Ábrahám Levente: Biomonitoring a Dráva folyó magyarországi szakasza mentén 2000-2004 - Natura Somogyiensis 7. (Kaposvár, 2005)
Juhász, Magdolna - Dénes, Andrea: Biomonitoring of alluvial willow forests - Ártéri fűzligetek monitoring vizsgálata
Natura Somogyiensis 7 11-18 Kaposvár, 2005 Biomonitoring of alluvial willow forests JUHÁSZ MAGDOLNA 1 & DÉNES ANDREA 2 ^Somogy County Museum Natural History Department, H-7401 Kaposvár, Fő u. 10., Hungary, e-mail :j uhasz@smmi.hu 2 Janus Pannonius Museum Natural History Department, H-7623 Pécs, Szabadság u. 2., Hungary JUHÁSZ, M., DÉNES, A.: Biomonitoring of alluvial willow forests. Abstract: Alluvial forests with Salix alba on floodplain of river Drava were studied in five consequent years. Year-to-year changes in coenological characteristics of the community were pointed out. These changes are unambigiously connected with changes of water supply of the growing place. Preservation of natural state of the community needs temporal surface flooding connected to the river floods. Key words: biomonitoring, alluvial willow forests, coenological changes Introduction Biomonitoring of alluvial willow forests along river Drava is part of an environmental monitoring system, which follows up changes of some abiotical environmental factors and wildlife. Studies aiming to survey environmental changes caused by a Croatian hydro-power plant planned on river Drava have begun in 2000. Coordinated botanical monitoring studies of alluvial forest communities and of populations of chosen herbaceous plants have been performed (JUHÁSZ & DÉNES 2001, 2004). Here we summarize results of five-year study of willow forests. Existence and characteristics of alluvial plant communities are strongly determined by water supply of their growing place and - in connection of this - by changes of water level of the river. Changes of height and duration of surface water coverage affects species composition of the community and coverage and physiological state of species. Goal of biomonitoring of willow forests is documentation of coenological and compositional state of the community and follow-up of degradational and regenerational processes and changes of growing place characteristics. Coenological indication is based first of all on evaluation of changes of species composition. Willow forests studied are situated on the left bank of river Drava, in county Somogy, Hungary. River Drava meanders here strongly, its valley runs approximately from northwest to southeast. Larger part of the floodplain belongs to Croatia, the smaller Hungarian part is cc. 300 km 2 . Drava enters Hungary at the mouth of river Mura; for twenty kilometers from here the floodplain is bordered by loess hills, further downwards for another fifty kilometers by aeolian sand areas.
