\V//, r\ / Xr'?4L \Wv TRANSACTIONS OF THE NORFOLK & NORWICH NATURALISTS’ SOCIETY Vol. 22 PART 2 : : OFFICERS OF THE SOCIETY, 1970-71 President: P. R. Banham, Field Study Centre, Polka Road, Wells, Norfolk President-Elect: Professor J. A. Kitching, Department of Biology, The University of East Anglia, Norwich Vice-Presidents: E. T. Daniels, E. A. Ellis, R. Jones, M. J. Seago, Professor J. A. Steers, F. J. Taylor Page General Secretary: R. E. Baker, 15 Southern Reach, Mulbarton, Norwich, NOR 93W Telephone: Mulbarton 609 Assistant Secretary (Membership and Publications): Miss E. M. Buttery, Keswick Hall, Norwich, NOR 93B Assistant Secretary (Minutes): K. B. Clarke, Decoy House, Browston, Great Yarmouth Excursions Secretary: Miss C. Gurney, Cow Comer, Ingham, Norwich, NOR 33Z Treasurer D. A. Dorling, St. Edmundsbury, New Road, Hethersett, Norwich, NOR 42X Assistant Treasurer : J. E. Timbers, The Nook, Barford, Norwich, NOR 38X Editor: E. A. Ellis, Wheatfen Broad, Surlingham, Norwich, NOR 07W Assistant Editor: J. A. Bushell, Newman College, Bartley Green, Birmingham, B32, 3NT Auditor: E. L. Swann, 282 Wootton Road, King’s Lynn, Norfolk Committee: A. L. Bull, Miss R. Carpenter, K. C. Durrant, J. Goldsmith, Dr. R. James (University Member), Miss D. M. Maxey, B. McWilliams (Museum Member), Mrs. R. Robinson, J. H. Silverwood, T. B. Terry, G. D. Watts ORGANISERS OF PRINCIPAL SPECIALIST GROUPS Birds (Editor of the Report) M. J. Seago, 33 Acacia Road, Thorpe, Norwich, NOR 7 IT Mammals (Editors of the Report): P. R. Banham and J. Goldsmith Plants: E. A. Ellis; E. L. Swann Insects: K. C. Durrant, 31 Sandy Lane, East Dereham, Norfolk . Editor: E. A. ELLIS Assistant Editor: J. A. BUSHELL CONTENTS Page Ringmere, by George Garrod 3 The Marine Protozoa, Mesozoa, and Porifera of Norfolk, by R. Hamond 13 The Leptostracan, Euphausiid, Stomatopod, and Decapod Crustacea of Norfolk, by R. Hamond 20 Changes in a Parish Flora, 1925-70, by C. P. Petch, m.d., f.r.c.p. 43 Some Notes on Ferns in Norfolk, by J. H. Silverwood 46 Locomotor Activity of Some Staphylinidae (Coleoptera), by Colin D. Williams, Keswick Hall College of Education 48 Potters Carr, by Alec Bull 55 E. A. Ellis 58 Major Anthony Buxton 62 Weather Summary for Norfolk, 1970, by T. B. Norgate 65 I A general view looking east, 1932. The same view, 1960. RINGMERE By George Garrod Introduction Ringmere adjoins the road leading from Thetford to East Wretham. It is situated (in common with other meres) in the Norfolk portion of Breckland where chalk comes to the surface or is covered with a superficial layer of glacial material. The flora of the area is much determined by the effects on the soil of two glacial periods, and the low precipitation, which is emphasised by the sandy soil and its low water retaining capacity. However, the influence which a biotic factor has had on the flora, and therefore ultimately on the fauna, is now increasingly clear. These notes are extracted mainly from an intensive study of the “bowl” of the mere in 1959 when the mere had much water, and in 1960 when it had dried out. Additional observations are included to complete the 10-year period up to 1970. Water Levels The Revd. Francis Blomefield, in 1739, suggests “it is supplied with land springs from the adjacent hills [sic], which in the extreme dry year ceased running, and so the water shrank into the sand”. There are no signs of land springs, however, and the crest of the bowl being 105ft. above sea level, is the highest point in the immediate neighbourhood. W. G. Clarke (in Trans. Norf. & Norw. Nat. Soc. Vol. VII, 1902-3) attempts to relate the fluctuation of water in the meres to rainfall, not directly, but through the level of saturation in the chalk. He also suggests that differences in height above sea level of the beds of the meres could account for some variations. This appears not to be the case in respect of Ringmere and its two neighbouring pools (the Wash Pit to the north, and the pool by the road to the east) as can be seen from Table 1. TABLE 1 FLUCTUATIONS IN WATER LEVELS Ringmere Wash Pit Pool by road Oct. 1959 Fairly full Dry Full Aug. 1960 Dry Fairly full Full Note : The bed of Ringmere is lower than either of the other pools. This suggests that while the chalk provides a common source of water supply, these pools are fed by different “pipes” which react differently to the saturation level of the water in the chalk, which may be artesian in nature, from a distant catchment area, and under pressure. There is a delay in adjustment of water level to local rainfall. The first months of 1959 were a period of exceptional dryness (rainfall at Kilverstone for the first nine months 15.62 in.) but the general water level in the mere remained steady until the end of August. Neither do water levels consistently coincide with the high losses due to evaporation and crop requirements in summer, or the soaking in of winter rains. Digging shows that at the edge of the bed of the mere the chalk dips sharply, and from being only a few inches below ground level at high water margin, cannot be reached with the spade about six yards further in. 73 Rainfall figures for the period 1959-70 together with observed levels are given in Table 2. (Since this paper was prepared for the printer, the Great Ouse River Authority have made available to the Society the first two Progress Reports on their Groundwater Pilot Scheme in the basin of the River Thet. These technical studies provide a great deal of information towards understanding the hydrology of the area.) TABLE 2 FLUCTUATIONS IN THE WATER LEVEL OF RINGMERE Annual Rainfall Date Water Level at Kilverstone (inches) (1957) 32.20 Dec. 58 Very low (1958) 31.12 March 59* Fairly high Aug. 59 falling (1959) until 21.89 March 60 Dry April 60 slight rise May 60 Dry Sept. 60 Dry Dec. 60 Fairly high (1960) 33.25 March 61 rising (1961) and steady until 30.90 Sept. 62 falling (1962) 23.47 June 63 Medium (1963) 27.16 Feb. 64 Dry (1964) until 23.97 (1965) 29.02 Feb. 66 Rising Nov. 66 Fairly high (1966) 25.59 (1967) 21.32 (1968) 30.54 March 69 High Dec. 69f Very high (1969) falling slightly to 26.22 Dec. 70 High (1970) 26.00 The water in Ringmere was about 180 yards by 120 yards at this time, and about 5 feet deep. Clarke in “In Breckland Wilds" 2nd Edn. p. 44 gives for 1882 an area of 250 yards by 150 yards. He records this as “full", f An area about 250 yards by 150 yards. 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M. scorpioides o Myosoton aquaticum f Nardus stricta Pastinaca sativa Phalaris arundinacea d r Phleum bertolonii Pinus sylvestris (seedling) Plantago lanceolata Poa annua o o P. pratensis o P. trivialis f Polygonum amphibium . f P. convolulus vr P. hydropiper o P. persicaria o Populus alba o P. alba (seedlings and suckers) r Potamogeton gramineus o P. lucens o P. natans o Potentilla anserina a f f P. argentea vr P. erecta o P. reptans o Primula veris vr 76 . +> G <D G <3 G a & Community G G a a G §>>, a o o o S.ts a U e§ o G <D CJ d> G G .a (3 a cn M a cn o Heather >> tS £ G d $ a Wt o u u u O Q O pq H O Prunella vulgaris f Prunus spinosa vr Pteridium aquilinum d r r Quercus robur r Ranunculus acris r o R. aquatilis o R. bulbosus r R. repens r R. sceleratus o Rorippa amphibia vr R.