Abstract
In an earlier study, regression models were developed which related black swan populations to macrophyte biomass and to phytoplankton productivity in Tomahawk Lagoon No 2, a small South Island, New Zealand, lake in which phytoplankton and macrophytes vary widely from year to year, in an irregular inverse cycle. Two years of further study confirmed that winter swan populations are directly correlated with macrophytes, for samples taken on a single day in winter each year. They also confirmed that winter maximum swan populations can be predicted from measurements of phytoplankton productivity in the previous summer. This relationship is inverse. For 6 other lakes, 9 of the 11 data points lay within the 95% confidence intervals of the macrophyte-swan relationship, with the only outlier being a lake in which the macrophytic vegetation is dominated by filamentous algae. Further analysis, giving equal weight to each of the 7 lakes in the sample, confirmed that there is a significant correlation in winter between swan populations and macrophyte biomass for these lakes which show a wide range of size and trophic status. There was no such significant correlation in summer. All of the 8 data points from 7 other lakes lay within the rather broad 95% confidence intervals of the phytoplankton- swan relationship. The 4 lakes which fitted most closely to the predictions of this relationship have silty sediment. The other 3, which all had lower swan populations than predicted, have sediment predominantly of sand or fine clay, and macrophyte biomass and swan populations may be constrained by the nature of the sediment, rather than by shading effects from phytoplankton.
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Bull, P. C., 1983. Aquatic birds of the lake and its surroundings. In Forsyth, D. J. & C. Howard-Williams (eds), Lake Taupo. DSIR Science Information Publishing Centre, Wellington: 133–150.
Burnet, A. M. R. & D. A. Wallace, 1973. The relation between primary productivity, nutrients, and the trout environment in some New Zealand lakes. Fish. Res. Bull. N.Z. 10: 28 pp.
de Nie, H. W., 1987. The decrease in aquatic vegetation in Europe, and its consequences for fish Populations. EIFAC occas. Pap. 19. FAO, Rome, 52 pp.
Frith, H. J., L. W. Braithwaite & J. K. McKean, 1969. Waterfowl in an Australian swamp. 2. Food. CSIRO Wildl. Res. 14: 17–64.
Hamilton, D. P., 1990. Sediment resuspension by wind in shallow lakes. Unpubl. PhD thesis, University of Otago, Dunedin, N.Z.
Hutchinson, G. E., 1975. A treatise on limnology, 3. J Wiley & Sons, New York, 660 pp.
Irwin, J. & W. deL. Main, 1989. Lake Ellesmere bathymetry 1:25000. N.Z. Oceanographic Institute chart. Lake series.
Kornijów, R., R. D. Gulati & E. van Donk, 1990. Hydrophyte-macroinvertebrate interactions in Zwemlust, a lake undergoing biomanipulation. In: Gulati, R. D., E. H. H. R. Lammens, M.-L. Meijer & E. van Donk (eds), Biomanipulation — Tool for Water Management. Developments in Hydrobiology 61. Kluwer Academic Publishers, Dordrecht: 467–474. Reprinted from Hydrobiologia 200/201.
Lake Omapere Task Force, 1986. Water quality problems in Lake Omapere. Northland Catchment Commission, Whangarei, N.Z., 34 pp.
Livingstone, M. E., B. J. Biggs & J. S. Gifford, 1986a. An inventory of New Zealand lakes. Part 1. North Island. Water and Soil Directorate, Ministry of Works and Development, Wellington, N.Z., 200 pp.
Livingstone, M. E., B. J. Biggs & J. S. Gifford, 1986b. An inventory of New Zealand lakes. Part 2 South Island. Water and Soil Directorate, Ministry of Works and Development, Wellington, N.Z., 193 pp.
Mitchell, S. F., 1971. Phytoplankton productivity in Tomahawk Lagoon, Lake Waipori, and Lake Mahinerangi. Fish. Res. Bull. N.Z. 3: 87 pp.
Mitchell, S. F., 1989. Primary production in a shallow eutrophic lake dominated alternately by phytoplankton and aquatic macrophytes. Aquat. Bot. 33: 101–110.
Mitchell, S. F., D. P. Hamilton, W. S. MacGibbon, P. K. B. Nayar & R. N. Reynolds, 1988. Interrelations between phytoplankton, submerged macrophytes, black swans (Cygnus atratus) and zooplankton in a shallow New Zealand lake. Int. Revue. ges. Hydrobiol. 73: 145–170.
North Canterbury Acclimatisation Society, 1986. Annual Report for 1986. North Canterbury Acclimatisation Society, Christchurch, N.Z.
Northland Catchment Commission, 1987. Environmental impact assessment for the introduction of silver carp to Lake Omapere. Tech. Publ. 1987/2. Northland Catchment Commission, Whangarei, N.Z. 38 pp.
O.E.C.D., 1982. Eutrophication of waters. Monitoring, assessment and control. Organisation for Econonomic Cooperation and Development, Paris, 154 pp.
Potts, K. J., 1982. Aspects of the feeding ecology of mallard duck and black swan in a small freshwater lake. Unpubl. PhD thesis, Victoria University of Wellington, N.Z.
Spence, D. H. N., 1982. The zonation of plants in freshwater lakes. Adv. ecol. Res. 12: 37–125.
Steel, R. G. D. & J. H. Torrie, 1960. Principles and procedures in statistics. McGraw-Hill, New York, 481 pp.
Strickland, J. D. H. & T. R. Parsons, 1972. A practical handbook of seawater analysis. Bull. Fish. Res. Bd Can. 167: 310 pp.
Wass, R. T., 1991. Regulation of macrophytes by black swans (Cygnus atratus) and wave action: a study on two shallow lakes. Unpubl. M. Sc. thesis, University of Otago, Dunedin, N.Z.
Wells, R. D. S. & J. S. Clayton, 1989. Lake Whangape: the macrophytes. Unpubl. Report, Aquatic Plants Section, Ministry of Agriculture and Fisheries, Ruakura, N.Z, 27 pp.
Wetzel, R. G., 1983. Limnology. Saunders College Publishing, Philadelphia, 867 pp.
Williams, M., 1979. The status and management of black swans Cygnus atratus Latham at Lake Ellesmere since the ‘Wahine’ storm, April 1968. N.Z. J. Ecol. 2: 34–41.
Williams, M., 1981. The demography of New Zealand's Cygnus atratus population. In Proceedings of the second international swan symposium, Sapporo, Japan. International Waterfowl Research Bureau, Slimbridge, UK: 147–160.
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McKinnon, S.L., Mitchell, S.F. Eutrophication and black swan (Cygnus atratus Latham) populations: tests of two simple relationships. Hydrobiologia 279, 163–170 (1994). https://doi.org/10.1007/BF00027851
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DOI: https://doi.org/10.1007/BF00027851