Rainforests2

Rainforests Biodiversity and Change:

Rainforests Biodiversity and Change Explain the concept and importance of biodiversity in tropical rainforests. Examine the causes and consequences of reduced biodiversity in this biome.

Rainforest:

Rainforest Located within 10 0 N or S of the equator Temperatures are high all year Rainfall is over 2000mm and falls throughout the year Vegetation is dense and mostly trees often found in 3 layers – shrub layer, canopy and ‘ emergents ’ (forest giants) NPP : 2200 gms /m 2 /year

Tasks:

Tasks Describe and explain the location of Tropical Rainforests in the world. 2. Find some facts and figures about biodiversity in Rainforests that I can use to fill in the next two slides. Why is the rainforest so biodiverse What amazing facts about its biodiversity can you find – with examples. 3. How might the existence of different layers in the forest account for higher biodiversity

Facts and Figures about biodiversity:

Facts and Figures about biodiversity Only one percent of the species have been discovered. At least 3000 fruits are found in the rainforest. 487 tree species in a hectare in the Amazon. In Peru there are 3532 species of butterflies. 170,000 of the worlds 250,000 known species of plants are found in rainforests.

Slide 5:

1 tree in a Peruvian rainforest is said to be home to 43 species of ants. 80% of worlds species of insects are found in rainforests. 90% of worlds primates 30,000 species of epiphytes found in the rainforest.

Why is it So biodiverse:

Why is it So biodiverse Age of tropical forest biome – been very stable climatically for a long time, especially some core regions. Size of the area – larger area means more species can exist – rainforests can cover very large areas. (allows for many separate niches) Geographical isolation – over time with climate change etc, certain zones have been isolated with certain species contained within them.

Slide 7:

Resources – The large variety of different habitats both horizontally and vertically within a rainforest. Energy and productivity levels (related to NPP – climate) Natural disturbances -

Slide 8:

As you can see certain physical and human factors will account for the level of biodiversity in an area. One physical factor yet to cover is

Slide 10:

Task: Redraw this to show what would happen after large scale deforestation.

Causes and Consequences of Reduced Biodiversity:

Causes and Consequences of Reduced Biodiversity

Slide 14:

Mongabay

Slide 15:

Causes of loss of biodiversity in Amazonian due to deforestation Clearing for cattle pasture Colonization and subsequent subsistence agriculture Infrastructure improvements Commercial agriculture Logging Explain each of the causes using the following resource: Mongabay – Why is the rainforest being destroyed? http://rainforests.mongabay.com/amazon/amazon_destruction.html http://news.mongabay.com/2008/0801-amazon.html

Slide 16:

Consequences of loss of deforestation

Slide 17:

We have already looked at the effect on the nutrient cycle. How will deforestation affect Water cycle locally Local weather systems Soil fertility Biodiversity Indigenous peoples of the forest Long term sustainable economic use? For each be able to talk for a minute

Medium Scale – Shifting Cultivation:

Medium Scale – Shifting Cultivation Clearing of small areas. Burning and planting for 2-3 years until nutrients depleted. Succession occurs whereby forest retains its original level of biodiversity, however only after a long time.

After large scale deforestation.:

After large scale deforestation. Rapid run off to rivers leads and no interception leads to Soil erosion – Up to 185 tonnes of topsoil has been measure to be lost from one storm per hectare after deforestion Humus lost Rivers flooded (quality of water decreases) Alternative wetting and drying of soils kills mycorrhizal fungi which is essential for trees to be able to obtain nutrients. Soils can become laterised (like brick) after drying and wetting, meaning no roots can break through and also increase local flooding .

Slide 21:

Effect on Microclimate This is very important for the whole of Brazil, as winds from the rainforest bring rain down onto the agricultural heartland in the south. Interception A tree releases 8-10 times more moisture into the atmosphere than a square meter of ocean water. Bare soil has increased albedo and therefore less rainfall occurs. Savannas have 1/3 rd less Evapotranspiration Local rainfall decreases as does seasonality. This further affects vegetation.

Explain this in relation to what you have learnt.:

Explain this in relation to what you have learnt.

Some Responses:

Some Responses Although the environmental importance of Rainforests has long been known, it is often destroyed for short term gain. Until economics plays its part in providing a real value to the rainforest in terms of its effect as a carbon sink, massive gene pool and potential source of future medicines and other industrial breakthroughs then it will continue to be depleted. Interesting Case Studies: Biodiversity and conservation at Batang Ai National Park, Sarawak (link with Higher level work on Indiginous groups and effect of cultural diffusion) Can Capitalism stop Amazon Destruction? - http://news.bbc.co.uk/2/hi/science/nature/7601344.stm Trees or oil in Ecuador - http://www.economist.com/node/13956307?Story_ID=E1_TPJVGPDS Look at the three case studies above and simplify what is being said.