BIOCLIMATIC REQUIREMENTS OF QUERCUS VULCANICA BOISS ET HELDR. EX KOTSCHY AN ENDEMIC SPECIES IN TURKEY
There are 18 Quercus species in Turkey, and Quercus vulcanica, called "Kasnak oak" in Turkish, is an endemic species. The Kas- nak oak has been studied in three localities where the well formed communities of this species exist. The evaluation of bioclimatic tolerance ranges of Kasnak oak in Turkey was the aim of the study. Overall results support that Kasnak oak prefers humid conditions in ambient habitat.
Studies of processes connected with various Phanerozoic mass extinctions suggest that although these events differ in details from each other, they manifest certain global mutual similarities. There is a number of detailed data on the mass extinction phases but only scarce information on the survival and recovery intervals directly following the crises. In connection with the biota crises studies also the problem of refugia started to be discussed very intensively, because namely fossil refugia can contain fossils representing important connecting links getting over boundaries of mass extinctions. The aim of this article is to join some general considerations of possible refugia structures, functions and spatial and temporal changes to the discussion being in progress.