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The objective of the study was to evaluate the impact of nitrogen fertilizer industry pollution on epiphytic lichen communities. The study plots are located in Scots pine Pinus sylvestris stands at different distances (up to 12 km) to the northeast and southwest of the nitrogen fertilizer producer plant in central Lithuania. The stands were semi-mature and mature and growing on sandy sites of the Vaccinio-myrtillosa site type. Species richness, composition and index of atmospheric purity (IAP) were assessed at each site. Species diversity was calculated by grouping species by their ecological values for eutrophication. Species frequency was calculated according to lichen life strategies (growth forms, photobionts, reproductive strategies). Twenty lichens species were recorded in the surrounding of the pollution source. An increase in species richness and diversity was found with increasing the distance up to 10 km from the plant. Based on IAP values three zones (< 5, 5–10, > 10 km) with different air pollution were distinguished. The increase in species richness was related to the increase in eutrophication-tolerating species along with sensitive to pollution species. The lichen diversity value of nitrophytic species (LDVnitro) increased with increasing distance from the pollution source. Foliose and fruticose growth forms were both positively significantly related with the distance, being common in the plots with lower level of pollution. Crustose lichens are less sensitive to this factor and the prevalence of crustose thalli was found in the nearest vicinity to the plant.
The aim of our study was to investigate the response in timing of phenological events and the duration of the growing season to climate warming for three deciduous tree species: birch, lime, and maple. The most significant advancement in phenological spring (leaf unfolding) – 14.3 days through the investigated 1956- 2009 period – was detected in the case of the early-season pioneer species birch. A shift in leaf unfolding for other two late season species, maple and lime, was less expressed and consisted of 9 days through the investigated period. The changes in timing of phenological autumn were detected to be even more species specific and it was delayed by almost 16 days for maple, 12 days for lime and, in contrast, leaf fall advanced by 12 days was detected for birch. The occurrence of leaf unfolding best correlated with March and April temperatures. A statistically significant correlation of leaf unfolding with January temperatures was characteristic of early-season species – birch. The relationship between timing in leaf fall and temperature was much weaker and in most cases statistically insignificant. The growing season for maple and lime was extended by 25.4 and 21.5 days, respectively, through the study period. The length of the growing season of birch did not experience any statistically significant changes and the entire growing period shifted earlier by almost two weeks during the investigated period.
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