Nitrogen deposition impacts on a nutrient-poor grassland ... - Cal-IPC

<strong>Nitrogen</strong> <strong>deposition</strong> <strong>impacts</strong>
on a nutrient-poor grassland
ecosystem: conservation,
management and restoration
Stuart B. Weiss
Creekside Center for Earth
Observations

Serpentinite forms discrete patches
of habitat

Serpentinite weathers to thin, rocky,
nutrient-poor soils:
high Mg, Ni, and Cr,
low Ca, N, P, and Mo

Hostplants and Nectar Sources

Rare Endemic Flora

Problem
In absence of cattle grazing in South Bay,
introduced annual grasses overrun habitat
within several years (repeatable).

Dry <strong>deposition</strong> – Dominant in California

Air Pollution Chemistry
Combustion
Simplified
NO
hv
O 3
NO 2
PAN
[OH - ]
HNO 3 + NH 3 NO 3 NH 4 (p)
Fertilizer, Vehicles

Dry Deposition
‣ Complex process
‣ Resistances: Aerodynamic, boundary layer, and
surface
‣ Surface resistance function of composition,
wetness, plant cover, and N-species
‣ Deposition directly to surfaces and/or through
stomata
‣ Up to 45 kg-N ha -1 yr -1 in San Bernardino Mtns,
20-30 kg-N ha -1 yr -1 in Riverside
‣ Flux = Dep Velocity X Concentration

Passive Sampling

Dr. Andrzej Bytnerowicz, USDA FS Riverside, CA

1-3 EW 5 RCAQ
4 JR
SJAQ
6 Tulare
7-8 KC

March
0
10
20
30
40
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Calm 4.8%
September
0
10
20
30
40
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Calm 3.9%
June
0
10
20
30
40
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Calm 2.1%
December
0
10
20
30
40
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Calm 11.1%

EWWest
EWEast
Highway 280
carries 100,000
cars per day, often
at capacity
southbound in AM
EW400E

July 9 2002 - Mar 11 2003
12
10
8
6
4
2
0
1EW-West
2EW-East
3EW-400E
4JR
5RCAQ
7TH
8KCLow
9KCHigh
Monthly differences (not shown) follow wind and
temperature
HNO3-N
NH3-N
NO2-N
ug-N/m^3

July 9 2002 - Mar 11 2003
15
kg-N/ha
10
5
HNO3
NH3
NO2
0
EW-West
EW-East
EW-400E
JR
RCAQ
TH
KC-Low
KC-High
mm/s
Dry
Wet
HNO 3 16
16
NH 3 10
16
NO 2 0.5
2

Ammonia from Cars
‣ Catalytic converters over-reduce NO x
when running fuel rich
‣ Emissions factor of ~ 0.05 g/km
‣ 1.8 Mg/km for Highway 280
‣ N 15 isotope signature
‣ Tahoe <strong>impacts</strong>
‣ Byron lunch

Conservation targets are well-defined

Impacts
Initial estimates 10-15 kg-N ha -1 yr -1

Environmental “Train Wreck”
‣ Silver Creek Hills 1990-2000
‣ Extinct Bay checkerspot populations
‣ Heavily degraded habitat
‣ Political pressure on USFWS
‣ Lawsuits
‣ Development delays
‣ Redesign of reserve
‣ Ongoing restoration

Metcalf Energy Center Site

Metcalf Energy Center (Calpine
Corp.)
‣ 600 MW gas-fired combined cycle electricity
plant
‣ Emissions - ~124 tons NO x , ~119 tons NH 3 per
year
‣ Mitigation strategy– Preserve habitat through
purchase/easements (131 acres), graze cattle
‣ Adaptive management, funded by endowment
‣Precedent setting!

Worst-case scenario modeling, all emissions as HNO 3

Former-future Cisco World Headquarters
(now just another office park, CVRP)
230 tons NO x /year, ammonia

Widening Highway 101

Grams NOx per km
Fleet Emissions
2.00
g NOx/km
1.50
1.00
0.50
0.00
0 20 40 60 80 100 120
kph
10
35
60
Range: 25-60 Mg (metric tons) NO x km -1 yr -1
~1.8 Mg NH 3 km -1 yr -1

669 acres of serpentine for CVRP
and Highway 101
Purchase being negotiated (not
simple)
Habitat Conservation Plan/Natural
Communities Conservation Plan
HCP/NCCP for Santa Clara County
Process starting, MOU signed

Local <strong>impacts</strong> of a freeway
Bay checkerspot
habitat (blue outlines)
bisected by Highway
280, carrying 100,000
vehicles/day
Prevailing NW winds
carry emissions onto
core habitat
What effects on
habitat and butterfly

9,000 larvae in 1997,
The last larva in 2003

EWWest
EWEast
EW400E
Plant transects
established in 2001
Percent cover of all
species in 0.5x0.5m
quadrats (10/transect)
Soil depth (4) in each
quadrat

Edgewood Patterns 2001
‣ Lolium cover higher on thicker soils (more
nutrients/water available), Plantago opposite
log(Cover+1)
2
Plantago
1.8
Lolium
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-200 0 200 400 600
W Meters from I-280 E
100
30
10
3

Grams NOx per km
Fleet Emissions
2.00
g NOx/km
1.50
1.00
0.50
0.00
kph 0 20 40 60 80 100 120
mph 10 10
35 35
60
Range: 25-60 Mg (metric tons) NO x km -1 yr -1
~1.8 Mg NH 3 km -1 yr -1

Restoration Experiments
‣ Small-scale (700 m 2 ), replicated
‣ Fire - Cancelled twice, sorry
‣ Mowing – Effective, known costs and
technology
‣ Goat grazing – Expensive, not as effective
‣ Seeding Plantago appears unecessary
‣ Reintroduction of butterfly in 3 -55 years

15
Plantago erecta
70
Lolium multiflorum
60
% Cover
10
5
% Cover
50
40
30
20
10
0
Control
Mowed
0
Control
Mowed
20
Lasthenia californica
15
Species Richness
% Cover
15
10
5
Species Richness
10
5
0
Control
Mowed
0
Control
Mowed
2001 2002

White-rayed Pentachaeta at long-term
risk Only known occurrence West of
280 across from Edgewood Preserve,
avoids first 75 meters from freeway

Problem is not going away soon
NO x Emissions
Tons/day
180
160
140
120
100
80
60
40
20
0
1975 1980 1985 1990 1995 2000 2005 2010
Santa Clara
San Mateo
San Francisco
2001 California Almanac of Emissions and Air Quality
Ammonia emissions likely to get worse

Problem is across California
ppm NO2
Trends in NO 2 Annual Average in Select California
Counties
0.08
0.06
0.04
0.02
0.00
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
Santa Clara
San Mateo
San Francisco
Alameda
Los Angeles
Orange
SanBernardino
Fresno
Kern
Sacramento
2001 California Almanac of Emissions and Air Quality

Other unique CA habitats at risk
‣ Annual Grass Invasions – CSS, Desert,
Serpentine grassland
‣ Other grasslands
‣ Lake Tahoe, alpine lakes
‣ Vernal pools –Lolium
invasions in
unmanaged vernal pools
‣ Forests and shrublands
‣ Statewide screening – CEC funded project

Acknowledgements
‣ Calpine Corporation
‣ Waste Management, Inc.
‣ National Fish and Wildlife Foundation
‣ Center for Conservation Biology
‣ USFWS
‣ San Mateo Co. Parks and Recreation
‣ California Native Plant Society, Santa Clara Valley
Chapter
‣ Generations of checkerspot butterfly researchers
‣ Generations of serpentine grassland researchers
‣ Air pollution scientist community