GRASSLAND ECOSYSTEMS
For the A2 exam, students need to have 1 case study of a GRASSLAND ecosystem: either TEMPERATE or TROPICAL.
I have usually gone for the TEMPERATE option (and then a TROPICAL forest for balance... wonder if most people do it like that...)
Temperate Grassland is a BIOME.
There are a couple of main locations where it develops (it appears once rainfall drops below around 500mm per annum, and trees begin to become less dominant): the PRAIRIES of the MID WEST of the USA, and the STEPPES of Asia - here grass is the climatic climax community.
The WYCOMBE HIGH SCHOOL site has an illustrated 30 page download all about TEMPERATE GRASSLANDS. This is one of many essential downloads from the site.
There is a link here through to the SOILS section. Students should be familiar with the profile of a CHERNOZEM (lots of alternative spellings here too...)
This has a Litter layer, then a deep dark brown humus layer with a good CRUMB structure. There are plentiful soil fauna in this layer. Beneath that is a layer of paler brown soil and a high calcium carbonate content, meaning that the soil has an alkaline pH. It is similar to the soil type that it 'replaces': the BROWN EARTH commonly found in association with deciduous trees (to which the students say: "isn't all earth brown ?")
Need to have some examples of management of grasslands.
They are obviously farmed, and this means that methods of reducing SOIL EROSION need to be used.
There are also measures in place to reduce DESERTIFICATION in some grassland areas.
A recent posting on the SLN website led me to some information regarding a possible case study: the MACHAKOS MIRACLE.
Remember that desertification is found in semi-arid areas, and marginal land. There are notes in Geog.2 textbook by OUP.
http://www.bluegecko.org/kenya/tribes/kamba/agriculture.htm
http://www.pbs.org/earthonedge/ecosystems/agricultural2.html
Thanks to Andrew Stacey for his links and information at
http://www.stacey.peak-media.co.uk/Year8/8-3Ecosystems/8-3Savannas/8-3EcosystemSavannas.htm