Trophic structure of the benthic invertebrate community in the littoral zone of a mountain cascade system

M Prus,P Bijok,T Prus

doi:10.5194/we-3-12-2002

Abstract

Abstract. The cascade of Solina/Myczkowce dam reservoirs situated in the West Carpathian Mts was investigated. The cascade consists of two reservoirs, the upper one built 35 yr ago on the San and Solinka Rivers of 2100 ha area separated from another one, of 190 ha area, with hypolimnion cold water supplied from the upper one. The offshore zone was investigated monthly (6 sites of upper, 3 sites of lower reservoir) using a tube bottom sampler. Besides numbers, biomass and biodiversity indices, the proportion of predators, plant/detritus-feeders and filter-feeders was assessed. In upper reservoir Solina, with a lack of filter-feeders, a clear preponderance of plant-detritus feeders was observed. Predators, consisting mostly of leeches and hydranchnellids were present. In lower reservoir Myczkowce, all three trophic classes were present in the first year of study in almost equal proportions and in 1998 with slight preponderance of plant/detritus feeders was observed. The Oligochaeta/Chironomidae index in both reservoirs was low, indicating low degree of eutrophication. Only one site in Solina reservoir (near a fish culture) and one in Myczkowce (influenced by tourist activity) showed a high value of this index.

Highlights

The cascade of Solina/Myczkowce dam reservoirs situated in the West Carpathian Mts was investigated
In the Myczkowce reservoir, all taxonomic groups belonging to three trophic classes were present
In 1998, the share of filter feeders decreased in favour of plant detritus feeders (Fig. 2)

Summary

Introduction

The cascade of Solina/Myczkowce dam reservoirs situated in the West Carpathian Mts was investigated. In the light of extensive investigations over the past three years (involving primary production, phytoplankton, zooplankton, littoral and profundal invertebrate fauna, broaded by studies of ichthyofauna) the elaboration of trophic structure in the benthic fauna of inshore zone seems to be of crucial importance for the trophic web modelling. This will serve for the estimation of the biocenosis structure and for establishing backgrounds against which future changes may be assessed. The same holds for the temporal scale – trophic relationships are estimated for one time point and summed up for longer periods (Warren 1989)

Methods

Results

Conclusion