L. Forró szerk.: Miscellanea Zoologica Hungarica 9. 1994 (Budapest, 1994)

Csányi, B.: The macrozoobenthon community of the Danube between Rajka and Budapest

Material and methods Sampling sites between Rajka and Budapest (1850 and 1659 river km) are shown in Fig. 1. Capitals MK and MD at a given location are referring to the macroscopic invertebrate (macrozoobenthon) littoral kick samples and profundal dredge samples, respectively. Fig. 1. Map of the sampling sites on the Danube between Rajka and Budapest. Legend: 1. Rajka (MK, MD); 2. Dunaremete (MK, MD); 3. Ásványráró (MK); 4. Medve (MK, MD); 5. Gönyü (MK, MD); 6. Komárom (MK, MD); 7. Esztergom (MK, MD); 8. Szob (MK); 9. Visegrád (MD); 10. Budapest, Drinking Water Works (MK, MD); 11, Budapest, Batthyányi Square (MD) Longitudinal sampling program was started in 1987 and was completed during the last five years at low water flow periods in order to reveal the invertebrate community of the Danube. Kick samples from the shore line were collected at 9 sites using the standard British FBA pond net with a mesh size of 950 m (Furse et al. 1984). An approximately 20 kg dredge sampler was applied successfully for sampling the middle deep parts of the Danube bed with motorboat. Qualitative benthon data were analyzed by multivariate classification and ordination methods using the SYN-TAX 5.0 program package (Podani 1993). Cummulated results of data collected by kicking between 1987 and 1993 and by dredging in 1991 are presented in order to illustrate the species distribution along the Danube. The most important faunal results are discussed in details with special emphasis on recent ecological changes as a result of the Slovakian diversion of the original river flow.