Lichen Biomass Research Articles

Patterns of Distribution and Abundance of Corticolous Lichens and Their Invertebrate Associates on Quercus rubra in Maine

Patterns of Distribution and Abundance of Corticolous Lichens and Their Invertebrate Associates on Quercus rubra in Maine

Vegetation Recovery Patterns following Overgrazing by Reindeer on St. Matthew Island

Heavy grazing by extremely high densities of reindeer (Rangifer tarandus) on St. Matthew Island in the Bering Sea resulted in degradation of the lichen stands. Grasses, sedges, and other vascular plants initially increased in response to the removal of lichens under heavy grazing pressure by the reindeer. Twenty-two years following the crash die-off of the reindeer, mosses had invaded large portions of the ground area denuded of lichens, and lichens had recovered to only 10% of the standing crop of living lichen biomass occurring on adjacent Hall Island where there is no history of grazing. Lichen species dominating the recovering lichen stands on St. Matthew Island were those of relatively low preference as forage by reindeer in contrast to those in climax lichen

Photosynthetic Patterns of Sonoran Desert Lichens I. Environmental Considerations and Preliminary Field Measurements

Summary In comparison to the Negev Desert environment, where extensive desert lichen photosynthetic and productivity studies have been conducted, the environment of the interior Sonoran Desert at Phoenix, Arizona, is shown to be much less favorable for lichen photosynthetic activity. Lack of dewfall events is inferred to be the major difference, as the estimated dewfall frequency of 12 d per year is only 6 % of the number of days when dewfall occurs at Avdat, Israel. Favorable moisture periods for lichen photosynthesis are shown to be largely restricted to the winter period when temperatures are cool. The occurrence of dewfall and periods with low vapor pressure deficits is generally coupled with the occurrence of winter rainfall periods. Fog, a factor responsible for luxuriant lichen communities in some maritime, arid environments, is shown to be almost non-existent at Phoenix. Preliminary photosynthetic measurements over 28 d confirmed that days with photosynthetic activity are tightly coupled with precipitation events. Moisture conditions favorable for photosynthetic activity may persist for a day or two after precipitation events. Because of the marked differences in moisture conditions and in lichen biomass estimates between the Negev and the interior Sonoran Desert, it is inferred that lichen productivity must be much lower at the Sonoran Desert site.

The effects of climatic pattern on lichen productivity: Cetraria cucullata (Bell.) Ach. in the arctic tundra of northern Alaska.

The climatic control of productivity for two populations of the lichen Cetraria cucullata (Bell.) Ach. growing in the arctic tundra of northern Alaska (70°28'N, 157°23'W) was examined. Respiratory losses of carbon vary with tissue temperature, tissue water content, and time since wetting. Potential net photosynthetic gains of carbon are affected by photon flux density, tissue temperature, and water content. The net CO2 exchange responses of populations growing on ridge tundra and on upland tundra differ and these differences reflect possible adaptation to the normal environmental regimes in the two habitats. Simulation of the lichen's net carbon balance using continuous hourly records of photon flux density, temperature, and water content for the unusually dry period June 28 through July 17, 1977 show that lichen biomass is actually lost during climatic regimes leading to frequent but short periods of lichen metabolic activity. This result is confirmed by the negative relative growth rates measured for C. cucullata over the same monitoring period. This observed loss of biomass may be attributable to depletion of carbon reserves to reactivate dormant metabolism without sufficiently long periods favorable for net photosynthetic activity to replenish the lost reserves. These results illustrate that environmental limits exist on the success of the dormancy strategy characteristic of lichen and moss carbon metabolism.

Dimension analysis of various components of black spruce in subarctic lichen woodland

Parabolic and logarithmic regressions were used to relate tree diameter to the biomass of root, root crown, bole, branch, needle, cone, and epiphytic lichens for a sample of 15 Piceamariana (Mill) trees occupying lichen woodland in the subarctic of eastern Canada. In 22 of 27 regressions both models yielded r2 values >0.82. Biomass estimates of total tree and individual component dry weights resulted in estimates with less than 6.5% difference between biomass estimates by logarithmic versus parabolic equations. For this data set the logarithmic model appeared more appropriate than the parabolic form. Validity of the regressions was judged on r2, analysis of variance, and examination of residuals. Equations generated in this study were considered to be inapplicable to P. mariana growing in closed forest. Problems in extrapolation were discussed.

Structure and Biomass Dynamics of Epiphytic Lichen Communities of Balsam Fir Forests in New Hampshire

Changes in species composition, cover, biomass, and elemental pools in space and time were determined for epiphytic lichens associated with balsam fir (Abies balsamea [L.] Mill.) forests on Mt. Moosilauke, New Hampshire, USA. Thirty—three species of epiphytic lichens were present; none was able to fix atmospheric nitrogen. Between 45 and 94% of the total lichen flora occurred in any given stand. Hypogymnia physodes, H. krogii, Bacidia chlorococca, Platismatia glauca, Hypotrachyna revoluta, and Parmelia saxatilis were the leading dominants in all stands and accounted for 74—93% of the bole cover. Each species exhibited an individualistic pattern of vertical distribution. Lichen cover was least in the lower part of the bole (<15%) and peaked in the mid— or top—canopy position (42—58%). Species richness, average percent bole cover, and epiphytic lichen biomass increased with stand age owing to change in stand structure. Lichen biomass ranged from 120 to 1603 kg/ha, with °80% of the biomass located on branches. Nitrogen and phosphorus concentrations increased with increasing canopy height, while no obvious trends were noted for calcium, magnesium, or potassium. Elemental pool sizes (average biomass multiplied by average lichen tissue concentration) were: 10.7 kg/ha for nitrogen, 3.34 for potassium, 1.26 for calcium, 1.20 for phosphorus, and 0.25 for magnesium. Epiphytic lichens contribute little (<1.0%) to biomass and elemental pool sizes within the balsam fir ecosystem.

Nitrogen Fixing Lichens in Forests of the Southern Appalachian Mountains of North Carolina

The abundance and species diversity of nitrogen fixing lichens were determined for several forests of the southern Appalachian Mountains of western North Carolina. Gray beech forests of wet, high-elevation beech gaps were aus- picious locations for these lichens. The bark of Aesculus octandra Marshal was the optimum habitat, particularly for the dominants Lobaria quercizans Michx. and Lobaria pulmonaria (L.) Hoffm. Lichen biomass in this gray beech forest commonly ranged from 7 to 9 kg ha-' but was higher where Aesculus octandra was abundant. Lichens were less abundant in oak forests and cove forests, and none was found on conifers. The annual contribution of ammonia nitrogen by lichens was roughly estimated to be 0.8 kg ha-' for the gray beech forest in beech gaps. The southern Appalachian Mountains are known for their scenic beauty, abundant rainfall and vegetation which is rich in community types and species diversity. Meteoro- logical records taken along the southern limits of the Blue Ridge escarpment and the adjoining mountain ranges indicate that annual precipitation commonly approaches or exceeds 200 cm yr-1. In the gorges along the Blue Ridge escarpment values exceeding 250 cm yr-1 occur with regularity (Cooper, 1963). Warm moist air from the south rises, as it moves from the flat Piedmont of Georgia and South Carolina, cools and loses this moisture as it proceeds into these mountainous areas. The combination of high rainfall and great diversity in habitats found in these old and geologically stable mountains has led to considerable complexity in the types of climax forests found there (Whittaker, 1956). Representatives of the northern boreal forests are found at high elevations, cove hardwood forests are common in many of the mesophytic locations, a variety of oak forests occupy the majority of the landscape and several other forest types are interspersed within these communities. From previous publications on the nitrogen fixing lichens it appears that there is an association between the abundance of these lichens and the moisture available to the lichen. In the arctic, where these lichens have been implicated as important contributors of reduced nitrogen (Kallio & Kallio, 1975; Schell & Alexander, 1973; Crittenden, 1975), moisture is not a limiting factor. In an investigation of the Colombian montane rain forest Forman (1975) estimated that the biomass of these lichens was 5.7 kg ha-1 and that the annual rates of nitrogen fixation were in the range of 1.5 to 8 kg N ha-'. In the tall Douglas fir forest of Oregon Denison (1973) reported a nitrogen fixing lichen biomass of 390 to 500 kg ha-'. Precipitation in the tropical rain forest is considered to be between 200 to 300 cm yr-' (Forman, 1975) and in the tall Douglas fir forest is greater than 200 cm yr-' (Zobel et al., 1976). These two forested areas, however, vary in the annual distribution of that

Bacterial ecology of an old-growth douglas fir canopy

Microbial populations associated with the major substrates of the canopy of a single 70 m old-growth Douglas fir were studied to determine potential activities. Seasonal samples from bark, foliage, epiphytic moss, lichens, and litter accumulations were collected to: (a) obtain population data, (b) isolate the major groups of microorganisms present, (c) measure enzymatic activities associated with cellulose and xylan degradation, and (d) examine the potential for nitrogen fixation. We tested 562 bacterial isolates for utilization of 25 compounds associated with the canopy substrates, and for activities in nitrogen and sulfur cycle transformations. Total bacterial populations, reflecting seasonal temperature and moisture conditions, were lowest on bark and foliage [21-266×10(3) colony-forming units (CFU/g)] and highest on moss and lodged litter (19-610×10(5) CFU/g). Lichens contained intermediate numbers of bacteria (3.3-270×10(5) CFU/g). The majority of the bacteria were classified as species ofArthrobacter, Bacillus, Flavobacterium, andXanthomonas. Isolates ofAlcaligenes (Achromobacter), Aeromonas, Chromobacterium, Micrococcus, andPseudomonas were less common. No measurable rates of nitrogen fixation attributable to free-living bacteria were detected by acetylene reduction. Eleven species in six genera of lichens containing a blue-green algal phycobiont showed positive acetylene reduction. One species,Lobaria oregana, accounted for 51% of the total lichen biomass of the canopy. Cellulase and xylanase activity was routinely detected in moss and litter samples, and less frequently in lichens. There was a strong correlation between the two activities for moss (r=0.94) and litter (r=0.81).

Discovering the Role of Lichens in the Nitrogen Cycle in Boreal-Arctic Ecosystems

Discovering the Role of Lichens in the Nitrogen Cycle in Boreal-Arctic Ecosystems

Ecological Relationships of Desert Fog Zone Lichens

Abstract. Patterns of environmental conditions prevailing in coastal desert fog zones provide habitats extremely favorable for lichen growth. Phylogenet- ically related groups of lichens occur in geographically isolated desert fog zones, but endemism at both the species and genus levels is relatively high. The ecological importance of lichens in these regions is related to morpholog- ical and physiological adaptations to water uptake in both a liquid and vapor form. Much of this moisture is unavailable to vascular plants, allowing a large biomass of lichens to occur in areas with little or no vascular plant cover. The relative importance of fruticose lichens in such habitats, in comparison to crustose and foliose forms, is determined largely by the physical form of at- mospheric moisture. Coastal deserts share many environmental features common to all deserts. Rainfall is low and vegetation is commonly sparse or lacking. At the same time, coastal deserts have certain distinctive characteristics not shared by inland deserts. Temperature differences between night and day are moderated by the proximity of the sea. More important for lichens, however, is the typical occurrence of high atmospheric humid- ity, fog and/or dew along the coast. Extensive coastal deserts occur in three areas of the world: the Peruvian and Chi- lean Atacama deserts, the coastal Sonoran Desert in Baja California and the Namib Desert in southwestern Africa. Each of these areas shares the same origin of climatic development in the movements of sub-tropical high pressure centers resulting in the transport and upwelling of cold currents adjacent to their coasts. Details of the general climatology of these regions has been described in many publications (e.g. Meigs, 1966; Rumney, 1968). Each of these coastal fog deserts is characterized by lichen floras rich in both diversity and biomass. This review describes the ecological and floristic relationships of lichens in these coastal fog deserts with particular emphasis on the coastal Atacama and Baja California regions. Coastal Atacama Desert.-The Atacama desert along the coasts of Peru and north- ern Chile, perhaps the driest region in the world in terms of measurable precipitation, extends from the region north of Trujillo near the Ecuadorian border of Peru (50?S) south to La Serena (30?S) in Chile, a total distance of more than 3500 km. Along this belt is a narrow strip of coastal desert whose biological characteristics are profoundly influenced by frequent maritime fogs. The cold northward flowing Humboldt current

Nitrogen Fixing Lichen Roles from Desert to Alpine in the Sangre de Cristo Mountains, New Mexico

Nitrogen Fixing Lichen Roles from Desert to Alpine in the Sangre de Cristo Mountains, New Mexico

Lichen Biomass in Acadian and Boreal Forests of Cape Breton Island, Nova Scotia

Lichen Biomass in Acadian and Boreal Forests of Cape Breton Island, Nova Scotia

Vegetation Types and Plant Biomass in Tundra

An attempt is made to group tundra sites (including the moorland sites of Ireland and the United Kingdom) on the basis of percentage of woody plants, forbs, and monocotyledons related to the total vascular aboveground living biomass, and the percentage of vascular plants, bryophytes, and lichens related to the total aboveground living biomass. The dominating species at several sites, mostly IBP tundra sites, are mentioned, and for the Scandinavian sites an attempt is made to classify the sites according to a joint Scandinavian IBP proposed vegetation classification.The living plant biomass of above- and belowground vascular plants is shown for some tundra sites as well as the living biomass of bryophytes and lichens when measured. The ratio of aboveground: belowground parts is calculated. A higher proportion of belowground biomass is found worldwide at sedge dominated wet sites with slow decomposition of belowground parts.

Vegetation Types and Plant Biomass in Tundra

An attempt is made to group tundra sites (including the moorland sites of Ireland and the United Kingdom) on the basis of percentage of woody plants, forbs, and monocotyledons related to the total vascular aboveground living biomass, and the percentage of vascular plants, bryophytes, and lichens related to the total aboveground living biomass. The dominating species at several sites, mostly IBP tundra sites, are mentioned, and for the Scandinavian sites an attempt is made to classify the sites according to a joint Scandinavian IBP proposed vegetation classification.The living plant biomass of above- and belowground vascular plants is shown for some tundra sites as well as the living biomass of bryophytes and lichens when measured. The ratio of aboveground: belowground parts is calculated. A higher proportion of belowground biomass is found worldwide at sedge dominated wet sites with slow decomposition of belowground parts.