Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 68. (Budapest 1976)

P. Verseghy, K.: Quantitative investigation of xerothermophilous lichens of sandy soil

ANNALES HISTORICO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus 68. Budapest 1976. Quantitative Investigation of Xerothermophilous Lichens of Sandy Soil by K. P.-VERSEGHY, Budapest Abstract — The xerothermophil lichen vegetation on the sandy areas of the Great Hungarian Plain was investigated with special regard to lichen phytomass seasonal changes and environmental conditions. Sequence of important factor was established by pathanalysis. With 3 figures and 1 table. Typical xerothermopil lichen vegetation is formed on some undisturbed areas of Bugac, Hortobágy, and near the village of Csévharaszt. Our patterns were studied on the Nature Conservation Area near Csévharaszt. The studied area is not too rich in lichen species but their quantity is often high surpassing the phytomass of the phanerogamous plants (Verseghy & Láng 1971). On basic sandy soil: Cladonia magyarica VAIN., Cl. furcata var. palamaea (ACH.) NYL., var subrangiformis (SANDST.) ABBAYES, Cl. rangiformis HOFFM. CI. convoluta (LAM.) COUT., Parmelia pokornyi (KÖRB.) SZAT., P. vagans NYL., Diploschistes scruposus var. arenaria (SCHAER.) MÜLL. ARG., Toninia coeruleonigricans var. argïllacea (WALLR.) ZAHLBR., Collema coccophorum TUCK., C. tenax (Sw.) ACH. Two species were collected under Juniperus trees: Cladonia subulata (L.) WIGG. and CI. fimbriata (L.) SANDST. Within the framework of the IBP and the MAB programmes, we have investigated the productivity and its seasonal changes (VERSEGHY & LÁNG 1971, Verseghy in press) as well as the mineral cycle of the xerothermophilous lichens living in great quantities in the grassland communities of sandy soil in the Great Hungarian Plain (LÁNG & VERSEGHY 1974, VERSEGHY & LÁNG 1975). We have analyzed the role of environmental factors. BESCHEL (1954, 1955) considered the climatic factors to be of great significance. Thegrowt of lichens shows proportionality to active lifespan taken in one day. Life activity is regulated by moisture and air temperature. In a dry state, life activity is latent. On these bases we sought interconnecting factoids between the productivity of lichens and the climatic effects. The several relationships, which mav arise were determined bv using path-analysis (cf. LEROY 1960). Material and method The productivity of xerpohitic lichens of sandy soil has been investigated in two sandy grass associations, namely, in a oneyear-old Brometum tectorum secaletosum and in the perennial, open calciphilous grassland community, i. e. in Festucetum vaginatae danubiale. The dominant species in Brometum is Cladonia furcata, while Cl. magyarica and CI. convoluta are less common. In Festucetum vaginatae, there is about the same ratio of CI. magyarica and CI. furcata, while there is a smaller quantity of Cl. convoluta, Parmelia pokornyi and Diploschistes scruposus var. arenaria. The description of the sampling method and detailed contributions are given in VERSEGHY & LÁNG, 1971, VERSEGHY (in press). The productivity of lichens was counted by growth-analysis (cf. Kvët, Ondok, Neèas & Jarvis 1971) and by paht-analyses according to LEROY (1960). Path-analysis is suitable for the examination of those systems in which the relationship between the variables is not mutual, but undirectional in course (cf. O'SVÁTH 1961, 1965). We sought the interconnecting factors between 1. radiation minimum, 2. humidity, 3. precipitation, 4. global radiation on the one hand, and the productivity of lichens, on the other. We have determined the order of relevance among these factors by using pathanalysis to trace the changes in the total productivity of certain lichen associations as well as in the case of two dominant species (Cladonia magyarica and Cl. furcata). Climatic effects The area investigated lies in the Danube

—Tisza Interfluve, on some sand dunes, 110-120 metres a.s.l., 40 kilometres from Budapest. The climate is continental. The annual mean precipitation is 515 mm, during the investigations (1968 and 1971) it was less (460 and 342 mm, respectively), while in 1970 and 1972 it was more (583 and 561 mm). The Walter climatogramm well characterizes the respective years. In each year there was a semi-arid period (Fig. 1.). Ann. Hist.-nat. Mus. Nat. Hung., 1976, 68.