1. Rangeland Principles (Rem 151)
Rangeland Succession
Rangeland Principles (Rem 151)

2. What is Succession? The directional change of
plant communities over time.
What is Succession? The directional change of plant communities over time.
The shifts are usually predictable and most often gradual.
Plants become more or less abundant depending on the stage of succession.
Seasonal changes are not succession.
The progressive replacement of one dominant type of species or community by another in an ecosystem until a stable climax community is established.

3. Primary Succession
Conceptual illustration showing the increasing complexity of species over time under primary succession.
Primary Succession begins in a place without any soil: sides of volcanoes, landslides, flooding. Starts with the arrival of living things such as lichens that do not need soil to survive…called PIONEER SPECIES.

4. Pioneer Species Primary Succession
These pioneer species are very important in soil formation.
Soil starts to form as lichen and the forces of weather and erosion help break down rocks into small pieces.
When lichen dies, they decompose, adding small amounts of organic matter to the rock to make soil…
Early seral species with are often annual, herbaceous, and have invasive characteristics.

5. Primary Succession Mount St. Helens Surtsey
del Moral, R. and Magnússon, B.: Surtsey and Mount St. Helens: a comparison of early succession rates, Biogeosciences, 11, , doi: /bg , 2014.
Surtsey

6. Primary Succession

7. Primary Succession
Succession is a process that changes the biotic (i.e., vegetation) and abiotic (i.e. soil nutrients levels) aspects of a site.
Primary succession on grassland rangelands. From Gay 1965

8. Climax or Potential Natural Community
Intro to Range--OBJ 4: PPT
Climax or Potential Natural Community
The end point of succession = Climax
A stable group of plants and animals that is the end result of the succession process
Trees in forests
Grasses in prairies
Cacti in deserts
Lichens and shrubs in the tundra
The end point depends on climate and soils
The end point of success depends on climate.
Lots of moisture = forest. Moderate precipitation and temperature = prairie, hot/dry = desert, cold/dry = lichens and shrubs, etc. etc.

9. Primary & Secondary Succession

10. Secondary Succession
Secondary succession: begins in a place that already has soil and was once the home of living organisms.

11. Pioneer Species Secondary Succession
Occurs faster and has different pioneer species than primary succession.
There are many examples of when secondary succession occurs = after drought, fire, landslides, floods, overgrazing, etc.
We often think of secondary succession as “site recovery” or stage in restoration.

12. Secondary Succession
Seral Stage: distinct community type within the sequence of succession.
Stages of Change:
Seral Stage = distinct community type within a the sequence of succession.
Initial stage referred to as pioneer community
Final stage referred to as a climax community.
The end points depends on climate. Lots of moisture = forests. Moderate precipitation and temperature = prairie, shrublands. Hot/dry = desert, cold/dry = shurblands
Pioneer Community
Climax Community

13. Secondary Succession https://www.youtube.com/watch?v=CQ2Xl6ZqzRI
Stages of Change:
Seral Stage = distinct community type within a the sequence of succession.
Initial stage referred to as pioneer community
Final stage referred to as a climax community.
The end points depends on climate. Lots of moisture = forests. Moderate precipitation and temperature = prairie, shrublands. Hot/dry = desert, cold/dry = shurblands

14. Review
Would the following events on rangeland lead to primary or secondary succession?
A prescribed fire to reduce juniper trees: ______________
An erosion event that removes all the soil and leaves bedrock: ______________
Overgrazing by elk and cattle on canyon grasslands: ___________
A restoration practice where the land managers sprayed cheatgrass with herbicide and reseeded with perennial grasses: ____________

15. Basic idea of Succession
The simple plants die, adding more organic matter.
The soil layer thickens, and grasses, wildflowers, and other plants begin to grow.
These plants die, and they add more nutrients to the soil.
Shrubs and trees can then survive.
Insects, small birds, and mammals begin to inhabit.
From rock to vegetation = the miracle of succession.
We manage forces that cause these changes. We simply try to understand success and guide or copy what nature does.

16. Forces of Ecosystem Change
Immigration and establishment of plants.
Competition between plants.
Site Modifications (add organic matter, change available moisture and nutrients)
Stabilization (reduce yearly variation in kind and amount of plants and animals).
These are 4 widely recognized forces of succession. As land managers, we manage these forces.

17. Forces of Ecosystem Change
Immigration and establishment of plants.

18. Forces of Ecosystem Change
Competition between plants.

19. Forces of Ecosystem Change
Site Modifications (add organic matter, change available moisture and nutrients)

20. Forces of Ecosystem Change
Stabilization (reduce yearly variation in kind and amount of plants and animals).
Hydrologic Cycle
Nutrient Cycle

21. Important Concepts of Succession
Ecological Sites
The product of all the environmental factors that influence the development of soils and vegetation, including disturbance
Community Resilience
The ability of a plant community to return to prior composition and structure after a disturbance
Community Resistance
The plant community’s ability to avoid being changed following disturbance

22. Ecological Services & Resources
forage for livestock
wildlife habitat
watershed management
biodiversity conservation
open space
carbon sequestration
Forces & Impacts
Herbivory
Climate Change
Fire
Human Uses Development, Fragmentations,
& Recreation
Invasion
Rangelands Grasslands, Shrublands, Woodlands
What changes nature? Discuss the forces of change (more discussion later in class). What services and products can rangelands provide? What are the tools that we have to manage these services and goods? These are essentially the same as the forces of change – the same tools that nature uses.

23. Ecological Services & Resources
forage for livestock
wildlife habitat
watershed management
biodiversity conservation
open space
carbon sequestration
Forces & Impacts
Herbivory
Climate Change
Fire
Human Uses Development, Fragmentations,
& Recreation
Invasion
Rangelands Grasslands, Shrublands, Woodlands
We use human tools in a managed way, unlike nature.
Fire
Livestock Grazing
Weed Mgmt
Human Impacts
Restoration/ Rehabilitation
Tools for Stewardship

24. Rangeland Principles (Rem 151)
Rangeland Succession
Rangeland Principles (Rem 151)