The heat is on: The impacts of climate change on species distributions
Janneke Hille Ris Lambers
Ailene Kane, Kevin Ford
University of Washington, Seattle

Anthropogenic climate change
+ 2-3 C by 2100
Intergovernmental Panel On Climate Change (IPCC) http://www.ipcc.ch/
How will this affect biological diversity?
What management actions can we take to preserve species?

Climate change
Climatic range limit
Range shifts expected…
Where will climatically suitable habitats move?
Will species expand into newly suitable habitat?

Study system: PNW forest (Western WA)
Important
Endangered species
Carbon sequestration
Timber

Study species
Pacific Silver Fir
Alaska Cedar
Western Red Cedar
Mountain Hemlock
Western Hemlock
Douglas Fir

Study location: Mount Rainier
A ‘natural laboratory’ for climate change research
Best case scenario: an undisturbed mountain reserve

The impacts of climate change on species distributions
A. Study system: Trees on Mount Rainier
B. Where will climatically suitable habitats move?
C. Will species expand into newly suitable habitat?

Where will climatically suitable habitats move?
Quantify species distribution Relate abundance to climate
“climate envelope”
Across a climatic gradient
Mean Temperature
Impose future climate scenarios
+ 2 °Celsius in time t
Project future range limits
Climatically suitable habitat:
Where persist? Expand?
Overall change?
Mean Annual Temperature
Climate Envelope Approach

Data: Species Distributions & Climate
Data set explain
Data: Presence / absence in 1000+ locations across Mount Rainier
(courtesy of Jerry Franklin, Regina Rochefort, NPS, Pacific Meridian)
Climate (explanatory variables):
MAT, Winter/Summer Precip,
SWE, Snow days, GDD , PET (?)

Statistics: relate abundance to climate
Pacific Silver Fir
Model fitting (GAM) & selection (AIC)

Species
Thpl
Psme
Tshe
Abam
Cano
Tsme
Statistics: model fit
Correctly predicted
87.4%
81.4%
87.0%
83.0%
83.4%
83.5%
Kappa
0.535
0.500
0.738
0.662
0.444
0.583

Impose future climate scenario
2020s
Low
Average
High
2040s
Low
Average
High
2080s
Low
Average
High
Changes in Annual Mean
Temperature Precipitation
+ 1.1ºF (0.6ºC)
+ 2.2ºF (1.2ºC)
+ 3.4ºF (1.9ºC)
-9%
+1%
+12%
+ 1.6ºF (0.9ºC)
+ 3.5ºF (2.0ºC)
+ 5.2ºF (2.9ºC)
+ 2.8ºF (1.6ºC)
+ 5.9ºF (3.3ºC)
+ 9.7ºF (5.4ºC)
-11%
+2%
+12%
-10%
+4%
+20% http://cses.washington.edu/cig/

Project future range limits

Calculate: change in climatically suitable habitat
Species
Thpl
Psme
Tshe
Abam
Cano
Tsme
Persist
(prop range)
100%
94%
68%
0%
7%
New Habitat
(prop park)
27%
41%
39%
22%
14%
12%
Change
(new / old)
3.13
2.55
2.03
1.07
0.73
0.58
Lower elevation species: persistence and habitat expansion
Upper elevation species: turnover and habitat contraction

The impacts of climate change on species distributions
A. Study system: Trees on Mount Rainier
B. Where will climatically suitable habitats move?
C. Will species expand into available habitat?

Will species expand into available habitat?
h/t m/t
1. Calculate: habitat expansion rates (h/t)
2. Quantify: species migration rates (m/t)
3. m/t > h/t? Species can expand into available habitat…

…calculate habitat expansion rates

…calculate habitat expansion rates
Species
Thpl
Psme
Tshe
Abam
Cano
Tsme
Mean
(m/yr)
44.1
36.2
29.3
24.1
35.9
29.8
Max
(m/yr)
187
170.4
122.6
69.2
94.0
68.7
(i.e. between 68 and 187 m/yr to fully expand into available habitat)

…quantify: species migration rates
Ideally : pgr dispersal
= m/t
This data is very difficult to get!

Instead, ask how fast have other trees moved…
Holocene invasions
(90 m / year)
McLachlan et al 2005
Tree invasions
30.6 m / year
Higgins et al 1996
Upward expansion of ecotone
2.1-2.7 m / year*
Beckage et al. 2008
Recall: h/t for focal species between 68 and 187 m/yr

Will trees on Mt. Rainier expand into available habitat?
Ecotone Invasion Paleo
If moving at treeline/invasion rates: They can’t keep up  !

The impacts of climate change on species distributions
A. Study system: Trees on Mount Rainier
B. Where will climatically suitable habitats move?
C. Will species expand into available habitat?

Climate
Many questions remaining…
Ecology Management
What climatic factors (if any) drive species range limits?
Assisted migration?
Does presence / absence indicate climatic sensitivities?
What role will disturbance & biotic interactions play?
Can we downscale?
Future climates?
Save the meadows?
Do rare long-distance dispersal events drive migration rates?

Thanks to HRL Lab!
…and funding
(DOE-NICCR; UW Royalty Research Fund)