Reports

20th June 2017 – Cliff End – Geology and fossils of Hastings III

In this year’s visit to Cliff End, east of Hastings, we were joined by Ken Brooks, a local expert who has been studying the geology of the Hastings coastline for more than 40 years and has written an accessible guide to the area “Geology and fossils of the Hastings area”. We met opposite The Smuggler Inn at Pett Level on one of the hottest days of the year! Ken had laid out a selection of locally found fossils and, following my brief introductory talk on the Lower Cretaceous geology of the area (see The Seaford Naturalist, no.172, Nov-2013, p.15–17; no.175, Nov-2014, p.12–14 for summary of geology), he passed them around the group for members to see. Ken had also brought along two fibreglass casts he had made of dinosaur footprints – one of a large iguanodont, and the cast of a smaller predatory theropod dinosaur that would have most likely preyed upon the iguanodonts. He had made these from plaster casts he had taken of footprints on fallen blocks on the beach. Colin Pritchard, who could not attend, also loaned us some fossils found locally by his grandfather, which included a large footprint, vertebra and piece of femur from an iguanodont.

Following this introduction, we proceeded along the concrete promenade to the beach. We noted that the vandalized information board explaining the 5,200-year-old sunken forest on the foreshore had been replaced, but sadly the sunken forest itself was obscured by sand – these exposures can change from week to week. In contrast to this, a lot of the shingle further up the beach towards the cliffs had been washed away, exposing far more rocks than are normally visible. These newly exposed rocks displayed a wide range of features including:-

dinoturbation (sediment trampled by herds of dinosaurs – most likely iguanodonts);

ripple marked sandstone (formed by wave currents on the shoreline of a Wealden lake);

gutter casts (formed when water carved small channels in the mud of the Wealden floodplain);

beds of the small Wealden bivalve Neomiodon – these can also sometimes be found in the base of gutter casts;

burrows that had been infilled by the creature that made them as it burrowed through the sediment;

and carbonized plant debris in red ironstone, sometimes the source of identifiable plant fronds such as ferns, conifers and cycads.

We also found blocks of the ‘Cliff End Bone Bed’, a fossil-rich conglomerate consisting of grains of quartz and irregular nodules of sideritic mudstone (ironstone), all bound together by a calcareous cement. It contains fish teeth and scales, sharks teeth, reptilian bone fragments and teeth, pterosaur teeth and, very rarely, primitive mammal teeth, and is one of the richest sources of microvertebrates in the Weald. Unfortunately most of the blocks were very water-worn, and identifiable fossils were few and far between.

At the start of the cliffs we stopped to look at the Cliff End Fault, where the section of cliff to the north-east had dropped by around 3 m against the cliff to the south-west (Fig. 1). This was as a result of the African tectonic plate colliding with the European tectonic plate around 40 million years ago, leading to the formation of the Alps in Europe and of the Wealden Dome in south-east England – subsequent erosion has given us the landscape we see today. The fault also illustrated how the hard, rigid sandstones fracture, whereas the softer clays deform. As we traversed the section we saw many more examples of the features we had seen at the start of the walk, as well as evidence of river channels in the cliff face and the occasional dinosaur footprint. The bed of quillworts in the Ashdown Sandstone at the foot of the cliff, so obvious in previous years, was now very eroded, with large blocks of the relatively soft Ashdown Sandstone having been broken away by falling blocks of the overlying, much harder Cliff End Sandstone. At the end of the section in Fairlight Cove we observed Haddock’s Reversed Fault, where lateral compression during the formation of the Wealden Dome had pushed up the rocks to the south-west by around 60 m against the rocks to the north-east. These had slipped back down a little at some point forming a smooth slip plane clearly visible in the cliff face. Sadly, erosion by the sea over the past decade has meant that much of the lower part of the slip plane has fallen away. Before we retraced our steps back to Pett we looked across Fairlight Cove to the extensive coastal defence works that had been undertaken along this section over the last 27 years. In Fairlight Cove itself is a berm constructed in 1990 from Norwegian larvikite to stop the foot of the cliff being undercut by the sea, and in the distance we could see another rock defence constructed in 2008 from French Carboniferous limestone to prevent rotational slipping of the clay cliffs. These two defences were linked together in 2015 by the placement of more Norwegian larvikite.

Peter and Joyce Austen

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Seven Sisters Country Park 4th July 2017

On a bright warm afternoon Mary Benjamin led us on a stroll through the country park looking at chalk grassland. Grass is a primary component of the grassland and within a few metres of the car park we could see at least 6 species of grass even though we were not yet on the chalk.

A little further on we saw pointed snails - Cochlicella acuta - also commonly known as chrysalis snails which climb up the grass stalks. These are common on the downs close to the sea. It was ideal butterfly conditions and Red Admirals, Meadow Browns and Marbled Whites as well as 6-spot Burnet Moths were flying. Also in evidence were the empty pupa cases of the 6-spot burnet moth.

We proceeded up the South Downs way along the old bostal into unimproved, species-rich short grassland. Mary pointed out 2 examples of chalk grassland plants and explained their survival strategy in the nutrient-poor thin soil. First Silverweed which forms a rosette of leaves covered in hairs so that moisture is retained and rain directed towards the centre of the plant. The second was Wild Thyme which has a different strategy sprawling across the ground. As we proceeded up the bostal other chalk grassland plants including Squinancywort, Lady's Bedstraw, Quaking Grass, Rough Hawkbit, Salad Burnet, Bird's-foot Trefoil, Eyebright, Restharrow and Mouse-ear Hawkweed could be seen. Above us a Buzzard was flying accompanied by the sight and song of skylarks.

At the top of the hill we passed through a gate into another field of totally different character. This field was much less diverse, having been an arable field in 1971 with a crop of oats. It was re-seeded in 1972 . The grass dominates and there are fewer flower species, the main ones being Bird's-foot Trefoil, Lesser Trefoil and Dove's-foot Cranesbill.

We descended the SDW back to the track that leads to Foxholes. At the base of the hill he vegetation was lusher, probably explained by a combination of collecting soil and rainwater run-off.

We proceeded a short way along the cycle-path towards the sea where we could see a small area of salt-marsh typified by Sea-purslane, glassworts, one of the Sea-sperrys and Annual Sea-blite. All of these plants have developed methods of coping with saline conditions.

A little further towards the cliffs we came across Pyramidal Orchids and Tufted Vetch in the taller vegetation.

Proceeding back towards the car park along the concrete track we saw further chalk grassland plants including Wild Marjoram and particularly Greater Knapweed which proved to be a rich nectar source for butterflies and moths including pairs of Marbled Whites nectaring on the same flower. many 6-spot Burnet Moth pupa cases, some with moths emerging and one or two pairs mating.

Further along the track was a Horse Chestnut Tree - Mary demonstrated why it was so-named by showing the horseshoe-shaped scar where the leaf joins the twig.

An enjoyable and instructive walk.

Chris Brewer

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18th July 2017 - Hastings Country Park Nature Reserve

13 members of SNHS visited the Reserve on a day of high temperatures and glorious sun. There was a stiff breeze particularly on the top of the hill which made butterfly identification tricky. Nevertheless we managed to see meadow brown, clouded yellow, painted lady and red admiral before we all gathered for a slide show and talk by Nikki Gammans in the Milking Parlour. We were joined by 3 members of the Park staff, one of whom, Murray Davidson, led our guided walk to the Reserve on 9th May when we had also visited Mallydams Animal Rescue Centre. He briefly reminded us of the sites mixed arable grazing, farmland, SSSI status, biodiversity, protection of habitat and species variety.

Nikki gave an introduction to bees. Bees originally developed from wasps and had a sting. Their genus is Bombus, tribe Bombini. There are 24 bumblebee species. The Queens will hide away for the winter. Unfortunately, bumblebees are in decline and some are even considered extinct in this country at least. There is a project to reintroduce the short-haired bumblebee.

There was then an outline of the 3 types of bees:

Solitary - females carry pollen, there are 230 solitary kinds of bees in the UK, a single female taking over the entire responsibility of making a nest for her family and collecting the food for their development which is stored in small holders. Cuckoo, miner and mason bees share a preference for poor soil for nests.

Honey Bees - there is one species in Europe, 8-12 world-wide, they have a complex society, produce honey, bees wax and royal jelly, there is a queen and worker caste, the grubs each live in a separate cell, the queen does not forage, she lives for about 5 years. She can be pushed out and she takes many bees – a swarm.

Bumblebees – there are 27 species with a queen and worker caste, the queen founds the nest and provisions it, has only one mate, the workers then take over. The queen will hibernate for7 months, the colony only lives 3-5 months.

Domesticated bees have 50,000 workers while Native bees have only 50-400 workers, the colony survives in the former but only the queen in the latter. Disease can affect domesticated bees but the loss of foraging habitat is a serious threat to them. Farming intensification and increased use of pesticides have produced highly fertile soils which are disliked by bees. However, sensitive land management has shown that efficient schemes with flower rich borders have increased yields because of the bees’ active pollination.

The 3 kinds of bees have tongues of different lengths to make use of the various food sources. Open flowers are best for nectar and pollen. “Beekind” suggest the following types of wild flowers in your own garden. Scabious, vipers bugloss, red clover, cornflower, tufted vetch etc.

Bees will make nests in used bird boxes which have been shown to be sheltered and safe. Bee hotels are popular. There can be one or two broods depending on the species. The early migrants may produce two broods. Bees are temperature sensitive.

The widest variety of bumblebees has been found at Rye, Dungeness, Romney Marsh, North Kent marshes, Sandwich and Petts Level. There is a 90% reduction in recorded level of the Great Yellow in 100 years. There is extensive work being done in introducing the short-haired bumblebee. Restoration of good management and water levels, and return of marsh-mallow and marsh-mallow moth show pollinators are returning.

Before we all stepped out to look for bees Nikki told us of the Project with Swedish bee staff and volunteers. Queens are collected for reintroduction here. This scheme is in its 5th year. The DNA of the bees is taken and is shown to be very close to our own bees. They are tested for any diseases and our bee populations are increasing. Nikki brought the bees back in the fridge in her camper van, 100/year. She recommended www.beewalk.org.uk

We all stepped out to the hedge boundary which was jumping with insects. We saw red and white-tailed, garden and buff-tailed bumblebees and much else. We noted common wasp, and common carder bumblebees and then moved to the wild flower border next to a wheat field where we saw many insects and crickets, Roessels bush cricket being the most colourful.

This was a talk and walk far beyond the time that we could give to it but it certainly showed us something of the complex and busy life of Bumblebees.

Dee Daines

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1st August 2017 – Seaford Head

On a pleasantly warm morning we met up with Sarah Quantrill, the Sussex Wildlife Trust ranger for the Seaford Head Nature Reserve. We set off by walking along the concrete path towards the golf course, on the way spotting a red admiral butterfly, a pied wagtail and two wheatears.

Just before taking the turn to cross the side of the course Sarah stopped to give a brief health and safety talk, including a warning to watch out for golf balls! More seriously she advised us to check ourselves for ticks after the walk. Sarah pointed out where the green winged orchids had flowered earlier, the numbers being down this year. The heath dog violet flowered there too. She explained that management of the whole area was undertaken in conjunction with the golf course manager, and a large part of this involved preventing the scrub from taking over. In order to encourage diversity, cutting down was done in rotation rather than going in and cutting everything down at the same time.

On this part of the walk we spotted gate keeper, speckled wood, hawker dragonfly, rosebay, woody nightshade, and blackcap.

We then walked along ride C, a wide path which was already narrowing despite having been recently well cleared by volunteers. To encourage diversity and improve the profile of the ride when tackling scrub clearance, some parts would be cut and left to grow back, and other parts would be cut and left as lower vegetation. There was also a need to avoid creating wind tunnels. Ideally this work would be done by grazing cattle but it is not practical here. We stopped at an island in the middle of the ride where Sarah explained that the idea was to create a u-shape with low and high growing profile. Unfortunately the green keeper had cut the whole lot down in one go with the flaps down on the machine which left the grass uncollected. SWT volunteers had to remove this to avoid leading to the unwanted result of enriching the soil. It had now been agreed that in future SWT would manage the edges by cutting in rotation over 3 years, each time raking up everything and doing each side separately. We noted agrimony, bird’s foot trefoil, common blue knapweed, eyebright, red tailed bumblebee, carder bee, and small mining bee.

Continuing along ride C we saw the first scallop, cut 4 years ago. Again, the greenkeeper had just flailed the area and then left it – it took volunteers some time to rake and remove. It was this work which drew a comment from a walker of “like Hiroshima in 1945”! There are now 4 scallops, with the intention of cutting a further one this year. The first 2 are being kept clear and the other 2 cut to maintain variety. Colin Whiteman and Paul Baker are monitoring these. Paul said that for the third year now they have been making weekly recording visits to two of them, reporting but not counting.

There was now a long species list. In the first year 250 species were noted, last year there were a few less species in scallop 4, and so far this year 170 species have been noted. They photograph everything and then check afterwards to ensure that identification is correct. Sometimes there is the excitement of recording something unusual. Sarah said that they would use a brush cutter or shears next time leaving an edge – this would involve volunteers on hands and knees removing cuttings and then burning them. At this point Sarah encouraged everyone to have a go at surveying; it was a fun way to learn more and much could be learnt from those who were more experienced. Chris Brewer said that many records are old and need updating. Sometimes nobody had thought about recording something fairly common; an example is rabbits where after many years only one rabbit had been recorded! Just before leaving the ride one of the members spotted a fly with red spots, Eriothrix maculata.

At a view point overlooking the sea and golf course to the west we were able to see over towards the rifle range area where the outline of buildings, including huts, from the 2nd World War can still be seen. The Archaeological Society have found many cap badges and toothbrushes in that area. Sarah pointed out the cotoneaster which spreads everywhere if left unchecked. They had had to resort to spot spraying and then removing the dead stuff. But it continues to grow back and can never be eradicated. Unfortunately there is also a lot of tor grass moving in. The plan agreed with the greenkeeper is that in September this year the area will be grazed by between 15 to 20 sheep which will be moved around and controlled by the use of electric fencing. Sarah said that much of the work to be done was long term – the good news being that SWT have finally been granted the new 25 year lease.

A number of plants were seen including: bird’s foot trefoil, bramble, burnet saxifrage, carline thistle, common centaury, eyebright, fairy flax, hairy violet, lady’s bedstraw, pink clover, perforate St John’s wort, salad burnet, scarlet pimpernel, self-heal, squinancywort, wild thyme, a wayfaring tree, yellow wort, and the seedpods of cowslip. Stonechats were nesting in the area. Also seen were 6 spot burnet moth, female fat thighed flower beetle and a meadow grasshopper. On the way back to the car park we saw hover fly and gate keeper.

We all thanked Sarah for another of her always enjoyable and informative walks.

Susan Painter

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15th August 2017 – Rathfinny

After a stormy night some twenty members and guests gathered and set out in brilliant sunshine for our walk around Rathfinny Wine Estate led by Richard James the manager.

Some hundred and eighty acres of the vineyard are already up and running with chardonnay, pinot blanc, pinot gris, pinot meunier, riesling and a small amount of pinot noir grapes to go into the sparkling wine. The site is ideal for a vineyard as the slope of the valley shelters the vines from frost.

The fruit is grafted high on wire as this makes it easier to harvest the grapes. All harvesting and pruning is done by hand with machines only being used for trimming the tops, weeds at the bottom and the leaves above the bunches of grapes. The runs between the rows of vines have been given over to a six year research project involving the planting of eight different wild flower mixtures to encourage the right sort of insects ie the parasitic wasp which kills off caterpillars and insects that are harmful to the vines. The seed mixtures have been expensive and the long term plan is to harvest their own seed for replanting. One of the main pests is the six spotted fruit fly thought to have been brought into the country on imported fruit to supermarkets. This fruit fly lays its eggs in the grape but causes more problems by exposing the fruit to other diseases. One of the other successful insects on the estate is the potter bee only found at a few other locations, the others being High and Over, two places at Seaford Head and the Isle of Wight. Another nuisance to the vines are badgers who, after a saunter up to the barley fields for worms, stop off on their way home for a dessert of grapes.

After a slow climb up towards the golf course to some spectacular views, Richard pointed out the barley fields which will by 2020-2021 also be planted with vines. There is also part of a field where they have put down rough grass to attract skylarks and there have been twenty nesting pairs this year. Other bird successes have been tawny owl, little owl, barn owl and buzzards all nesting.

On the slopes above the vines the estate has spent around £30,000 clearing scrub and initially will bring in cattle to graze as there is a high percentage of tor grass which is too sharp for sheep to eat. Later sheep will be brought in to graze under the vines in winter. Nine thousand trees have been planted to act as windbreaks and garden waste is put under the vines which helps to keep heat and moisture in the soil. The emphasis at Rathfinny is on a very sound ecological footing with solar panels, waste water recycling and as far as possible sourcing everything from workers to materials within a twenty mile radius. Rathfinny provides a fine example of how working with the environment can achieve great results.

Grace Morrison

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28th/29th August 2017 - Moth Event

The evening of August Bank Monday was mild, windless and there was a clear sky. This was almost perfect for running moth traps and Steven Teale had set up three on Seaford Head Nature Reserve just to the east of the Seaford Head Golf Course. The mercury vapour trap and the two actinic traps were distributed across open grassland and the edges of bracken and scrub in the hope of attracting moths from these different habitats. By the start time of 9.00pm it was almost dark and a good few moths were already being attracted to the lights. About 20 members and guests spent a couple of hours catching, examining and trying to identify the moths that came to the traps.

The following morning about 26 of us met again to examine the moths that had come into the traps overnight and it is estimated that several hundred moths were attracted by the lights. Forty-three species were identified during the evening and the following morning took the count up to 59. A list of the species identified can be found here.

At the time of writing it is thought that 35 of the species identified are new records for Seaford Head Nature Reserve. The moth of the night was the Portland Ribbon Wave (Idaea degeneraria), that until recently has been mainly found in Dorset and is deemed to be uncommon; this is thought to be a first sighting in Seaford. The most commonly seen moth was probably the Setaceous Hebrew Character (Xestia c-nigrum ) which was gratifyingly easy to identify with its distinctive marking, and a close second was the Large Yellow Underwing (Noctua pronuba), a large brown or fawn moth with striking yellow hindwings. The distinctive and unusually shaped Angle Shades moth (Phlogophora meticulosa) was also common. Photographs of some of these moths can be seen on the Society’s facebook page.

There was much of interest, including the Spectacle Moth (Abrostola tripartita), who on close examination appears to have rings round its eyes that make it look as if it is wearing goggles; the Garden Tiger moth (Arctia caja) – one of our larger and brighter moths; and the pretty Brimstone Moth (Opisthograptis luteolata) with its bright yellow wings. We also saw the Spindle Knot-Horn moth (Nephopterix angustella) that is designated as scarce, and an uncommon migrant from Africa called the Scarce Bordered Straw moth (Helicoverpa armigera). The traps not only attracted moths but also several species of flies, ladybirds and wasps. At about 05.30hrs a large swarm of wasps (Vespula vulgaris) was attracted to the traps, stinging Steven Teale several times and causing a certain level of anxiety when the traps were opened later in the morning.

Steven Teale not only identified moths but also provided information about their lifestyles and of particular interest was the Parsnip Moth (Depressaria radiella). The caterpillar of this moth is easy to find because it lives on hog weed and wild parsnip where it weaves a conspicuous silken web around the flowers that are its major food source. It later pupates within the stem of the plant.

It was generally agreed that the Moth Event had been successful and it is planned to run another one in June of next year.

Marion Trew

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page updated 6th September 2017