Geoecology

1. Geoecology Option

2. 2008: Q.18 • Examine 2 of the natural processes that influence soil formation (80)

3. What you need to do • Explain how soils form • Name 2 processes influencing soil formation • Explain in detail how each process affects soil • Refer to 2 named soil types in your answer

4. 2008: Q.18 • Soil : loose material on earth’s surface formed by weathering and erosion of rocks. • Formed due to a combination of factors such as climate, relief, living organisms, parent material and time. • E.g., latosols form in tropical wet climates and brown earth soil form in temperate climates where deciduous trees are present.

5. 2008: Q.18 • Climate: affects temperature and rainfall in a region. They have important effects on soil. • Rainfall washes nutrients + humus down through soil. • Temperature affects activity of living things. • Climate affects the vegetation that can grow in a region. E.g.: Arctic region; few plants can survive • Vegetation is important in developing soil type, e..g. brown earth + podzol • Climate affects weathering that takes place in a region; colder regions > more freeze – thaw action • Climate controls the amount of leaching in a region

6. 2006, q 16: Examine the factors that influence soil characteristics. • What you need to do: • Choose 3- 4 soil characteristics • Discuss how these characteristics are affected by soil – forming processes • Refer to specific soils in your answer

7. 2008: Q.18 • Relief: means ‘ lay of the land’ or angle and length of slopes. • Relief influences the amount of water that runs off soil, how much water seeps into soil + amount of erosion. • Steep slopes have thinner soils due to mass movement such as soil creep and landslides. • Soils on flatter land is deeper and has more organic content because more plants can grow. • Relief influences aspect aswell . Which in turn affects soil quality as north facing slopes receive less heat + light.

8. 2006, q 16 • Characteristics of soil: colour, texture, structure, pH, humus content, water content

9. 2006, q 16 • Factors affecting soil colour: • Colour of soil depends on soil – forming processes acting upon it. • Humification tends to produce dark – coloured or black soils. Humification is method by which dead organic matter converted to humus by action of fungi and bacteria. • Leaching affects soil colour as it tends to lighten the colour of soils. It washes nutrients such as phosphorous down through soil, leaving soil pale and ash coloured.

10. 2006, q 16 • Factors affecting soil texture: • Soil texture is the way soil feels when rubbed in our hands > soil can have 4 types of texture; a) sandy, b) silty, c) clay, d) loam • Freeze – thaw action and other mechanical weathering processes acting on sandstone rocks can produce sandy soils. Marine action can also produce these soils. • Granite rocks are chemically weathered by hydrolysis. This is the action of water on feldspar minerals in granite. The feldspar is converted to clay which produces clay – texture soil. • Soils with a silty texture are found in areas where river deposition has occurred.

11. 2006, q 16 • Factors affecting humus content: • Humus content is affected by factors such as climate and relief • Climate: affects temperature and rainfall in a region. They have important effects on soil. • Rainfall washes nutrients + humus down through soil. • Temperature affects activity of living things. • Climate affects the vegetation that can grow in a region. E.g.: Arctic region; few plants can survive • Vegetation is important in developing soil type, e..g. brown earth + podzol • Climate affects weathering that takes place in a region; colder regions > more freeze – thaw action • Climate controls the amount of leaching in a region

12. 2006, q 16 • Relief: means ‘ lay of the land’ or angle and length of slopes. • Relief influences the amount of water that runs off soil, how much water seeps into soil + amount of erosion. • Steep slopes have thinner soils due to mass movement such as soil creep and landslides. • Soils on flatter land is deeper and has more organic content because more plants can grow. • Relief influences aspect aswell . Which in turn affects soil quality as north facing slopes receive less heat + light.

13. 2007, q 17: Examine the general composition and characteristics of any one soil type that you have studied • What you need to do: • Name the soil type you’re discussing • Discuss composition and characteristics giving reasons

14. 2007, q 17 • In this answer the composition and characteristics of brown earth soil will be examined • Zonal soil: developed in response to a climatic zone and its natural veg. • In this case, BES have developed in response to cool temp. oceanic and mixed deciduous forest

15. 2007, q 17 • Composition of BES: • BES contain all materials> mineral matter, air, water, living things, humus. • BES contain mineral matter that has developed in response to mechanical and chemical weathering > freeze thaw action in uplands and sheltered lowlands. • BES contain air and water held in the pore spaces btwn grains. Water comes from moderate amounts of rainfall. • Organic matter and humus present in BES because cool, temperate oceanic climate is mild; BES contains lots of living things

16. 2007, q 17 • Characteristics of BES: • Texture: loam texture. Loam have roughly equal mix of sand, silt and clay particles. BES developed on variety of parent rock such as limestone, slate and sandstone • Humus content: High because of action of humification. Soil – forming process dominant in cool temperate oceanic climates. • pH: Varies from mildly acidic to mildly alkaline. Due to moderate rainfall that only mildly leaches soil. • Structure: BES have a crumb structure, where peds are clumped together in round grains or crumbs. Crumb soil structures develop in soils with lots of living things. • Colour: BES are uniformly brown due to being well mixed by plant roots and animal activity. High humus content.

17. 2007, q 17 • Variations of BES • Acidic BES: developed in upland areas 500m + in altitude • Shallow BES: limestone areas such as Burren • Podzolised BES: Developed where podzolisation has occurred in low – lying areas.

18. Biomes Tropical Rainforest

19. Vegetation: Emergent Layer • Emergent layer consists of tops of tallest trees, from 40m to 80m • Trees have small, pointed leaves • Trees have straight smooth trunks • Root system shallow

20. Emergent Species Hummingbird Squirrel Monkey Scarlet Macaw

21. Vegetation: Canopy • Canopy upper parts of trees which grow below emergent • Canopy found 20-40m above ground

22. Canopy Species Toucan Hornbill Orangutan

23. Vegetation: Understorey • Dark environment under canopy • Plant growth limited • Short, leafy, mostly non – flowering shrubs

24. Understorey: Species Jaguars Beetle Lizard

25. Forest Floor • Teeming with animal life • Less than 1% of light that strikes top of forest reaches forest floor • Few plants grow

26. Forest Floor: Species Tapir Anteater

27. Leaves • High Level Rainfall > Plants have made adaptations • Drip tips • Grooved leaves • Oily coatings • Large leaves to absorb light

28. Roots and Trunks • Emergents grow fast to absorb light • ‘Stilt’ roots for support • Smooth, thin bark • Epiphytes

29. Parasitic Plants • Live off nutrients of host plant • Lianas catch a host tree and take lift to light

30. Poison Arrow Frog

31. Sloths

32. Flying Foxes

33. Deforestation and intensive agriculture in Brazil

34. Deforestation and intensive agriculture in Brazil Causes of deforestation in Brazil: • Intensive agriculture • Logging • Demand for wood as fuel • Construction of large dams / reservoirs drown forest • Mining and industry clear forest • Government – organised colonisation schemes clear forest

35. Underlying social and economic conditions in Brazil • Overpopulation and poverty in Brazil creates political difficulties • Government wants to open up rainforest to take advantage of timber and mineral wealth • Beef producers require more land • Industry requires more power

36. Deforestation • Timber companies given rights to remove forest and sell timber abroad • Licences given to mining companies to clear forests and mine for metals • Roads are being built across the Amazon rainforest to allow access to logging companies • New capital city, Brasilia, built from scratch during 50s and 60s in heart of Amazon • Over 125 new HEP dams have been built in the Brazilian rainforest area • January 2000: Brazilian government announced plans for Avanca Brasil > €30m plan to develop much of Amazon rainforest

37. Impact of agriculture on biome Effects of intensive agriculture: • Deforestation • Destruction of natural habitat: soils damaged due to intensive agriculture, animals and plants cant survive in the plantations • Introduction of exotic species

38. Impact of clearance on people and wildlife • Suggested that some Amazonian Indians may have been murdered for resistance • Area of natural habitat has been severely reduced • Many species of plant have been lost > serious concern as some contain chemicals that could 1 day cure illnesses • Increase in global warming

39. Impact on Brazilian soils • When forest is cleared, nutrient cycle is destroyed • Soil then becomes baked hard which cannot support plant growth • Useless for farming