Chapter 2 Land

1. Chapter 2 Land • Announcements? • IN AFS tonight • 5 pm, CL 167 Nick Haunert, Eagle Creek Reservoir Fish Molles: Ecology 2nd Ed.

2. Objectives: • Describe climate based on climate diagrams • Explain how climate controls geographic distribution of biomes based on: • Temperature extremes • Temperature and precipitation seasonality • Match biomes to their geographic locations • Describe soil characteristics that influence plant species distribution within biomes Molles: Ecology 2nd Ed.

3. Chapter Concepts • Uneven heating of earth’s surface by sun and tilt of earth’s axis, combine to produce predictable latitudinal variation in climate Molles: Ecology 2nd Ed.

4. Chapter Concepts • Geographic distribution of terrestrial biomes closely corresponds to variations in climate, especially temperature and precipitation Molles: Ecology 2nd Ed.

5. Introduction • Janzen studied tropical dry forests in Costa Rica for restoration efforts • Guanacaste tree (E. cyclocarpum) Molles: Ecology 2nd Ed.

6. Introduction • Janzen studied tropical dry forests in Costa Rica for restoration efforts. • Guanacaste tree (E. cyclocarpum) • No current dependable dispersers; trees produce massive numbers of fruits Molles: Ecology 2nd Ed.

7. Introduction • Janzen studied tropical dry forests in Costa Rica for restoration efforts. • Guanacaste tree (E. cyclocarpum) • No current dependable dispersers; trees produce massive numbers of fruits. • Last native dispersers extinct 10,000 years ago (sloths, camels). • Cattle and horses (exotics) dispersers. Molles: Ecology 2nd Ed.

8. Natural history info isimportant! Molles: Ecology 2nd Ed.

9. Soil Factors that Determine Species Distributions Molles: Ecology 2nd Ed.

10. Mineral composition • Nutrient availability • Toxic substances (metals) • pH Solubility of nutrients / toxic metals Molles: Ecology 2nd Ed.

11. Soil Texture • Relative amounts of gravel, sand, silt, clay • Silt & Clay • Water retention • Nutrient retention and availability • Gravel & Sand • Aeration (oxygen for roots) • Organic matter has beneficial influence on water/nutrient availability AND aeration Molles: Ecology 2nd Ed.

12. Texture, Aeration, and Soil Water Molles: Ecology 2nd Ed.

13. Molles: Ecology 2nd Ed.

14. Soil : Foundation of Terrestrial Biomes • Soil: Complex mixture of living and non-living material. • Classification based on vertical layering (soil horizons). • O Horizon • A Horizon • B Horizon • C Horizon Molles: Ecology 2nd Ed.

15. Soil Horizons O: Organic Layer freshly fallen organic material – most superficial layer. Fig. 2.3 Molles: Ecology 2nd Ed.

16. Soil Horizons O: Organic Layer freshly fallen organic material – most superficial layer. A: Mixture of minerals, clay, silt and sand. Fig. 2.3 Molles: Ecology 2nd Ed.

17. Soil Horizons O: Organic Layer freshly fallen organic material – most superficial layer. A: Mixture of minerals, clay, silt and sand. B: Clay, humus, and other materials leached from A horizon – often contains plant roots. Fig. 2.3 Molles: Ecology 2nd Ed.

18. Fig. 2.3 Soil Horizons • O: Organic Layer freshly fallen organic material – most superficial layer. • A: Mixture of minerals, clay, silt and sand. • B: Clay, humus, and other materials leached from A horizon – often contains plant roots. • C: Weathered parent material. • Soil profile = snapshot of soil structure in constant state of flux. Molles: Ecology 2nd Ed.

19. Molles: Ecology 2nd Ed.

20. Drainage • Water retention & Aeration • Topography Run-off • Flat vs. Sloped • Upper vs. Lower Slope • Convex vs. Concave • Impervious soil layers • Infiltration • Soil texture Molles: Ecology 2nd Ed.

21. Soils influence local distribution of plants • Texture: water, nutrients • Parent rock: pH, nutrients, toxic metals • Organics: water, nutrients • pH: nutrient availability, solubility of metals • Drainage: aeration of roots, solubility of metals • Plants add organics, influence weathering Molles: Ecology 2nd Ed.

22. Climate • Temperature and precipitation regime that is typical for a specific location or region: • Average temp. and precipitation • Temp. extremes (especially minimum) • Seasonality of temp. and /or precipitation Molles: Ecology 2nd Ed.

23. Factors That Control Regional Climate • Latitude(affects solar radiation) • Direction of prevailing winds • From ocean or from land (moist vs. dry) • From tropical or polar (warm vs. cold) • Rain shadow of mountains • Proximity to large water bodies • Elevation Molles: Ecology 2nd Ed.

24. Climate variability Large-scale patterns Molles: Ecology 2nd Ed.

25. Large Scale Patterns of Climatic Variation:Temp., Atmospheric Circulation, and Precip. • Spherical shape, tilt of earth’s axis: • uneven heating of earth’s surface. Molles: Ecology 2nd Ed. Fig 2.5

26. Drives air circulation patterns and consequently precipitation patterns. • Warm, moist air rises. • Cools, Condenses, and falls as rain. • Cooler, dry air falls back to surface. Molles: Ecology 2nd Ed. Fig 2.5

27. Rainforests at equator. • Major Deserts at 30o N and S. Molles: Ecology 2nd Ed. Fig 2.5

28. Molles: Ecology 2nd Ed. Fig 2.5

29. Temp., Atmospheric Circulation, and Precip. • Coriolis Effect = • winds clockwise in N hemisphere; counterclockwise in S hemisphere. Fig 2.5 Molles: Ecology 2nd Ed.

30. Fig 2.7 Climate Diagrams • Summarize various env. variables for area. • Allows quick comparison between areas for vegetative growth predictions. Molles: Ecology 2nd Ed.

31. Molles: Ecology 2nd Ed. Fig 2.7

32. Fig 2.8 Molles: Ecology 2nd Ed.

33. Fig 2.8 Molles: Ecology 2nd Ed.

34. Terrestrial Biomes • Biomes: distinguished by plants – associated with particular climates Molles: Ecology 2nd Ed.

35. Biome • A major geographic region characterized by a distinctive assemblage of life forms. • Defined by dominant plant life forms on land. • Defined by dominant plants or animals in sea. • Terrestrial biomes generally the result of large-scale climate patterns. Molles: Ecology 2nd Ed.

36. Natural History and Geography of Biomes • Main factors determining biomes are: • Temperature and Precipitation Molles: Ecology 2nd Ed.

37. Molles: Ecology 2nd Ed.

38. Tropical Rainforests • Within 10o lat. of equator • Little temp variation • Annual rainfall 2,000 – 4,000 mm • Heavy rainfall leaches soil nutrients • Organisms add vertical dimension • Staple foods + medicines for human pop’s – increasingly exploited Molles: Ecology 2nd Ed.

39. Molles: Ecology 2nd Ed. Fig 2.10

40. Tropical Dry Forest • 10o – 25o latitude • More seasonal than tropical rainforest • Soils richer in nutrients, but erosion • Shares many animal and plant spp. w/ tropical rainforests • Heavily settled by humans – extensive clearing for ag Molles: Ecology 2nd Ed.

41. Molles: Ecology 2nd Ed. Fig 2.13

42. Fig 2.14 Molles: Ecology 2nd Ed.

43. Tropical Savanna • N / S of Dry Forests • Alternate between wet / dry seasons • Drought w/ dry season = dry conditions; lightning-caused wildfires. • Soils low water permeability. • Saturated soils keeps trees out. • Increasing pressure to produce livestock. Molles: Ecology 2nd Ed.

44. Fig 2.16 Molles: Ecology 2nd Ed.

45. Desert • 30o N and 30o S • ~ 20% of earth’s land surface • Water loss > precip. most of year • Soil usually extremely low in organics • Plant cover sparse to absent • Animal abundance low; biodiversity may be relatively high • Strong behavioral adaptations • Human intrusion increasing. Molles: Ecology 2nd Ed.

46. Fig 2.19 Molles: Ecology 2nd Ed.

47. Warm Desert Molles: Ecology 2nd Ed.

48. Cold Desert Molles: Ecology 2nd Ed.

49. Temperate Woodland and Shrubland • All continents except Antarctica • Cool and moist in fall, winter, and spring, can be hot / dry in summer • Fragile soils w/ moderate fertility • Trees and shrubs typically evergreen • Fire-resistant plants due to fire regime • Long history of human intrusion Molles: Ecology 2nd Ed.

50. Fig 2.22 Molles: Ecology 2nd Ed.