(weathers, 2003)atmospheric deposition in mountainous terrain

8/13/2019 (Weathers, 2003)Atmospheric Deposition in Mountainous Terrain

1/23

Report

for research conducted for the

Park Research and Intensive Monitoring of

Ecosystems Network (PRIMENet)

EPA Assistance Agreement CR826558-01-0

Title: Atmospheric Deposition in Mountainous Terrain: Scaling up to the

Landscape

2003

PI:

Kathleen C. Weathers, Institute of Ecosystem Studies, Box AB, Millbrook, NYPhone: (845) 677-5343; E-mail: [email protected]

Co-PIs and support:

Gary M. Lovett, Institute of Ecosystem Studies, Box AB, Millbrook, NY

Steven E. Lindberg, University of Tennessee, Knoxville, TN

Samuel M. Simkin, Research Assistant II, Institute of Ecosystem Studies, Box AB, Millbrook,

NY

1


2/23

Summary:

Atmospheric deposition has long been recognized as an important source of pollutants

and nutrients to ecosystems. The need for reliable estimates of total atmospheric deposition

(wet+dry+cloud) is central, not only to air pollution effects researchers, but also for calculationof input-output budgets, and to decision-makers faced with the challenge of assessing various

policy initiatives. Although atmospheric deposition continues to represent a critical

environmental and scientific issue, estimates of total deposition still contain large uncertainties,particularly across heterogeneous landscapes such as montane regions. We developed an

empirical modeling approach that characterizes total deposition as a function of landscape

features such as vegetation type, elevation, topographic exposure, slope, and aspect. Wemeasured indices of total deposition to the landscapes of Acadia (ACAD; 121 km

2) and Great

Smoky Mt. (GRSM; 2074 km2) National Parks. Using 300+ deposition point measurements,

whose values ranged over an order of magnitude, and corresponding landscape attributes at eachPark, we are constructing a general linear model relating the deposition index to the landscape

variables. We are using a GIS database of digital elevation models and vegetation type, as wellas wet and dry deposition data from the closest national network monitoring stations, to scale-up

point measurements of total deposition fluxes and create park-wide maps of total deposition.Preliminary deposition maps show high spatial heterogeneity in the distribution of hotspots

(highs) and coldspots (lows) of deposition across these Park landscapes. The EPA PRIMENet

funding supported the data collection and sample analysis for this effort; current NPS fundingwill allow final statistical analysis and map creation.

2


3/23

Introduction:

Atmospheric deposition is an important source of pollutants and nutrients to ecosystems

(e.g., Likens et al. 1977, Weathers et al. 1986). Total deposition includes wet (rain and snow),

dry (gases and particles) and cloud or fog (also rime ice) deposition. The National Atmospheric

Deposition Program (NADP) provides good coverage of wet deposition at a national scale, andits continuous operation allows for detection of both spatial and temporal trends in wet

deposition. However, there are not sufficient sites to look at small-scale (e.g., meters to 10s of

kms) local variability. For example Great Smoky Mountains (GRSM) and Acadia NationalParks (ANP) each have only one NADP site. Dry deposition is highly spatially variable (e.g.,

Lovett 1994), however, the national air chemistry monitoring stations (CASTNet) whose data are

used in modeling dry deposition, are ~1/3 fewer than NADP, and station siting is limited, in part,by the expense of the infrastructure (e.g., towers). Cloud and fog chemistry monitoring has been

limited to a few mountaintop sites in eastern North America (e.g., Mountain Acid Deposition

Monitoring Program, MADPro; Driscoll et al. 2001, Andersen et al. 1999). Estimates of totaldeposition to landscapes are restricted to areas immediately adjacent to monitoring sites.

Further, model assumptions for both dry and cloud deposition estimates make the resultantvalues for heterogeneous terrain highly uncertain (e.g., Weathers et al. 2000, CASTNet website:

www.epa.gov/castnet/sites).

In order to quantify total deposition to heterogeneous landscapes, it is necessary to

capture local variability in fluxes. Previous work indicates that local variability in depositionrates can, in part, be controlled by such landscape features as aspect, elevation, vegetation type

and the presence of gaps or edges (Weathers et al. 2000, Fig. 2). For example, as a result of

orographic effects, cloud deposition, and possibly enhanced dry deposition (Johnson andLindberg 1992, Weathers et al. 2000), atmospheric inputs to high elevations are greater than

those to adjacent low elevation regions (e.g., Lovett and Kinsman 1990); coniferous forests aremore effective scavengers of particles and gases than deciduous forests (Weathers et al. 2000),

and edges and gaps have been show to have higher rates of atmospheric deposition relative to

forest interiors (Weathers et al. 1992, 1995, 2001; Lindberg and Owens 1993). Variations inslope and aspect can influence deposition as well (Weathers et al. 2000). By measuring indices

of deposition that include deposition via wet, dry and cloud processes, as well as local landscape

features, this project was designed to produce an improved calculation of ecosystem inputs.

These data and this analysis will permit scaling up from intensive measurement points (e.g.,monitoring stations) to complete landscapes. This will lead to the identification of hot and

cold spots of deposition across the landscape, and, ultimately, allow assessment of forest

ecosystem function at the finer spatial scales required for many management decisions.

Methods:

Sites

We focused our research on Acadia National Park (ACAD) in Maine (ACAD; 121 km2)

and Great Smoky Mountains National Park (GRSM; 2074 km2) in Tennessee and North

Carolina (Fig. 1). Both Parks have high rates of atmospheric deposition (Weathers et al. 1986,

1988, Johnson and Lindberg 1992, Ollinger et al. 1993), suspected deleterious effects of

3


4/23

deposition on terrestrial and aquatic ecosystems, highly heterogeneous terrain, and local

atmospheric monitoring programs (NADP and CASTNet, and for GRSM, MADPro).

Indices of Deposition

Direct measurement of atmospheric deposition rates via micrometeorological techniques

(such as eddy correlation) or inferential methods (i.e., measurement of air concentrations andmodeled deposition fluxes) is expensive and difficult to maintain. In addition, the assumptions

of these methods are generally not applicable to heterogeneous canopies and complextopography (e.g., Lovett 1994). As a result, their use is generally limited to intensive monitoring

sites, usually at low elevations, and they can give no indication of the range of variation of

deposition across a complex landscape. For some ecological, management, and policy questions,the resolution and accuracy of these deposition data are insufficient. To be logistically and

financially feasible, patterns of deposition in heterogeneous (mountainous) terrain must be

determined using easy-to-measure indices that record spatial variation, are not subject to

assumptions about homogeneity of terrain and canopy, and those indices must be related tomeasured deposition at an intensively monitored reference sites (e.g., NADP and CASTNet).

We used twosuch indices of spatial patterns of deposition in this research: sulfate flux inthroughfall (Lindberg and Garten 1988), and lead concentration in the surface soil (e.g.,Weathers et al. 2000). While we had intended to use lead in the forest floor as our primary index

at both sites, it was not possible to use this index at ACAD because of disturbance: a fire burned

to mineral soil in about half the Park in 1947. Similarly, at GRSM, bear disturbance andlogistical constraints made all but short-term throughfall collections problematic. Thus, sulfate

flux in throughfall was the primary measurement made at ACAD, while lead concentration in the

forest floor was the primary measurement at GRSM. These methods are explained in more detail

below.

Lead in surface soil

Lead deposited to forests from the atmosphere is known to be retained by organic matter

in the surface soil (e.g., Reiners et al. 1975, Friedland et al. 1984, Weathers et al. 1995, 2000).

Once bound, Pb is relatively immobile, even under acidic conditions, and accumulates as

deposition continues over many years (Smith and Siccama 1981). For example, at four

southeastern U.S. watersheds, ranging from ~300-1000m elevation, the average annual export of

Pb in streamflow represented only 1-2% of annual atmospheric deposition (Lindberg and Turner

1988). Thus lead concentration in the surface soil is a useful indicator of long-term average

patterns of deposition across a landscape (Weathers et al. 1995, 2000). Because Pb in the

atmosphere resides mainly on fine aerosols which can be dry deposited or scavenged by rain or

cloud droplets (Graustein and Turekian 1989), Pb content in the surface soil is an index of total

atmospheric deposition via the combination of wet, dry and cloud deposition pathways. The

measurement of lead in surface soil is particularly useful for identifying historical patterns ofdeposition, indicative of depositional patterns that range from decades and centuries (Johnson et

al. 1982).

4


5/23

Sampling design for lead

In GRSM,we measured Pb concentration on 380 surface forest floor samples distributed

randomly throughout the Parks. We used a stratified-random sampling design and selected

sampling locations using a GIS. Due to logistical constraints, sampling locations were limited to

the center swath of the park (Fig 2), and to areas not far from trails. In this way, locations were

chosen that were 1) within the central swath of the park, 2) within 2 pixels (30-60 m) of trails,and 3) representative of the Park landscape (Table 1). We sampled forest floors that had been

undisturbed for the last 50+ years. At each sampling location, GPS location was determined and

stored and the characteristics of the site with respect to aspect, elevation, vegetation type, and

slope were noted.

Specific methods:At each sampling location, at least 8 (up to 16 where O horizon was

thin) randomly located surface soil subsamples (Oe and Oa horizons) were collected with a 5.8

cm diameter soil corer. The subsamples were combined to yield one composite sample per

location. Forest floor material was placed in Ziploc bags in the field and sent to the Institute of

Ecosystem Studies (IES) laboratory for processing and analysis: Samples were dried at 60C,

weighed, sieved (8.0 mm mesh), ground in a Wiley Mill (number 20 mesh), ashed at 475C for 4

hours, digested in 35% ultra-pure nitric acid, filtered with #42 ashless paper, brought to volume

with deionized water and chemically analyzed for Pb using an Inductively Coupled Plasma

spectrometer (ICP). Certified reference samples were included with each batch of samples

processed.

Sulfate in throughfall

In areas of high S deposition, forest canopies exchange only small amounts of S between

internal assimilated pools and external pools on the leaf surface. Sulfate is a particularly good

tracer of deposition because it encompasses every major deposition process, almost equally,

including dry, wet and cloud deposition. As a result, deposition of SO4=

in throughfall (below-canopy drip) has been shown in a variety of canopies to be a good measure of total S deposition

to canopies (Lindberg and Garten 1988, Garten et al. 1988, Lindberg and Lovett 1992). In

contrast, throughfall cannot be used to accurately measure atmospheric deposition of nitrogen

(N) because NO3-and NH4

+are actively taken up by forest canopies (Lindberg et al. 1986,

Lovett and Lindberg 1993). However, because N and S are deposited by similar processes (wet,

gas and particle, and cloud deposition) there is a strong correlation between spatial patterns of S

and N deposition across forested sites in North America (e.g., Lindberg and Lovett 1992, Lovett

and Lindberg 1993, Ollinger et al. 1993), and along an elevation gradient (Miller et al. 1993).

Thus, broad-scale geographic as well as elevational (e.g., Lovett et al. 1999) and forest edge

studies (Weathers et al. 1992) indicate thatSO4=deposition in throughfall is a good indicator of

spatial patterns of atmospheric deposition of both S and N to the forest canopy.

Sampling design for throughfall

Because all throughfall samples needed to be collected on the same day and between

precipitation events, we selected a set of 10 trail systems at ACAD that could all be visited in

fewer than two days and that traversed elevation and vegetation gradients. We then used a GIS

to randomly select locations along those trail systems. Analysis of the distribution of landscape

5


6/23

features throughout Mount Desert Island, the Acadia National Park, the trail buffer areas, and the

points we sampled showed that those sites were representative of the larger areas (Table 2).

Specific methods: Throughfall samples were collected in 8 (20.32 cm) polyethylene

funnels with polywool plugs placed in the neck of each of the funnels to filter local organicdebris. The water collected in funnels drained through a plastic column containing anion

exchange resins (see Simkin et al., in press, for details of the samplers and method). In brief, the

resin collector consisted of a funnel attached to an anion-exchange resin column (Fig. 4). As

water passed through the column, sulfate, and other anions, were held on the column with >95%

efficiency (Simkin et al., in press). The ionic bonds between anions in the sample and the

positively charged exchange sites on the resin produce a more chemically stable sample than

anions in solution, which allowed for monthly rather than event-based sampling. The ion

exchange resin samples were retrieved from the field every 4-6 weeks during the summer of

2000. The resin columns were transported back to IES, extracted with a 1.0N KI solution and

analyzed via ion-chromatography (IC) to determine the flux of anions over the period of resin

column exposure.

GIS Coverages

Information for GIS datalayers we are using is as follows:

ACAD

Vegetation:

coverage name: VEG79

raw datafile name: veg79.e00 (ArcInfo polygon coverage)

projection: UTM zone 19datum: NAD83

scale of source material: 1:9000source material: interpreted from color infrared photography from August 1979 overflightoriginator: Acadia National Park (Karen Anderson)

Elevation:

coverage name: mdigrd2_fill1raw datafile name: mdidtm.exe

projection: UTM zone 19

datum: NAD27 (converted to NAD83 by Sam Simkin at IES)

resolution: 30 m pixeloriginator: College of the Atlantic (Gordon Longsworth) from USGS 24k DEM

GRSM

Vegetation:coverage name: Great Smoky Mountains National Park Land Cover

raw datafile name: gsmnp_lc.e00 (ArcInfo grid)projection: Albers Equal Area

datum: NAD83

6


7/23

resolution: 30 m pixel

source material: Landsat TM satellite datacitation: MacKenzie, M.D. 1993. The vegetation of Great Smoky Mountains National

Park: Past, present, and future. Ph.D. Dissertation, The University of Tennessee,

Knoxville, TN 154 p.

originator: Southern Appalachian Man and Biosphere project (www.lib.utk.edu/samab)Elevation:

coverage name: GSMNP 30 METER DEM

raw datafile name: gsm_dem.e00 (ArcInfo grid)projection: Albers Equal Area

datum: NAD83

resolution: 30 m pixelsource material: 30 meter (1:24,000) digital elevation data from USGS EROS data center

originator: Southern Appalachian Man and Biosphere project (www.lib.utk.edu/samab)

Summary of Results (to the end of the EPA funding period):

Much of the work that was completed with EPA funding included: (1) setting up andexecuting the data collection phase of the study--our data collection efforts were extensive, both

in numbers of samples collected and in spatial extent of area covered; (2) gathering and

validating GIS datalayers; (3) analysis of samples collected in the field; (4) setting up andmaintaining the database. Thus, only preliminary results are reported here. National Park

Service funding, which is now in place, will allow completion of the project. There are several

highlights from the results obtained up to the end of the EPA funding period. We compared thedistribution of landscape features throughout the Parks with the regions from which we collected

samples, and were pleased to see that the sampling points provided an excellent representation ofthe larger areas (Tables 1 and 2). Therefore, our final deposition maps will cover the complete

Park regions. Throughfall flux of S is consistently greater than bulk deposition, as shown by acomparison of co-located bulk and throughfall deposition collectors at low and high elevationsites at ACAD (Fig. 5). The additional S deposition is a result of a combination of dry and wet

(cloud and other droplet capture) deposition. For these two locations, total S deposition is 2-fold

and 3-fold greater under the canopy vs. in the open (low and high elevation locations,

respectively). Overall, there was a ten-fold variation in indices of deposition within both GRSMand ACAD (Figs 6 and 7). Preliminary analysis suggests that deposition to conifer forests was

consistently higher than to deciduous forests and that deposition was positively correlated with

elevation; when combined, forest type and elevation explain most of the variance in depositionfor both Parks. Preliminary deposition maps show hotspots of deposition in high-elevation

conifer forests (Fig 8).

Implications

These early analyses suggest that landscape features, especially vegetation type(coniferous vs. deciduous vegetation) and elevation explain much of the variance in the

deposition index data, thus relationships between GIS-available landscape features and total

deposition can be established. In addition, hotspots (higher deposition) of deposition exist in the

7


8/23

landscape, often adjacent to cooler spots of deposition. Whether or not total deposition to the

region of the Park is different using this spatially explicit model or deposition measured andmodeled using data from the national networks, capturing the spatial variability in deposition

may be important when evaluating links between deposition and biotic response, or when

establishing watershed input-output budgets.

8


9/23

Presentations and Publications:

Simkin, S.M., K.C. Weathers, G.M. Lovett, S.E. Lindberg, and D.N. Lewis. 2003. Atmospheric

deposition hotspots within Acadia and Great Smoky Mountains National Parks. Spatial

Odyssey 2003, December 1-5, 2003 Orlando, FL. National Park Service GIS meeting.

Weathers, K.C., T.J. Butler, G.M. Lovett, V.R. Kelly and G.E. Likens. 2003. Emissions and

Deposition of Atmospheric Pollutants: An update. NYSERDA meeting, October 2003

Lindberg, S.E. 2003. Dry Deposition of Mercury, Is It Real? Invited presentation at the SETAC

Workshop on Mercury Monitoring and Assessment, Pensacola, FL. September 2003.

Weathers,K.C., Simkin, S.M., G.M. Lovett, and S.E. Lindberg. 2003. Scaling-up point

measurements of atmospheric deposition to mountainous landscapes: an empirical

modeling approach. Cary Conference X, Millbrook, NY, April 2003.

Weathers, K.C. 2002. Atmospheric Inputs and Ecological Function. A presentation for theWorkshop on Ecological Thresholds, Woodrow Wilson Center, 4-5 November 2002.

Simkin, S.M., K.C. Weathers, G.M. Lovett, S.E. Lindberg, D.N. Lewis and K. Schwarz. 2002.

Scaling-up point measurements of atmospheric deposition to mountainous landscapes: an

empirical modeling approach. Ecological Society of America Annual Meeting, Tucson,AZ.

Weathers, K.C., G.M. Lovett, M.A. Arthur, S.M. Simkin. 2002. Watershed controls onstreamwater nitrate concentrations, Catskill Mountains, NY.Ecological Society ofAmerica Annual Meeting, Tucson, AZ.

Weathers, K.C., G.M. Lovett, S.E. Lindberg, and S.M. Simkin. 2001. Atmospheric Depositionto Heterogeneous Terrain: Scaling-Up to the Landscape. American Geophysical Union,

Spring Meeting, Boston, MA.

Weathers, K.C., G.M. Lovett, S.E. Lindberg, S.M. Simkin, D.N. Lewis, K. Schwarz and J.

Beeler. 2000. Atmospheric Deposition to Complex Terrain: Scaling-Up to the

Landscape. National Atmospheric Deposition Program Meeting, Saratoga Springs, NY.

Weathers, K.C., G.M. Lovett, S.E. Lindberg, S.M. Simkin, D.N. Lewis and M.L. Chambers.1999. Atmospheric deposition in mountainous terrain: Scaling up to the landscape. EOS,Transactions, American Geophysical Union, Volume 80 (No. 46), 16 November 1999.

Page F390.

Simkin, S.M., D.N. Lewis, K.C. Weathers, G.M. Lovett and K. Schwarz.In press,Determination of sulfate, nitrate and chloride in throughfall using ion-exchange resins.Water, Air and Soil Pollution.

Weathers, K.C., S.M. Simkin, G.M. Lovett, S.E. Lindberg,In prep,Hotspots of Deposition:Vegetation and Elevation Controls on Total Atmospheric Deposition in HeterogeneousLandscapes. To be submitted to Ecosystems.

9


10/23

Acknowledgments:

We are indebted to Kirsten Schwarz, Lala Chambers, Joe Beeler, and the staff at Acadia andGreat Smoky Mountains National Parks for their many contributions to this work. Current

funding to complete the project is via the National Park Service.

10


11/23

References Cited:

Anderson, J.B., R.E. Baumgardner, V.A. Mohnen, and J.J. Bowser. 1999. Cloud chemistry in the

eastern United States, as sampled from three high-elevation sites along the Appalachian

Mountains. Atmospheric Environment 33:5105-5114.

Driscoll, C.T., G.B. Lawrence, A.J. Bulger, T.J. Butler, C.S. Cronan, C. Eagar, K.F. Lambert,

G.E. Likens, J.L. Stoddard, and K.C. Weathers. 2001. Acidic deposition in the

northeastern United States: Sources and inputs, ecosystem effects, and managementstrategies. Bioscience 51:180-198.

Friedland, A.J., A.H. Johnson, and T.G. Siccama. 1984. Trace-metal content of the forest floorin the Green Mountains of Vermont - Spatial and temporal patterns. Water, Air, & Soil

Pollution 21:161-170.

Garten, C.T., E.A. Bondietta, and R.D. Lomax. 1988. Contribution of foliar leaching and dry

deposition to sulfate in net throughfall below deciduous trees. Atmospheric Environment22:1425-1432.

Graustein, W.C., and K.K. Turekian. 1989. The effects of forests and topography on the

deposition of sub-micrometer aerosols measured by lead-210 and cesium-137 in soils.

Agricultural and Forest Meteorology 47:199-220.

Johnson, A.H., T.G. Siccama, and A.J. Friedland. 1982. Spatial and temporal patterns of lead

accumulation in the forest floor in the northeastern United States. Journal ofEnvironmental Quality 11:577-580.

Johnson, D.W., and S.E. Lindberg (eds.). 1992. Atmospheric Deposition and Nutrient Cycling

in Forest Ecosystems. Springer-Verlag, New York.

Likens, G.E., F.H. Bormann, R.S. Pierce, J.S. Eaton, and N.M. Johnson. 1977. Biogeochemistry

of a Forested Ecosystem. Springer-Verlag, New York.

Lindberg, S.E. and C.T. Garten. 1988. Sources of sulfur in forest canopy throughfall. Nature336:148-151.

Lindberg, S.E., G.M. Lovett, D.D. Richter, and D.W. Johnson. 1986. Atmospheric depositionand canopy interactions of major ions in a forest. Science 231:141-145.

Lindberg, S.E. and G.M. Lovett 1992. Deposition and forest canopy interactions of airbornesulfur: results from the Integrated Forest Study. Atmospheric Environment 26A:1477-

1492.

Lindberg, S.E., and J.G. Owens. 1993. Throughfall studies of deposition to forest edges and

gaps in montane ecosystems. Biogeochemistry 19:173-194.

11


12/23

Lindberg, S.E. and R.R. Turner. 1988. Factors influencing atmospheric deposition, stream

export, and landscape accumulation of trace-metals in forested watersheds. Water, Air,& Soil Pollution 39:123-156.

Lovett, G.M. 1994. Atmospheric deposition of nutrients and pollutants to North America: An

ecological perspective. Ecological Applications 4:629-650.

Lovett, G.M., and J.D. Kinsman. 1990. Atmospheric pollutant deposition to high-elevation

ecosystems. Atmospheric Environment 24A:2767-2786.

Lovett, G.M. and S.E. Lindberg. 1993. Atmospheric deposition and canopy interactions of

nitrogen in forests. Canadian Journal of Forest Research 23:1603-1616.

Lovett, G.M., A.W. Thompson, J.B. Anderson, and J.J. Bowser. 1999. Elevational patterns of

sulfur deposition at a site in the Catskill Mountains, New York. AtmosphericEnvironment 33:617-624.

Miller, E.K., A.J. Friedland, E.A. Arons, V.A. Mohnen, J.J. Battles, J.A. Panek, J. Kadlecek, and

A.H. Johnson. 1993. Atmospheric deposition to forests along an elevational gradient atWhiteface Mountain, NY, USA. Atmospheric Environment Part A- General Topics.

27:2121-2136.

Ollinger, S.V., J.D. Aber, G.M. Lovett, S.E. Millham, R.G. Lathrop, and J.M. Ellis. 1993. A

spatial model of atmospheric deposition for the northeastern United States. Ecological

Applications 3:459-472.

Reiners, W.A., R.H. Marks, and P.M. Vitousek. 1975. Heavy metals in subalpine and alpinesoils of New Hampshire. Oikos 26:264-275.

Simkin, S.M., D. N. Lewis, G.M. Lovett and K. Schwarz.In press,Determination of sulfate, nitrate and chloride in throughfall using ion-exchange resins.

Water, Air and Soil Pollution.

Smith, W.H. and T.G. Siccama. 1981. The Hubbard Brook Ecosystem Study - biogeochemistryof lead in the northern hardwood forest. Journal of Environmental Quality 10:323-332.

Weathers, K.C., G.E. Likens, F.H. Bormann et al. 1986. A regional acidic cloud/fog event in theeastern United States. Nature 319:657-658.

Weathers, K.C., G.E. Likens, F.H. Bormann et al. 1988. Cloud water chemistry from ten sites inNorth America. Environmental Science and Technology 22:1018-1026.

Weathers, K.C., G.M. Lovett, and G.E. Likens. 1992. The influence of a forest edge on clouddeposition. Pages 1415-1423 inS. E. Schwarz and W. G. N. Slinn, editors. Precipitation

Scavenging and Atmosphere-Surface Exchange- Volume 3. Hemisphere Publ. Co.,

Washington, D.C.

12


13/23

Weathers, K. C., G. M. Lovett, and G. E. Likens. 1995. Cloud water deposition to a spruceforest edge. Atmospheric Environment 29:665-672.

Weathers, K.C., G.M. Lovett, G.E. Likens, and R. Lathrop. 2000. The effect of landscape

features on deposition to Hunter Mountain, Catskill Mountains, New York. EcologicalApplications 10:528-540.

Weathers, K.C., M.L. Cadenasso, and S.T.A. Pickett. 2001. Forest edges as nutrient andpollutant concentrators: Potential synergisms between fragmentation, forest canopies,

and the atmosphere. Conservation Biology 15:1506-1514.

13


14/23

Table 1:Comparisonof percent land coverage in various landscape features thought to control

deposition for Great Smoky Mountain National Park (Park), the region of the Park sampled forthis project ("Sampled Swath"; see also Fig. 2), and the landscape features measured at sampling

points (Sam. Loc.).

Park Sampled Swath Sam. Loc.

Vegetation Type

Percent (%)

Conifer 13 11 34

Decid 82 87 66Other 5 3 0

Elevation (meters)

0-500 4 1 3501-1000 45 39 44

1001-1500 42 48 191501-2000 9 12 33

2001-2500 0.01 0.01


15/23

Table 2: Comparison of percent land coverage in various landscape features thought to control

deposition for Mount Desert Island (MDI), Acadia National Park (Park; a subset of MDI) and thesampling locations for this project (Sam. Loc.; see also Fig 3).

MDI Park Sam. Loc.

Vegetation TypePercent (%)

Conifer 31 30 60Decid 41 53 40

Other 28 18


16/23

Figure1:Locationofstudylocations

:AcadiaNationalPark(AC

AD),MEandGreatSmoky

Mountain

NationalPark(GRSM),TN,

NC(Weathersetal.,inprep).

16


17/23

Figure2:LocationofforestfloorsamplingatGRSM(Weathersetal.,inprep).

17


18/23

Figure3:Locationofthrough

fallcollectionssitesatACAD(Weathersetal.,inprep

).

18


19/23

Figure4:Throughfallresin

collectorusedinthisstud

y(Simkinetal.,inpress).

19


20/23

012345

wet

Monitoringsite

(160m)

thro

ughfall

Sulfur

kg/ha/103dayperiod

Figure5:Sulfurfluxes(kg/ha/10

3-dayperiod)atACADatlo

w(160m)andhigh(413m)

eleva

tionlocationsforwatercollectedintheopen(bulk)andundertheforestcanopy

(throughfall)(Weathersetal,inprep).

20


21/23

Figu

re6:DistributionofPbconcentrationinforestfloors

amplesthroughoutGRSM

sam

plingarea.Largerbubbles

=higherconcentrations(Weathersetal.,inprep).

21


22/23

Figure7:Distributionofsulfatefluxe

sinthroughfallthroughoutACADsamplingarea.Lar

ger

bubbles=

higherconcentrations(We

athersetal.,inprep).

22


23/23

23

Figur

e8:Preliminarydeposition

mapforGRSMshowing"h

ot"(red)and"cooler"(gre

en)

spots

ofdeposition.(Weathersetal.,inprep.).

(weathers, 2003)atmospheric deposition in mountainous terrain

Documents