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Potential Pathways of Ecosystem Responses to Climate Change Landsat MSS Image Mosaic 1977-1986 USGS Torre Jorgenson ABR, Inc.

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Presentation on theme: "Potential Pathways of Ecosystem Responses to Climate Change Landsat MSS Image Mosaic 1977-1986 USGS Torre Jorgenson ABR, Inc."— Presentation transcript:

1 Potential Pathways of Ecosystem Responses to Climate Change Landsat MSS Image Mosaic USGS Torre Jorgenson ABR, Inc.

2 Types of Land Change Geomorphic processes –Coastal (increased erosion, flooding, salt kill) –Fluvial (changed channel migration rates, sedimentation –Lacustrine (mid-summer drying, bank erosion, tapping, paludification) –Permafrost (ice-wedge degradation, slower permafrost formation) Hydrology –Earlier snowmelt and spring discharge –Higher spring water levels –Mid-summer lake drying (faster drawdown) –Lower mid-summer river discharge, active channel shrinkage –Decreased glacier meltwater input –Lake tapping and drainage Vegetation –Longer growing season (more biomass) –Earlier forage quality curve –Shrub expansion (height and infilling), (migration) –Succession after disturbance –Migration (alder, spruce, sphagnum)(corridors) –Microsite moisture shifts (wetter troughs, drier centers) –Leaching and acidification –Paludification (bog meadows, productivity decrease) –Species composition-community shifts

3 Approaches to Predicting Change Extrapolate from past changes –Soil/sediment stratigraphy, remote sensing, historical photos Complex modeling Comparative ecosystem analysis –North Slope versus Seward Peninsula

4 Ecosystems of Northern Alaska

5 Coastal Pathways Nearshore Water Higher TundraDeltas, Basins, Lagoons, Barrier Islands Coastal Wet Sedge Tundra (brackish) Coastal Wet Sedge Tundra (saline) Coastal Grass Tundra Coastal Dwarf Shrub (willow) Coastal Barrens (including salt-killed tundra) Upland Tussock Tundra Lowland Moist Sedge- Shrub Tundra Lowland Wet Sedge Tundra Lowland Wet Sedge Tundra (swales) Lowland Moist Sedge-Shrub Tundra flooding, salinization bank erosion sedimentation mudsand sedimentation sedimentation, less flooding

6 MudflatC. subspath.D. fisheri

7 Coastal Meadow Toposequence

8 Lake Basin Evolution Ice-rich Center Ice-rich Margin Erosion of Ice-rich Center

9 Lacustrine Wet Sedge Tundra Lowland Moist Sedge- Shrub Tundra Lacustrine Barrens Lacustrine Low Willow Scrub Deep Lakes Lacustrine Grass Marsh Non-basinsBasins Upland Tussock Tundra Lowland Moist Sedge- Shrub Tundra Shallow Lakes, Pits Lowland Wet Sedge Tundra Lowland Wet Sedge Tundra (swales) complete drainagepartial drainage Lacustrine Sedge Marsh Lacustrine Grass Meadows Lowland Bog Meadows Lowland Low Birch- Willow Shrub Upland Shrubby Tussock Tundra succession paludification paludification, acidification bank erosion, thermokarst ice aggradation, paludification shrub expansion paludification, acidification paludification thermokarst troughs and pits Coastal Plain Pathways ice aggradation, paludification drying

10 Lowland Moist Sedge-Shrub Tundra: Lowland Wet Sedge Tundra Conversion by lowering water table

11 Wet Sedge - NPRA Bog Meadow – Seward Peninsula

12 Intermediate Degradation Dead Tussocks Advanced Degradation Initial Stabilization

13 Infilling with Sphagnum

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15 Drying After Permafrost Degradation Photo by Torre Jorgenson

16 Lacustrine Ecosystems

17 Lower Noatak Lowlands

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19 Lacustrine Marsh: In deeper water (30–100 cm), Arctophila fulva In shallower (<30 cm) water, Carex aquatilis, Eriophorum angustifolium and Utricularia vulgaris Lowland Water: Shallow (<1.5 m) ponds: water freezes to the bottom during winter, thaws by early to mid- June, and is warmer than water in deep lakes. Deep (  1.5 m) lakes: water does not freeze to the bottom during winter in deeper portions of the lake.

20 Thermokarst Lake, Koyukuk Flats

21 Meander Active- Overbank Deposit Riverine Barrens Riverine Wet Sedge Tundra Riverine Low Willow Scrub Riverine Moist Tall Willow Shrub Riverine Dryas Dwarf Shrub Lowland Wet Sedge Tundra Lowland Moist Sedge-Shrub Tundra Riverine Lake Riverine Grass Marsh Riverine Moist Sedge-Shrub Tundra Fluvial Processes Meander Inactive- Overbank Deposit Meander Abandoned Overbank Deposit Active Channel Deposits reduced flooding, frequent sedimentation, increased drainage channel abandonment reduced flooding, less sedimentation, increased drainage paludi- fication reduced flooding, less sedimentation, ice aggradation, decreased drainage sedimentation, paludification ice aggradation, less sedimentation paludification thermokarst, bank erosion thermokarst cutbank, increased drainage channel migration riverbank erosion increased drainage Lower Perennial River Upland Dryas Dwarf Shrub Upland Dry Tall Willow Shrub Eolian Sand Deposit Eolian Processes Riverine Tall Alder- Willow Shrub Lowland Bog Meadow Riverine Cottonwood Forest Riverine White Spruce Forest Upland Cassiope Dwarf Shrub paludification, acidification drainagesedimentation, alder expansion, reduced flooding, less sedimentation, ice aggradation, decreased drainage ice aggradation, reduced sedimentation paludification Upland Low- Birch- Willow Shrub Upland Crowberry Dwarf Shrub Riverine Pathways

22 Lower Perennial River Riverine Barrens Riverine Moist Tall Willow Shrub Riverine Moist Low Willow Shrub Upland Dry Dryas Dwarf Shrub Riverine Wet Sedge Meadow Lowland Wet Sedge Meadow Water

23 Riverine Succession

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27 Floodplains as Migration Corridors

28 Upland Hydrology: 8-10 ka (loess) to 60 Ma surfaces Highly integrated drainages Suprapermafrost Groundwater Flow Soil highly leached Water-tracks Upland Ecosystems

29 Swales/ Watertracks/ Troughs/ Basins Mid-SlopesRidges Upland Tussock Tundra Lowland Birch- Willow Shrub Deep Thaw Lakes Upland Shrubby Tussock Tundra Wet Sedge Meadow Upland Alder Tall Shrub Upland Dryas Dwarf Shrub Tundra (including ericaceous dwarf shrub, cassiope dwarf shrub) Lowland Bog Meadows Upland Moist Sedge-Shrub Tundra Upland Low Birch- Willow Shrub See Coastal Plain Basin Pathways extremely ice-rich thermokarst troughs and pits Upland Alder Tall Shrub (including alder-tussock) thaw slumps Upland Pathways acidification shrub growth acidification shrub growth alder expansion alder expansion ice aggradation, paludification

30 Noatak Basin Thaw Slumps Ice-rich Colluvium

31 Alkaline Toposequence

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33 Upland Low Birch-Willow Shrub Tundra:

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35 NPRA Seward Peninsula King Salmon High resilience of tussock tundra MAAT = -12 C MAAT = -6 C MAAT = +2 C

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37 Lichen Loss – Noatak Basin 1909 – Phillip Smith

38 2006 Photo by Torre Jorgenson

39 Shrub Expansion

40 Upland Tall Alder Shrub Alnus crispa, Salix pulchra, Salix glauca, Vaccinium uliginosum, Vaccinium vitis-idaea, B. glandulosa, Ledum groenlandicum, Empetrum nigrum, Equisetum arvense, Spiraea beauverdiana, Calamagrostis canadensis, Petasites frigidus, Sphagnum spp., Hylocomium splendens

41 1918 Near Naknek River, King Salmon P. Hagelbarger

42 2005 G. Frost

43 1918 Near Naknek River, King Salmon P. Hagelbarger

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45 Fire Disturbance

46 Ecosystems of Northern Alaska

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50 Circumpolar Arctic Vegetation Map Walker et al. 2003


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