1. Plant Ecology - Chapter 17 Climate & Physiognomy

2. The Abiotic Components of Ecosystems 1) Outside energy source 2) Physical factors that determine weather, climate weather, climate 3) Chemicals essential for life

3. Outside Energy Source Powersphotosynthesis Warms earth Powers water cycle

4. Physical factors that determine weather, climate HeatWindPrecipitationTopography

5. Heat  Location  Reflection  Retention

6. Heat

7. Heat

8. Heat

9. Heat

10. Heat Daily temperatures can also vary dramatically in some habitats Deserts - dry air, loses heat rapidly High altitudes - thinner “blanket” of atmosphere

11. Heat Long-term changes in earth’s orbit, position Collectively produce Croll-Milankovic effects on climate Orbit shape change Affects range of seasonal variation

12. Heat Degree of tilt Affects range of seasonal variation

13. Heat Direction of the tilt - the “wobble” Changes which hemisphere is pointed toward sun when orbit is closest to sun Affects severity of seasonal shift

14. Wind and Precipitation Uneven heating Ascending, descending air masses - Hadley cell

15. Modifiers Rotation of the globe - Coriolis effect Hadley, Ferrel cells, jet streams

16. Modifiers Ocean currents, gyres induced by surface air mass movements

17. Modifiers Topography - mountains Rain shadows

18. Modifiers Topography - lakes Lake effect precipitation

19. Modifiers Annual precipitation

20. Modifiers

21. Seasonal Patterns

22. Multi-year Patterns 3-7-year El Nino Southern Oscillation

23. Multi-year Patterns Combined ocean currents and jet stream

24. Multi-year Patterns Milder winters along US-Canada border Increased winter storms in California Floods in SE, snow in SW mountains Decreased hurricane activity in Atlantic El Nino

25. Multi-year Patterns More, stronger tornadoes in Midwest More, stronger hurricanes Drought, forest fires in SW La Nina

26. Plant Physiognomy North-south gradient in vegetation form due to temperature West-east changes in response to precipitation

27. Plant Physiognomy Evergreen broadleaf Deciduous broadleaf Evergreen coniferous Tree line

28. Plant Physiognomy Tree line climate can produce strange tree forms - krummholz Atypical growth pattern resulting from borderline growth conditions - mean annual soil temps. <5-8°C, air temps. ~10°C

29. Plant Physiognomy Gradual transition from west to east, grassland to woodland to forest Changes in amount, seasonality of rainfall

30. Plant Physiognomy East of Rockies, start with short-grass prairie Low-growing clumps of grass with bare patches between clumps

31. Plant Physiognomy Gradual shift from midgrass prairie to tallgrass prairie in Nebraska/Iowa Taller grasses, forbs, more diversity and biomass Follows pattern of increasing rainfall

32. Plant Physiognomy Further east - trees appear in places other than along streams Woodlands - dominated by trees, but without a closed canopy (oak savanna)

33. Plant Physiognomy Forests appear near Illinois-Indiana border Continue to the east coast

34. Plant Physiognomy Seasonality of precipitation (spring and fall) and warmer temperatures increase chance of drought in grasslands

35. Plant Physiognomy Mid-, tall-grass prairies experience fire every 3-5 years (too little combustible material in short-grass prairie) Trees can’t survive frequent fires (apical meristems)

36. Plant Physiognomy Woodlands appear where fire frequency is low enough to allow trees to grow tall enough to avoid fire Still are more fire-tolerant species

37. Plant Physiognomy Precipitation in forests is high enough to keep fire frequency low