Somogyi Múzeumok Közleményei 17/B. - Természettudományi tanulmányok (2006)

Farkas, Sándor: The terrestrial Isopod Fauna of South Transdanubia (Hungary) - Dél-Dunántúl szárazföldi ászkarák (Isopoda: Oniscidea) faunája

162 FARKAS SÁNDOR Collected material Pitfall trapping (0.2 I plastic glasses, 65 % ethylene glycol and five traps / site) and random hand sampling were used as collecting methods. The traps were used in a sampling site between March and November and emptied ten times during a year. The material was determined by GRUNER'S (1966) and SCHMÖLZER'S (1965) keys. Taxonomy and nomenclature followed SCHMALFUSS (2003). The collected specimens are deposited in the isopod collection of University of Kaposvár. Data analysis The analysis of species' distribution was based on the presence - absence data in the UTM squares and 343 sampling sites. Zoogeographical evaluation was based on FLASAROVÁ (1995), GRÜNER (1966) and SCHMALFUSS (2003). Characteristic species of the habitats were pointed out using IndVal statistical computer program (DUFRENE and LEGENDRE 1997). Differences obtained at levels of P < 0.01 were considered significant. Cluster analysis (complete link; Euclidean distance) by the percentage occurrence of species in the firstorder habitat classes was applied to draw the hierarchical tree of habitats using Syn-Tax program package (PODANI 2001). Habitat classification followed the Hungarian General Habitat Category System (HGHCS) (MOLNÁR 1997). Applying the HGHCS, the 343 sampling sites were divided over 15 first-order classes (Table 1.). Some of them (D, G, H, I, М, N, O, P, T) were omitted from the analysis because of the low number of samples. Results Species list and distribution In the period 1996-2004 110,039 terrestrial isopod specimens were sampled in the South Transdanubia region, and belonged to 31 species (Table 2.). The frequencies of the species in the UTM squares are given in Table 3. The most frequent species, Armadillidium vulgare and Porcellium collicola were found in 81 % of the investigated UTM squares, Hyloniscus riparius in 77 %, and Trachelipus rathkii in 58 %. Nine species were discovered in only one to three UTM squares, all of them are introduced species, except Porcellium recurvatum and Protracheoniscus franzi that live in natural habitats. Fig. 2. Hierarchical tree of the first order habitats. 1: marsh; 2: riverine and swamp woodlands; 3: fresh oak woodlands; 4: closed, dry oak woodlands; 5: black locust plantations; 6: synanthropic habitats.