Biomonitoring with Lichens in Southern Californiacalnat.ucanr.edu/files/249994.pdf · 2016. 10. 18. · Using lichens to monitor nitrogen pollution in Southern California Jennifer

Using lichens to monitor

nitrogen pollution in Southern

California

Jennifer Riddell

AAAS Science and Technology Policy Fellow, US EPA

Tom Nash- Arizona State University

Sarah Jovan, Pamela Padgett, USDA Forest Service

Figure courtesy of NASA GSFC program: http://ltpwww.gsfc.nasa.gov/globe/NFTG/nitrocyc.htm

The Nitrogen Cycle

Important N deposition factors to consider

• Toxicity in the ecosystem

• Critical loads

National Trend Network (NTN) monitoring sites

1985

Nitrate Ion Concentrations

1985-2008

Maps from National Atmospheric Deposition Program

http://nadp.sws.uiuc.edu/data/animaps.aspx

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1985-2008

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2008

Drawbacks: NTN sites in Southern

California

History of study area: Air quality

Data source: CA Air Resource Board 2013 Almanac

0

20

40

60

80

100

120

140

160

180

200

Da

ys

> S

tan

da

rd

San Bernardino 4th St Monitor: Days exceeding ozone standards

State 1-hr Standard

State 8-hr Standard

National 1-hr Standard

National 8-hr Standard

Poly. (State 8-hr Standard)

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

500000

Population/100

Avg. Daily VMT/1000

South Coast Air Basin

Percent Growth in Population and Vehicle Miles Traveled

CARB 2013 Almanac figure 4-2

381,013,000 VMT per day!

17,800,000 people in SCAB counties

Barton Flat

Crestline

Study Area

Estimated Historic Total N Deposition (data from Fenn et al . 2008)

0

10

20

30

40

50

60

70

80

1930 1940 1950 1960 1970 1980 1990 2000 2005

kg

ha

-1 y

r-1

Camp Paivika

Barton Flat

Crestline

History of study area: Air quality

Critical load for

elevated stream

water [NO3- ]

(~17 kg/ha/year)

(Fenn and Poth 1999)

Critical load for

elevated Letharia

vulpina tissue % N

(~3 kg/ha/year)

(Fenn et al. 2008)

So Why Lichens?

• Lichens extract nutrients and moisture

almost entirely from the air.

• Consolidate airborne elements, and

respond quickly to shifting air quality.

Clean Polluted

Sites Sites

Community composition

changes in relation to

air quality

Nitrophytic lichen

cover at Camp

Paivika (near

Crestline)

~ 71 kg/ha/year

N deposition

Morphological changes in pollution tolerant species

Hypogymnia imshaugii

at a clean site

H. imshaugii

At polluted sites

Twofold Study Objectives

Compare community

composition changes

over 30 years

Create and test model using lichen

communities to predict air quality,

particularly N deposition

• Hasse-1913 • Lichen flora of Southern California

• Sigal (1979) • ~ 50% montane spp. extirpated

• Spp. loss correlated with O3 gradient

History of study area:

Lichen studies

Methods19 Sigal sites revisited – 22 total sites

• Lichen % cover transects

– Considerations:

• Secondary stand

attributes

• Substrate pH

• Twig NO3-

Study Area

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

1976 2008 1976 2008 1976 2008

Angeles National Forest Mt Palomar / Cleveland N.F. San Bernardino N.F.

Parmelia subolivacea

Physcia tenella

Physia grisea

Xanthoria fallax

~ Moderately tolerant

~Nitrophyte (tolerant)



Changes in % cover 1977-2008

Physconia spp.

Model: PCORD community ordinations

generated lichen species community “air scores” by comparing site % cover

Added 32 environmental parameters in model:

• CMAQ modeled N deposition NHx, Ox. N

• Through fall total N deposition (collected in resin tubes

under the canopy)

• Passive monitor NH3, HNO3, NO2, and O3

• Twig N

Predicting N Deposition

Using Lichens

Ordination axes for 2008 lichen cover

on oaks

85.6% of community variation

explained by model, with

49.7% of variation explained

by N related axes

NMS index Eutroph

index

r2 r2

Deposition measurements Throughfall N 0.94 0.77

Twig NO3- 0.58 0.42

Deposition estimates

Total Dry N 0.62 0.34

Dry NOx 0.60 0.35

Total N (wet + dry) 0.49 0.22

Dry NHx 0.48 0.24

Dry atm. NH4+ 0.38 0.27

Dry atm. NO3- 0.36 0.21

All atm. N 0.06 0.00

Wet NHx 0.05 0.00

Wet atm. NH4+ 0.05 0.00

Total Wet N 0.03 0.01

Wet NOx 0.01 0.03

Wet atm. NO3- 0.01 0.02

Gas concentration

measurements

HNO3 average 0.59 0.27

Total N average 0.50 0.23

O3 maximum 0.49 0.43

NH3 average 0.47 0.27

NO2 average 0.42 0.19

Site environmental

variables

Temp. 0.49 0.63

Dew point 0.49 0.53

Elevation 0.48 0.40

pH of oak bole 0.43 0.24

pH of twigs 0.01 0.00

Precipitation 0.00 0.021

Key findings:

Pearson’s correlations

significance p < 0.05 bolded

(1) indices correlated

similarly but NMS

stronger

(2) eutrophs closely tied

to throughfall dep.

(3) next best: dry and

oxidized N dep.

(4) HNO3 correlation is

comparably good; best

gas predictor for NMS

index

(5) NH3/reduced N vars

are comparatively weak

Thrufall N measurements / Twig

N correlation

0

2

4

6

8

10

12

14

16

18

0 10 20 30 40 50 60 70 80

Twig Nitrate vs. Thrufall

Through fall N (kg/ha/year)

Tw

ig s

urf

ace

NO

3-(μg

cm

2)

r2 = 0.87

CMAQ Modeled Dry Oxidized N Twig Nitrate

Lichen Community Air Scores

Community

Air Score

CMAQ Dry Ox. N r2 = 0.78

Twig surface

NO3- r2 = 0.76

Throughfall N r2 = 0.94

Conclusions• Nitrogen = important driver of lichen community

composition in S. California (communities shifted from neutrophytes to nitrophytes)

• Twig nitrate was a useful tool to estimate relative N deposition

• Nitrogen pollution seems to have an increasing influence on lichen communities in S. CA over the last 30 years.

Thanks ToLorene Sigal ~ for providing inspiration and

data from 1977

Tom Nash, Pam Padgett and Sarah Jovan

~for constant intellectual and fiscal support

David Jones ~ for running untold numbers

of samples on the Dionex

Funding Sources

USDA Forest Service Pacific Southwest

Research Station

USDA FIA P3 Program

US EPA STAR Fellowship Program

Arizona State University

Documents

Biomonitoring with Lichens in Southern Californiacalnat.ucanr.edu/files/249994.pdf · 2016. 10. 18. · Using lichens to monitor nitrogen pollution in Southern California Jennifer