We can change the world as we know it….

Jayne BelnapJill BaronUSGS

How I define drought

• Increased temperature with or w/o reduced precipitation = reduced soil moisture, less/early melt snowpack

• Reduced soil moisture, less/early melt snowpack = drought

• Indicators of drought = monitoring ecosystem variables affected by drought. What are they?

Climate monitoring

GCM

PDO (CP)

Climatemonitoring

MonsoonboundaryWinter precip

Summer precip

Precipitation timing:Monsoonal boundary will likely shift

ClimateMonitoring

“Expected values” of warming effects on RAIN-vs-SNOW

Derived from monthly IPCC GCM-grid pdfs, and UW’s VIC model

daily inputs, 1950-1999

2025

2050

By 2025

By 2050

Climate Monitoring Needs

But what are the ecosystemImpacts???

Center of Mass as a proxy for spring onset is biased towards higher elevations and latitudesWhat are the ecological impacts?

Climate monitoring

With rain/snow shift, early melt, recharge to basin aquifers across mountain fronts may also

change

Basin aquifers

Mountain aquifers

?

?

??

(Where does the snow go?)

A simulation experiment A simulation experiment

SIMULATED CHANGES IN SIMULATED CHANGES IN MOUNTAIN (in situ) MOUNTAIN (in situ) RECHARGE under a uniform RECHARGE under a uniform +3ºC warming+3ºC warming

Simulated with the U of WA VIC-hydrologic model: Hidalgo et al, in prep

Widespread 15 to Widespread 15 to 25% changes 25% changes projected, mostly as projected, mostly as declines in rechargedeclines in recharge

Notice that these fractions are MUCH larger than in the preceding “total outflow” map.

Expect large changes in plant communities

BoulderGlacierGlacier National Park, MT

1910

2007

Morton Elrod photoCourtesy of GNP Archives

Pederson/Fagre photoUSGS

Will impact lakes, streams Temperature Nutrients BiotaSurface albedoPlant/soil/animal comm before and after

Water Chemistry1991-1999 vs. 2000-

2006

Solute Sky Pond

Inlet% Change

The Loch Outlet

% Change

Calcium +33 +16

Nitrate +31 +50

Sulfate +45 +31

Silica +23 +2

DOC +4 -18

Drought has big effect on chem and thus biota!!

Generalized ecosystem response to reduced soil moisture

Year

1985 1990 1995 2000

Tre

e m

orta

lity

rate

(% y

r-1)

0.0

0.5

1.0

1.5

Long-term USGS research in the Sierra Nevada shows that in foreststhat otherwise appear to be healthy: • Tree mortality rates have doubled • This doubling parallels temperature-driven increases in drought

van Mantgem & Stephenson 2007

HigherTemperatures/Reduced

Soil Moisture

r2=0.97

Loss of mosses, lichens

• Less soil moisture• Less N fixation, greater N loss • Less C fixation, greater C loss• Less soil roughness• Less soil stability• Less soil biota activity• Less plant-available nutrients

Higher temperatures (+ surface disturbance)

Future warming willreduce soil moisture *Decreased plant cover (esp. shallow rooted plants)

*Slower recovery from disturbance

*Decreased soil stability,forage, habitat

Decreased, altered precipitation will also affect biocrusts, plants

*Treeline *Plant community composition (species, functional type) *Plant cover *Phenology at all life stages *Slower nutrient cycling, lower plant available nutrients

With lower soil moisture(drought), will get shiftsin:

Reduced vegetative cover (droughts, ORVs, grazing, blading, pumping) = fewer clouds, less precipitation

30% less than average rain for light area/ + 10% rain over dark

Early snow melt, urbanization, and irrigation will affect precipitation too

Large wildfires increased suddenly and dramatically in mid-1980s in West

• More large wildfires• Longer wildfire

durations• Longer wildfire

seasons• Strongly associated

with increased spring and summer temperatures and earlier spring snowmelt

Westerling et al. 2006

Drought increases fires; 1.4 – 5 times more area is expected to burn with increased temperature.

Fire reduces plant cover, increases water and wind erosion

Invasive annuals are spreading rapidly*Drought = no or little cover, more soil erosion

*Wet followed by drought = more dry fuels, more fire

Soil surface disturbance

Reduces plant/crust cover Increases albedo, soil erosion

*ORVs in so. CA alone produce 6 billion pounds dust/year*Need to separate from climate

Means less plant and crust cover, more roads = > albedo, more soil erosion, less wildlife habitatALL THESE USES TAKE WATER

UT/CO/WY: Oil, gas, oil shale, uranium, tar sands, wind/solar, potash, gold, silver, you name it

Dust inputs to the Mojave and Colorado Plateau

average 20-40 g/m2/year. Vehicle-disturbed surfaces

produce up to 610 g/m2/minute.

Pumping water from shallow aquifers can lowerwater tables. Drought will exacerbate. Leads to >plant death, albedo, dust

Drought, invasives and disturbance interact to create huge amounts

of dust

Invasives and disturbance interact to

create more dust

Dust production is a local, regional, and global issue

Coral reefs die!

Vehicle accidents, Valley Fever, asthma,

other respiratory diseases

Dust creates economic woes as well

Soil Variable % Loss

Silt 38-43

Organic Matter 60-70

Nitrogen 15-60

Phosphorus 66-79

Potassium 68-96

Magnesium 68-86

Manganese 43-57

Sodium 44-62

Impact of 100 years of grazing on CP soils

Thus, soil water-holding capacity and soil fertility is greatly reduced

Most dust from western drylands ends up in nearby mountains

~1860

~1000 BC

~3000 BC

~1920

~1000 BC

~1850

~1920

Pacific Railway Act - 1862

Taylor Grazing Act - 1934

Dust from the Colorado Plateau (Mojave) in San Juan Mountain lakes

(Neff et al. 2008)

Dust melts snow >30 days earlier

Impact on snowpack

•Less snowpack storage•Less late season water •Less water = reduced water quality

Colorado River Compact

Averag

e ann

ual stream

N

O

3 m

g/l

and

flu

x kg

N/y

r

0

1

2

3

4

Excess N in Surface Water

Flux, kg N

Conc, mg NO3

90 92 94 96 98 00 02 04 06

• Nitrogen in LVWS surface waters elevated since ~1950

• [NO3] and N flux increase post-2001

LOCH OUTLET NO3

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

82 86 90 94 98 02 06

Stream NO3

mg/L

What info do we need to predict drought impacts and inform mgmt actions?

• WAY more climate stations (snow melt rates, dust inputs, precip type/timing/intensity)

• Redmond (“effective” rainfall) index• Distinguish land use/N dep from climate across

rainfall timing, elevational gradients– Veg/crust change (e.g., invasives, dominants, T/E)– Faunal response to veg changes (habitat, forage)

• Maps of current and future land uses (and thus bare ground (get at cumulative impacts)

• Soil moisture (surface 1 cm and subsurface)• Soil vulnerability maps (wind, water erosion)• Response of aquatic biota to glacier loss,

snow/rain, early melt, low water• Fate of water from snow/rain, early snow

melt (recharge? runoff?), infrastructure impact