The Role of Lichens in Air Quality Monitoring on Federal Lands

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					               The Role of Lichens in
               Air Quality Monitoring
                  on Federal Lands

What information can lichen monitoring
  provide to air resource managers?

 Linda Geiser, US Dept. of Agriculture-Forest Service, Pacific Northwest
  Region Air Resource Management, PO Box 1148, Corvallis OR 97330
                   What are lichens?

British soldiers       Button lichen   Lung lichen
 Lichens are symbiotic
 organisms consisting
 of a fungus and an
 alga and/or a
What physiological properties make lichens
          useful indicators of air quality?
 Range of air pollution sensitivities across species. Lichens exhibit a range
  of sensitivities to S- & N compounds in acid rain, sulfur dioxide, ammonia,
  and fluoride. Changes in distribution or populations of the most sensitive
  lichens provide an early warning that air pollution is beginning to adversely
  affect the ecosystem. The mix of species and abundances at any one site
  can be used to position the site along an air quality gradient.

 High surface area and no roots. Lichens on trees and shrubs obtain
  nutrients from the air, precipitation, and substrate run-off. Tissue levels of
  many pollutants are correlated with ambient atmospheric levels.

 Readily absorb water and lack specialized barriers to prevent vapor loss.
  Daily cycles of wetting and drying produce a dynamic equilibrium between
  concentration and leaching of pollutants. As pollution concentrations
  change, so do concentrations in lichens. Mobile elements: S, N, K, Ca,
  Mg, Na. – can change significantly over a few months. Less mobile
  elements: Pb, Cd, Ni—change more slowly.
   What kinds of data are
Lichen communities and floristics
Tissue analyses
#1. Documenting deposition of pollutants in
  a Class 1 Area and tracing their source.
                                                   Mt. Zirkel
                                                   Routt NF,

                                              REFERENCE: Jackson, LL, L
                                              Geiser, T Blett, C Gries, D
                                              Haddow. 1996: Biogeochemistry of
                                              lichens and mosses in and near Mt.
                                              Zirkel wilderness, Routt National
                                              Forest, Colorado: influences of
                                              coal-fired power plant emissions. -
                                              Open-File Report, 96-295, U.S.
                                              Department of the Interior, U.S.
         Yellow lines circle lichen           Geological Survey. 162 pp.
         monitoring plots (black triangles)
                        Mt. Zirkel Wilderness, Routt NF, Colorado

Stable S isotope ratios in lichens were significantly heavier in the MZW and Routt NF
than at regional sites. This was consistent with a local sulfur source with a heavy
isotopic signature resulting from the combustion of marine-influenced coals from the
Yampa Valley.
                                                                Lichen monitoring
                                                                sites indicated by
#2. Check a site within an                                      yellow triangles
  area with established
   background ranges.

            Klondike Gold Rush
          National Historic Park,
               Skagway, Alaska

 REFERENCE: Furbish, C.E., L.H. Geiser and C. Rector. 2000. Lichen-air quality pilot study
 for Klondike Gold Rush National Historical Park and the City of Skqaway, Alaska. Klondike
 Gold Rush National Historical Park Natural Resources Management Program. Report released
 December 2000.
Klondike Gold Rush National Historic Park, Skagway, Alaska

  Mean concentrations of Al, Cd, Cr, Cu, Fe, Pb, Ni, P, K, S, Zn in the
  lichen, Hypogymnia enteromorpha, were higher in Klondike Gold
  Rush NHP samples than Tongass National Forest samples.
Lichen tissue was collected               #3. Mapping
along a transect from the APC
mill, through the town of Sitka
                                     deposition patterns
to the Ferry Terminal (red dots).   from a point source.

                                         Tongass National
                                         Forest, Sitka, Alaska

                                     REFERENCE: Geiser, LH/ Derr, CC/ Dillman, KL
                                     1994: Air Quality Monitoring on the Tongass
                                     National Forest. Methods and Baselines Using
                                     Lichens. - USDA-Forest Service, Alaska Region
                                     Technical Bulletin 46. 85 pp.
        Tongass National Forest, Sitka, Alaska
                              Lichens were absent from alder
Typical cover of lichens on
                              <0 .25 mi from the pulp mill, an
alder in the Sitka area
                              SO2 source.
                 Tongass National Forest, Sitka, Alaska
3-D view of lichen tissue concentrations in # of sd from Tongass clean sites mean
(vertical axis) vs sampling site location (horizontal axes). Far right is < 1km from the
pulp mill, center is Sitka city center, far left is the ferry terminal, 14 mi distant.
 #4. Estimating deposition from calibrated
               lichen data.
           Pacific Northwest National Forests

Lichen tissue collections were made within 1 km of 8 NADP monitors
in Oregon and Washington (black dots on national map above).
           Pacific Northwest National Forests
Lichen sulfur concentrations, weighted by precipitation,
accurately predicted wet deposition of sulfur to within about 0.3

                                                                                         Hoh RS

                                       6                                     Bull Run
          SO4 deposition (kg/ha/yr )

                                                                 Pac k For

                                       4                              HJA


                                               Silver L
                                           0          5           10           15            20
                                                   Lic hen % S (pptn weighted)
 Pacific Northwest
 National Forests

A map of wet deposition of
sulfur in Pacific NW
national forests constructed
using calibrated lichen data.
Values ranged from < 0.7
(dark blue) to > 4.0 (red)

A map of wet deposition of
nitrogen was similar.
 #5. Combining lichen community and tissue data to
 indicate patterns of anthropogenic influence and its
                 effects on vegetation.
                      Alaska and Pacific Northwest Regions

Red dots indicate monitoring locations where lichen community surveys and tissue
analysis have been completed by the USFS Air program. In PNW forests, monitoring is
co-located with the CVS (= USFS national Forest Inventory Assessment) 3.4 mi grid.
Sensitive, ecologically important lichens, many endemic, are sparse to
                absent in areas where acid rain is high.
Growth of pollution-loving, weedy species is enhanced where nitrogen
                          pollution is high.
                             Lichen communities indicate a pollution gradient
                                                                               Willamette N.F.
                          Lichen communities                                   Siuslaw N.F.
                                                                               Gifford Pinchot N.F.
         80                                                                    Mt. Hood N.F.
                                                                               Willamette Valley
                                                                               Urban Parks

Axis 2


         40                                                          AirQual


                                           Ordination of sites by lichen communities. Plots (represented by
                             Easting       triangles) with smiliar communities are close together in space.
                                           Environmental variables are overlaid on the ordination Axis 1 is
         0               KMocean           correlated with increasing sulfur and nitrogen pollution. Axis 2 is
              0              40            correlated with decreasing distance from the coast and warmer winter
                                           temperatures. In this analysis, urban parks and the Columbia River
                                  Axis 1   Gorge National Scenic plots receive the highest pollution scores.
           #7. Determining whether instrumented
                  monitoring is warranted
                 Hell’s Canyon National Recreation Area

Could ancient rock art be threatened by air pollution?
            Hell’s Canyon National Recreation Area
                           % N (dw) By Dista nce (km)




                                    % N (dw)





                                                           1.1                                                                     Wi th Co ntro l
                                                                           0           0.4          1.6               >1 .6        Du nnett's
                                               Xanthor ia Cov e r (%) By Distance (k m)                                             0.05
                                                                                       Di stan ce (km)

                                    M ea ns Comparisons
                                     Dif=Mean[i]-Me an[j ]                                          0               0.4          >1 .6          1.6
                                               Xa nthoria Cover (%)

                                    0                                                        0.00 000 0        0.32 806 8     0.33 119 3   0.34 119 3
                                    0.4     40                                               -0.328 07         0.00 000 0     0.00 312 5   0.01 312 5
                                    >1 .6                                                    -0.331 19         -0.003 12      0.00 000 0   0.01 000 0
                                    1.6                                                      -0.341 19         -0.013 12          -0.01    0.00 000 0
                                    Al pha = 0.05
                                    Compa risons with a contr ol using Dunne tt's Me thod
                                       2.484 75
                                     Abs(Dif)-LSD                                          0
                                    0                                              -0.166 19
                                    0.4                                            0.14 696 5
                                              0                                                                     Wi th Co ntro l
                                    >1 .6                                      0
                                                                                   0.15 009 0
                                                                                          0.4            1.6           > 1.6
                                    1.6                                            0.16 009 0                       Du nnett's
                                                                        me ans th at a
                                    Po si ti ve val ues sh ow pai rs of Di stan ce (km) re sig ni fi ca ntly d ifferent.
Nitrogen concentrations in lichen tissue and abundance of the nitrogen-loving lichen,
                                         to the Snake
Xanthoria, were highest at sites closest ea ns ComparisonsRiver.
                                           Hell’s Canyon National Recreation Area
log (% N in Xanthoparme lia) By Comparison Are a s


log (% N in Xa nthopa rme lia )







                                                                                                            With Control
                                          CRGNSA   HCNRA: 0 km    HCN RA:>.3 km     R2 Eleva   R2/6 Backg
                                                                 Comparison Areas

          Average tissue concentrations of nitrogen at all sites in Hell’s Canyon
          were elevated relative to background sites in the western US
      M ea ns and Std De v iations
   Le v el                                             Instrumented monitoring is warranted.
                                          Conclusion: Mea n Std Dev Std Err Mean
Summary: Advantages of lichen monitoring
  Good indicators of deposition containing sulfur, nitrogen, metals, other
   elements, radionuclides and some hydrocarbons/organochlorines.
  Demonstrates presence of contaminants in the ecosystem.
  Lichen communities are good summarizers of air quality—respond to
   the synergistic mix of pollutants in the air.
  Lichen communities (species richness, composition and abundance) can
   be used to indicate whether anthropogenic activities are affecting the
  Relatively fast and inexpensive—many measuring points can be made in
   a short time that summarizing air quality over past months or years.
  Useful in areas of rugged topography where modeling is inadequate.
  Useful in remote areas—does not require electric power.
  Can be used to map relative differences in air quality over a
   geographical area of interest and to track changes over time. If air
   pollution tolerant species are used, can map polluted areas.
  Source apportionment is possible using multi-element analysis and
   isotope ratios.
Summary: Advantages of lichen monitoring
  Compliments instrument measurements and other monitoring
   information. Element analyses, community analyses used in combination
   with direct measurements or other bioindicatorscan corroborate each other,
   making a more convincing argument for decision-makers.
  Plentiful existing data for the PNW and Alaska and Canada for metals, and
   in arctic for POPs, some data for radionuclides from Canada. Preliminary
   thresholds for metals.
  Can link to existing programs: FHM (lichen communities) and USFS-
   PNW (communities and tissue analysis).
  Not mobile, concentrations reflect local conditions.
  Easy to collect, lichens are widespread and easy to recognize.
  Deposition can be estimated from lichen tissue levels if instrumented sites
   are available for calibration.
  Multi-element analysis can evaluate multiple stressors simultaneously,
   good idea to measure effects of sulfur and nitrogen deposition together with
   other pollutants.
Summary: Limitations of lichen monitoring
 Lichens are relatively insensitive to many air toxics (metals,
  radionuclides, organics)– lichen communities affected more by acid
  rain, SO2, N deposition and fluorine. I.e. may be able to show presence
  of enhanced tissue levels but not adverse effects to ecosystem.
 Cannot separate wet from dry deposition or different forms of sulfur
  or nitrogen containing pollutants using lichens—measure total N, total
  S and total deposition.
 Some metals are not easily leached from lichen thalli and may remain
  concentrated for 10+ years. Can use transplants, select species with
  annual growth (Hylacomium splendens) or collect from substrate of
  known age (last five terminal bud scars). Or, because epiphytic lichens
  grow rather quickly, can monitor changes over time of the population
 Interference from local dust: use enrichment factor from local soils
 Tissue analysis cannot differentiate wet from dry deposition. May
  not be able to distinguish different forms of a single element.
Summary: Limitations of lichen monitoring
  Multivariate analysis is often required to separate the pollution
   signal from other environmental variables (elevation, precip, forest
   continuity, relative humidity, available substrates) OR restrict the range
   of these variables within the study area.
  To obtain accurate and repeatable readings of metals, tissue
   concentrations of metals should be in the 0.1 ppm range or higher.
   Check detection limits of laboratory before analysis.
  Lichen analysis for POPs is analytically challenging because
   concentrations are usually low and natural lichen substance interfere with
   analyses. But much base work has been completed for the arctic.
  Must have sufficient material– lichens may be difficult to find where
   acid rain, SO2 or N deposition is a problem. Can use transplants. Must
   compare different sites using the same species.
  Regulatory personnel are often unfamiliar with lichen monitoring
   methods. Can establish LACs, develop an MOU, or calibrate data to
   units used by regulatory agencies.

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