Comparison of invertebrate sampling methods in the Middle Rio Grande

Complementary sampling methods are sometimes necessary to gain accurate representation of aquatic invertebrate communities.  In this study, we used two techniques to obtain both benthic and pelagic taxa in slow-flowing areas of the Rio Grande in New Mexico. The first technique was an epibenthic corer, pelagic tube, and dipnet used in a 0.25m² throw trap and the second technique was a stovepipe sampler. We then evaluated whether relative abundance and diversity of invertebrates differed between the two techniques. In general, the stovepipe captured greater diversity of pelagic and epibenthic invertebrates, especially microcrustaceans, compared to the corer and pelagic tube used within the throw trap. However, the stovepipe was ineffective at sampling macroinvertebrates compared to the dipnet. The stovepipe sampler was a more efficient method of processing invertebrate samples - both in the field and in the laboratory - and was similar enough to replace the epibenthic and pelagic samplers.  However, we recommend that dipnet samples be taken as a complement to the stovepipe to more fully reflect the invertebrate community in the Rio Grande.