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Lichen sensitivity to air quality has been recognized in Europe for over 125 years: recently Federal agencies in this country have begun using lichens as air quality bioindicators. This study presents the results of three different approaches to air quality biomonitoring using lichens: (1) a lichen community analysis, (2) an elemental analysis of lichen tissue content, and (3) the growth of removable lichen transplants. The lichen community and elemental tissue content analyses were part of an air quality baseline on the Tongass National Forest in southeast Alaska. The lichen transplant experiment compared the growth of three different lichen species and evaluated and refined a transplant technique in western Oregon. Lichen communities were sampled on 50 Pinus contorta peatlands in southeast Alaska. These peatlands make good air quality biomonitoring sites because: (1) the trees are slow growing and provide stable substrates for lichen colonization; (2) many branches are at eye level, making the canopy epiphytes easily observable; (3) the scattered, open distribution of the trees allows for good air circulation on the sites; and (4) precipitation, light conditions, and relative humidity are high, which stimulate lichen growth. A total of 100 lichen species were encountered during whole-plot ocular surveys of each plot. Multivariate ordination revealed what appears to be a successional gradient represented by high cover of Bryoria species at older sites and high cover of Platismatia norvegica, P. glauca, Hypogymnia enteromorpha sens. lat. and H. inactiva at younger sites. A second pattern revealed by ordination analysis appears to be a climatic gradient with high Alectoria sarmentosa cover on moister, warmer sites, and high cover of Bryoria species on drier, colder sites. The first two gradients contained 35% and 21%, respectively, of the information in the analytical data set (cumulative r��=56%). Elemental tissue content of Alectoria sarmentosa was determined from 43 of the peatland plots in southeast Alaska. The range of values for 16 elements are reported and compared to other regional studies; the ranges of values for most elements were within normal background levels. Quality assurance techniques are described for separation of laboratory and field noise from elemental content signal. Principal components analysis was used to create three synthetic gradients of plot-level elemental content. The first three principal components captured 55% of the correlation structure among elements. Iron (r=-0.91), aluminum (r=-0.80) and chromium (r=-0.71) are all highly correlated with the first gradient. This gradient could represent sites enriched by elements from dirt; aluminum and iron silicates are both persistent and abundant components of weathered rock and soil. Potassium (r=-0.82), phosphorous (r=-0.63), zinc (r=-0.60), manganese (r=-0.58), magnesium (r=-0.51) and nickel (r=0.54) are correlated with the second gradient. Many of these elements are supplemented by salt water aerosols (Nieboer et al. 1978; Rhoades 1988). Lead (r=0.70) and cadmium (r=0.59) were correlated with the third axis. This gradients could represent enrichment from fossil fuel combustion. Recommendations for standardizing future regional studies of lichen elemental content are made. Removable lichen transplants were constructed using live thalli of known weight, a 5 cm length of nylon monofilament, silicone glue, and reusable attachment mechanisms. Transplants were returned to several sites in Western Oregon and were weighed every several months for 13 months. Reference standards for each species were used to correct for changes in lichen water content due to changes in lab humidity. Despite apparent vigor, Alectoria proved unsuitable for repeated weighings because of biomass loss due to fragmentation (average of 9% biomass loss). Growth of Evernia and Lobaria transplants differed both between species and between sites. Average growth over the 13 months for Evernia in the foothills and valley was 40% and 30% respectively; for Lobaria it was 16% and 15%. Differences in growth between species could be due to different: (1) growth rates; (2) sensitivities to air quality; (3) sensitivities to microhabitat; and (4) sensitivities to transplant trauma. Differences in growth between valley and foothill sites could be due to differences in: (1) micro- or macrohabitat conditions; and (2) air quality. / Graduation date: 1995

Pannes are rare intradunal wetlands. Though small, they are known to exhibit extremely diverse and sensitive vegetation and are home to a number of reptile and amphibian species. In the United States, pannes are known to occur only around the Great Lakes Basin and Cape Cod. At Indiana Dunes National Lakeshore, the fifteen known pannes have an unusually large variety of plant species for such a small geographic area and provide habitat for plant species found nowhere else in Indiana. However, these sensitive ecosystems have been exposed to over a century of atmospheric pollutants from the surrounding steel and coal industries. Since 1986, the native vegetation of the area is slowly being replaced by invasive species like Phragmites australis and Typha spp. This study attempts to explain the shift in vegetation. Pannes in two other locations, at a distance from the industrial complex, were used as control sites as they were not expected to be exposed to the same levels of heavy metal concentrations. Four of the fifteen pannes at the Indiana Dunes National Lakeshore, two of the four pannes at Sleeping Bear Dunes National Lakeshore, Michigan, and two of the three pannes at Warren Dunes State Park, Michigan, were studied, resulting in a total of eight pannes. The pannnes were stratified and sampled by hydroperiod. Surface soil samples and sediments at depth, were recovered from each of the pannes considered in this study and analyzed for heavy metal, phosphorus, carbon and nitrogen content. Results show that high levels of organic matter coupled with high nutrients and high metals, in the soil, are a combination that may be considered a risk factor for future invasion of pannes by invasive species. It appears to be difficult for the native vegetation to deal with the high metals and high nutrients which are deleterious to the native vegetation and facilitate establishment of invasive vegetation which is more tolerant to the altered geochemical conditions.

Graduation date: 2005

An existing individual tree growth and yield model (PT AEDA2) was modified study the potential effects of air pollution stress on the growth and yield of loblolly pine plantations. These modifications were based on the assumption that pollution stress on older trees could result in reductions in diameter and height growth, decreases in photosynthesis, and increased losses of older foliage, as demonstrated in some seedling studies. One modification applied differential levels of reductions of diameter and height increments to various percentages of trees. Results indicated no sizeable losses on total volume per acre except at severe stress levels (-32 and -64 percent annual diameter and height increments on 50 and 67 percent of the trees). Another modification consisted of developing a measure of photosynthetic potential to drive diameter and height growth in the model. This new measure was an estimate of foliage weight which was weighted by a factor of photosynthetic efficiency and needle retention for each age class of needles. Reductions of these weighting factors were applied to simulate air pollution stress. Results of this modification show that if air pollution does cause a decrease in photosynthesis and needle retention rates, the impact on over-all stand productivity is minimal. These results are not intended to be quantitative estimates of the effect of air pollution on tree growth but to identify potential areas within an existing growth and yield model where biologically-oriented processes to simulate air pollution impact can be incorporated. / Master of Science

Field surveys and biomonitoring network experiments were conducted in selected areas in South Africa to assess possible air pollution damage to vegetation. During field surveys, atmospheric fluoride was identified as an important pollutant that damaged vegetation in residential areas north of Cape Town. Gaseous air pollutants, including acid deposition and acidic mist, probably play a major role in the development of characteristic air pollution injury symptoms observed on pine trees in the Eastern Transvaal area. The impact of urban air pollution in the Cape Town area was evaluated by exposing bio-indicator plants in a network of eight biomonitoring network stations from June 1985 to May 1988. Sensitive Freesia and Gladiolus cultivars were used to biomonitor atmospheric fluoride, while a green bean cultivar was used as a biomonitor of atmospheric sulphur dioxide and ozone. At one location, bio-indicator plants were simultaneously exposed in a biomonitoring network station (plant cages), open-top chambers (filtered and unfiltered), as well as in open plots. The responses of plants grown under these different conditions were compared. During both the winter and summer seasons, ambient fluoride concentrations were estimated to be particularly high at the Loumar biomonitoring station (eastern side of Cape Town), as compared to that at the other biomonitoring stations. Elevated levels of atmospheric fluoride, as well as sulphur dioxide, appeared to prevail in the vicinity of industries located in the northern suburbs of Cape Town (Bothasig, Table View and Edgemead). Interveinal bleaching, which is characteristic of sulphur dioxide injury, was regularly observed on bean plants exposed at the Bothasig biomonitoring station and was usually determined to be significantly worse at this location than at the other biomonitoring stations. These results were confirmed by the evaluation of foliar sulphur content Ambient pollutant concentrations appeared to be effectively reduced inside filtered open-top chambers, as exemplified by higher biomass production and lower foliar fluoride and sulphur levels in the relevant bio-indicator species, compared to that of plants grown in the open plots. The methodology used during this research provided baseline data of the impact of air pollution on vegetation in South Africa which, in the absence of networks of sophisticated state of the art equipment, can be applied to aid in air pollution control strategies. / Ph. D.

No description available.