N.Z. E,COLOGICAL SOCIETY 21 veloped by being caught and being thrown back. minded her of the intake pump in use tat Lake They are as good as dead when they are caught. Grasmere salt works near Blenheim. This pumped Even if thrown back they do not survive. Fish in a considerable amount of sea water, and many can see a trawl coming, and gee a hook on a line. 'other things as well. She wondered whether any Some fish are mOre intelligent than, others, and modern binlogist had thought of using it. have a better instinctive reaction, simply by being , DR. R. M. WILLIAMS asked whether Mr. Cassie alert to a trawl coming through the water near had been assuming a stationary population. them. Many more fish swim away than are ever CASSIE caught. MR. said he had assumed that it was a stationary population. He had, smoothed all MIss L. B. MOORE said that Mr. Cassie's slide natural fluctuations, mortality and so on, so that of the "vacuum-cleaner" fishing devicehad 're- it was a stationary population.

The Occurrence of Fungal Associations in Soils . P. ]. Culliford

Within the soil, mould fungi occur as spores b. Does the same habitat, if it ren~ains un- and as actively growing myeelium. By plating changed otherwise, yield a similar list of species on. nutrient agar identifiable colonies are produced after a lapse of time? . from these true soil organisms, both active and An initial isolation from field samples from inactive, and also from spores present as chance inclusions from the air. Furthermore; the species Himatangi sand yielded seventeen species amongst so isolated are not the full complement since slow- which Penicillium (2 spp.), Stenophyllum, Geomyces, and Fusarium (one sp. each) were growing fungi are swamped by others more suited numerically dominant. Twelve months later, by the culture media. Keeping these faets in mind the species lists secured by plating tech- from an adjacent spot, the same species were niques may be reviewed to see if they provide obtained in abundance, while two other species had increased in numbers. This flora seemed to any evidence that fungi form stable associations . in the soil. have remained fairly stable over this period of time. Three kinds 01 tests were applied. c. Does a change in the habitat produce a a. Do similar habitats produce similar aggre- change in the species content? gations of species? The similar habitats chosen were the' litter mounds characteristic of rimu Using Himatangi sand, as in the previous test, (Dacrydium cupressinum). Such mounds, each copper sulphate was applied at rates equivalent to derived largely from the litter of a single tree, 5 lb. and 25 lb. per acre, the samples and controls display the same pH pattern throughout the profile being incubated at 22¡ C. and kept at a constant and yield similar results. from. organic analysis moisture level for the experimental period of 96 days. The lighter application which about doubles by Waksman's method. of proximate analysis of organic matter. Six litter mounds were studied, the amount of copper in the soil was regarded at Silverstream, , , Rau- as a rather slight change, the heavier dressing as rimu, Tokaanu, and Mt. Egmont. Of 37 species a major change. After the initial period of of mould fungi isolated eleven appeared to be . disturbance due to addition of copper sulphate typically present in rimu litter, the rest being only and transportation 'and mixing of the soil, the sporadic. Of the eleven constant species eight environment remained constant under each treat- belonged to the genus Penicillium and one each ment. The 5 lb. treatment, showed the same to Mucor, Fusarium and Trichoderma. These general pattern as the control though Penicillium organisms appear frequently in New' Zealand soil, decumbens had given way to P. chrysogenum as but have not previously been recorded all to- the' dominant and some copper-tolerant species gether. In contrast an adjacent site under beech had increased in frequency. With more copper (Nothofagus truncata) at Silverstream provided as about two-thirds of the species disappeared and dominants a Trichoderma, a Cladosporium and a of' the four principal species left tWo were different Penicillium. Penicillium species well-known for their ability to 22 N.Z.. ECOLOGICAL SOCIETY withstand high copper concentrations. Stability litter decomposition mounds under rimu one would was reached after about 25 days,and there was expect Basidiomycetes and cellulose-decomposing little later change. organisms that were not represented in the lists. In these tests similar environments produced He would recommend using as many techniques similar floras, a stable environment produced a as possible, including those that involved a mini- stable flora and change in the environment induced mum of change from natural conditions. a parallel change in the flora. Even allowing DR. R. G, EVERSONsuggested that succession that the recorded lists of species give a quite would be expected as the fungi altered their erroneous picture of what constitutes the micro- , substrata. He too criticized the method used flora of the soil there does seem to be some close and suggested that more might be learned by harmony between the moulds and the environ- sterilizing the soil and material of the litter ment. mounds and inoculating with individual fungi to DISCUSSION seehow they exploited this substratum. DR. R. H. THORNTONemphasized the import- MR. CULLIFORD pointed out that in a rimu ance of methods of study in investigations of litter mound new material is constantly being micro-organisms. The plating method gives an added so that various stages of decomposition are always present through the depth of the indication of the potential of the soil, rather. than . any measure of the current activity in the soil. mound. He agreed that more variety of method Only in the mycelium stage is the fungus active would have been desirable had the experiments in the soil, but the plating method favours spore- been planned for this particular purpose. forming fungi. This may be why the results DR. J. G. GIBBS referred to the wide field for presented showed a predominance of Penicillium investigation of rhizosphere problems in crop which is notorious as a spore-forming group. In plants, still almost untouched in New Zealand.

Exhibits

As an adjunct to the more formal Annual The following is a list of the exhibits which Meeting members of the Society were asked if were on display:- they could bring to the Conference exhibits I. Animal food chains associated with a lupin illustrative of aspects of their work. A most bush, Prof. B. J. Marples heartening response was received. The exhibits, 2. Intertidal communities, G. A. Knox. which had been brought by members from as far 3. Invertebrates of a saltmarsh, Miss K. Paviour- away as and Dunedin, covered a wide Smith. . range of topics and took the form of photo- 4. Vegetation of the Burma Road, Westport graphs, maps, diagrams, specimens and appa- District, Miss R. Mason.and N. T. Moar. ratus. They were displayed on the walls and 5. Map of Rabbit Distribution, Dr. K. A. benches of the zoology laboratory, where supper Wodzicki. was served after the Annual General Meeting. 6. Rabbit ParasiteDistribution, P. C. Bull. Although the exhibition had been intended only 7. Methods of marking Rabbits, J. S. Watson. as part of the arrangements for the evening 8. Speciesof Rats found in N.Z., J. S. Watson. gathering, it proved so popular that members 9. Erosion studies of Horokiwi Stream, B. T. flooded round it at every opportunity throughout . Cunningham. the rest of the meeting. In addition to the 10. Peat Bogs in Raumati Area, W. F. Harris photographs and specimens illustrating ecological and N. T. Moar. work in progress, the exhibits included two II. "Yellow leaf" of Phormium, W. R. Boyce. student publications, "Tane", produced by the 12. Light integrator made hy Dominion Physical Auckland University College Field Club, and Laboratory, Miss L. B. Moore. "Tuatara", from the Victoria University College 13. Vegetation changes at Molesworth, Miss Biological Society. "Tane" contained many in- L. B. Moore. teresting articles of an ecological nature written 14. Vegetation of Rangitoto Island, Dr. L. H. by the club members, while "Tuatara" included Millener. a number of useful keys to various groups of 15. "Tane", A.U.C. Field Club. plants and animals. 16. "Tuatara", V.U.C. Biological Society.