Overview of ProposedClimate Sensitivity Research

(Serreze et al., Climatic Change, 2000)

High Latitude Temperature

Trends

(1966-1995)

Annual data

°C per decade

Courtesy of G. Juday

P-PET

Time (years)

1960 1970 1980 1990 2000

P-P

ET

(m

m)

-800

-600

-400

-200

0

Coastal Plain: -2.0 mm/yr (p<0.01)Interior: -5.5 mm/yr (p<0.002)

June-August Water Deficits in Alaska

Oechel et al. 2000. Nature

Courtesy of G. Juday

Slope = -0.25 days per year

23-Apr

28-Apr

3-May

8-May

13-May

18-May

23-May

28-May

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998

Date of leaf-out in Fairbanks (Chena Ridge) 1974-1998

Data courtesy of J. Anderson

Overview of ProposedClimate Sensitivity Research

Hypothesis: The effects of climate change on boreal ecosystem processes are primarily indirect, acting through temperature and precipitation effects on other environmental parameters. The most important of these indirect effects differ among landscape units, with south-facing uplands being most responsive to summer drought (conifers) and season length (deciduous), north-facing uplands to early-winter soil temperature, wetlands to water table height, and active floodplains to river height, which correlates positively with summer temperature and glacial melt.

Proposed Climate Sensitivity Tasks

Question 1. How has climate change altered the physical environment of the BNZ LTER site and how have different stand types (conifer vs. deciduous; upland vs. floodplain vs. wetland) differed in their responses to the direct and indirect effects of summer warming?

C1 - Conduct a retrospective analysis of the relationship of litterfall, diameter increment, and seed production to thaw date, summer air temperature, growing degree days, daily temperature maxima and minima, summer soil temperature and moisture, early-winter soil temperature, and precipitation. (McGuire, J. Hollingsworth)

C2 - Use tree-ring analysis to assess the sensitivity of tree-ring width to climatic variation. (Juday, Lloyd)

C3 - Document the effects of climate variability, vegetation type, and predation on herbivore abundance. (Kielland, Werner, Hanley)

C4 - Manipulate soil moisture to assess its effects on NPP and other ecosystem processes. (Yarie, Turetsky, Harden, McGuire, Valentine)

Proposed Climate Sensitivity Tasks

Question 2. How does winter warming influence ecosystem processes in Alaska’s boreal forest?

C5 - Document the relative importance of winter and summer processes through observations and field experiments.

(Kielland, Turetsky, Harden, McGuire)

Synthesis of Climate Sensitivity

• Motivational Talks (this morning)

• Breakout Groups (this afternoon)

• Summarized Plan of Action (tomorrow morning)

Synthesis of Climate Sensitivity

• Motivational Talks (this morning)1. Paleo Perspectives – Andi Lloyd2. Growing Season Changes – Eugenie Euskirchen3. Summer Drought – John Yarie4. Winter Ecology – Knut Kielland

• Breakout Groups (this afternoon)

• Summarized Plan of Action (tomorrow morning)

Synthesis of Climate Sensitivity

• Motivational Talks (this morning)

• Breakout Groups (this afternoon) 1. How do we achieve more effective integration? 2. What product(s) should be generated by the synthesis? 3. How should we organize monthly meetings this year?

• Summarized Plan of Action (tomorrow morning)

Charge to Breakout Groups

• How do we achieve more effective integration? 1. Among climate sensitivity tasks 2. With tasks in successional and threshold themes 3. With the synthesis tasks 4. Across the LTER Network

• What product(s) should be generated by the synthesis? 1. BioScience Paper? 2. Special issue of a journal?

• Identify three or more climate sensitivity talks for themonthly meetings (list of titles and speakers).

Table 6. Major activities of the BNZ research program, showing ongoing research (black) and new research initiatives (red). Task numbers are in parenthesis.

Climate sensitivity Succession Thresholds Drivers Met stations (C1) Exptl. Burn (S2) Thermokarst (S3)

Rain exclusion (C4) Fire record analysis (S2) Fire severity (S2, T2)

Snowmelt exclusion (C4) 2004 fire monitoring (S2) Hydrologic change (T1) Winter warming (C4) Hydrologic synthesis (S1) Watertable manipula. (C4)

Biotic Biomass & NPP (C1) Stand-age maps (S2) Disease & insect response Tree rings (C2) Species effects (S5) impacts (T3)

Insect monitoring (C3) Invasive species (S5) Hare & moose monitor (C3) Herbivore exclosures (S6) Biogeochem. monitor (C1) Plant & animal diversity (C1) Seasonal biogeochem. (C5) Fungal diversity (S7)

Landscape Community mapping (I/S2) Succession models (S4) Watershed proc. (I/S1)

response Wetland transects (C1) Biogeochem models (I/S3) Threshold model. (I/S4)

Societal Ecosyst. service synth. (I/S5) Ecosyst. service model (I/S3) impacts Synthesis focus (I/S6) Climate feedbacks (I/S3)

Charge to Breakout Groups

• How do we achieve more effective integration? 1. Among climate sensitivity tasks 2. With tasks in successional and threshold themes 3. With the synthesis tasks 4. Across the LTER Network

• What product(s) should be generated by the synthesis? 1. BioScience Paper? 2. Special issue of a journal?

• Identify three or more climate sensitivity talks for themonthly meetings (list of titles and speakers).

Breakout Groups

• Direct Responses to Summer Warming

• Indirect Responses to Summer Warming

• Winter Warming/Changes in Growing Season