Conceptual model Source: Knight, 1994

Transcription

1 Rangelands

2 Conceptual model Source: Knight, 1994

3 What are rangelands?

4 Task (3 minute each) Why are rangelands important?

5 Why are rangelands important? Livestock Production Forage Wildlife Habitat Recreation Water Native Plants Open Space Energy Minerals Source: Karen Launchbaugh

6 Rangeland management Multiple Use Source: Karen Launghbaugh

7 Terminology Difference between a tree and shrub?

8 Terminology (cont.) Source: Krasny et al., 2003

9 Invasives Source:

10 Task (5 minute each) How do you think earthworms (introduced from Europe) could have changed ecosystems? Source:

11 Weed/Invasive Control Approaches

12 Grazing Source:

13 Task (3 minute each) What factors affect nutritive value of plants?

14 The 3 major factors determining nutritive value in plants

15 Plant adaptations - Grazing

16 Task (3 minute each) Examples of how plants avoid and tolerate grazing?

17 Plant adaptations - Grazing

18 Secondary compounds Chemical defenses against pathogens and herbivores are most strongly developed in species adapted to low-resource environments such as infertile soils and drought Why?

19 Morphological adaptations Source: Karen Launchbaugh and

20 Plant adaptations - Grazing

21 Morphological adaptations Growing points the more, the better

22 Comparative Nutritive Value of Grasses, Forbs, and Shrubs Source: Karen Launghbaugh. Graph adapted from Parker, 1969.

23 Effect of grazing on plant communities Source: Rangelands An Introduction to Wild Open Spaces. Roselle et al., 2011

24 Effect of grazing on plant communities (cont.) Preferred forage

25 Effect of grazing on plant communities (cont.) Cattle Sheep

26 Natural landscape Source:

27 Wildlife and livestock interaction Source: Star-News Increased patchiness Source:

28 Vegetarian Solution? Shorter food chain/web = less loss of energy Vegetarianism results in a decrease of human position on food chain. Is vegetarianism is the best way to feed a large population? Will this solve the world food problem?

29 Two Good Reasons 1) Cellulose most abundant, naturally occurring organic molecule on earth Humans can t digest cellulose, Ruminants & Hind-gut fermentors can. We need cows, sheep, goats, horses, llamas, alpacas, etc. to digest cellulose for us. 2) Only about 10% of the earth land surface can be farmed. The rest is too rocky, too cold, or too dry. We need animals to harvest these land for us.

30 Allelopathy Source:

31 Fire Adaptation Suppression Benefit Source: and and Mike Pellant

32 Impact on Invasives (e.g., Cheatgrass) on wildfire cycle Source: Mike Pellant

33 Fragmentation Source: and

34 Rangelands weather and climate Robert Whittaker s classification of biomes, based on annual precipitation, temperature

35 General adaptation to drought conditions Drought avoidance Drought deciduous Thick roots Shallow and deep rooting system Increasing root to shoot ratio Stomata are sunken below the leaf surface Thick cuticle layer Vessel instead of tracheids in the xylem Changes in leaf angle

36 Photorespiration Reaction catalyzed by Ribulose-1,5-bisphospate carboxylase/oxygenase (RubisCO)

37 C 4 Plants Leaf Surface (Epidermis) C3 and C4 Mesophyll cells Leaf Cross-section Epidermis Catalyzed by Phosphoenylpyruvate carboxylase Mesophyll cells Bundle sheath cells Oxygen concentration decreases only C4 Mesophyll cells Epidermis Bundle sheath cells Catalyzed by RubisCO C3 and C4 Source: Raven et al., 1999

38 C 4 Plants No rubisco Spatially separated O 2 Concentration decreases Source:

39 Task (15 minutes/3 groups) Explain C4 photosynthesis Jennifer Peterson

40 Measuring plant water status Water potential

41 Should I close or should I open? Source: Raven et al and Gurevitch et al., 2002

42 Task (1 minute each) Most important invention in the last hundred years? Source: wickedreport.com

43 Fertilizer Hydrogen feeder stock 5000 C Pressure (200 bars)

44 Source:Phillips et al., 2008 Source: Importance of N

45 Source:

46 Bacteria Fixation NΞN Rhizobia Source:

47 Microphytic Crust Source:

48 Lichen

49 Bluebunch Wheatgrass Jennifer Peterson Jennifer Peterson

50 Tailcup Lupine Poisonous plant contains alkaloids Jennifer Peterson Jennifer Peterson

51 Video