduction in species diversity
What’s the index of species diversity like in agricultural ecosystems
It’s low
What practices have directly removed habitats and reduced species diversity
Removal of hedgerows and grubbing out in woodland
Creating monocultures
Filling in ponds and draining marsh and other wetland
Over grazing of land
What practices have an indirect effect of reducing habitats and species diversity
Use of pesticides and inorganic fertilisers
Escape of effluent from silage store and slurry tanks into water courses
Absence of crop rotation and lack of intercropping or undersowing
What’s an example of conservation that can increase species and habitat diversity
Maintaining existing hedgerows at the most beneficial height and shape
Plant hedges rather than erect fences as field boundaries
Maintain existing ponds and where possible create new ones
Leave wet corners of fields rather than draining them
Plant native trees on land with a Lowe species diversity rather then in species rich areas
Reduce the use of pesticides
Use organic, rather then inorganic fertilisers
Use crop rotation that includes a nitrogen fixing crop, rather then fertilisers to improve soil fertility
Use intercropping rather then herbicides to control weeds and other pests
Leave the cutting of verges and field edges of fields until after flowering and when seeds have dispersed
Introduce conservation headlands - areas at the edges of fields where pesticides are used restrictively so that wild flowers and insects can breed
Explain why there is a Reduction in species diversity when a forest is replaced by grassland for grazing sheep or cattle
Because forests, with their many layers, have many habitats with many different species - high species diversity. Grasslands have a single layer , fewer habitats, fewer species and lower species diversity
Suggest why the draining of ponds on agricultural land might have a greater effect on biodiversity than removing a hedgerow
Ponds provide a habitat for a wide range of aquatic species that are unlikely to find alternative habitats as aquatic habitats are few and far between. Ponds may be a source of food and water for terrestrial species which may also not survive without them. Hedgerow species are likely to have a larger range of alternative habitats as most of the area will be terrestrial with other sources of food and shelter so fewer species are likely to be lost
