Sunday 15 April 2018

Shropshire Botanical Society - Out and about with beginners at Oswestry Hill Fort

In the giddy heights of an English summer with the surrounding countryside humming with life, Sue Townsend, the Botanical Society Treasurer looks back on two beginners plant hunts where great records were made, learners engaged and conservation objectives were discussed.  What more can you want from a beginners day?

The first of the two beginners field meetings last year was at Old Oswestry Hill Fort on 1st July 2017.  Most of the records were taken at SJ2931.  This fabulous ancient monument is owned by English Heritage and managed mostly through volunteer efforts.  It was even reported in the Oswestry Advertiser as we were part of a Bioblitz event.  The headline was “This was a special day as It’s official – Oswestry Hillfort is a haven for wildlife galore”.  This event was organised by a Botanical Society member Clare Knight who works for the Shrewsbury based consultantsTurnstone Ecology.

Entrance to Old Oswestry Hill Fort
So we were not alone.  Specialists in moths, bats, birds, bees, beetles, spiders and small mammals came from all over Shropshire to take part in the BioBlitz.

The aim was to take a snapshot of the hillfort’s flora and fauna over 24 hours, most likely the first major ecological study in its 3,000-year history.

Data was collected to guide on-going landscape maintenance to ensure it safeguards the hillfort’s archaeological structures and thriving ecology.  More than 400 species of flora or fauna were logged on the day, including an encouraging number of invertebrates not previously recorded.

The Botanical Society assembled from midday and Clare joined us along with members Dan Wrench, Tina Tearu, Ed Lomax and Gill Wilson.  Members of the public joined in along the way and eagle eyes spotted plants which we were hunting from pre-existing records. 

Old Oswestry was built and occupied during the Iron Age (800 BC to AD 43) and is one of the best-preserved hillforts in Britain. It remained in use for almost 1,000 years.  It is composed of banks and ditches which would have been formidable obstacles to any attacker – but more importantly for the naturalist gives a mixture of sands, clays and gravels lifted up and away from the influence of agriculture and roads to give us a selection of grassland habitats. The ramparts are among the most impressive of any British hillfort, enclosing a central area of 8.4 hectares. 

The steep grassy ramparts with scrub and trees
For centuries the slopes were densely covered by trees, and an 18th-century writer describes threading his way ‘through the thorny intricacies of this sylvan labyrinth’. 

This tells us that there was scrub and perhaps wooded areas – but there are also deep clay lined pools which were a joy to descend into and discover some aquatics.  

Our full list is a little long to include here – so I thought I would concentrate on the 21 axiophytes which you will all remember as those special plants, often but not always rare – but indicative of Shropshire’s special flora.  The full list of the plants recorded at the site can be accessed from the Records Database at Shropshire Ecological Data Network.  All these records have been checked by Sarah Whild, our County Recorder, who received our 166 plant records for this site to add to this data.  

We did not record some species found in previous years, particularly the ferns Scaly Male-fern Dryopteris affinis, Broad Buckler-fern D. dilatata and Male Fern D. felix-mas; they were possibly  there – but too small to confirm with no spores.  We were also unsure of the presence of Nodding Bur Marigold Bidens cernua (there were some young shoots but in amongst the Trifid bur-marigold Bidens tripartita) and the Water Starworts or Water Crowfoot Ranunculus peltatus were not found in the drying, shallow ponds. We saw no violets as they would have withered to nothing being spring flowers but other spring flowers were seen hidden amongst the lovely Great Wood-rush Luzula sylvatica.  These included both Bluebell Hyacinthoides non-scripta  and Wood Anemone Anenome nemorosa which were thriving relics of past woodland cover on the slopes.  We were determined to work at the hawkweeds that we discovered on the steep sandy slopes and valiantly keyed them out using the well-known tome of Stace.  We did send samples as pressed specimens to Tim Rich – national referee, as these are cryptic species that are very difficult for the non-specialist to determine.  Tim was really helpful and got back to us within 2 weeks so we could add these to our species list with confidence. The hawkweeds Hieracium argillaceum and H.vulgatum were confirmed and to our delight we actually got one right ourselves! We found some really lovely plants and one of the highlights was Greater Broomrape Orobanche rapum-genistae Thuill. We found this in it’s usual place, just off the footpath in the patch of broom to the left of the path.  It has been there for years and as a parasitic plant, has no chlorophyll but inserts its roots into the roots of the host plant and extracts nutrients direct from the Broom Cytisus scoparius.  It was very withered so our photos did not do it justice – the photo below is taken from the BSBI website.   Another lovely plant was Wild Basil Clinopodium vulgare which we found at the foot of one of the ramparts, photo from the NBN Atlas

Greater Broomrape Orobanche rapum-genistae

Wild Basil Clinopodium vulgare

The day was a great success in terms of enjoyment and interaction with many other naturalists.  We had fun, learnt some botany and rediscovered some lovely plants.  The full list of axiophytes is shown in the table below:

Scientific name
Common name
Aira praecox
Early Hair-grass
Alchemilla filicaulis
Common Lady's-mantle
Allium ursinum
Anemone nemorosa
Wood Anemone
Bidens cernua
Nodding Bur-marigold
Blechnum spicant
Hard Fern
Calluna vulgaris
Carex vesicaria
Bladder Sedge
Clinopodium vulgare
Wild Basil
Deschampsia flexuosa
Wavy Hair-grass
Galium odoratum
Sweet Woodruff
Hyacinthoides non-scripta
Hypericum pulchrum
Slender St John's-wort
Luzula sylvatica
Great Wood-rush
Lythrum portula
Water Purslane
Orobanche rapum-genistae
Greater Broomrape
Oxalis acetosella
Polygala serpyllifolia
Heath Milkwort
Trisetum flavescens
Yellow Oat-grass
Vaccinium myrtillus
Veronica officinalis
Heath Speedwell

I would like to thank Claire Knight and Turnstone Ecology for making the Botanical Society so welcome and English Heritage for their permission to use the site on the day.