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
30 Natura Somogyiensis from Dráva-sík, it can be found only at the edges of Alföld, with the greatest number in Szatmár-Beregi-sík (1500 ha). It occurs on incoherent sedimentary rocks, especially on sand and clay, mainly on the humid parts of lowlands and hilly regions. On lowlands, it appears typically in high floodplains, whereas in river and stream valleys in the hilly regions of Hungary. This habitat type frequently occurs together and forms mosaic with sessile oak-hombeam woodlands (K2). Beech woodlands (K5) are high growing, closed mesic forests, connected to cool and humid climate with beech monodominance {Fagus sylvatica). The habitats occur with the greatest extension in the Északi-középhegység (45000 ha). In certain parts of Transdanubia 12500 ha, with larger extension in Zselic and Mecsek, and sporadically in Külső- and Belső-Somogy. Under less favourable abiotic environment (too dry) and/or under strong human impact the habitat is gradually reducing (e.g. Külső- and Belső- Somogy). Habitat nomenclature is by Molnár Zs. et al (2008), vegetation characterization is by Bölöni et al. (2008). Data analyses By the set of temperature variables regional climatic envelopes are reported for seminatural habitats (A-NÉR), and types of mesic deciduous woodlands disposing statistically appropriate plot number (K, Kla, K2, K5). In the first step, scatterplots were constructed from the relative distribution (%) on total area covered by any semi-natural vegetation as the regional habitat envelope (Á-NÉR) and on woodland types as the habitat envelope according to temperature variables. Data originated from the associated dataset of habitat occurrence and climatic variables, were sorted for the analyses representing all of the sampling points (MÉTA hexagons). In second step, area version of Gaussian function as a nonlinear single or multipeak analysis was executed on each scat- terplot, computing Levenberg-Marquardt algorithm as an iterative procedure by Origin 6.0. Area based Gaussian model describes a bell-shaped curve like a normal probability distribution function, ecologically defined as realized niche by temperature index. Temperature weighted Gaussian curves were statistically compared by a one-way analysis of variance (ANOVA). Pairwise significant differences were counted if p<0.05. Temperature sensitivity of a habitat by a given bioclimatic variable was interpreted as significant difference among variabilities in the temperature envelopes (e.g. Kla to A-NÉR by BIOCLIM-2, see Table 2). Overlapping distributions without any significant difference are interpreted as a climate or habitat gradient, curve that has significant difference to any other are defined as a regional climate or habitat functional group. Results Climate envelope is a realized range of abiotic environmental variables that could effect pattern and distribution of habitat types potentially in geographical or natural landscape areas. Basic statistics of 9 calculated bioclimatic variables of temperature, as minimum, maximum, mean values and the range at several scales are given for the studied regions (Table 1). Referring to general temperature relations of semi-natural habitats the most relevant index is the mean annual temperature (BIOCLIM-1). It varies between 9.8 and 11.3 °C, with the range of 1.5 °C in the regions. Range of variable is differed among habitat types, with the lowest value by pedunculate oak-hombeam woodlands (Kla) and beech woodlands (K5) opposite to sessile oak hornbeam woodlands (K2) that
