Ábrahám Levente (szerk.): Válogatott tanulmányok VIII. - Natura Somogyiensis 23. (Kaposvár, 2013)
Salamon-Albert É.: Climatic conditions and habitats in Belső-Somogy, Külső-Somogy and Zselic as vegetation-based landscape regions IV. Precipitation envelopes of mesic deciduous woodlands
78 Natura Somogyiensis hornbeam woodlands, K2 the sessile oak-hornbeam woodlands, K5 the beech woodlands, K7a the acidofrequent beech woodlands and K7b the acidofrequent oak-hornbeam woodlands (Molnár et al. 2008, Salamon-Albert et al. 2008, 2010, 2011). In our paper we focus on significant mesic woodlands having sufficient sample size for the analysis as Kla (n=1792), K2 (n=2042), K5 (n=926), the associated habitat group of K (n=3848) and moreover, with high attention on totality of natural habitats as ANER (n=9187) using presence-absence data of occurrence. Sessile oak hornbeam woodlands (K2) are the most abundant in the regions as well as in Hungary. They mostly occur in submontane and colline elevation, usually on deep soils and dominated by Quercus petraea, Carpinus betulus and Fagus sylvatica. In Belső-Somogy, this habitat type is replaced by lowland pedunculate oak-hornbeam woodlands, according to geographical distribution and connected to cool-humid climate suitable and available. It occurs on all types of (but mainly on solid) bedrock, it can rather be found on loess or loess-like sediments and misses on sand, and occurs on clay, where it forms mosaic with lowland oak-hombeam woodlands in the hilly regions. Pedunculate oak-hombeam woodlands (Kla) are the next by their abundance among mesic woodland habitat types in the regions. Shadowed and mesic forests of lowlands and hilly landscapes with Quercus robur and Carpinus betulus in the tree layer. The centre of the distribution is in the western part of Transdanubia: with greatest area in Belső-Somogy (14000 ha) and in Dráva-sík (6000 ha) connected to. Apart from lowland of Drava (Dráva-sík), it can be found only at the edges of the Great Plain (Alföld), with the greatest extension in lowland of Szatmár-Beregi sík (1500 ha). It occurs on incoherent sedimentary rocks, especially on sand and clay, mainly on the humid parts of the regions. Along the rivers it appears typically in high floodplains formated by 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). Submontaneous beech woodlands (K5) are high growing, closed mesic forests, connected to cool and humid climate with (mono)dominance of European beech (Fagus sylvatica). Habitat occurs in the Északi-középhegység macroregion with the greatest extension (45000 ha). In certain parts of Transdanubia there is 12500 ha of beech woodlands, especially in Zselic and Mecsek with the larger extension, and in Külső- and Belső-Somogy sporadically due to less favourable abiotic conditions (e.g. low precipitation) and several types of human impact and the high disturbance regime. Nomenclature of the habitats is by Molnár Zs. et al (2008), habitat description is by Bölöni et al. (2008). Data analyses By the set of precipitation variables climate envelopes of semi-natural habitats are reported (Á-NÉR) as the basic, and ones of associated group of mesic deciduous woodlands and the types disposing statistically appropriate plot number (K, Kla, K2, K5). In the first step, scatterplots of relative distribution (%) were calculated for the total area covered by any semi-natural vegetation as the regional habitat envelope (A-NÉR) and on woodland types as woodland 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 probability curve as a nonlinear multipeak analysis was executed on the scatterplots, computing Levenberg-Marquardt algorithm as an iterative procedure using a smooth approximation. Gaussian model of climate envelope can be described as a non-parametric probability density function computed as a summarized series of normal distributions called kernel densities as realized precipitation
