The effects of sampling technique on the ecological characterization of shallow, benthic macroinvertebrate communities in two Newfoundland ponds

The influence of sampling technique on the characterization of benthic macroinvertebrate communities on boulder-cobble substrate in two shallow freshwater ponds was analysed. Sweep-net and rock-bag sampling techniques were used to collect macroinvertebrates from two ponds in Newfoundland, Canada. Abundance and diversity of macroinvertebrates were compared in relation to the nature of the substrate and the technique. The two sampling techniques provided different estimates of diversity and density of the benthos. Neither method truly represented the benthic community as neither collected all taxa and each method typically over- or under-estimated the abundance of taxa. The difficulty of interpreting such data is discussed, with special reference to the rapid assessment of water quality in biomonitoring studies.