Sharon Eversman

Vertical distribution of epiphytic lichens on three tree species in Yellowstone National Park

Twelve species of lichens were recorded as epiphytes on the trunks of Pinus contorta Dougl., P. albicaulis Englm. and Abies lasiocarpa (Hook.) Nutt. in the lodgepole pine zone of Yellowstone National Park. All 12 species were on A. lasiocarpa; nine were on P. albicaulis, and five were on P. contorta. The most frequent lichen species were Lecanora piniperda Korb., Parmelia exasperatula Nyl., and Bryoria lanestris (Ach.) Brodo & Hawksw. Lichens were most frequent more than two meters above the ground.

Patterns of Lichen Diversity in Yellowstone National Park

Abstract We here report 359 species in 103 genera from Yellowstone National Park. We found 71.3% of the total number of species in Picea engelmannii forests and 57.4% of the total number in Pseudotsuga menziesii stands. This compares to 42.3% of the species in Pinus contorta and 37.0% of the species in Pinus contorta/Pinus albicaulis stands. The presence of old Pseudotsuga menziesii and mature Picea engelmannii indicates that the forests have not burned for at least 300 yr, contributing to higher lichen diversity. The drier lodgepole pine and whitebark pine forests burn more frequently than every 300 yr and have fewer microhabitats for lichen growth. Species with thalli large enough to identify are beginning to recolonize substrates burned in the 1988 fires. Bryoria fremontii and Letharia vulpina exhibit levels of mercury and sulfur higher than those in other specimens in the region.

Effects of low-level SO/sub 2/ on Usnes hirta and Parmelia chlorachroa

Respiration rates of Usnea hirta (L.) Wigg. and Parmelia chloro- chroa Tuck. exposed in the field to SO, fumigation decreased significantly, compared to control rates, within 30 days at 94 ppb SO2 and within 60 days at 33 ppb. Nearly 100% of the algal cells were plasmolyzed within 60 days. The respiration rates of P. chlorochroa samples were not significantly different from those of control samples after 60 days of exposure to 18 ppb SO2. The respiration rates of U. hirta samples were significantly less than those of con- trol samples after 96 days of exposure to 18 ppb SO2. A significantly greater percentage of the algal cells were plasmolyzed in U. hirta and P. chlorochroa, compared to control samples, after 31 days of exposure to 18 ppb. Damage to the lichens was more obvious and occurred faster than damage to adjacent vascular vegetation. It has been noted for over a hundred years that epiphytes, particularly bryophytes and fruticose and foliose lichens, disappear from polluted urban and industrial areas. Laboratory tests confirm that SO2 can produce pathological symptoms that adequately

Epiphytic Lichens of a Ponderosa Pine Forest in Southeastern Montana

Nineteen lichen species were collected from Pinus ponderosa Dougl. in Custer National Forest in southeastern Montana; 340 trees in four vegetation types were sampled. The dominant lichen species at all heights of the trunks and on lower branches was Usnea hirta (L.) Wigg., constituting 31-74% of total lichen cover. The percentage of U. hirta was highest in the driest vegetation type (P. ponderosa-Agropyron spicatum) and lowest in the most moist vegetation type (P. ponderosa-Prunus virginiana). The majority of lichen cover and diversity on tree trunks was on the lowest 50 cm; diversity and cover increased with ascending moisture levels. Parmeliopsis ambigua (Wulf.) Nyl., Bryoria fuscescens (Gyeln.) Brodo & D. Hawksw., and Cetraria pinastri (Scop.) S. Gray increased most sub- stantially from drier to wetter sites. Most of the lichen species found in this forest type are regular components of Rocky Mountain and/or northern coniferous forests. Other conifer forest types in the Rocky Mountains and Black Hills support richer lichen floras. Because epiphytic lichens are largely dependent on atmospheric sources of water and nutrients for their survival, the study of the composition of lichen communities may fre- quently be used to document changes in atmospheric conditions (Barkman 1969). In this capacity, lichen studies have frequently been useful in documenting air quality as reflected by variation in air pollutant levels (Hawksworth 1971; Nash 1976). The high plains of Wyoming and eastern Montana contain extensive coal fields that are currently and in the upcoming decades will be a major energy source for the United States. The potential for air quality degradation due to emissions from coal-fired power-generating plants is con- siderable, and consequently knowledge of the regions lichen flora is of interest. Although much of the region is dominated by short-grass prairies, both scattered-open and extensive- dense stands of ponderosa pine (Pinus ponderosa Dougl.) do occur in the region. To the best of my knowledge, the current study is the first report on quantitative variation in epiphytic lichens of the region. The epiphytic lichen flora of most of Montana is relatively poorly known. The majority of collections have been from the diverse and extensive conifer forests of the northwest portion of the state (Habeck 1963; McCune 1979). Imshaug (1950) collected alpine lichens in Glacier National Park and one western county. A preliminary distributional study of epiphytic lichens compared presence of those species in various areas of Montana (Ev- ersman 1979). The epiphytic lichens of Pinus ponderosa, the only conifer species in southeastern Montana forests, have not been studied. Gough (1975) described the epiphytic communities of Pseudotsuga menziesii (Mirbel) France and Abies lasiocarpa (Hook.) Nutt. in Colorado, 1100 km to the south of this study area. Wetmore (1967) made a floristic study of the Black Hills, 160 km to the east, where the primary coniferous species are P. ponderosa on 007-2745/82/204-213

Isolation of protoplasts from loblolly pine needles and their flow-cytometric analysis for air pollution effects

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Ultrastructural effects of peroxyacetyl nitrate (PAN) on two lichen species

Abstract Flow-cytometric analysis was used for the first time to determine the effects of air pollutants on plant biochemistry. The methods used were exploratory, but the results indicate that the technique is a valuable tool for researchers interested in the effects of air pollutants on vegetation. Evidence of carryover effects was seen in protoplasts isolated from new needles of 2-year-old loblolly pines ( Pinus taeda L.) which had been treated with ozone and simulated acidic rain the preceding year. Overall, staining of the protoplasts with constituent-specific fluorescent dyes showed decreased levels of fluorescence for esterase activity, protein, neutral lipids, and RNA in the ozone-treated samples compared with the charcoal-filtered or ambient samples. However, within pollutant treatments, low-level shifts in biochemistry were seen; for instance, simulated acidic rain at pH 5.0 ameliorated the effects of ozone on neutral lipids and RNA, and at pH 4.3 ameliorated the effects of ozone on protein. This research provides evidence at the biochemical level that pollutant treatments given in one year may be reflected in the succeeding years growth. Image analysis of cross sections of fresh young pine needles supported the biochemical data.

Flow cytometric measurement of pollutant stresses on algal cells

Samples of Hypogymnia enteromorpha (Ach.) Nyl. and Parmelia sulcata Tayl. were fumigated with peroxyacetyl nitrate (PAN) for 28 hours in seven days at 100 ppb and 32 hours in eight days at 50 ppb. Photosynthesis rates decreased in both species, with more decrease in P. sulcata than in H. enteromorpha. Analysis of transmission electronmicrographs revealed abnor- mally high accumulation of starch in the chloroplasts of both lichen species and slight decreases in amount of pyrenoid area. Anticipated significant deterioration and disappearance of thylakoid membranes did not occur. Peroxyacetyl nitrate (PAN) is an air pollutant characteristic of southern California. It is formed