Links and Feedbacks Between Climate, Links and Feedbacks Between Climate, Ecosystems, and Geomorphic ChangeEcosystems, and Geomorphic Change

Grant Meyer, Joe Galewsky, Les McFadden Department of Earth and Planetary SciencesDepartment of Earth and Planetary Sciences

University of New MexicoUniversity of New Mexico

Joseph R. McAuliffeResearch Ecologist, Desert Botanical Garden, Phoenix, ArizonaResearch Ecologist, Desert Botanical Garden, Phoenix, Arizona

• also thanks toalso thanks to

Jen Pierce, Tom Swetnam, Jed Frechette, Ben Burnett, Lyman PersicoJen Pierce, Tom Swetnam, Jed Frechette, Ben Burnett, Lyman Persico

Major Links Between Climate, Ecosystems, and Major Links Between Climate, Ecosystems, and Geomorphic ChangeGeomorphic Change

Ecosystems linked to the atmosphere through modulation of water and energy fluxes by vegetation.

Vegetation exerts a strong control on geomorphic processes: • weathering and soil development • surface and subsurface runoff• slope erosional resistance and stability re. landsliding• and etc. …

Climate controls the structure, function of plant communities• however, climate-induced geomorphic changes (e.g. affecting soil hydrology) may have greater long-term impacts than direct climate effects on plant function.

The Climate System (after Saltzman, 2002; Bartlein and Hostetler, 2004)

slow forcing through tectonics-geomorphology

Long-term geomorphic and ecosystem change and atmospheric connections, Hawaii (Chadwick et al. 1999; Hotchkiss et al. 2000)

long-term mean phosphorus input from dust

P loss rate from soil

% phosphorus contribution from

atmosphere

Modeled erosion and trade wind change, Kauai

4 Myr

present

3 Myr

2 Myr

The Climate System (after Saltzman, 2002; Bartlein and Hostetler, 2004)

Geophysical, Geomorphic

Biosphere-Atmosphere Feedbacks and Links

to Geomorphic Changesimulated surface T change (°C) with

future land-cover change (Feddema et al. 2005)

Deforestation, Rondonia district, Brazil NOAA/AVHRR images (http://www.tric.u-tokai.ac.jp/)

Mamoré River (Rolf Aalto/Geotimes)

Sonoran desert piedmont near Yuma, AZ with desert pavement and dark varnish on late Pleistocene fan surfaces

(J. McAuliffe photo)

GEOMORPHIC-ECOLOGIC-CLIMATE LINKAGES in an ARID ENVIRONMENT

Desert pavement: low albedo, high surface temperature,

reduced plant cover

Plant scars on desert pavement showing Holocene vegetation contraction (McAuliffe and McDonald 2006)

Aspect-related microclimatic effects on weathering, vegetation, and slope processes produce valley asymmetry on same rock types, NE Arizona

Dec Mar Jun

Insolation differences with aspect, NE Arizona canyons

(Burnett, 2004)

Weathering of Morrison Fm sandstone by hydration of clay cement- stripping exposes bare bedrock, increases runoff generation (positive feedback)

Fire-climate-vegetation-geomorphic process linkages…

burned area >600 km2:decreased albedo, warmer, drier surface

POTENTIAL IMPACT OF BURNED AREAS ON PRECIPITATION, ALASKA (Mölders and Kramm, 2006)

GEOMORPHIC IMPACT OF SEVERE FIRE

Postfire erosion by reduced infiltration and surface runoff in brief, intense convective storms (e.g. 10 mm/15 min)

1988 fire, 1989 storm, Yellowstone NP

Debris flows-flash floods result:

OR, postfire erosion following loss

of root strength; saturation and

slide failure of colluvium with rain

on snow in winter frontal storm:

1989 fire-1997 storm, central Idaho

debr

is

f

low

s

central Idaho ~xeric central Idaho ~xeric ponderosa pine, dominant ponderosa pine, dominant

regime of light surface fires, regime of light surface fires, RI 5-30 yr fueled by RI 5-30 yr fueled by grassgrass, ,

BUT still subject to severe BUT still subject to severe

fires in extreme droughtfires in extreme drought

Yellowstone subalpine Yellowstone subalpine lodgepole-mixed conifer lodgepole-mixed conifer forest, large, severe stand-forest, large, severe stand-replacing fires, RI 200-400+ replacing fires, RI 200-400+ yryr

FIRE REGIMES ARE FIRE REGIMES ARE STRONGLY CLIMATE-STRONGLY CLIMATE-ECOSYSTEM ECOSYSTEM DEPENDENTDEPENDENT

Blue Gum Creek, SE Australia Blue Gum Creek, SE Australia eucalypt foresteucalypt forest

X

5 MONTHS AFTER severe fire (Rick Shakesby photos)

GEOMORPHIC GEOMORPHIC

RESPONSE TO RESPONSE TO

SEVERE FIRE IS SEVERE FIRE IS

ECOSYSTEM-ECOSYSTEM-

CLIMATE CLIMATE

DEPENDENTDEPENDENT

Cataract River basin, SE Australia, shortly after severe fire (Rick Shakesby photo)

ant burrows promoting deep infiltration in burned area, SE Australia – limits runoff and erosion (Rick Shakesby photo)

litter dam trapping sediment in burned area, SE Australia (Geoff Humphreys photo)

weighted mean cal yr BP

buried soil

Fire-related deposits shaded

Medieval “warm period”, 900-1300 AD: 25% of fan Medieval “warm period”, 900-1300 AD: 25% of fan deposition in last 4000 yr, Idahodeposition in last 4000 yr, Idaho

Idaho ‘large events’ (n = 29)

Holocene drought-fire-geomorph linkages, Yellowstone and Idaho: Holocene drought-fire-geomorph linkages, Yellowstone and Idaho: fire-related alluvial fan sedimentationfire-related alluvial fan sedimentation

Idaho ‘large events’ (n = 34) including high-elevation sites

Fire-related debris flows in Fire-related debris flows in Idaho ponderosaIdaho ponderosa

Medieval “warm period” or “climatic Medieval “warm period” or “climatic anomaly”, 900-1300 ADanomaly”, 900-1300 AD

(AD)

Late Holocene drought, fire, and geomorphic change in the Late Holocene drought, fire, and geomorphic change in the Northern Rockies Northern Rockies

(Pierce et al., 2004)(Pierce et al., 2004)

Fire-related debris flows in Fire-related debris flows in Yellowstone lodgepole – mixed Yellowstone lodgepole – mixed coniferconifer

Medieval “warm period” or “climatic Medieval “warm period” or “climatic anomaly”, 900-1300 ADanomaly”, 900-1300 AD

(AD)

Late Holocene drought, fire, and geomorphic change in the Late Holocene drought, fire, and geomorphic change in the Northern Rockies Northern Rockies

(Pierce et al., 2004)(Pierce et al., 2004)

Frequent small events in Frequent small events in Idaho ponderosa; very few Idaho ponderosa; very few events YNPevents YNP

Late Holocene drought, fire, and geomorphic change in the Late Holocene drought, fire, and geomorphic change in the Northern Rockies Northern Rockies

(Pierce et al., 2004)(Pierce et al., 2004)

(AD)

Warmer, drought-prone periods

Cooler, wetter periods

Yellowstone NPYellowstone NP

central Idahocentral Idaho

FIRE VULNERABILITY:FIRE VULNERABILITY: control by snowmelt timing, from Westerling et al., 2006 from Westerling et al., 2006

YNP, Idaho fire YNP, Idaho fire vulnerability increases vulnerability increases with low snowpack, with low snowpack,

earlyearly snowmelt snowmelt

Sacramento Sacramento MtnsMtns

SE New Mexico fire SE New Mexico fire vulnerability not as vulnerability not as

sensitive to snowmelt sensitive to snowmelt timing – summer timing – summer

monsoon IMPORTANTmonsoon IMPORTANT

comparison of Yellowstone & southern New Mexico fire-erosion recordscomparison of Yellowstone & southern New Mexico fire-erosion records

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Ely (1997) southwestern USA large floods

(112)

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cal yr BP

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Sacramento Mtns., NM fire-related sedimentation

Yellowstone fire-related sedimentation and debris flows

major fan aggradation

“Great Pueblo Drought”

DROUGHT-VEGETATION-GEOMORPHIC PROCESS LINKAGES (and feedbacks?):

Initiation of runoff-generated debris flows in recent drought with intense convective storms, central Idaho

30 km

Nebraska Sand Hills

Wind shift in Medieval

droughts (Sridhar et al.

2006)

modern

Medieval Warm Period

Bartlein and Hostetler (2004)

Geophysical

The Climate System (after Saltzman, 2002; Bartlein and Hostetler, 2004)

-provide paleoclimate proxy data

Heat flow (boreholes); Geomorphic including dunes, fans, fluvial systems, ...

Summary Questions-ChallengesSummary Questions-Challenges• What are the important biosphere properties and dynamics

to consider in climate-landscape linkages?

• Given fast vegetation response times to climate change, can real-time ecologic-geomorphic field studies yield data relevant to landscape-evolution timescales (YES … )

• How can paleo data (climatic, biologic, hydrologic, geomorphic) best provide insights on long-term climatic control of landscape evolution? (aided by OSL, AMS 14C, CRN dating …)

• What time and space scales of (paleo)climate models can best be used to understand ecologic-geomorphic change?

• How can we more effectively integrate historical and numerical modeling approaches to climate-landscape evolution?