Determinants of occurrence of epiphytic mosses in the urban environment; a case study from Katowice city (S Poland)

Katowice is the largest city within the Upper Silesian Industrial District (S Poland). The investtigation conducted in this town earlier (1998-2000) showed limited number of epiphytic species. Recent study showed significant increase in number of localities of obligate epiphytes (mainly from the genera Orthotrichum and Ulota). They colonize mainly the edges of strongly urbanized areas bordering forest complexes and larger parks. This paper is an attempt to answer the question as currently in Katowice shape the main factors determining the occurrence of epiphytes. Crucial factors which govern epiphytes colonization processes in urban areas have been confirmed: bark chemistry (taking into account natural attributes and the influence of pollution) and air humidity. The preference of epiphytes towards inhabited phorophytes was confirmed as well. The most commonly and abundantly inhabited species were poplar and willow trees (which have a higher pH of bark).

Environmental quality assessment of the drainage basin of Lake Engure using Scots pine as a bioindicator

Environmental quality assessment of the drainage basin of Lake Engure using Scots pine as a bioindicator Environmental quality assessment of the Lake Engure drainage area, which is the LT(S)ER region of the Latvian National Long-term Ecological Research network (Latvia LTER), was conducted using three bioindication methods based on Scots pine Pinus sylvestris L.: unspecific bioindication by pine needle tip necrosis, ground level ozone assessment by pine needle chlorotic mottling, and chemical analysis of pine bark. Samples were collected from 40 sites of the region in November 2010. Extent of needle tip necroses did not exceed class 4 (maximum possible value 6). The highest value of index of needle damage by ozone was Idam = 1.62 (maximum possible value 6). Multiple regression analysis of variables describing bark chemistry and needle damage in relation to distance from the sea, nearest roads and villages was performed. Pine bark acidity pH(KCl) and concentration of Mg and Fe decreased significantly (βpH(KCl) = -0.672, P < 0.001; βMg = -0.676, P < 0.001; βFe = -0.514, P < 0.001) with distance of sample site from gravel roads. Electric conductivity (EC) of pine bark and the extent of ozone damage of the first year needles Idam significantly decreased with distance from the sea (βozone = -0.507, P < 0.01; βEC = -0.453, P < 0.01). PCA of the pine bark chemistry data showed dust pollution from gravel roads to be the main factor responsible for the 33% variation of data. No statistically significant correlations were found between different bioindicator characteristics, except between first and second year ozone damage (ρ = 0.589, P = 0.01).

Spatial distribution of lichens on twigs in remote Siberian silver fir forests indicates changing atmospheric conditions

The distribution of different ecological groups of lichens (acidophytes, ‘nitrophytes’, indifferent species) was compared on 1–24 year-old twigs of Abies sibirica sampled in the ‘pristine’ West Sayan and the polluted East Sayan Mountains (Krasnoyarsk District, South Siberia, Russia) to test their value as indicators of current pollution effects. Bark pH of twigs and bark chemistry (N, S, Ca, Mg, Al, Fe) were measured, and a preliminary estimate of emissions in the Krasnoyarsk District from livestock animal populations was calculated. In both regions, an unusually high twig bark pH and an abnormal species composition for A. sibirica canopy were found (e.g. Physcia aipolia, P. dubia, P. tenella, Phaeophyscia sp., Melanelia exasperatula and Candelariella vitellina), with P. tenella (East Sayan) and M. exasperatula (West Sayan) as dominants. The results confirm that the distribution of lichen species on Abies sibirica twigs is a valuable indicator of current changes in atmospheric conditions.

Using 13C nuclear magnetic resonance spectroscopy for the study of northern hardwood tissues

Nuclear magnetic resonance (NMR) spectroscopy is a useful tool for examining the structural chemistry of natural organic matter. The use of cross-polarization and magic-angle spinning to study 13C functionality (CPMAS 13C NMR) is convenient, but not always quantitative. We used various 13C NMR techniques to examine the structural chemistry of bark and wood of sugar maple (Acer saccharum Marsh.), American beech (Fagus grandifolia Ehrh.), and yellow birch (Betula alleghaniensis Britt.). Spin counting experiments showed that 87%–97% of the 13C in the samples was observable by CPMAS 13C NMR. A comparison of CPMAS and Bloch decay experiments revealed few differences in spectral properties. Together, these results suggest that CPMAS 13C NMR is quantitative for these tissues. We observed little variation in the structural chemistry of wood, either among samples of the same species or among species. Within-species variations in bark chemistry were greater than in wood, probably because of variations in environmental conditions. However, we observed no significant differences in bark chemistry among the species. Bark and wood chemistry differed significantly, with the bark spectra displaying greater contributions from lignin, suberin, waxes, and resins. Hardwood spectra differ from softwood spectra in the aromatic C regions because of the contribution of syringyl units to hardwood lignin. Hardwood bark appears to contain less tannins than softwood bark. Together, the quantitative and qualitative features of CPMAS 13C NMR spectra are useful for studying the ecology of living and detrital wood and bark.

A transplant experiment on the factors preventing lichen colonization of oak bark in southeast England under declining SO2 pollution

To investigate the factors responsible for limited lichen recolonization on oak with declining SO2 concentrations, Parmelia caperata (L.) Ach. and Parmelia saxatilis (L.) Ach. were transplanted to five stations along a transect running from central London (U.K.) into the surrounding countryside. Healthy thalli were transplanted onto young and mature Quercus robur L. (pedunculate oak) and Betula pendula Roth (silver birch), and some were moved with their original bark attached to investigate the importance of bark acidification. Relative growth rates and visible injury were monitored over 2 years, along with concentrations of atmospheric SO2 and NO2, measured using diffusion tube samplers and bark chemistry. SO2 concentrations were low in central London in comparison with the situation in previous decades, but they remain sufficiently high to harm the most sensitive lichens. NO2 concentrations increased sharply on approaching London, and levels were higher in winter than in summer. Bark pH was lower in mature oak than in birch or young oak at the two innermost stations, and levels of bark Mg also declined in London. Transplants of P. caperata survived on birch and young oak at all transect stations except Hyde Park, whereas P. saxatilis failed to grow over a wider range of the transect stations. We conclude that modest SO2 levels, interacting with low bark pH, still inhibit recolonization of oaks by P. caperata in central London. Parmelia saxatilis, in addition, appears to be limited by another factor such as the high NO2 concentrations that now characterize urban and suburban London, rather than through an inherently poor dispersal potential.Key words: atmospheric pollution, bark acidification, epiphytic lichens, NO2, recolonization, SO2.

The significance of stemflow chemistry for epiphytic lichen diversity in a dieback-affected spruce forest on Mt Brocken, northern Germany

Epiphytic lichen diversity in a boggy stand of Norway spruce (Picea abies) was studied in the eastern Harz Mountains, northern Germany. Spruce trees at wet sites were affected by forest dieback, whereas trees on drier sites remained unaffected. Lichen diversity was higher on diebackaffected trees than on healthy ones. The foliose lichen Hypogymnia physodes was significantly more frequent on dead trees, whereas the crustose, extremely toxitolerant Lecanora conizaeoides occurred more frequently on healthy trees. Stemflow concentrations of NH⊂4⊃+, NO⊂3⊃-, PO⊂3⊃-, and SO⊂4⊃2- were lower on affected trees. This is attributed to reduced interception from the atmosphere due to needle loss. Cover of H. physodes decreased with increasing mean SO⊂4⊃2- concentration in stemflow. The total of lichen species per sample tree also decreased with increasing SO⊂4⊃2- concentration in stemflow, indicating that most species reacted in a similar way as H. physodes. Cover of L. conizaeoides increased with increasing SO⊂4⊂2- concentration, but decreased at higher SO⊂4⊃2- concentrations. Bark chemistry had a minor influence on lichen diversity.

Variation in the root bark phenolics/sugar ratio of Douglas-fir grown in two plantations in northern Idaho

Several studies have linked high phenolics/sugar ratios in the inner root bark tissue of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to decreased susceptibility to Armillaria spp. While these studies have identified environmental factors that influence root chemistry, none have examined whether the phenolics/sugar ratio is genetically controlled. In this study, we investigated the effects of genetics and environment on the root bark chemistry of 20 families of 15-year-old Douglas-fir planted in two sites in northern Idaho. Only sugar concentrations varied significantly among families, but site was a significant source of variation for phenolics and the phenolics/sugar ratio. Family × site interactions were significant for the concentrations of all measured root bark compounds as well as for the phenolics/sugar ratio. Phenotypic correlations between height and the phenolics/sugar ratio and between height and sugar concentrations were not significant. However, families with superior height growth and below-average sugar concentrations could be found at both sites. Should a high phenolics/sugar ratio prove effective in selecting genotypes for resistance to Armillaria infection, these results suggest that gains could be made more efficiently by selecting for low sugar concentrations.