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

KOVÁCS GY., NAGY Á. & WINKLER D.: WATERFOWL POPULATION SURVEY 269 Table 3: Dominant species (Do>5%) in different seasons Spring Summer Autumn Winter Early Spring Study period Plialacroeorax carbo 24.0% 23.4% 8.3% 8.2% 40.7% 18.0% F.gretta alha 6.5% 9.2% 63% Ardea cinerea 12.3% 5.9% 5.1% Anser albifrons 56.5% 1 20.4% Anser anser 1 Anas crecca •m • Anas plutyrhynchos 1 27.5% 143% i a 12.9% Fulica atra 12.5% 15.8% Vane Ilus vanettus 11.1% 15% I.arus ridihundus 32.3% 12.1% U-0% 14.9% 11.2% Species richness, similarity and diversity Species richness was the highest (32) at the end of March, while the lowest value (10) was recorded at the end of December and in February (Fig. 5). Highest average species richness (25) was found in early spring (Fig. 6), while total species richness was the highest (36) in spring period (Fig. 7). Average species richness and total species richness were both the lowest in the winter period, 12 and 23, respectively. Average species richness for the whole study period was 17, while total species richness was 58. SP SU AU VV HS ST 3

1 ^ Fig. 5: Species richness on the Marcali reservoir during the 07.04.2007-03.26.2008 period Fig. 6: Seasonal average of species richness; Fig. 7: Seasonal total species richness (SP - spring, SU - summer, AU - autumn, W - winter, ES - early spring, ST - study period average) Jaccard index showed the highest similarity between communities of the spring and summer seasons (Table 4), since the species observed during the spring period are mostly species that breed on the reservoir and stay there during the summer. The weakest similarity was observed between communities of the winter and spring periods. This clearly reflects the difference between the winter waterbird community, rich in migratory species, and the spring community which mostly consists of breeding species. Table 4: Values of Jaccard similarity index between seasons (%) Season Summer Autumn Winter Early Spring Spring 55.00 48.84 28.26 51.06 Summer 42.1 1 28.95 41.86 Autumn 41.67 46.51 Winter 34.88