New Zealand Journal of Marine and Freshwater Research abstracts
Seasonal abundance of small cladocerans in Lake Mangakaware, Waikato, New
Zealand
TRACEY L. GREENWOOD*
JOHN D. GREEN
BRENDAN J. HICKS+
M. ANN CHAPMAN
Department of Biological Sciences
The University of Waikato
Private Bag 3105
Hamilton, New Zealand
*Present address: Biozone International Limited,
P. O.
Box 13 034, Hamilton, New Zealand.
Abstract The seasonal changes in the dynamics and life
histories of the Cladocera in Lake Mangakaware, North Island, New Zealand, were
studied over 19 months by sampling at weekly or 2-weekly intervals. Lake
Mangakaware is a 13.3 ha polymictic lake with high nutrient status, low Secchi
disc transparencies, and an unstable thermal regime. The four planktonic
cladoceran species (Bosmina longirostris, B. meridionalis,
Ceriodaphnia pulchella, and C. dubia) exhibited disjunct
population maxima. Only B. longirostris was perennially present. All
species exhibited low fecundities and low lipid content, indicating that food
resources were limited and that competitive interactions and resistance to
starvation were probably important in determining species success. Increases in
body size in cooler seasons were unrelated to clutch size, giving further
support for the view that available food was limited. These results are
consistent with previous experimental findings that subtle differences in life
history can determine seasonal success and the outcome of competition between
similar species.
Keywords Cladocera; Bosmina; Ceriodaphnia;
seasonal abundance; life history; competition; New Zealand
+Corresponding author.
M98082
Received 2 December
1998; accepted 23 March 1999
PDF file of entire paper: medium quality (1666K); (scanned from paper original: notes about this process)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
