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Zooplankton in Rainbow Bay, a Carolina bay pond: population dynamics in a temporary habitat
Author(s) -
TAYLOR BARBARA E.,
MAHONEY DIANE L.
Publication year - 1990
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1990.tb00735.x
Subject(s) - copepod , biology , zooplankton , ecology , bay , population , fecundity , daphnia , crustacean , predation , oceanography , demography , sociology , geology
SUMMARY.1 Rainbow Bay is a temporary freshwater pond in South Carolina, U.S.A., that typically fills in winter and dries in spring or summer. We studied population dynamics of zooplankton in 1984 and 1985 when it held water for 282 and 57 days, respectively. The zooplankton were diverse, including one species of calanoid copepod, nine or more cyclopoid copepods, nineteen or more cladocerans, and twelve or more rotifers. The community was initially dominated by the copepods Diaptomus stagnalis and Acanthocyclops vernalis or Diacyclops haueri , later by cyclopoids and cladocerans including Daphnia laevis and Simocephalus spp. 2 Laboratory experiments with sediments from the dry pond support the inference from field data that time of emergence from resting stages was a proximate cause of the initial succession of species. The experiments also showed that eggs of the calanoid copepod, Diaptomus stagnalis , were inhibited from hatching in early November, but became ready to hatch by late November. A similar inhibition was not observed for cladocerans or cyclopoid copepods. 3 Food limitation appeared to influence population dynamics following emergence. For the cladocerans Daphnia laevis and Simocephalus spp., great reductions in size‐specific fecundity occurred 1 month (1985) or 3 months (1984) after the pond filled and were associated with disappearance of the rotifer Conochilus hippocrepis . The cladocerans produced ephippia when their fecundities declined. Reproduction of Diaptomus occurred before cladoceran fecundities decreased in 1984, but during their decline in 1985. Broods of Diaptomus were smaller in 1985. 4 The impact of invertebrate predators was probably greater than that of vertebrate predators, but neither was sufficient to prevent over‐exploitation of food resources. Prey consumption rates by salamander larvae were estimated from diets and population densities of the larvae in 1984 (Taylor et al ., 1988). Their impact on the zooplankton was low in February, increased in March and April as the larvae grew, and then