Upload
fitzgerald-prince
View
17
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Paleo-perspectives on climate sensitivity. What are the patterns of climate variation and ecosystem response? What are the most important climate drivers? What is the role of disturbance in moderating ecosystem response to climate variation? - PowerPoint PPT Presentation
Citation preview
Paleo-perspectives on climate sensitivity
• What are the patterns of climate variation and ecosystem response?
• What are the most important climate drivers?• What is the role of disturbance in moderating ecosystem response to climate variation?
• How does sensitivity to climate variation differ among species?
• How do boreal ecosystems respond to climatic conditions outside the range of observed variability?
What are the patterns of climate variation and ecosystem response?
030006000900012000Years B.P.
`Dry Increasing
moisturemoist dry moist
Cool warm cooling modern
Cooldry
warmdry
warm<dry
warmmoist
Coolingmoist
(based on Edwards et al. 2001, Mann et al. 2002, Hu et al. 2001)
What are the patterns of climate variation and ecosystem response?
Populus zone
P.glauca zone
Alnus expansion
P. Mariana expansion“modern” boreal forest
What are the patterns of climate variation and ecosystem response?
What are the patterns of climate variation and ecosystem response?
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
(From Bigelow and Edwards 2001)
Paleo-perspectives on climate sensitivity
• What are the patterns of climate variation and ecosystem response? – Substantial climate variation during Holocene– Three major vegetation transitions– Unknowns: rate of transitions, significance of high-frequency variation.
What are the most important climatic drivers?
Transition time Hypothesized climate driver
Shrub tundra --> deciduous forest
11,500 Warming
Deciduous forest --> white spruce expansion
9,500 Increased moisture
White spruce--> black spruce
5,500 Increased moisture
What are the most important climatic drivers?
0
1
2
3
1800 1825 1850 1875 1900 1925 1950 1975 2000
year
ring-width index
Paleo-perspectives on climate sensitivity
• What are the patterns of climate variation and ecosystem response?
• What are the most important climate drivers?– Moisture
What is the role of disturbance?
0
0.1
0.2
0.3
0.4
0.5
0.6
0 2500 5000 7500 10000
Calibrated Years before present
Charcoal influx
Black spruce forests White spruce foreststransition
Paleo-perspectives on climate sensitivity
• What are the patterns of climate variation and ecosystem response?
• What are the most important climate drivers?
• What is the role of disturbance in moderating ecosystem response to climate variation?– Few studies with enough resolution to disentangle climate/veg/disturbance but…
– Preliminary evidence suggests climate --> veg --> fire
How does sensitivity to climate vary among species?
How does sensitivity to climate vary among species?
Paleo-perspectives on climate sensitivity
• What are the patterns of climate variation and ecosystem response?
• What are the most important climate drivers?
• What is the role of disturbance in moderating ecosystem response to climate variation?
• How does sensitivity to climate variation differ among species?– Black spruce: low sensitivity?– White spruce: high sensitivity?
How do boreal ecosystems respond to climatic conditions outside the range of observed
variability?
(From Edwards et al. 2005)
Paleo-perspectives on climate sensitivity
• What are the patterns of climate variation and ecosystem response?
• What are the most important climate drivers?• What is the role of disturbance in moderating ecosystem response to climate variation?
• How does sensitivity to climate variation differ among species?
• How do boreal ecosystems respond to climatic conditions outside the range of observed variability?– Non-analog ecosystems
Future directions…
• Examine time slices with large changes in climate: what, if any, was the vegetation response?– 9000 BP increase in moisture– Early Holocene rapid warming
• Examine time slices with ‘abrupt’ vegetation change.
• Explore fine-scale variation in abundance as it relates to climate variation