1. Vegetation Types of North America

2. Handy descriptors
Growth form spectrum: % spp. phanerophytes, chamaephytes, hemicryptophytes, geophytes, therophytes

3. Handy descriptors Precipitation/Evapotranspiration (P/E) Ratio.
Evapotranspiration (potential evapotranspiration):
Ratio > 1 wet, < 1dry
NPP: Net primary productivity

4. Tundra Hi latitude (arctic) or hi elev. (alpine)
20% N. America (lavender)
Cold! Growing season <3 mo. Lo NPP.
Lo precip.: high P/E ratio (why?)

5. Growth Form Spectrum: Tundra
Solution: grow low (no trees!)
Growth form %
Phanerophytes 0 (min.)
Chamaephytes 23
Hemicryptophytes 61 (max.)
Geophytes 15
Therophytes 1 (min.)

6. Tundra
Special growth form: cushion plant
Alpine
tundra

7. Conifer forest
Covers more N. America (lt. green)

8. Conifer forest
Several types: boreal forest (hi latitude)

9. Conifer forest Other conifer forests (hi altitudes):
Spruce-fir (S. Appalachians)
Mixed conifer: Rockies, Cascades/Sierra Nevada
Spruce-fir forest
Mt. Mitchell, N. Carolina

10. Conifer forest Cold winters: growing season 3-4 mo. P/E > 2
Lake Tahoe
(6624 ft. elev.)
June 1983
9,000 ft

11. Conifer forest
Highest LAI (9-11): conifers+ summer herbs

12. Conifer forest Soils: acid, leached (E & Bh horizons) Order: Spodosol
CEC: hi or lo?

13. Growth Form Spectrum: Conifer Forest
Phanerophytes 15
Chamaephytes 9
Hemicryptophytes 51
Geophytes 19
Therophytes 6

14. Ecotone between conifer forest/tundra
Timberline or treeline: tree

15. Ecotone between conifer forest/tundra
Twisted tree form: krummholz
Enforced by environment (review: how test?)

16. Ecotone between conifer forest/tundra
Flagging: pruning

17. Ecotone between conifer forest/tundra
Why timberline? Lack
NPP=Gross Ps-resp.

18. Deciduous forest
Our trips

19. Deciduous forest Greatest rainfall P/E= Greatest NPP Liriodendron:
1990 Plant Ecology
trip to Joyce Kilmer
Memorial Forest,
North Carolina

20. Growth Form Spectrum: Deciduous forest
Phanerophytes 26 (tied max.)
Chamaephytes 3 (min.)
Hemicryptophytes 44
Geophytes 20
Therophytes 7

21. Deciduous forest: Review
Spring herbs
Summer green herbs
Late-summer herbs
Semievergreen herbs

22. Deciduous forest: Review
Seed dispersal by ants (term?): Herbs (30-70%!)
Viola seed: name of
“food body?”

23. Deciduous forest: Review
Disturbance

24. Deciduous forest: Review
Plant Defenses
Physical
Chemical
Behavioral
Crypsis (camouflage/mimicry)
Associational

25. Deciduous forest: Review
Relationship?

26. Grasslands
Central/Western North America

27. Grasslands Several types: shortgrass, mixed grass, tallgrass Palouse
Grassland-forest
ecotone
Annual
grassland
Desert
grassland

28. Grasslands
P/E ratio
LAI =
NPP 2nd highest

29. Grasslands
Soils: thick dark A horizon!
Order?

30. Growth Form Spectrum: Grassland
Phanerophytes 2
Chamaephytes 23
Hemicryptophytes 46
Geophytes 3
Therophytes 14

31. Grass life forms
Annual, bunchgrass, sod-forming (fire resistant)

32. Grass review
Community history

33. Grass review
Herbivore counterdefenses

34. Grass Ps types
Latitude gradient: C3 (cool-season) north, C4 (warm-season) south

35. Grass Ps types
C4 review…..
PEP Carboxylase
Rubisco

36. Carbon isotope ratios C4 Enzyme affinity CO2 C3 delta C-13;
Rubisco: less
PEP carboxylase: more
C3 delta C-13;
C4 delta C-13;
More negative =
more discrimination

37. Herbivore Feeding Preferences
Ex., rhinos Africa
Black rhino: more rare (3,600).

38. Herbivore Feeding Preferences
White rhino: less rare (11,700).

39. Herbivore Feeding Preferences
Rhino poaching: