The potential for using flower-visiting insects for assessing site quality: hoverfly visitors to the flowers of Caltha in the Far East region of Russia

Hoverfly (Diptera: Syrphidae) assemblages visiting Caltha palustris in 12 sites in the Far East were analysed using partitioning of Simpson diversity and Canonical Coordinates Analysis (CCA). 154 species of hoverfly were recorded as visitors to Caltha, an extraordinarily high species richness. The main environmental gradient affecting syrphid communities identified by CCA was human disturbance and variables correlated with it. CCA is proposed as the first step in a method of site assessment.