Ábrahám Levente (szerk.): Válogatott tanulmányok V. - Natura Somogyiensis 17. (Kaposvár, 2010)
ERDŐS, L. & MORSCHHAUSER, T.: A déli gyöngyvesszős cserjés (Helleboro odori-Spiraeetum mediae) a Villányi-hegységben
8 NATURA SOMOGYIENSIS Material and methods The study area is the Szársomlyó Mt, situated in South Hungary, in the Eastern part of the Villány Mts. The bedrock consists of limestone ( LOVÁSZ 1977). Mean annual temperature is 10-10,5 °C. The coldest month is January, the hottest July ( FODOR 1977). Mean annual precipitation is 670-690 mm ( AMBRÓZY and KOZMA 1990). Because of the east-west direction of the ridge, microclimates of the southern and of the northern slopes are quite different, the northern slopes being considerably cooler and wetter ( HORVÁT and PAPP 1964). The Szársomlyó Mt belongs to the phytogeographic province Pannonicum, region Praeillyricum, district Sopianicum (BORHIDI and SÁNTA 1999, BORHIDI 2003). Coenological relevés were made in 8 m x 8 m and in 6 m x 10 m plots (6 m x 10 m plot size was necessary because of the elongated form of the Spiraea patches). Percentage cover of all vascular species was estimated in July 2009 and in April 2010. The relevés of the Szársomlyó Mt were compared to the relevés of the Mecsek Mts. In the case of the Mecsek Mts, we used the data published by BORHIDI et al. (2003). For the classification, the program package SYN-TAX 2000 was applied (PODANI 2001). In this analysis, we used presence-absence data. As dissimilarity function, Baroni-UrbaniBuser index was applied. We were also interested in species which are typical only of the Mecsek or of the Szársomlyó. For this purpose, we used fidelity values calculated by the program JUICE 7.0 (TICHY 2002). The phi-coefficient was computed, since it is an appropriate measure of fidelity (TICHY and CHYTRY 2006). Species with high phi-values occur significantly (p<0,01) more frequently in the stand of the Mecsek or of the Szársomlyó. Fisher's exact test was made to exclude non-significant differences. In order to characterize the ecological features of the community, we used the relative ecological indicator values of Ellenberg extended for the Carpathian basin by BORHIDI (1993, 1995). Characterization of the vegetation was carried out by using the social behaviour types (SBT) of BORHIDI (1993, 1995). In both cases calculation was done by frequency and cover data as well. Plant species names are used according to SIMON (2000), and plant community names according to BORHIDI (2003). Results The stands of the Helleboro odoro-Spiraeetum mediae can be found on the northern side of the Szársomlyó Mt, west from the top. Declination is between 30 and 40°. The bedrock is limestone, that is covered by a rendzina soil. The community forms a mosaic with the karst shrubforest Inulo spiraeifoliae-Quereetam pubescentis and the closed rock sward Inulo spiraeifoliae-Brometum pannoniéi. Sometimes the stands of the Helleboro odori-Spiraeetum mediae form an edge of the karst shrubforest. In the five relevés (Table 1), we found a total of 99 species, 13 of which are protected. Compared to the Mecsek Mts, these stands are much more species rich; average species number of the plots is 63 in the case of the Szársomlyó, and only 44.5 in the case of the Mecsek. In the shrub layer, Spiraea media forms a dense stand. Other shrubs are relatively sparse; the most abundant among them is Cornus mas. There are also some low trees spreading over the shrub layer from the neighbouring shrubforests. We found only
