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Seven members met on Saturday 14th July in fine weather to survey a section of the River Loddon and associated former gravel extraction pits and a small marsh near or in Dinton Pastures Country Park near Reading. The meeting was planned so that members attending were able to come by train, which proved the most popular mode of transport on the day. Once assembled at Loddon Bridge, Earley, the group moved a short distance into Riverside Park (where Cornu aspersum was observed mating) to sample the river adjacent to the bridge, where Theodoxus fluviatilis was found as expected. Other species found included Viviparus viviparus, Potamopyrgus antipodarum, Bithynia tentaculata, Physa fontinalis, Physella acuta, Lymnaea stagnalis, Bathyomphalus contortus, Gyraulus albus, Anisus vortex, Pisidium amnicum, P. milium, P. henslowanum , P. subtruncatum and P. nitidum. Other terrestrial species found included Deroceras panormitanum and Trichia hispida. A particular hazard of the recent wet weather was the muddiness of the riverbank, such that one member slipped nearly into the river at this point and another member had a similar near miss later in the day.
The party then moved into Dinton Pastures. The country park is largely the result of reclamation of the gravel pits formed when aggregate was taken during the building of the adjacent motorways, but once the workings were exhausted, the area was taken over by Wokingham District Council and planted with native shrubs and trees or allowed to recolonise naturally for restoration. The insertion of bridges links the two sides of the Loddon and the area is very popular for local recreation. Fortunately the gravel workings appear to have had little effect on the river which arises on chalk near Basingstoke, and the area provides a useful, and only a week later, very necessary floodplain! Some ditches drain into the river from the A329M motorway but these do not appear to have a significant effect on river water quality.
Once in Dinton Pastures, the translucent leaves of Loddon Pondweed (Potamogeton nodosus), one of the special plants of the river, attracted attention. One of the larger ditches was sampled and Viviparus contectus, Galba truncatula, Pisidum personatum and P. obtusale were found. This ditch is known to virtually dry out during hot spells in summer.
After lunch fishing pitches along the river itself proved more promising, each providing a lucky dip with different species. Those molluscs new to the list included Ancylus fluviatilis, Valvata piscinalis, Lymnaea peregra, Hippeutis complanatus and Pisidium casertanum. Shells of Unio pictorum and Anodonta anatina were dredged out of the river bed. The fish miller’s thumb and three-spined stickleback were also found in the river.
The long jetty on White Swan Lake provided a good opportunity for several of us to work together. Here the additions to the list were Planorbis carinatus, Gyraulus laevis, Planorbarius corneus and Musculium lacustre. A juvenile pike was also examined. While some members of the party chose to look in the marshy part of a recently created scrape for wading birds next to a reedbed in the lake, others moved on to Middle Marsh a small wet area not connected to any water body but with a good range of wild flowers including common spotted orchid Dactylorhiza fuchsii, common fleabane Pulicaria dysenterica and rushes Juncus spp. To the surprise of some of those present, Ron Boyce had not been joking when he had said that he had a vacuum cleaner in his field bag. Vacuum sampling of the area revealed Vertigo antivertigo among the litter, with the other terrestrial species present including Arion subfuscus, Cochlicopa lubrica seg, Deroceras laeve, Euconulus fulvus, Nesovitrea hammonis and Zonitoides nitidus.
June Chatfield had visited the area of the survey in November 1997 to look for Vertigo moulinisana but this species was not found then or during the meeting. There does not appear to be suitable fen habitat along the river for this species, probably as a result of drainage of habitat in the 1970s. However, other terrestrial species found on the same occasion were mostly present. These included Aegopinella nitidula, Arion intermedius, Cochlicopa lubrica seg, Discus rotundatus, Eucnulus fulvus seg, Monacha cantiana, Oxyloma pfeifferi, Succinea putris, Trichia hispida and Vitrea crystallina.
The party then retired to Rosemary’s house for tea before their return journeys. The organiser would like to thank Dinton Pastures Country Park for permission to hold the meeting, Loddon Bridge Park and Ride for permission to park vehicles and all participants for their records. It is most fortunate that the meeting was not held a week later, as after the torrential rain on the Friday the river became a torrent and entire floodplain was submerged and several houses were flooded out. How many of the snails and other wildlife we had enjoyed a week before were swept away?
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 1. Cornu aspersum mating. Photo Peter Topley
 2. Sampling the lake. Photo Peter Topley
 3. Theodoxus fluviatilis. Photo Peter Topley
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