FIELD NOTES
NOVEMBER 2002 continued....
ARTICLES
Rare Plants of SW Herts
Having concluded general tetrad recording for "Flora 2000", I have made some attempt to search more diligently for some of the rarer plants in SW Herts and to re-find those recorded by earlier botanists.
It is fascinating to study the older floras and read of plant records made over nearly two centuries, though sad to realise how much we have lost. However, many species have been re-discovered or have turned up in other places. It is an interesting challenge trying to find some of these species, often ending in disappointment, but in searching special habitats, something other than what you are looking for sometimes turns up.
This happened in Bishops Wood near Rickmansworth. Whilst unsuccessfully searching for Mountain Fern Oreopteris, I came across a damp heathy clearing and was amazed to find two of Hertfordshire's rarest plants, Star Sedge Carex echinata and Green-ribbed Sedge Carex binervis growing together. Star Sedge was recorded from Moor Park in 1953. Here too was Bulbous Rush Juncus bulbosus, only to be found in a few wet heathy places. It was like being on some northern moor where they are of course often common. In another very wet area by a stream, Lesser Skullcap Scutellaria minor survives, and one small plant of Hard Fern Blechnum spicant.
As if this was not enough excitement for one day, I had good views of two White Admiral butterflies on brambles. Their food plant is Honeysuckle, which is frequent in the woods.
On an earlier visit here, I re-found the rare Forster's Wood-rush Luzula forsteri. Similar to the common Hairy Wood-rush Luzula pilosa, but with narrower leaves and the flower branches more erect, not de-flexed. Commonly found by Shire Lane in Chorleywood, I have made a search of other likely sites in the area, with some success. Three patches in Ladywalk Wood by the M25 near Maple Cross, and Limeshill Wood near Chenies, the former a good enough reason to stop making the M25 any wider!
It has also been long known at Easnye Wood near Ware, but we failed to re-find it on a recent flora group meeting, so it does now seem to be confined to this small area of Herts.
My first thrill of the year was to find a small colony of Wild Daffodils Narcissus pseudonarcissus, the real thing, along a little used old green lane near Bovingdon. Six-nine inches tall, they are I think much more attractive than most of the cultivars, especially those planted in rural areas. But how sad that these are probably survivors from what Pryor in his flora of 1887 describes as "large fields of it at Bovingdon and Little Gaddesden and very common about Hemel Hempstead."
In his flora of 1967, John Dony states that "without doubt the best water meadows in the county are those beside the R Chess at Sarratt Bottom". They are certainly not that now having been much de-spoiled and de-graded, but those further up the river towards Chenies arguably are. They include the SSSI of Frogmore Meadows. Here by the river is a good colony of Southern Marsh Orchid Dactylorhiza praetermissa, whilst on the drier acidic heathy soil over gravel a few Heath Spotted Orchids Dactylorhiza maculata ssp ericetorum. Other rarities amongst a rich wetland flora are Marsh Valerian Valeriana dioica, Marsh Arrow-grass Triglochin palustris, Marsh Speedwell Veronica scutellata, the tiny Bristle Club-rush Isolepis setacea and eight different sedges, Carex hirta, C acutiformis, C ovalis, C nigra, C flacca, C disticha, C panicea and C demissa.
The Boxmoor Trust land includes some special habitats with several rare plants. Sheethanger and Roughdown Commons have a wealth of chalk-loving plants including Frog Orchid Coeloglossum viride. The moor itself has the only extant site in Herts for Flat Sedge Blysmus compressus. Here too is Ivy-leaved Crowfoot Ranunculus hederaceus and the rare grass Bromus racemosus.
Croxley Common Moor is another fascinating habitat with many uncommon plants, with the bonus of the beautiful Flowering Rush Butomus umbellatus in the R Gade.
Most rare plants are rare because their special habitats are rare. Some always have been, but much has been needlessly destroyed. As one whose livelihood has been farming but whose love is of natural things, it makes me sad and angry about what agriculture has done to the countryside, though one cannot entirely blame farmers. Successive governments and the EEC have handed out endless subsidies to pull out hedges, drain wetlands, plough up down and heathland and what are they doing now? Paying them to set it aside. Crazy or what!
Hopefully there is now some change of direction with farmers being encouraged to farm in a more environmentally friendly way. But what has been destroyed can never be replaced. We can only do our utmost to conserve what remains, or our flora and fauna will become ever more impoverished and the next generation of recorders will fail to find many of the rare and beautiful things that do still survive today.
Gerald Salisbury
Rare Dragonflies In Hertfordshire
2002 has been a good year for rare dragonflies in Hertfordshire with Red-veined Darter Sympetrum fonscolombii and Black Darter Sympetrum danae both being seen, the discovery of new colonies of White-legged Damselfly Platycnemis pennipes and the first ever Herts record of the Small Red-eyed Damselfly Erythromma viridulum.
Two Red-veined Darters were found by Steve Murray at Tyttenhanger Pits on the 30th June and he saw a single specimen on 14 July. There are six previous records for this species in Hertfordshire on the Darter database and two of these earlier sightings were at Tyttenhanger Lakes in 1998 and 2000.
The earliest record on the database was in 1992 at Hilfield Park Reservoir. The species was also seen at Amwell Quarry in 1996, Broxbourne Gravel Pits in 1998, and Folly Farm Chalk Pit Lake at Bulborne in 2000.
The Black Darter, an adult male, was discovered at the "brick ponds" at Hertford Heath on the 28th July by Alan Reynolds. It was seen again on the 31st July and the 4th August.
The last record in Hertfordshire was at Crabtree Pond, at Goldingtons, Hertford Heath, in 1995. The other site with several old records is the HMWT reserve at Patmore Heath (1960, 1975 and 1987), which like Hertford Heath, is a remnant of acid heath with several ponds.
At the start of the Atlas Project in 2000, White-legged Damselflies were only recorded from a single tetrad in Cheshunt. In 2001 sightings at Admirals Walk Lake, Hoddesdon, Silvermeade Nature Reserve, Broxbourne and the Lea Valley Park car park at Windmill Lane, Cheshunt showed an increase in range in the Lea Valley.
The first recent sighting of this species along the canal system in West Herts also came in 2001 when Steve Murray reported White-legged on the Wendover Arm of the Grand Union Canal. This year, new White-legged Damselfly colonies were found by Mike Campbell during Dragonfly Atlas work on the Aylesbury Arm of the GUC west of Wilstone and south of Puttenham. This brings the total number of known Herts tetrads recorded during the Atlas Project to eight.
The Small Red-eyed Damselfly Erythromma viridulum was first discovered in Great Britain at three sites in Essex in July 1999 . Since then, it has continued to spread into English counties at an incredible rate and last year was recorded in Norfolk , Suffolk , Essex , Kent , Isle of Wight , Bedfordshire and Buckinghamshire, but not Hertfordshire.
However, on the 24th August 2002, Graham White saw a male Small Red-eyed Damselfly at Bowyers Pit, Cheshunt, the first ever record for Hertfordshire. This is an exciting time for Herts dragonflies and it pleasing that evidence of these events is being captured by the survey.
Alan Reynolds and Christine Shepperson
Early To Bud
Plants are flowering up to 55 days early because of global warming, scientists said recently. They found that animals are also changing their behaviour in response to rising temperatures with some moving to colder places.
The white dead nettle has showed the most dramatic change, blooming 55 days earlier in 1990 compared to 1954-1990.
Alistair Fitter, of York University, and his father Cambridge naturalist RSR Fitter, studied 47 years of data on 350 British plants. They found that flowers had bloomed an average four and a half days prematurely over the past 10 years, compared to the previous 40 years.
In 150 to 200 species, flowering time moved forward by 15 days. Average spring temperatures have risen 1.6ºC since the 1960s. Professor Fitter expects plants to move habitats as it gets warmer. He said "We could see species growing in the wild for the first time, many of which could escape from gardens like rhododendron bushes have."
| First Flowering Dates |
| Species | 1954-1990 | 1990-2000 |
| |
| Opium Poppy | Jul 5 | Jun 15 |
Hairy Bittercress | Mar 3 | Feb 7 |
Greater Stitchwort | Apr 15 | Mar 21 |
White Dead-nettle | Mar 18 | Jan 23 |
Lesser Periwinkle | Mar 7 | Feb 11 |
Spurge Laurel | Feb 16 | Jan 20 |
Hornbeam | Apr 22 | Mar 26 |
Lesser Celandine | Feb 27 | Feb 7 |
Ivy-leaved Toadflax | Apr 15 | Mar 11 |
Herb Bennet | May 22 | Apr 30 |
Reproduced by the kind permission of The Daily Mirror.
Another study by French and British scientists found that warm water copepods, shrimp-like plankton, had travelled 10 degrees northwards.
WATCH THIS SPACE
WANTED: Articles for the 2003 edition of Hertfordshire Naturalist
The Herts Naturalist offers YOU the opportunity to publish your findings, observations and investigations into the fauna and flora of the County.
After the bumper edition of 2002, I would like to keep up the momentum with another packed issue.
Already I have articles on topics as diverse as myxomatosis, the Barbastrelle bat, the status of the Wild Service Tree and aquatic insects at Amwell. However, I need more.
For example, have we any studies, observations or comments on the impact of the foot and mouth epidemic in Herts? I would welcome information on the species richness of our special sites, habitat management and species responses, unusual observations and so on. In addition there will be the regular 'Recorders Reports' section, which I hope will cover as many taxonomic groups as possible.
I would like to sort out the next edition over the Christmas break, so please send submissions by 18th December 2002 to:
Stuart Warrington
Dept of Environmental Sciences
University of Hertfordshire
Hatfield
Herts AL10 9AB
Tel : 01707 284137
Email: S.Warrington@herts.ac.uk
Do contact me if you are thinking about an article but would like to talk it over.
Dr Stuart Warrington
Editor
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