Research of the climatic seasons of the annual cycle and its influence on the living components of peatland biogeocoenosis (by example of oligotrophic peatland in subtaiga of Western Siberia)

This work is devoted to the multipurpose study of features of the structure of natural climatic seasons and their influence on the seasonal development of higher vascular plants and testate amoebae communities in the bog microlandscape. The object of research is the oligotrophic afforestation peatland in the subtaiga subzone at the West Siberian Plain. The observations were carried out during two years: 2011 and 2012. Both of the years are different by climatic structure from the average long-term data, and from each other. If compared with the long-term average data of 1967-1997 the investigated years are characterized by a shorter cold and snowy part and a longer vegetation part in the structure of the annual cycle. The vegetation part of the annual cycle in 2011 was wet and normal by the temperature regime, and in 2012 it was very dry and very warm. Although the air temperature at the peatland is lower than at the nearest weather station the data revealed a high correlation of air temperature fluctuations. On this basis, it is concluded that in the bog microlandscape there are similar seasonal variations in climatic rhythms; and their time can be determined by the data of Tomsk weather station. Phenological changes of five species of shrubs and a species of herbaceous plants are studied in the peatland. It is shown that their seasonal development begins at the end of the spring season (florification and gemmation) and ends at the beginning of autumn (preparation for winter rest). The main phenological changes occur in the central phase of the summer season (moderately-warm summer phase): the growth of new shoots, fruit ripening. Differences in the climatic structure between the two investigated years appeared in the shift of the time of certain phenological stages of peatland shrubs. Testate amoebae communities were studied in the typical microsites of the peatland microrelief, in depressions between tussocks with sphagnum moss, one in 2011 and another - in 2012. Only the living cells of testate amoebae were taken into account: separate active and encysted. The number of live active cells of testate amoebae per 1g of absolutely dry matter of the substrate varies considerably during the vegetation part of the annual cycle, the number of peaks were observed in May, June and August. The values of the Shannon Index and evenness increased by the end of the vegetation part of the annual cycle. Species diversity varied slightly. The number of cysts increased a little in the spring season and increased sharply in the autumn months (September, October). Overall, the combination of high numbers of live active cells of testate amoebae and the high value of the index of species diversity in their community were observed at the end of the central phase of the summer season in the period of maximum heating of the peatland soil.

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