Ábrahám Levente: Válogatott tanulmányok II. - Natura Somogyiensis 9. (Kaposvár, 2006)

Juhász Magdolna - Dénes Andrea: Biomonitoring of alder swamp forests - Égeres mocsárerdő monitoring vizsgálata

Natura Somogyiensis 9 39Kaposvár, 2006 Biomonitoring of alder swamp forests 1 JUHÁSZ MAGDOLNA & 2

DÉNES ANDREA Somogy County Museum Natural History Department, H-7401 Kaposvár, Fő u. 10., Hungary, e-mail: juhasz@smmi.hu 2

Janus Pannonius Museum Natural History Department, H-7623 Pécs, Szabadság u. 2., Hungary JUHÁSZ, M. & DÉNES, A.: Biomonitoring of alder swamp forests. Abstract: Studied stand of alder swamp forest (Angelico sylvestri - Alnetum glutinosae) is situated on alluvial plain of river Drava. Coenological survey of designated area has been made in every year. In this paper we analyze data of five consequent years (2000-2004). There are year-to-year changes in coenological characteristics of the community. Experienced changes are connected undoubtedly to changes of water supply of the growing place. Keywords: floodplain, alluvial forests, river Drava. Introduction Studied stand of alder swamp forest is situated on the left-side alluvium of river Drava, in south-western part of Hungary, about five kilometers from present riverbed. In this section of the river there is no flood protection dam, but floods do not reach study area; although subsoil water moves in the gravel bottom of the wide valley in connection to the floods of Drava. Climate of study area is moderately warm, humid. Annual mean temperature is about 9.8°C. Annual precipitation, based on many years' average is 800840 mm. Floods of Drava come in spring, early summer and autumn, low waters in late summer and winter. Biomonitoring of alluvial alder swamp forest by river Drava is a part of an environmental monitoring system. Studies aiming to survey environmental changes caused by a Croatian hydro-power plant planned on river Drava have begun in 2000 (JUHÁSZ & DÉNES 2001, 2004, 2005, JUHÁSZ & LÓKI 2005). Coenological characteristics of partially flooded plant communities depend greatly on water supply of the growing place. Goal of study of the alder swamp forest are: documentation of coenological state of the community and monitoring of changes in growing place conditions through degeneration and regeneration processes. Material amd methods Previously to this study many field trips were made in Drava valley by the authors (JUHÁSZ 1997, 2004, MARKO & JUHÁSZ 1997). Detailed observation of this alder swamp