This meeting, the first London Natural History Society field visit to the Esher/Oxshott SSSI site for many years, was held jointly with the British Plant Gall Society and Elmbridge Natural History Society. Ten people participated on what was a clear, sunny and very hot day. The meeting began at Oxshott station, the traditional starting point for exploration of the expansive Commons of Esher and Oxshott, though the tea rooms, once a welcome feature of the day, have sadly long since disappeared.
The Esher site, almost 400 ha in area, largely comprises acid, sandy soils (Bagshot Sands) with heathland as well as a wide range of other terrestrial and aquatic habitats. These include both ancient and secondary woodland composed particularly of Carpinus, Quercus and Fagus, with much Pinus and Betula, both of the latter being invasive onto the managed heathland. London Clay outcrops to the east of the site. Aquatic habitats, including ponds, streams, a spring line and bog, plus the bank of the river Mole, support Alnus glutinosa and Salix fragilis and in places sallows, mostly Salix cinerea ssp. oleifolia and S. caprea, are common. They are important sites for many invertebrates and are especially noted for dragonflies.
This was a general recording day for invertebrates but with some emphasis on plant galls. We started below the south-facing heather slope and struck out into the herb rich grassland where dense stands of freshly flowering hogweed (Heracleum sphondylium) proved an excellent place to begin hunting for insects. Several beetles were quickly identified, including two metallic green Oedemera species found feeding on pollen. Oedemera nobilis, the thick-kneed beetle, is the more distinctive of the two due to the greatly swollen hind femora of the male. The second species, O. lurida, is smaller, duller in colour and not so well endowed. The malachite beetle, Malachius bipustulatus, named for the conspicuous red spots at the tip of the elytra, was also abundant, hunting other insects. Another hunter we encountered was the female crab spider, Misumena vatia, variable and changeable in colour from white to green. She lies in wait, seemingly camouflaged to the human eye, but as insect vision differs from our own it has been suggested that she is actually a lure in the eyes of an insect.
Lepidoptera were also abroad in the grassland, with painted ladies, meadow browns, large skippers and cinnabar moths all on the wing. Also notable on oaks nearby were huge blotch mines due to larvae of the scarce micromoth Acrocercops brongniardella, only recently recorded from the area. Several shieldbugs were noted here: the bishops mitre (Aelia acuminata), green shieldbug (Palomena prasina) and the rather inappropriately named sloe bug (Dolycoris baccarum). The last is rarely found on sloe (Prunus spinosa), and a more apt common name would be the hairy shieldbug! The dock bug (Coreus marginatus), not a true shieldbug but a member of the family Coreidae, was also frequent, particularly on sorrel (Rumex acetosa).
Further up the slope the vegetation gradually changes to Calluna-dominated heathland and scrub, and we began to encounter the internationally protected wood-ant Formica rufa hunting and scavenging underfoot. Its great mound nests, thatched with sticks and pine-needles were soon located at the woodland edge. The notable scarce 7-spot ladybird (Coccinella magnifica), which is usually only found in association with wood-ants, was found feeding on the aphids tended by the ants on bushes a few metres from the nest. In Surrey this ladybird is predominantly confined to the west of the county but it is well known at Oxshott. Searching under dead wood revealed the striking beetle Scaphidium quadrimaculatum, a local species that is thought to feed primarily on fungi in dead wood (mycetophagous). However, the larvae, and possibly the adult, may also be predacious upon other insects. Several longhorn beetles, again associated with dead wood, were also recorded, including the common wasp mimic Clytus arietis, which can often be found in suburban gardens, and several former members of the genus Strangalia. The most striking of these were the common longhorns Rutpela maculata and Leptura quadrifasciata. The former breeds in various hardwoods and can often be found in numbers around flowers at the woodland edge, while the latter mostly occurs with birch. Another saproxylic beetle recorded was the black-headed cardinal (Pyrochroa coccinea). This species appears to have become more common and widespread in recent years and could soon lose its ‘notable b’ status.
We also investigated the chestnut rail fencing and horse barriers. This type of elevated habitat has produced some excellent records in the past for fungi and larvae of the rare psychid moth, or bagworm, Proutia betulina at Esher. Unfortunately we did not record Proutia in this area, but we noted several of the more common psychids: the cigar-like tube of Taleporia tubulosa, the algae-covered bag of Luffia ferchaultella and the distinctive case of Psyche casta which is formed from cut lengths of grass stems. The distinctive but uncommon spider Gibbaranea gibbosa, notable for the prominent bumps at the front of the abdomen, was also recorded near here.
We continued up to the war memorial and then north past the sand pit to Sandy Lane and Esher Common, skirting round Oxshott Bog quite swiftly, as the habitat here is becoming desperate and barely resembles a bog any longer. We headed into Esher Common and took our lunch stop under the shade of young oaks at the small but excellent A3 pond, a fortuitous creation following the mound of soil and spoil produced by the destruction of the old Round Hill area during the construction of the A3 bypass in 1976. The pond supports a range of dragonflies, several of which were flying, as well as a good range of other invertebrates, and both palmate and smooth newts. During lunch we observed the daring aerial battles of male broad-bodied chasers (Libellula depressa) and a hawking emperor (Anax imperator). Many blue damselflies were conjoining over the water. Several were netted and identified from abdominal markings as the azure damsel (Coenagrion puella). After lunch the party continued on, eventually to Black Pond, before returning by a slightly different route to the station.
About 30 gall-causing species were recorded during the day, including eriophyid mites on Fagus and Pteridium, some Pontania species on Salix, and Rhabdophaga salicis near Black Pond. Several oak galls were noted, including ramshorn galls due to the introduced gall-wasp Andricus aries, though spangle galls were quite absent.
The records for the day, which included a total of about 100 species, will be added in due course to the newly created Access database (‘Rucksack’) designed by Sandra Rickwood to handle the many thousands of records available from the area. It is one of the most richly recorded sites anywhere, with close to 9000 species (all groups) recorded to date, and is especially well known for fungi, with over 3300 species, and for insects (for example, over 1100 beetle species occur). Although modern records of many of these are still needed, specialist recording in the past few years has proved extremely encouraging in relocating species not recorded for decades, since the frequent field visits ceased and the site was inappropriately seen as too degraded due to invasion of the heathland by pine and birch. The new management plan, proposed by English Nature and endorsed by the Forestry Commission, to restore significant areas of heathland over the next five years, should secure the future of many of the associated flora and fauna.
Thanks to everyone for their contributions. All records from the area are of interest and welcomed. The next meeting, same details and format, will be on 23 September.
Scott Dodd and Brian Spooner