| Summary: | The growth, survivorship and reproduction of Arctic region Daphnia middendorffiana was investigated in several lakes and ponds on the tundra in northern Alaska and additionally in a laboratory study. Growth rate equations, reproduction rates and survivorship under natural conditions were determined. The natural environments differed in the available resources; investigations were made in undisturbed oligotrophic lakes, lakes undergoing nutrient manipulations, lakes recovering from nutrient manipulation, and a small human-created pond. The lakes also differed in the presence or absence of fish. The results indicated that resource availability affected the growth, survivorship and reproduction of D. middendorffiana. The lake with the highest resources produced the greatest reproduction. The lake with the lowest resources had the least reproduction.The growth, survivorship and reproduction of Arctic region Daphnia middendorffiana was investigated in several lakes and ponds on the tundra in northern Alaska and additionally in a laboratory study. Growth rate equations, reproduction rates and survivorship under natural conditions were determined. The natural environments differed in the available resources; investigations were made in undisturbed oligotrophic lakes, lakes undergoing nutrient manipulations, lakes recovering from nutrient manipulation, and a small human-created pond. The lakes also differed in the presence or absence of fish. The results indicated that resource availability affected the growth, survivorship and reproduction of D. middendorffiana. The lake with the highest resources produced the greatest reproduction. The lake with the lowest resources had the least reproduction. - - -
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