Ábrahám Levente (szerk.): Válogatott tanulmányok VI. - Natura Somogyiensis 19. (Kaposvár, 2010)

SALAMON-ALBERT É., HORVÁTH F., & ORTMANN-AJKAI A.: Climatic conditions and habitats in Belső-Somogy, Külső-Somogy and Zselic as vegetation-based landscape regions II. Temperature and precipitation sensitivity of woodlands

SALAMON-ALBERT ET AL.: CLIMATIC CONDITIONS AND HABITATS 61 BIOCLIM19 has a three-peaked regional climate envelope, showing three climate functional groups (ENV1, ENV2, ENV3). Most of woody habitats completely seize the range of this bioclimatic variable, with the exception of riverine and swamp woodlands (J) and mesic deciduous woodlands (K). J habitats have a three-peaked distribution but it is shifted toward the medium and high precipitation range (>120 mm). Mesic deciduous woodlands (K) have a two-peaked distribution, fitted to the second and third peak of regional climate envelope. Closed dry and deciduous woodlands (L) and other tree dominated habitats (R) both have a three-peaked distribution, properly fitted to the multipeak of regional climate envelope by the precipitation of coldest quarter. Spatial pattern and distribution of regional climate surface (Fig 4) contrasted to multipeaks of climate envelopes (Fig. 2 and 3, Table 2) also had to be analysed to get better understanding habitat differentiation affected by bioclimatic factors. BIOCLIM 1 the mean annual temperature, shows the smallest variation with a fine scale pattern on the climate surface. Moreover this bioclimatic index had no distinctive power among vegetation types. BIOCLIM-4 the temperature seasonality, showed a distinct SW-NE spatial gradient, similar to that of many other bioclimatic indices in South Transdanubia (SALAMON-ALBERT et al. 2010b). This bioclimatic index had a strong distinctive power within and between vegetation types, especially for J and K habitats. BIOCLIM-8 the mean temperature of wettest quarter, separated three NW-SE zones, represented with higher values in Külső-Somogy, with lower ones in Zselic and Belső-Somogy occurs as a transitional zone. This bioclimatic index had a significant distinctive power within and between vegetation types, as well as the climate surface. BIOCLIM-9 the mean temperature of driest quarter, showed a most variable spatial pattern: although values of bioclimatic indeces were corrigated with elevation, valleys of medium-sized water courses (e.g. Kapós, Koppány) were distinguished by higher temperature values. This bioclimatic index had a moderate distinctive power within and between regional and habitat climate envelope. All studied precipitation indices (Fig 5) show a distinct SW-NE change direction, similar to that of many other climatic indices in Southern Transdanubia, reflecting a gradient from a wettest, slightly atlantic-submediterranean climate to a driest subcontinental one. Belső-Somogy and Zselic can be characterized by atlantic climate character, mostly with regionally high precipitation. Transitional regions, the zones of more rapid climate change, are in Külső-Somogy, indicating that this area represents a regionalscale ecotone between Transdanubia, belonging to the mesophilous forest zone and the Great Hungarian Plain, belonging to the forest steppe zone (BORHIDI 1961, OZENDA and BOREL 2000). Distribution of semi-natural woodland habitat types of riverine and swamp woodlands (J2-J6), mesic deciduous woodlands (Kla-K5) and closed dry deciduous woodlands (Ll-L2x) differentiates well in the three vegetation based landscape regions (Fig 6). Zselic is covered with mesic deciduous woodlands, especially with oak-hornbeam woodlands (K2) and beech woodlands (K5). Belső-Somogy mostly characterized by azonal riverine and swamp woodlands, including alder and ash swamp woodlands (J2), riverine ash-alder woodlands (J5) and riverine oak-elm-ash woodlands (J6). They are developed on sandy soils with locally favourable and extreme groundwater conditions, originated from the precipitation. In the transitional-positioned Külső-Somogy all three woodland categories of semi-natural habitat groups and types are to be found. Riverine and swamp woodlands (J habitats by Fig 6b) show the highest diversity in Belső-Somogy. The riverine ash-alder groves (J5) in the valleys and the alder and ash swamps (J2) at the lower end of the valleys, where streams leave the hills and slow down in the lowlands, are dominant. Ash-alder groves occur sporadically in valley between