Biological consequences of

earlier snowmelt from

desert dust deposition in

alpine landscapes

Heidi Steltzer, Chris Landry,

Tom Painter, Justin Anderson, and Ed Ayres

Painter et al. (2007) Geophysical Research Letters

Neff et al. (2008) Nature Geoscience

Human activities in

the adjacent

deserts have led to

5 fold more dust in

the mountains since

the mid-1800’s.

dust

vegetation snow

people people

AGRICULTURE DESERT

• Effects on ecosystem services: – Water quality and quantity

– Biodiversity

– Wildlife

– Aesthetics

Three alternative hypotheses Different models of how snowmelt affects

plant community life history

Day of year

snowfree

On

set

of

even

t

(Day o

f year)

Day of year

snowfree

On

set

of

even

t

(Day o

f year)

Steltzer et al. (2009)

Proceedings of the National Academy of Sciences

On

set

of

gre

enin

g(d

ay o

f yea

r)160

180

200

220

Day of year snowfree

150 160 170 180 190 200

On

set

of

flow

ering

(da

y o

f yea

r)

160

180

200

220

R2 = 0.97

wr = 1.00

R2 = 0.96

wr = 0.96

Day of year snowfree

150 160 170 180 190 200

R2 = 0.94

wr = 0.63

R2 = 0.95

wr = 0.83

All species observed Species common to all plots

- Dust

Control

+ Dust

Fabric

Key result

• Earlier snowmelt from desert dust

deposition changes the climate

cues that regulate plant community

life history in the alpine tundra.

Onset

of

gre

en

ing

(day o

f year)

160

180

200

220 SE aspect

NE aspect

- Dust Control + Dust Fabric

Onset

of

flow

ering

(day o

f year)

160

180

200

220

P = 0.07P = 0.89

P = 0.88P = 0.41

P = 0.01

P = 0.01

Earlier snowmelt

Key result

• Earlier snowmelt synchronized

plant community life history events

Synchronization of plant growth across

hillslopes is a change in the fundamental

ecology of Colorado alpine ecosystems

“A tendency of plants to grow and bloom in lockstep

would lead to a feast-and-famine ecology for

both plants and animals, rather than one with resources

distributed throughout the growing season.”

Christian Science Monitor (2009)

• The case is building that the transfer of desert

dust to the mountains has environmental

consequences for alpine plants, wildlife, and

people.

• Our use of desert landscapes is linked to the

life cycles of mountain plants and changes the

environmental cues that determine when alpine

meadows will be in bloom, possibly increasing

plants’ sensitivity to climate warming.

dust

vegetation snow

people people

AGRICULTURE DESERT

$

Special Thanks • Center for Snow and

Avalanche Studies

• British Ecological Society

• U.S. National Science Foundation

• Andrew Temple, CSAS

• Michael Barton, CSAS

• Koren Nydick, MSI

• David Inouye, RMBL

• Natural Resource Ecology Laboratory, CSU

• Uncompahgre National Forest

• Fort Lewis College