Ecological Questions. An International Journal on Controversial Problems of Ecology. 9/2008

Foreword
At present, biocoenoses of extreme habitats form a broad spectrum from natural polar ecosystems to anthropogenic agrocoenoses or ruderal communities developing on habitats extremely degraded by industry. The common and still increasing human pressure on already rare natural ecosystems causes that most of the ecological processes take place in the disturbed conditions. Such conditions are often tantamount to extreme conditions.
The subsequent volume of Ecological Questions includes fourteen papers dedicated to diverse issues concerning the functioning of biocoenoses in extreme habitats. Although the issues presented here do not deal exhaustively with the extensive problems of the subject, they provide however some interesting illustrations, out of which a consistent picture emerges, depicting the adaptation of the structure of biocoenoses at different organization levels to natural and anthropogenic extreme conditions. A significant element of this adaptation, emerging out of the presented material, is the fact that the extent of disturbance determines a level of organization at which its effects are discernible. And thus, depending on the extent of changes in the availability of resources or physical elements of the environment, we can observe adaptations from the cell level to changes in the species structure of a biocoenosis.
As a consequence of increasing anthropopressure, on the one hand, biocoenoses of extreme habitats become peculiar ecosystems of the future, and on the other hand, by studying them we can identify the principles and regularities of the man-ecosystem system. These principles also constitute a chance for the development of theoretical bases for the conservation and management of natural environment.

Balcerkiewicz S., Pawlak G., Formation and persistence of plant communities under extreme conditions - selected aspects /9
Ulrich W., Species abundance distributions in space and time /15
Zalewski M, Ulrich W., Local and regional interspecific abundance - body weight relationships of ground beetles/ 21
Zubel P., Gugnacka-Fiedor W., Rusinek A., Barcikowski A., Different faces of polar habitats extremity observed from the angle of arctic tundra plant communities (West Spitsbergen) /25
Zmudczyńska K., Zwolicki A., Barcikowski M., Iliszko L, Stempniewicz L., Variability of individual biomass and leaf size of Saxifraga nivalis L. along a transect between seabirds colony and sea in Hurnsund, Spitsbergen /37
Giełwanowska L, Bochenek A., Lord P., Anatomical responses of Colobanthus quitensis (Kunth) Bartl.and Deschampsia antarctica Desv. to abiotic stress factors /45
Leśniański G., Lichens from pyrite Schist Mines in the Wielka Kopa Massif (Rudawy Janowickie, Western Sudety Mountains) /57
Karg J., Słowik J., Dulamsuren Ch., Mühlenberg M., Above-ground insect communities in the forest-steppe zone of northern Mongolia /63
Koprowski M., Zielski A., Extremely narrow and wide tree rings in the Norway spruce (Picea abies (L.) Karst.) of Bialowieza National Park /73
Hutorowicz A., Hutorowicz J., Seasonal development of Vallisneria spiralis L. in a heated lake /79
Załuski T., Gawenda-Kempczyńska D., Paszek L, Rapacka-Gacowska A., Formation of flora and vegetation on the emerging lake bed of the Rakutowieckie Lake /87
Sawilska A. K., Dynamics of Helichrysum arenarium (L.) Moench populations growing in fallow field on barren soil /93
Wolnomiejski N., Woźniczka A., A drastic reduction in abundance of Dreissena polymorpha Pall, in the Skoszewska Cove (Szczecin Lagoon, River Odra estuary): effects in the population and
habitat /103
Jonczak J., Czarnecki A., Risk assessment for biomass plantations planning on marginal soils as an effect on increasing frequency of weather extreme events /113

Marian Rejewski