Taxa occurrences and composition of benthic macroinvertebrates from biodiversity surveys on Lake Victoria, Uganda (2001-2006)

Study Extent

The datasets present data for surveys conducted between 2001 and 2006.

Sampling

The surveys considered several sites along the shoreline of Lake Victoria in Uganda. A Ponar grab with an open jaw area of 238 cm2 was used to take samples of benthic macroinvertebrates. Three spread hauls were taken from each sampling point or site, and mixed to form a composite. The bottom type at each point was described from the grabbed contents. The composite sample was concentrated and then placed in labeled sample bottles and preserved with 5% formalin solution and taken for laboratory analysis. In the laboratory, each sample was rinsed with water and then placed on a white flat-bottomed tray. Macro-invertebrates were sorted, and individual taxa identified to the lowest possible taxonomic level using identification keys (Mandahl-Barth, 1954), Pennak, 1953), Merritt and Cummins, 1997, De Moor et al. 2003). All taxa were recorded, and individuals of each taxon enumerated to estimate their densities.

Quality Control

The samples were immediately processed in the field and treated with formalin to keep the organisms of interest intact. To avoid loss of organisms during sample processing, nets with appropriate mesh sizes were used.

Method steps

1. Collection of the macroinvertebrates In the field, sediment samples were collected using a Ponar grab with an open jaw surface area of 238 cm2. At each site, three sediment samples were obtained. The three samples were mixed and concentrated to form one composite sample for each site. Preserving the samples The composite sample for each site was separately preserved in 5% formalin to maintain the organisms in good condition prior to analysis in the laboratory. Identification of macroinvertebrates In the laboratory, formalin was rinsed off from each sample and placed in white flat-bottomed trays. Using pairs of forceps, all benthic macro invertebrates were sorted from the sediment and the individual taxa identified to the lowest possible taxonomic level using appropriate identification keys and a dissecting binocular microscope at 4x 25 magnification.

Aquatic benthic macro-invertebrates

1. Oligochaeta
   rank: class
2. Podocopa
   rank: order
3. Conchostraca
   rank: order
4. Cordulidae
   rank: family
5. Ephemeridae
   rank: family
6. Glossiphoniidae
   rank: family
7. Leptoceridae
   rank: family
8. Libellulidae
   rank: family
9. Ablabesmyia
   rank: genus
10. Bellamya genus
    rank: genus
11. Biomphalaria
    rank: genus
12. Bulinus
    rank: genus
13. Byssanodonta
    rank: genus
14. Caelatura
    rank: genus
15. Caenis
    rank: genus
16. Chaoborus
    rank: genus
17. Chimarra
    rank: genus
18. Chironomus
    rank: genus
19. Clinotanypus
    rank: genus
20. Corbicula
    rank: genus
21. Cryptochironomus
    rank: genus
22. Economus
    rank: genus
23. Neochetina
    rank: genus
24. Palpomyia
    rank: genus
25. Procladius
    rank: genus
26. Sphaerium
    rank: genus
27. Tanypus
    rank: genus
28. Tanytarsus
    rank: genus
29. Caridina nilotica
    rank: species
30. Gabbia humerosa
    rank: species
31. Melanoides tuberculata
    rank: species
32. Mutera bourguignat
    rank: species
33. Povilla adusta
    rank: species

The dataset covers sites on Lake Victoria, Uganda