Flashcards in Lecture 7 Notes Deck (25):
What are 4 examples of natural disturbances?
1. Climate change
4. Insects/pathogen outbreaks
What is disturbance essential for?
Natural part of ecosystems
- some species are particularly adapted to and rely on disturbances
What does diversity depend on?
What do paleo-records allow us to study? (example)
Long term scales
- example = we can use lake sediments to find out past forest and fire regimes
What are 3 factors that control fire regimes on long term scales? (decades to millennia)
3. Severity of fire
What 3 things effect fire regimes?
1. Climate --> hot and dry
2. Vegetation --> composition, density, species
3. Ignition --> sparks, volcanic eruptions, cigarettes
What are 2 examples of taphonomic filters?
What are 2 examples of data collection?
What does is mean when charcoal is high in the lakes?
There is large accumulation
What kinda of change happens with charcoal?
What do fossil charcoal records help us to understand/manage?
Help us to understand/manage ecosystems by providing records of natural variability
What is the size of macroscopic charcoals?
> 150 um
How do you calculate charcoal accumulation rate?
Use sedimentation rate from 14C dating (number of particles/ cm^2 yr)
Charcoal Accumulation Rate
What does fire history or periods of increasing fire not tell us about?
What are 4 fire characteristics?
1. Charcoal production
2. Vegetation type
3. fuel load
4. Fire intensity
Does grass lands produce more or less charcoal compared to a more dense forest area? Why?
- because in a more dense forest there is more vegetation to burn
What type of particles travel further?
Smaller particles travel farther (regional fires) vs. secondary charcoal introduced during non fire years
What happens to secondary charcoal?
It sits on the land for a while and will eventually get deposited into the lakes
What 2 things influence source area?
1. Lake size
2. Catchment size
What happens with lodgepole is replaced with Douglas fir?
The fire return decreases
What does lodgepole rely on?
- open cones from spreading
What happens when fire return is less frequent?
Fire occurs more
- even dispute it is colder and wetter
What do people use fires for?
To modify their land