Saturday 12 May 2018

Top ten natural history delights of w/e at Juniper Hall FSC centre – from the invasive Green Cellar Slug – to a dawn chorus walk up Box Hill.

Could you be a naturalist?

Would you like to come on a field course? (FSC)
I have just returned from teaching a group of 9 people – on the course – Grass Identification in Spring (4-7 May 2018)
Box Hill Viewpoint
- i.e. how to identify grasses before they come into flower.

The participants were 
enthusiastic and good fun. – Six do survey work  and related work for a living (e.g. bat surveys, and environmental impact assessments) and three were on holiday – just learning about wildlife for fun.

At the same time Dr June Chatfield was teaching the annual Juniper Hall Snails course to a group of four people.

So, when not teaching my grasses group, I crept into the snails group to see what they were doing (as did many of my students too)

Field Studies Council courses are open to everyone (for adult ones you may have to be above 16yrs, or accompanied by a guardian) ..

This post (still under construction, ) will list 10 highlights. It's to encourage you to come on courses run by the FSC (Field Studies Council). And to remind myself what a good weekend I had.

The Grasses course ran from Friday evening to Monday afternoon on May Bank Holiday.

Juniper Hall is hidden in a hollow in the North Downs. It is just 25 miles by road from Hyde Park and the centre of London (18 miles as the crow flies) but our walks and short 3 mile drive to Headley Heath meant that we never left the beautiful countryside.. with the leaves just coming out, the woodland floor carpeted with bluebells, and special chalk loving plants growing in grassy slopes

Here are my top ten memories:-

1. The Green Cellar Slug.
2. The Roman Snails.
3. Pre-breakfast walk on National Dawn Chorus Day to Box Hill
4. History
5. Totals: Twitching - Molluscs, Grasses, Birds.
6.  Acid and Basic Soils - and the colourful BDH soil indicators

(6-10 still to be written)

1. The Green Cellar Slug.

If you have a damp kitchen or cellar, you may have seen a yellow cellar slug crawl across the floor at night. “A new species has arrived  – this time a green one” says June. “The trouble is it grows faster than the yellow one and it hybridises with it. The yellow one has a yellow line up its back. The green one does not.. but there are now hybrids that have a bit of a yellow line. And there are back-crosses.”Left: Young Green Slug:Rright: Hybrid Green-Yellow Slug

"Why do so many types of invasive slug come from Spain?" I asked.

“Well we import lots of vegetables and salad from Spain” suggested June. 

That evening I went out with my new Petzl torch that I had bought on my lichen trip last month. What did a see on the fig tree outside the lab?

A Green Cellar slug! I was watching history taking place

2. The Roman Snails.

These are a treat to see each time I visit Juniper Hall. June showed us two of these in the sun on grasses just below the haha (wall). I have seen more of these in previous years, June was keen to know what grass the snail was eating – well sitting on. She was concerned that the Smelling garden/ Garden for the blind which had supported so many Roman Snails was going to be replaced by flat lawn, to improve the haha and view. The grass was Poa trivialis - Rough Meadow-grass

3. The pre-breakfast walk on National Dawn Chorus Day  up Box Hill

Two participants and myself set off at 6.15am on the same three mile route that all nine of us would do later in the day. But what a contrast. At 6.30am the Burford Bridge Car Park was empty. We listened to the birds, the dew glistened on the grass. 

At 11am that car park was  packed, motorbikes roared out, their drivers revving, and gleefully driving without silencers..  mobile pneumatic drills in a procession to the roundabout.

In the early morning we followed the river Mole to the stepping stones, searching (without luck) for kingfishers,  then climbed up through the cool of the morning to the view point on Box Hill; In previous years we had heard Bullfinches and Firecrests but not this year. 

We found just two other walkers and asked them to photo us.

Then took the quickest route to get us back in time for late breakfast at 8.25pm

 By 2 pm on this blazing hot bank holiday Sunday we had to share the viewpoint and surrounding grassland with (tens of) thousands of others. But it was  delightful seeing so many families enjoy themselves.

4. History

These really are famous places. So famous that I had had to  learn  about the Mole Gap for “O levels” when I was 15. I have memories of being brought to Box Hill on a Day’s Field Trip from London University. What a privilege to visit such a famous place. And what a miracle it survives so close to London.

5. Totals / Twitching


June’s group would be leaving a day earlier than mine, on Sunday teatime, though June stayed on till Monday. She was busy totting up scores, and comparing her results with previous years.

 "48 total!" she said, very pleased. As there are only about 100 land snails and about 30 slugs (maybe more now with the invasive ones in greenhouses) 48 /150 is a good percentage.. One in three of the British Fauna! 

(The Molluscs of Ireland say: "We have about 150 native or naturalised species with another 25 or so non-native species found in heated greenhouses or aquaria." 

Total of British Grasses = 173 plus 47 casuals= 220
We had found 46 species of grass on the course. 

46/177 or 46/220  averages at 1 in four.

According to “Grasses of the British Isles by Tom Cope and Alan Gray there are 113 native species, 10 archaeophytes, 50 neophytes, 47 casuals – total = 220, ( archaeophytes in Britain are considered to be those species first introduced prior to 1492, when Christopher Columbus arrived in the New World and the Columbian Exchange began. In Britain, neophytes are defined as plant species that were introduced after 1492, )

(The day after I found Molinia caerulea and Deschampsia cespitosa and I know where Hordelymus europaeus and Catabrosa aquatica grow, bringing my score to 50)

On the Monday morning we searched under the glorious sun for grasses in Juniper Hall lawn and found 24 species. 24! That's an amazing lawn. (Most lawns would just have half a dozen) 1/8th of the total grass flora.

6. Acid and Basic Soils at Headley Heath

"Ten out of ten" to Juniper Hall in still providing the colourful BDH soil test kit - which enabled us to compare the acidity of soils on different parts of Headley Heath.
(N.B. it is important to start off with clean tubes.. and to give the indicator and soil mix time to work. Add 1/2 cm soil, (or less), about 1ml of indicator and a tiny bit of barium sulphate and some distilled water, shake well and wait.

Left two pots: Wavy Hair-grass /Heathland area; Right tube: Chalk grassland soil
The two heathland samples gave acid results.
The chalk grassland gave a result of pH8.

N.B Most garden plants grow best at about pH 6.5;
Although pH 7 is chemically neutral, and pure water has a pH of 7, 
clean unpolluted rainwater naturally has a pH of 5.6 due to the carbon dioxide dissolved in it. 

Hard at work  keying out a grass on heathland
Now looking at chalk grassland

For the other four points I shall ask the participants what they remember!! -
Click for a poem about this grass

Schedonorus  (Festuca) arundinacea: (Tall Fescue)
Note the very string ribs on the blade and the hairs on the auricles. It is the only gras with hairs on the auricles. This often grows on shingle/cobbles and in damp depressions just back from rivers, roads or sea.    It is a surprising plant to find in a lawn .. but Juniper Hall lawn is full of surprises.

Scheconorus (Festuca) arundinacea
The edge of one side of the the sheath at the
base of the shoot appears to be hairy

Elymus caninus
Bearded Couch is a tufted woodland plant.