Alpine Vegetation reference: Körner, Ch. 1999. Alpine Plant Life. Springer Verlag, Berlin

1. Alpine Vegetation reference: Körner, Ch. 1999. Alpine Plant Life. Springer Verlag, Berlin Some slides courtesy of Bill Bowman Mountain Research Station, INSTAAR

2. MOUNTAINS • Have the highest plant species diversity • High mountain environments have a high percentage of endemic plants • Alpine areas have a much high plant diversity than forested areas

3. Weld County: ~600 species Boulder County: 1550 species (50% of flora of Colorado) Regional scale plant diversity in S. Rockies; the influence of mountains:

4. Nival Alpine treeline Subalpine Montane

5. Mixed Aspen - Lodgepole Pine Forest : 8,500 to 10,000 feet • yellow - green color • foliage • dense trees • straight, pole-like • Used by humans since prehistoric times • light construction, finishing lumber, poles

6. Lodgepole pine • needles attached to twigs in bunches • paired, twisted • long, green

7. Aspen • only deciduous tree at this altitude • grow in a variety of soil conditions from wet to dry

8. Subalpine Forest: 10,000 -11,000 ft spruce and fir dominate. narrow crowns dark green color cool,dark, humid E.g. Engelmann Spruce Humans have seldom used these forest due to their remoteness

9. Engelmann Spruce • short needles attached to twigs • rounded, spiky • Spruce bark is reddish and outer layer flakes off

10. Rocky Mtn. Douglas Fir • short needles attached to twigs; • flat needles • smooth bark

11. Forest- Tundra Transition: CLIMATE • Situated between timberline and treeline (lower) (upper) • Windier and colder • mean annual soil temps ~ 0 deg. • Snow covered

12. Wind snow Forest-tundra transition: VEGETATION "Krummholz”: crooked wood slow growth (few inches trunk) ”Flag trees”

13. Forest-tundra transition: TREE ISLANDS • Trees grow into bands • form microsites -- reproduction occurs Lee side: snow Windward side: wind

14. Quenual, up to 4,800m World’s highest tree?

15. Nival Alpine Subalpine Montane treeline

16. Elevation of treeline corresponds with: 1) minimum growing season temperature around 6 °C 2) wind zone 3) geomorphic disturbance- avalanches

17. large variation in altitude at mid-latitudes Global distribution of treeline from Körner, 1999 associated with continentality- treelines lower in moist, maritime locations

18. Nival Alpine treeline Subalpine Montane

19. Alpine Tundra: 11,200 to 12,000 ft • Definition: windswept, treeless area found at highest altitudes in the mountains Niwot Ridge in May

20. Alpine environmental conditions: CLIMATE • cold (<0 deg C) • temperatures may change rapidly • windy (mainly temperate zone) • 100 mph at Niwot Ridge! • Precipitation as snow

21. Alpine environmental conditions: SOIL • low nutrients in soil • Rocky • Thin soil cover • low soil temperature ice present in the ground -- creates periglacial features “polygons”

22. Alpine Tundra distribution

23. Alpine is a globally distributed biome- plants have similar "growth forms:" graminoids (grasses, sedges) forbs (broad leaved plants) prostrate shrubs flowers

24. Major life forms of alpine vegetation

25. Incas used them as fuel source Cushion plants – Coropuna, Peruvian altiplano

26. Note the leaves Puya Raimondi, Pastoruri (Peru) Blooms evey 40 years!

27. Alpine environment summarized: • Cold + windy • snowy! • short growing season • low nutrient availability • High UV radiation How do plants survive in these conditions?

28. Plant adaptation to alpine environment (1) evolutionary adaptation (2) ontogenetic modifications, which are non-reversible during the life of an individual (3) reversible adjustment, often termed “acclimation”

29. Limiting factors in alpine and arctic tundra Limiting factor in arctic tundra only 4 things plants need: • Liquid water • nutrients • warmth • light

30. Adaptations to cold 1) Cushion plants: grow in small, rounded humps • conserve heat • reduce wind chill

31. Adaptations to cold 2) Develop a blanket of white hairs • protect them from cold at night • White to reflect radiation during the day • e.g. Giant Lobelia, in Kenya

32. Adaptations to cold 3) Keep dead leaves on the stem • prevents ground from freezing • e.g. Groundsel

33. Adaptations to cold 4) Grow short and small • to avoid harsh winds and crushing snow • the air temperature is warmer 10-15cm above the soil.

34. Adaptations to cold 5) Grow in balls that roll around w/frost heave, eg. Kenya moss deal w/expansion and contraction of soil due to freezing and thawing. Stone circles

35. Adaptations to cold 6) Rosette plants • cabbage-like • leaves surround a central bud • winter: central bud is protected by the remaining vegetation.

36. More adaptations to cold • high investment into belowground biomass (high root:shoot ratio) • tolerance to low temperatures • (= intolerance of high temperatures)

37. Cold-tolerant species examples • Heaths: hard evergreen leaves that can withstand drying winds and cold temperatures. • Common heaths: cranberries, blueberries, and rhododendrons

38. II. Adaptations to dry conditions • Many high mountains plants are succulents, with water stored in thick leaves; • minimize evaporation E.g. cactus

39. Adaptations to High UV irradiance • Cover their leaves with white hairs (reflect the suns rays). • Some plants contain a red pigment called anthocyanin which absorbs UV sunlight before it has a chance to damage the leaves.

40. Short growing season • Cold nights • short daylight hours • 180 days/year • Adaptation: • start to grow as soon as the snows melts • store food during the summer months • pollination strategies? The Fireweed's seeds are plume- shaped. This allows them to ride on the wind before falling to the ground where they can take root.

41. Summary LIMITATIONS ADAPTATION • Cold - grow short, close to ground - grow horizontally -cushion trees • wind - grow in clumps (island trees) • low nutrients -carnivorous • UV -white hairs; antocyanin • low growing seasons - grow fast; store nutrients; -pollination strategies • dry -wax leaves