1. Changes to Rangelands Over Time
Intro to Range--OBJ 4: PPT
Changes to Rangelands Over Time

2. Intro to Range--OBJ 4: PPT
Range Change Factors
Grazing
Fire
Invasive Species
Weather/Climate
Human Activities

3. Goal of ecosystem management
Efficiently capture sunlight
Reduce losses of nutrients and water from system
Land managers will have more specific goals

4. Forces of Ecosystem Change
Immigration and establishment of plants
Competition between plants
Fire
Grazing
Site modification
Stabilization

5. How does grazing affect plants
Some plants are extremely sensitive to grazing (A)
Most plants are somewhat tolerant of grazing (B)
A few plants actually benefit from grazing, especially light grazing (C )

6. How does fire affect plants
Some plants are extremely sensitive to fire (A)
Most plants are somewhat tolerant of fire (B)
Other plants actually benefit from fire especially light grazing (C )

7. Adaptations to Fire and Grazing
Grasses
Woody Plants

8. Location of Growing Points - Grasses
Range Plants -- OBJ 2: PPT
Location of Growing Points - Grasses
Also called:
Buds
Meristems
From: How Pasture Plants Grow by Stephen K. Barnhart; Iowa State Cooperative Extension
There are 16 slides in this presentation

9. Location of Growing Points - Grasses
Range Plants -- OBJ 2: PPT
Location of Growing Points - Grasses
You can use an example of how lawn grass looks ragged soon after mowing – not a smooth topped looked like after mowing. Plant pushes new growth from the base of the plant, pushing old growth upwards.
Grasses “push” growth from the growing point --- old growth at tips of leaves
There are 16 slides in this presentation

10. Range Plants -- OBJ 2: PPT
Location of Growing Points - Grasses
As long as the growing point is present growth continues.
If removed - growth stops and new growth has to initiate from a dormant bud.
For grasses, when you’re applying a management practice, you must be aware of the morphology of the plants in the community being treated. Grasses with growing points at the base are more resistant to fire and grazing.
From National Range and Pasture Handbooks Chapter 5 page 2-13
There are 16 slides in this presentation

11. Range Plants -- OBJ 2: PPT
Location of Growing Points - Grasses
Stolon
Rhizome
Plants that have stolons and rhizomes are more resistant to disturbance.
New growth can come from below Stolons & Rhizomes
There are 16 slides in this presentation

12. Location of Growing Points - Grasses
Range Plants -- OBJ 2: PPT
Location of Growing Points - Grasses
Culmed
Apical Meristem
Culmless
Culmless grasses have growing points that are more protected because they are located at the base. Plants with exposed axillary buds along the stem that can be removed by fire or grazing, they are more damaged by these disturbances.
Axillary Buds
There are 16 slides in this presentation

13. Location of Growing Points - Grasses
Location depends on season
Early in the growing season - close to the ground and protected.
As the season progresses - elevates and subject to removal.

14. Range Plants -- OBJ 2: PPT
Location of Growing Points – Shrubs & Trees
When you see areas that have been hedged, you know that it has been heavily browsed. Disturbances that remove biomass stimulate new growth from buds along the branches. Shrubs have defenses from grazing including thorns and chemicals that protect their buds or growing points.
How well shrubs survive fire depends on if they have basal buds (e.g. mesquite) or if they have thick enough bark
Forbs and shrubs initiate growth outermost points
There are 16 slides in this presentation

15. Location of Growing Points – Shrubs & Trees
Meristem
J. Peterson

16. Location of Growing Points – Shrubs & Trees
May have basal buds and be able to resprout form base after fire

17. Other fire adaptations – Shrubs & Trees
fs.fed.us
J. Peterson
Insulating bark
Serotinous Cones

18. Differences between fire & grazing?__ __

19. Differences between fire & grazing?
Selects palatable over unpalatable
Live tissue preferentially removed
No heat produced
Recycles nutrients in organic (feces) and inorganic (urine) forms
Recycles nutrient in patches
Patchiness on a plant-scale
Occurs year round
Can cause compaction through hoof action
Generally reduces seed viability though some seeds require consumption to become viable
Not selective for specific plants
Removes dead and live tissue
Produces heat
Recycles nutrients in inorganic form
Recycles nutrients in a relatively even layer across the landscape
Patchiness on a landscape scale
Most likely in dry-hot season
May create hydrophobic soil layer but, doesn’t yield compaction
Generally reduces seed viability, though some seeds require fire to be viable.

20. Intro to Range--OBJ 4: PPT
Weather/Climate
Most important factor in long-term changes to rangeland plant communities
Normal variation
Year-to-year (annual)
Long-Term
Drought
Impacts on plant composition

21. Exotic of Introduced Species
Intro to Range--OBJ 4: PPT
Exotic of Introduced Species
Definition: “plants that are not native to a region that have been brought in either intentionally or unintentionally”
Invasive vs. weed
Response to disturbance
How do they increase?
Negative environmental impacts

22. Intro to Range--OBJ 4: PPT
Invasive Species
Species that that increase in a community in a way the suppresses other plants in the community and reduces there abundance or fitness.
Can native or introduced
Negative environmental impacts
Have characteristics, such as high seed production or root sprouting, that allow them to increase with disturbance.

23. Intro to Range--OBJ 4: PPT
Human Activities
Include development, recreation, subdivision
Humans affect other forces of nature
Invasion
Fire
Grazing
Climate/weather?

24. Current Issue of Ecological Change:
The “Pristine Dream” - many environmentally concerned people wish that rangelands could return to pristine conditions similar to what Lewis and Clark observed.
Possible or Not?

25. Current Issue of Ecological Change:
Sustainability (or Sustained-yield) is the concept that we can graze or otherwise use the rangeland resource in such a way as to not jeopardize future productivity.
Possible or Not?

26. Current Issue of Ecological Change:
Biodiversity (or Biological Diversity) is an attribute that describes for the variety of organisms the genetic variation they contain and the variety of communities, ecosystems and landscape pattern in which they occur.
Believed that more diverse ecosystems are generally more stable and able to cope with disturbance than less diverse ecosystems.
Many agencies and environmental organizations espouse the concept that we should manage for high biodiversity.
Yes or No?