Ábrahám Levente (szerk.): Válogatott tanulmányok VI. - Natura Somogyiensis 19. (Kaposvár, 2010)

KOVÁCS GY., WINKLER D. & FARAGÓ S.: A kárókatona fészekalj és tojásméret vizsgálata a Kis-Balatonon és a Nagyberekben

Natura Somogyiensis 19 263-274 Kaposvár, 2011 Waterfowl population survey of the Marcali reservoir (2007-2008) '^KOVÁCS GYULA, 1'

2NAGY ÁDÁM & 2WINKLER DÁNIEL 'South Balaton Nature Conservation Group (Local Group No. 35. of BirdLife Hungary) H-8638 Balatonlelle, Irmapuszta, Hungary, e-mail: del-balaton@mme.hu 2 University of West Hungary, Institute of Wildlife Management and Vertebrate Zoology H-9400 Sopron, Ady E. u. 5., Hungary, e-mail: dwinkler@emk.nyme.hu KOVÁCS, GY., NAGY, Á. & WINKLER, D.: Waterfowl population survey of the Marcali reservoir (2007-2008). Abstract: This study has shown that the Marcali reservoir is an important waterbird wetland habitat especially during the migration period. Based on our findings early springtime season proved to be the most important season concerning bird activities on the reservoir. The reservoir and its surroundings are not specifically important as breeding areas; although, some strictly protected species can be found among the breeding species. It is noteworthy to mention the strong disturbance (waterfolw hunting, intensive fishing, poaching) in the area that can have a negative impact on the breeding success of bird species. The results of similarity measures showed remarkable differences between the bird communities of different seasons. Waterbird communities of the spring season and summer season showed the highest similarity, since part of the species observed during the spring surveys were most probably breeding species that remained in the reservoir area for the summer. Comparison based on bird species diversity showed significant differences between communities of the different seasons. Diversity was higher both in the breeding and the migration season compared with the winter period characterized by the lowest species richness and number of individuals. Water level has proved to be an important determining factor of waterbird species richness. Keywords: artificial wetland, bird monitoring, bird communities, breeding waterbird population Introduction In Hungary, in addition to natural wetland habitats, there are also a number of manmade (artificial) water bodies such as fishponds and reservoirs created for various use. Extensive fishpond construction work began as early as the beginning of the 19th century and continued until the Second World War. From the 1950's construction restarted and fishponds were established at a rapid rate. In the Transdanubia region alone, we can find a great number (more than 50) of water bodies that are larger than 50 ha in size. Most of these are artificially created while only 6 of these are natural or semi-natural water bodies. There have been a number of ornithological studies conducted at the southern shore of Lake Balaton and surrounding fishponds, these publication include: HOMONNAY (1939a, 1939b, 1940), KEVE (1973, 1975, 1978), HAVRANEK et al. (1995) IIAVRANEK (1996) and HAVRANEK & SZABÓ (1997). Since the turn of the 21st century the South Balaton Nature Conservation Group regularly surveys the area (

KOVÁCS 2008a, 2008b, 2008c, 2009). Since the establishment of the Marcali reservoir starting in the 1990's research focused