Abstract:

Indicator groups are often used for biodiversity monitoring and conservation, however, the effectiveness of these groups in representing biodiversity is rarely tested. To explore community congruence among different aquatic insect groups and how this may be affected by spatial factors and environmental variables, we carried out an investigation on aquatic insects in April 2010 in 21 headwater streams within the Dongtiaoxi Basin, China. In total, we recorded 130 species from 92 genera, 44 families and 7 orders. We divided the stream insects into three groups, Coleoptera (C), Ephemeroptera + Plecoptera + Trichoptera (EPT), and Diptera + Megaloptera + Odonata (DMO). In Mantel tests, three aquatic insect groups showed significant cross-taxon concordance, C versus EPT (r= 0.65, P< 0.001), C versus DMO (r= 0.67, P< 0.001) and EPT versus DMO (r= 0.82, P< 0.001). According to variance partitioning procedures, environmental variables were the major determinants of aquatic insect community structures, while spatial factors were less important. Species composition in different taxon groups exhibited similar relationships to environmental gradients. Altitude, pH, mean velocity and concentration of oxygen were the most important drivers of aquatic insect assemblage patterns. Overall, our results indicated that, at least in the studied region, community congruence among different aquatic insect groups was strong. We propose that one group, such as the EPT group, may be used as a biodiversity indicator in future cost-effective surveys.

Key words: community congruence, aquatic insect, spatial factors, environmental variables, biodiversiy