Hydrobiologia

, Volume 571, Issue 1, pp 123–132

Dormant egg bank characteristics and hatching pattern of the Phallocryptus spinosa (Anostraca) population in the Makgadikgadi Pans (Botswana)

Authors

    • Laboratory of Aquatic EcologyKatholieke Universiteit Leuven
  • Sofie Bracke
    • Laboratory of Aquatic EcologyKatholieke Universiteit Leuven
  • Kelle Moreau
    • Laboratory of Aquatic EcologyKatholieke Universiteit Leuven
  • Bruce J. Riddoch
    • Biological SciencesUniversity of Botswana
  • Luc De Meester
    • Laboratory of Aquatic EcologyKatholieke Universiteit Leuven
  • Luc Brendonck
    • Laboratory of Aquatic EcologyKatholieke Universiteit Leuven
Primary Research Paper

DOI: 10.1007/s10750-006-0233-x

Cite this article as:
Hulsmans, A., Bracke, S., Moreau, K. et al. Hydrobiologia (2006) 571: 123. doi:10.1007/s10750-006-0233-x

Abstract

The anostracan Phallocryptus spinosa has an almost exclusively palearctic distribution. The Makgadikgadi Pans area in Botswana represents the only distribution record south of the Sahara. In this ephemeral wetland, it is an important food item in the diet of migrating birds. By studying egg bank characteristics (such as depth and density) and hatching requirements, we investigated the persistence of this sub-Saharan population. At localities in the middle and north basin of Sua Pan, sediment cores were taken along a transect, and dormant eggs were isolated. Densities of the active dormant egg bank ranged from 833 to 31449 dormant eggs m−2, indicating that this species is well established. Most of the dormant eggs were found in the top 4 cm of the sediments, and densities decreased to zero at a depth of 13 cm. Considering the expected low sedimentation rate, the presence of dormant eggs down to 13 cm indicates long-time occurrence of P. spinosa in the Makgadikgadi Pans area. We observed high hatching fractions (up to 85%) at a temperature of 22 °C and a salinity of 5 ppt. A second anostracan species, Branchinella ornata, co-occurred with P. spinosa in our study site. This population also had a large active dormant egg bank (ranging from 6634 to 50557 dormant eggs m−2) with dormant eggs present until a depth of about 11 cm. This pattern indicates a long-time co-occurrence of P. spinosa and B. ornata.

Keywords

Sua PananostracansBranchinella ornataresting egg bank characteristicshatching requirements

Copyright information

© Springer 2006