Ábrahám Levente (szerk.): Válogatott tanulmányok VII. - Natura Somogyiensis 22. (Kaposvár, 2012)
Salamon-Albert É.: Climatic conditions and habitats in Belső-Somogy, Külső-Somogy and Zselic as vegetation-based landscape regions III. Temperature envelopes of mesic deciduous woodlands
28 Natura Somogyiensis Thompson et al 2005, Attore et al. 2007, Thompson et al 2008). Requirements for small-scale studies are expressed by more and more authors continually (e.g. Lindner et al. 2010), but the conclusions derived from scientific results based on the studies have to be applied with caution. Quantifying distributions and determining which factors influence species or habitat range limits is an ongoing challenge for ecologists nowadays (Guisan and Thuiller 2005, Colwell and Rangel 2009). The studies of how objects vary in their requirements for and tolerance of environmental factors has advanced, in part due to the quantification of the ecological niche, continued the complementary concepts of the environmental and the trophic niche, serve as a basis for assessing the ecological and biogeo- graphical similarities and differences (Chase and Leibold 2003, Soberón 2007). Numerous variety of measures have been used to quantify distribution characteristics leading to construct the environmental niches and analyse their overlap (e.g. Schoener 1970, Colwell and Futuyma 1971, May and Arthur 1972, Fitzpatrick et al. 2008; Peterson and Nakazawa 2008). In recent studies differences in niches that are quantified using observed occurrences of objects can reflect an unknown conjunction of the environmental status (Soberón 2007, Colwell and Rangel 2009). The subset of the environmental conditions that is actually occupied by the species corresponds to the realized niche (FIutchinson 1957). The environmental conditions resulting the realized environmental niche are described using e.g. a set of geographically referenced variables come from widely used, systematic databases of climatic parameters (FIossell et al. 2003, Beaumont et al. 2005, FIijmans et al. 2005, Attorre et al. 2007, Czúcz et al. 2009). However, niche characteristics and overlap is estimated through the projection of those functions derived from SDMs across a landscape by any plant species or habitat as well, evaluating range of occurrence from environmental point of view. Novel analyses, e.g. connecting distribution models with other ecological phenomena, can provide novel capacities for understanding specific and general drivers of ranges in occurrence. In this study our aims were to analyse 1) climate envelopes of mesic deciduous woodlands by mean and extreme short-, medium- and long-term climatic temperature variables, 2) range relations as climatic niche corresponding each other and to set of seminatural habitats, 3) detecting environmental variable(s) could be the most significant for the distribution by their temperature response. Material and method Study area The study area is located in Külső-Somogy, Belső-Somogy and Zselic as three vegetation based landscape regions of South Transdanubia in Hungary, defined on the basis of present zonal or dominant extrazonal or edaphic vegetation (Molnár Cs. et al. 2008). Elevation varies in a moderate range from lowlands (96 m a.s.l.) to hills (300 m a.s.l.), average altitude is 161 m a.s.l. Long-term annual temperature varies between 9.8 °C and 11.3 °C, the average was 10.8 °C (Salamon-Albert et al. 2011). Studied regions are at the intersection of three climatic zone: from west as the atlantié, from east as the continental and from south as the mediterranean, that can influence the climatic surface. According to the main geobotanical division of Europe, the regions are fitted in the submontaneous oak-hornbeam woodlands as mesophilous woody habitats and thermophilous oak woodlands with open steppe oak woodlands and riparian vegetation (Ozenda and Borel 2000).
