Janus Pannonius Múzeum Évkönyve 40 (1995) (Pécs, 1996)

Természettudományok - Nógrádi, Sára–Uherkovich, Ákos: Trichoptera communities of the river Fekete-Körös in Hungary

46 A JANUS PANNONTUS MÚZEUM ÉVKÖNYVE 40 (1995) Fig. 2. The light trap on the riverside of Fekete-Körös. 2. ábra. A fénycsapda a Fekete-Körös partján. Discussion Faunistic remarks Due to the long-term (6 years) investigation, the number of species is considerable high comparing with other localities of the Great Hungarian Plain. Only one locality is known in this region which has more than 57 species. This site is Túristvándi, situated along the river Öreg-Túr, on NE part of the Plain. Along the Tisza river there were made sporadic faunistic samplings by Dr. S. Andrikovics, and his result was also very deficient. The members of this caddisfly community are very common and wide-spread species, they occur all over the country, as well as in the plains. The occurrence of some species are restricted only to a few localities. Accordingly Hydroptila forcipata and H. lotensis were collected in larger number only during the past years along some larger rivers. Hydropsyche ornatula is common in Southern Transdanubia, mainly in the Dráva-region, but it is a rarity in the Great Hungarian Plain. Some specimens have already been captured in the NE part of the Plain. Limnephilus binotatus became rare in the last decade, but a few specimens could be occasionally collected. The occurrence of Ceracleafulva is also rather sporadic throughout the country. Some other species - e. g. Ceraclea riparia, Oecetis tripunctata and Triaenodes simulans are also rare. The firstly mentioned one as well as 0. tripunctata can be collected in larger number only in NE part of the Plain, while T, simulans lives mostly in West Hungary and in a few places in the system of Körös rivers. Composition of Trichoptera communities as sampled in different years Although the composition of the species is almost permanent year by year, the sequence of their dominance differs in each year. Some examples for this phenomena: Agraylea sexmaculata Curt., which is a very frequent and widely distributed species according to our knowledge, was the subdominant member of the community in 1993. In contrast its quantity was low in 1990 and 1991. The quantity of further hydroptilids is also extrapolated between the very low and the high individual number. Athripsodes cinereus Curt, was rare in the first three years of the lighttrapping (1989-1991), then the number of the specimens started to increase. The gradation of the population developed in 1993, when the species was the dominant member of the community). Then the population broke in 1994. The species became also very common in other rivers in the same year: e. g. in the branch of upper Danube and in the small river Túr in NE part of the Plain. Neureclipsis bimaculata L. was most frequent during the first year of our field work, but later it became rare.