Aquatic and Semi Aquatic Heteroptera Communities from South-East Transylvanian Small Rivers

Abstract

AbstractThe paper presents the analysis of the relations between aquatic and semi aquatic Heteroptera from south-east Transylvanian small rivers and habitat characteristics of the sampling sites. Biological material was collected from 23 sampling sites from Hârtibaciu Plateau (8), and Făgaraş (12) and Sibiu (3) Depressions. A large number of species were identified, almost a third (22 out of 69) of the species sampled so far in Romania. Gerris (Gerris) lacustris (Linnaeus, 1758) has the highest relative abundance and frequency, seconded by Nepa cinerea Linnaeus, 1758 and Sigara (Pseudovermicorixa) nigrolineata nigrolineata Fieber, 1848. Community composition is influenced by habitat characteristics, the most important role being held by the presence of aquatic vegetation, favoring G. lacustris and N. cinerea, and the inconstancy of the hydrological regime, favoring S. nigrolineata. Habitat conditions are having a low influence on biodiversity values, although substrate and hydrological heterogeneity and aquatic vegetation seem to be responsible for higher species richness, while mild anthropic impact and a larger site size are resulting in higher species heterogeneity.