Methods for sampling benthic macroinvertebrates in tropical lentic systems

Abstract

Reliable quantitative methods for sampling invertebrate communities are critical for effective freshwater biomonitoring. We tested a range of devices and protocols for sampling benthic macroinvertebrates in shallow tropical lakes; this is the first time this has been attempted in Southeast Asia. First, a pilot study to identify a suitable artificial substrate and colonisation period was conducted. Coconut brushes combined with split palm fronds attracted the greatest macroinvertebrate abundance and richness. A colonisation period of 4 wk was sufficient to capture the key macroinvertebrate families and orders. Second, the sampling efficiencies of 7 artificial substrate sampler designs and 2 hydraulic suction devices were compared in rocky and soft-sediment littoral habitats of a reservoir in Singapore. Among the 9 different sampling techniques tested, the samplers containing coconut brushes and split palm fronds again were the most effective at capturing the greatest total abundance and family richness of benthic macroinvertebrates. Variation in community structure among sampler types was largely explained by the abundance of Chironomidae and Polymitarcyidae (Ephemeroptera). Results were similar between sites dominated by 'rocky' and 'vegetated' littoral habitats. This project identified a sampling device suitable for biomonitoring Singapore's lentic environment, with protocols likely to apply to shallow tropical lentic systems elsewhere. © Inter-Research 2010.