Report of the Nelson Lakes Survey 1971 by the Cawthron Institute / editor, M.E.U. Taylor.
Contributor(s): Cawthron Institute.Material type: BookPublisher: [Nelson, N.Z.] : Cawthron Institute, Description: 1 volume (various pagings, unfoliated) : illustrations, maps (1 colour) ; 34 cm.Subject(s): LAKES | SURVEYS | EUTROPHICATION | LAKE MORPHOLOGY | AQUATIC PLANTS | ALGAE | FRESHWATER MUSSELS | LAKE SEDIMENTS | PLANKTON | WATER CHEMISTRY | AQUATIC WEEDS | EPILIMNION | MOSSES | AQUATIC INSECTS | ELODEA | THERMAL STRATIFICATION | TROPHIC STATUS | LAKE ROTOROA | LAKE ROTOITI (ROTORUA DISTRICT) | NELSON | NEW ZEALANDHoldings: GRETA POINT: OUTSIZE 574.5:556.55 (931.312) TAY
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“This is a cyclostyled copy of an original report prepared by Dr M.E.U. Taylor, Cawthron Institute, on behalf of the Nelson Lakes National Park Board. Additional copies have been produced to meet a heavy demand for the work but, for reasons of economy, appendices and diagrams have not been reproduced. Interested readers may obtain a copy of the original on loan from the Park Board. This is not an official publication and is not to be quoted in any form without permission of the author.” 2nd October 1972. J.H. Tisdall, Secretary, Nelson Lakes National Park Board, P.O. Box 443, Nelson.
Includes bibliographical references ([section] 11).
1. INDEX -- 2. SUMMARY -- 3. INTRODUCTION -- 3.1 The reason for the survey -- 3.2 Previous studies of the Nelson Lakes -- 3.3 The scope of the survey -- 3.4 Personnel involved in the survey -- 3.5 Diary of the survey -- 3.6 Notes on some concepts in limnology -- 4. LAKE MORPHOMETRY -- 4.1 General -- 4.2 Physical features -- 5. MACROPHYTE SURVEY -- 5.1 General -- 5.2 Survey methods -- 5.3 The distribution of the macrophytes -- 5.4 Factors affecting the distribution of the macrophytes -- 5.5 Chemical analysis of the macrophytes -- 5.6 Productivity studies -- 5.7 Discussion -- 6. ALGAE -- 7. ANIMAL STUDIES -- 7.1 Introduction -- 7.2 Animal communities on Nitella and Elodea stems and leaves -- 7.3 A quantitative study of an Elodea community -- 7.4 Animals living in the lake sediments -- 7.5 A quantitative analysis of animals from sediment samples -- Some notes on the freshwater mussel, Hyridella menziesi -- 8. PLANKTON STUDIES -- 9. CHEMICAL STUDIES OF THE LAKE WATER AND SEDIMENTS -- 9.1 The lake water -- 9.2 The ‘feeder’ streams to Lake Rotoiti -- 9.3 The sediments -- 10. DISCUSSION -- 10.1 The physical classification of the lakes -- 10.2 The trophic status of the lakes -- 10.3 The Elodea problem -- 10.4 Other potential problems -- 10.5 A suggested programme of future study for the Nelson Lakes -- 10.6 Outstanding problems needing some administrative action -- 11. REFERENCES -- 12. ACKNOWLEDGEMENTS -- 13. GLOSSARY -- 14. APPENDICES -- 1. The area of the weedbeds -- 2. The volume and dry mass of Elodea -- 3. The volume of the epilimnion -- 4. The monthly mean flows through the Buller outfall -- 5. Fig. 4: Transect positions and Elodea beds in lake Rotoiti -- Fig. 5: Transect positions in Lake Rotoroa -- 6. Transect profiles for Lake Rotoiti -- 7. Transect profiles for Lake Rotoroa -- 8. Species lists of macrophytes and aquatic mosses.
When the distribution of the aquatic macrophytes in the Nelson Lakes was mapped it was found that dense Elodea beds occupied all the areas of the two lakes between about 1.5m deep and about 8.5m deep which had a substrate of nutritious fine silt. Only in West Bay, Lake Rotoiti, which has a sand and gravel bottom, low in nutrients, and in those areas where the bottom was covered by a shingle slip, was Elodea either sparse or absent. Elodea was not found in the Nelson Lakes before 1968, but has now almost completely replaced the indigenous plant community. The Elodea beds are probably the densest in New Zealand, having a maximum height of at least 5m in contrast to the 2-3 m maximum found in most lakes. The maximum dry weight per square metre of the densest beds in the Nelson Lakes also appears to be higher than any previously recorded. On the basis of their morphometry and chemical analyses the lakes are provisionally classified as second class, warm monomictic, large lakes with a nitrogen limited mesotrophic status, except that Lake Rotoiti may be occasionally dimictic. It is recommended that steps be taken to prevent further acceleration of eutrophication in Lake Rotoiti due to human activities, and that active steps be taken to prevent any further infestation of the lakes by introduced water weeds.
GRETA POINT: OUTSIZE 574.5:556.55 (931.312) TAY