Summer Meeting at SouthamptonSource: Journal of Animal Ecology, Vol. 22, No. 2 (Nov., 1953), pp. 413-416Published by: British Ecological SocietyStable URL: http://www.jstor.org/stable/1838 .

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British Ecological Society 413 or diel, according to the animal's reactions to light and temperature. Field investigations in Wytham Woods, Berkshire, confirmed that the wood-mouse (Apodemus sylvaticus) is strictly noctumal; and showed that the bank-vole (Clethrionomys glareolus) has a diel rhythm similar to that of Microtus, being active during day and night. Both species were studied in the laboratory under controlled conditions of light and temperature. Increasing the length of night from 8 to 12 hr. caused the mice to store food in their nests, and their recorded activity was subsequently reduced to about half that shown during 8 hr. nights. The further increase in length of night to 16 hr. did not affect the amount of activity recorded, but did result in a change from a rhythm with bimodal distribution during the night to one with no definite peaks of activity. The bank-voles showed no appreciable response to the change from an 8 to 12 hr. night; but when the night was lengthened to 16 hr. they also reduced their activity outside the nest in about the same proportion shown by mice, and a previous tendency to show peaks of activity during the night disappeared. Comparison of the ratios of day and night activity of the two species indicated that both had a preference for night-time activity which could not be easily accommodated in an 8 hr. night, with the result that composite histograms for each experiment showed sharp peaks. But when a 16 hr. night was reached, this preference was easily satisfied, and individual variations in time of activity became more apparent.

The meeting was terminated by a paper by H. T. Blank on census methods in partridge population studies. Census work on a partridge population involving peaks of up to 4000 birds over a 4000-acre area in west Hampshire was undertaken primarily as a means of elucidating the factors controlling partridge densities, and secondly to measure the effect of any habitat modification that may be carried out. Three complete censuses are carried out annually. In March, after the coveys have broken up and the birds have paired, the first complete census takes place. The second complete census occurs in September as soon after the peak population period as crop conditions will allow. By careful planning and use of transport and ten to twelve men the 4000 acres are covered in 4 days. On the other estates where the manpower is not available the September census is replaced by an August young/old ratio count which in combination with the March census supplies a useful substitute figure for the September census. After the cessation of shooting a third census is made during December. The September census methods are repeated but the individual driving areas are larger. Supplementary information is provided by detailed nesting records (from which an estimate of the total number of chicks hatched can be made) and by examination of the samples obtained as a result of shooting and netting, and from the August young/old ratio count. For investigating particular aspects of population problems (age-composition, local move- ment, territories, etc.) over 400 partridges have already been individually marked and the analysis of observations on these birds is providing valuable information. Thus, by use of the above methods, a full and accurate picture of the seasonal rise and fall, and age and sex composition of a partridge population is being built up.

At the close of the meeting the President thanked all the contributors for the very interesting papers presented during the two days of the meeting. He also thanked all at Kew who had made the soir6e there so successful.

SUMMER MEETING AT SOUTHAMPTON

21-26 JULY 1952

The Summer Meeting was held at Highfield Hall, Southampton University, between 21 and 26 July. On the evening of 21 July a soiree was held at Highfield Hall, at which several exhibits were shown

dealing with the ecology of the New Forest and Southampton region. Immediately preceding this, the Principal of the University, Sir Robert Wood, cordially welcomed the Society.

TUESDAY, 22 JULY

The excursion opened with a visit to the Lymington Estuary under the leadership of Mr C. E. Hubbard. A very extensive area of Spartina townsendii was examined. This community had in recent years shown some recession and reduction in the vigour of growth of individual plants. Some mortality of tirers and

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414 British Ecological Society plants was noted. All this has led to the severe erosion of the hitherto stabilized estuarine silt and mud, which has necessitated extensive dredging of the main channel of the river by British Railways.

Some fungal infection of the Spartina has been noted, but this alone was not considered sufficient to account for the marked deterioration of the stand that has occurred. The Society was not able to suggest the cause of this nor a means of checking it.

After lunch the members visited New Park, near Brockenhurst, under the leadership of Dr Hockley. Here an opportunity was had to examine the stream fauna of the area.

A visit was made to the origin of the Lymington River, at the confluence of Ober Water and Highland Water. These are acid streams flowing from considerable areas of bog, and with a pH range of 6-1-7-0. The flow is fairly rapid and the bottom is mainly of gravel, with only short stretches of mud and weed. In eddies of the stream a debris of sticks and leaves accumulates, often forming quite large banks. Here the ammocoete larva of Lampetra planeri lives just below water level, consuming the finest particles of debris and micro-organisms. The relationship between larval and spawning sites was demonstrated by Dr Hockley.

During periods of heavy rainfall Ober Water floods the adjacent land, leaving quite large and semi- permanent pools. Mr R. E. Hall demonstrated the situations here, and in the main stream, from which he obtained chironomid larvae in mud samples, and reared the adults for identification. Seventeen species were noted, mainly from the stream edge, and three other species were recorded only from the stagnant water.

The leech, Hirudo medicinalis, is also common in this locality, and many species of dragonflies, but these were not in evidence on this occasion.

After tea, White Moor, near Lyndhurst, a typical New Forest Valley Swamp, was visited under the leadership of Miss Jean Dilnot.

At the roadside, near White Moor, a well-developed podsol under Calluna heath was inspected, and the party then passed from the drier heath through wetter heath with abundant Sphagnum compactum to the swamp in the valley bottom, where peat is developed to a depth of 1 metre masking the Tertiary surface drift of Barton sand, and the dominants are variously Eleocharis, Eriophorum angustifolium, Myrica and Carex rostrata, always with a carpet of Sphagna. Alder carr, with marginal Salix atro-cinerea, masks the course of poorly developed streams. The carr lacks some of the typical fen species, but never- theless Carex paniculata stools are prominent and the pH is above 6-0, in contrast to readings of 4-15 under Sphagnum compactum heath and 5-5 in the swamp. Conductivity measurements support the view that the high basicity of the carr soil is due to a supply of base-rich soligenous water flowing in above a gravel bed, which lies at about 30 in. depth, under the permanently water-logged valley bottom peat, whilst acid flushing by water draining in from the surrounding heath influences the marginal communities.

Plants of interest included a patch of Rhynchospora fusca, and occasional individuals of Lycopodium inundatum. Dr Dahl named about twenty-five species of lichens and Dr Wallace and Mr Austwick found Inocybe halophila, which is normally regarded as a sand dune species and was very frequently associated with Salix repens in the 'slacks' of Studland, and a species of Cortinarius growing together under Alnus and Salix atro-cinerea.

Members then retumed to Southampton. During the evening Captain C. Diver gave a very interesting account of his work on Studland Heath,

this being in the nature of a general introduction to the area which was to be visited the following day (see C. Diver, Geogr. J. 81, 1933, and R. Good, J. Ecol. 23, 1935).

WEDNESDAY, 23 JULY

First, the party travelled by coach to Hartland Moor, a small bog to the west of Studland, and one of the few sites in the district where deep peat occurs. This area was drastically bumt with flame-throwers after the war but is now being recolonized. The bog surface was composed of Sphagna and associated plants, with non-tussocky Schoenus nigricans. A small adjoining valley contained a fen dominated by large tussocks of S. nigricans. A fine stand of Erica ciliaris was noted on the adjoining heath.

Lunch was taken at Studland Heath after a brief halt at a point from which a bird's-eye view of the whole area could be obtained.

In the afternoon the party split into several groups. Some studied the south end of Little Sea and the

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British Ecological Society 415 adjoining dunes, while others made their way northwards, completing a circuit of the whole peninsula,

which consists of a narrow spit separated from the sea by three rows of dunes with slacks between them and a larger expanse of water, the Little Sea, between the dunes and the land. Stages in the primary succession from strand vegetation to dunes dominated by Ammophila arenaria and then dry heath with Calluna vulgaris and Erica cinerea were seen. In the slacks areas dominated by such plants as E. tetralix,

Myrica gale and Salix sp. (resulting from the accumulation of fresh water) were visited. It was noted that the swamp dominated by Phragmites communis, Scirpus spp., etc., had in places encroached considerably on the Little Sea since the survey was made by Prof. Good (J. Ecol. 23, 1935, pp. 361-405), and that much of the woodland described by him had been felled.

The party reunited for tea and the return journey during which a halt was made to observe the vigorous and healthy Spartina townsendii at Holes Bay, Poole Harbour.

After dinner at Highfield Hall, Dr G. Dahl, of Oslo University, spoke on 'The Ecology and Analysis of Scandinavian Mountain Vegetation'. He dealt in particular with high altitude vegetation in Norway,

and the part played by such factors as relative duration of snow cover, and the effect of frost pockets. Dr Dahl showed how these factors had such a dominating effect on vegetation that the composition of the plant communities studied was a direct reflexion of the intensity of these factors, and they apparently did not change in nature from year to year. Hence there was little evidence of the kind of succession that we are familiar with in Britain. He went on to suggest that apparent instances of succession between communities here should be re-examined in the light of his observations.

Dr Dahl also demonstrated a continuous temperature recorder which he had devised, and used in the course of his work.

Several members of the Society took part in the discussion which followed. The necessity for detailed ecological work of the kind outlined by Dr Dahl was stressed.

Finally, Dr C. B. Williams thanked the speaker for his paper, and expressed the pleasure of the

Society at his presence throughout the Summer Meeting.

THURSDAY, 24 JuLY

In the morning a stretch of Highland Water south of the main road bridge (Lyndhurst-Wilverley Post

road) was visited under the leadership of Dr A. R. Hockley. This stream is among large beech trees and scattered holly, and has a 2-3 ft. weir under the bridge.

Nearly 300 yards of this stream was surveyed by Southampton students in September 1947, and later

changes have been recorded. In March/April each year the spawning sites of Lampetra planeri have been

observed, and the distribution of the larvae. The locations of these sites and factors influencing their choice were described and discussed by Dr Hockley.

Following this, Mr D. R. Browning, the Assistant County Agricultural Officer, demonstrated to the

party the scheme, started in 1944, for reclaiming areas of the New Forest for agricultural purposes

(World Crops 4 (1), January 1952). The areas visited were between Brockenhurst and Burley. Since the

open forest is all common land, permission to enclose up to 1000 acres was granted for a limited period only. The plots selected, usually bearing bracken and gorse, were fenced off and ploughed. Up to 10 tons

per acre of chalk were added, as well as some superphosphate and other fertilizers. Arable crops grown first included potatoes and oats, with some wheat and sugar beet. After 3 or 4 years under arable crops, the plots were sown with various grass-clover mixtures, the surrounding fences being removed a year or

so afterwards. The persistence of these leys under very heavy grazing was quite remarkable, though invasion by

bracken and gorse was occurring locally. After lunch at Burley, the party visited Cranesmoor under the leadership of Mr P. J. Newbould. This

is a slightly atypical New Forest valley bog. After crossing the marginal heath communities and the wet

heath characterized by Erica tetralix, Calluna and Sphagnum compactum, the party were able to contrast

the heavily flushed areas bearing S. papillosum and Rhyncospora alba. Cranesmoor differs from White

Moor, visited on the 22nd, in that it has a more extensive Sphagnum carpet, no appreciable carr formation, and occupies a fairly large (lake) basin rather than a small river valley. It is remarkable in having nearly 5 m. depth of Sphagnum peat in one part.

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416 British Ecological Society After tea the party was met at Stoney Cross by Mr P. L. Winchester of the Forestry Commission, under

whose guidance a visit was made to Salisbury Trench Enclosure where Quercus petraea, which was perhaps the indigenous New Forest oak, was seen to be regenerating abundantly.

FRIDAY, 25 JULY

For the final excursion on 25 July, lead by Dr J. F. Hope-Simpson, the objective was Butser Hill, near Petersfield-the westernmost hill of the South Downs and also the highest, bearing chalk grassland, scrub and yew woods and a broad plateau of strongly acid clay-with-flints (surface pH 3 9). Although presenting no great floristic excitement, and sadly impoverished by the recent destruction of its plateau grass-heath, Butser Hill is rich in ecological demonstrations which are the more instructive because for over 30 years it has been the scene of published observations by members of the Society-Tansley, Adamson, Watt, and Hope-Simpson.* The party was conducted by Dr Hope-Simpson to the precise viewpoints of photo- graphs taken in 1920 and 1940. With their aid it was seen that one of the yew societies, freed from heavy rabbit pressure, had recently been re-developing in the coombe-head, while another had remained almost stable. By a similar photographic comparison the deep, rabbit-ridden western coombe (Rake Bottom) showed an apparent waxing and waning of its elder scrub. The spur beyond (Ramsdean Down) showed two or three grassland ecotones (e.g. the limit of co-dominant Poterium sanguisorba). On its crest, small islands of clay-with-flints were found to bear a sharply localized dominance by Agrostis (canina and tenuis). Members who faced a whirlwind battle-course across Rake Bottom saw Rhacomitrium lanuginosum, a moss otherwise almost unknown on the chalk, and a little Phyteuma tenerum, a straggler from its region of great abundance centred a good 30 miles to the east. Tea was followed by a short inspection of the nearby Windmill Hill, where a further photographic comparison showed that the rabbit-devastated ground of 1940 now, after war-time destruction of rabbits, bore an almost closed fescue turf. Sonchus sp. was seen by a shaded trunk reaching a height of 6-7 ft.

This terminated a very successful Summer Meeting, during which so much of ecological interest was seen. The weather was excellent, and everyone thoroughly enjoyed the beautiful countryside through which we passed.

The Society is greatly indebted to both Miss F. M. London and Dr Manners who were respectively responsible for the arrangements and for accommodation, travel and food during the itineraries, and for leading many of the excursions.

We also thank Sir Robert Wood, and Prof. W. T. Williams for the hospitality given us at Highfield Hall, and Dr Hockley and Dr Hall for leading the fresh-water biology excursions.

AUTUMN MEETING AT LIVERPOOL

17-19 SEPTEMBER 1952

The Autumn Meeting was held at the Department of Zoology, The University, Liverpool, by kind permission of Prof. Pumphrey, F.R.S. Local arrangements were made by Dr H. B. N. Hynes. Members and visitors attending (30) were accommodated at Derby Hall.

On the evening of 17 September at 8 p.m. a Soiree was held at the Department of Zoology, at which Dr J. W. Jones exhibited his film of spawning salmon.

18 September was devoted to a symposium of stream fauna. Dr C. B. Williams was in the chair. The first paper was given by Dr L. Davies on quantitative studies on the black-fly Simulium ornatum

in a lowland stream. The work was carried out on, and near, a small stream in east County Durham, where S. ornatum composed about 99 % of the Simuliid aquatic stages. Fortnightly samples of larvae and pupae were taken at three stations. Up to September of the first season's work, the figures indicated three peaks of pupal abundance, producing adults in April, late May and June, and in August, respectively.

Oviposition activity was studied by means of cylindrical sticky-traps placed horizontally a few inches above water-level, at suitable sites. Three such traps caught up to 300 female S. ornatum per week. Great

* Tansley & Adamson, J. Ecol. 13, 1925; A. S. Watt, J. Ecol. 14, 1926; J. F. Hope-Simpson, J. Ecol. 28, 1940; 29, 1941.

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