Factors Affecting Macroinvertebrate Distribution in a Mediterranean Intermittent Stream

ABSTRACT

The relative influence of water regime and other environmental factors on the organization of benthic macroinvertebrates was studied over three years in a small intermittent river basin (River Pula) in Sardinia. The intermittent nature of the led to high spatial and temporal variability of abiotic characteristics. Twenty-eight invertebrate taxa accounted for 90% of the sampled individuals; and of there four (Chironominae, Caenis luctuosa, Diamesinae, Protonemura ichnusae) accounted for more than 50% of the total density. Canonical correspondence analysis showed that 34.6% of the biological variance was accounted for by abiotic factors and that different environmental features, including sediment structure and stream order, had a larger influence on benthic macroinvertebrate distribution and abundance than the intermittent water regime, even though local drought events completely disrupted the macroinvertebrate community.