No abstract

The distribution of biomes on land is characterized by altitudinal zonality, which is explained by the fact that the amount of incident solar radiation decreases from the equator to the poles (Chernov, 1975). However, there are many other factors that influence the formation of terrestrial biocenoses and that are responsible for their marked heterogeneity, such as specific combinations of heat and moisture gradients on continents, the orientation of large mountain ranges, and some historical factors (Chernov and Penev, 1993). Analysis of the causes of the spatial heterogeneity of biocenoses is among the most complex tasks in modern ecology. Islands are convenient model objects for a broad spectrum of studies in different fields, from synecological and biogeographic to evolutionary. Insular biocenoses of high northern latitudes have been studied fragmentarily: on the one hand, access to northern islands is difficult; on the other hand, researchers have always been more interested in investigating tropical islands. This is also true of the Solovetskiye Islands. This unique archipelago has been studied mainly from the historical and cultural aspects. It has the status of a national park, which is famous for its historical-architectural museum: its architectural ensemble is on the United Nations World Heritage List. Nevertheless, data on components of the natural environment of these islands are still fragmentary.In this study, we made an attempt to answer the controversial question as to why biocenoses characteristic of several natural zones have developed within the small area of the Solovetskiye Islands. MATERIAL AND METHODS Studies of vegetation.The distribution of biocenoses over the area of the archipelago was studied using images made by the Landsat 7 satellite in different regions of the spectrum (channels 3, 4, and 5) at a resolution of 30 m on June 21, 2000. They were synthesized into an integrated image, which was deciphered by means of cluster analysis in the i.cluster module of the GRASS 5.0.3 GIS program package.The results of deciphering were interpreted on the basis of materials obtained in the course of field studies on the islands (Fig. 1). Expeditions launched in 2001 and 2003 made concise geobotanical descriptions of biocenoses along their routes, including the identification of dominant plant species. In 2003, an additional 39 descriptions of forest phytocenoses in 10 × 10-m test plots were made on the Bol'shoi Solovetskii Island. Geographic coordinates of each plot were determined using a Garmin 3 Plus GPS receiver. A cluster analysis of the geobotanical descriptions for similarity in the species composition of the herb-dwarf shrub layer (the Czekanowski-Sørensen index) and interpretation of the resulting dendrogram allowed us to distinguish three groups of forest biocenoses that were close to the middle taiga, northern taiga, and subtundra biocenoses.These data were used to make a raster map of the plant cover of the Solovetskiye Islands, which was subAbstract -On the Solovetskiye Islands, subt...