Bat Park Acid Lowland Grassland Project
Centaury - one of numerous wild flowers now appearing at Bat Park
6 Sept 2023
Following 2022 being declared the hottest year in human history, 2023 looks set to be taking its place. Throw in that today looks likely to be the hottest September day in 2023, I have intentionally arrived early at Wilderness Wood. Much to my surprise it doesn't feel particularly warm, but I suspect that will soon change. This will not be the best day for doing one of my botanical surveys at Bat Park, since it is a treeless area of grassland facing south.
Much as I wish to get started, there are always interesting folk to chat to first. I run into Martin Brockman, one of our regular artists/sculptors, so I have to see what he is up to. It comes as no surprise that he is busy working on a commission for a client. This one is a housing development near Sittingbourne, at some old brick pits. As we chat he carves lumps of wood out of a large piece of oak, based upon drawings done by local school children.
I leave him to his work and sneak past Rowana and two students busily going through a Qigong routine at Middle Paddock. They are so busy tapping into the energy of the wood that I suspect they hardly notice the mysterious figure making his way to Bat Park.
Qigong exercises on Middle Paddock
Passing through Upper Paddock it is evident that the sun has been turned up a few notches already, which probably explains why a clump of Oxeye Daisies have decided to burst into flower several weeks after completing their original flowering/fruiting cycle. Perhaps they think “warm days will never cease, for summer has o'er-brimmed their clammy cells”.
Oxeye Daisy enjoying a second flowering
Arriving at Bat Park I set about my recording system - a couple of photos of the site from the usual locations, followed by a photo of each of the four recording quadrats. I have been recording the flora here since 2018 when the site was little more than bare rocks with a thin veneer of soil upon it.
Rabbit excluded recording quadrat at Bat Park
This former hill-side had previously been chestnut coppice, but was so acidic and nutrient poor that the trees had become susceptible to a fungal disease, probably Phytophora. In 2014/15 it was decided to fell the trees to contain the fungus and then excavate some of the ground to form a terrace.
Bat Park - a terrace excavated into the hillside and seeded with a grass/wildflower mix
(looking SW from the main gate)
Volunteer Charlie Whitestone agreed to oversee the sowing of grass seed and also planted wild flowers in it. Well that was the great plan, but alas nature stepped in - with heavy rain washing away what little soil there was, rabbits consuming all the wild flowers and a hot dry period killing whatever remained. Conservation it seems is not as easy as you might expect!
I took on management of the site in 2018 and coincidentally attended a course at Wakehurst Place funded by the High Weald AONB, on restoring acid lowland grassland - a nationally rare habitat. The natural vegetation of the High Weald, outside of the woodland areas, would have been this kind of grassland. This was the result of centuries of farmers felling trees and cultivating the land as hay meadow. Each year they would remove a hay crop for winter cattle feed, thereby removing nutrients from the soil. This nutrient poor soil favoured wildflowers, with the High Weald’s meadows a Monet oil painting of colour each summer. Over the last century however, the push for agricultural productivity has seen farmers adding fertilizer to the soil, encouraging a monoculture of grasses. Good for the fertilizer companies, not so good in the long term for farmers and terrible for biodiversity.
Looking at Bat Park I realised that we had to ‘work with the grain of nature’ rather than against it. An area of low nutrient soil is ideal for the encouragement of acid lowland grassland, the thinner the better. Well they didn’t come much thinner than Bat Park’s. Dan reluctantly had to accept that it would be years before his dreamed of wildflower meadow became a reality.
We sowed seed from a local wild flower rich meadow, dug a French drain to intercept excessive rainfall run-off and strewed bracken fronds over the site to provide some degree of shade for the germinating seeds. Somehow life returned to the soil, although it was somewhat patchy at first.
Now, 5 years on, most of the site has grass cover, but not the hard-wearing Italian Rye Grass monoculture you will find at Middle Paddock. The patches of bare ground are ideal for wildflower seeds to germinate, especially where grasses give a little shade from the blazing summer sun. Everthing here is diminutive in stature due to our friendly neighbourhood rabbits. However, they are serving their purpose since they do reduce the need for mowing of the area.
Rabbit grazing of Hard Rush at Bat Park (most of the stem tips have been nipped-off).
The first flowering plants to return were Heather whose seed would have lain dormant in parts of the site where some soil still existed. Within two years, small Heather plants started to appear and can now be seen in August and September with their beautiful pink flowers. The seeds from these are naturally being spread all over the site, which potentially throws up a new problem. If ungrazed or unmown, grassland will revert to heathland and our promised grassland flowers will be crowded out. This in turn will be replaced by birch and other tree species. So, if we want to keep our acid lowland grassland habitat, we are going to have to consider the annual mowing regime which existed for centuries in the High Weald.
The Bat Park ‘desert’ of April 2018
Bat Park 2021 - five years on and the heather is flowering. Seed dispersal and seedlings to follow.
Botanical Surveying
It is no bad idea to monitor the health of the ‘patient’. This equally applies to habitat creation. It is time consuming but the results reveal much about the best way forward. Patience is a virtue.
Four 2m x 2m fixed sampling squares (quadrats) were originally selected, whose flora is still recorded several times each year. Two of the quadrats are fenced to keep rabbits out, whilst the other two are open to bunny grazing (this is known as a controlled experiment - one Mr McGregor may have carried out to determine the impact of Peter and Benjamin on his lettuces).
The area covered by each species within the quadrat is recorded each time, including the area covered by just bare soil. The Domin scale is employed - a scientifically devised means of estimating plant cover using a 1-10 scale. In the first years bare ground scored 9 and 10. It was as if the ice sheets had withdrawn from Britain and all that was required was for plants to move in. Thankfully Dan and Emily haven’t had to wait hundreds of years for this to happen!
Grasses quickly moved in, now collectively scoring 7 or 8, whilst Heather was a little slower, reaching a score of 5 after perhaps 3 years. Over the last 5 years these two have been gradually accompanied by Catsear, Ribwort Plantain and Hawksbeard scoring perhaps 2s, 3s and 4s.
The last 2 years have seen significant increases, with the apperance of several other flowering plants including Tormentil, Centaury, Birdsfoot Trefoil, Self Heal, Oxeye Daisy, Ragwort and Lesser Knapweed. I am optimistic that 2024 will finally reveal the natural acid lowland grassland vegetation of short grasses with a scattering of wildflowers amongst it.
Centaury, Ragwort and Selfheal all flowering at Bat Park
One day I intend to process the results and discover something really interesting. What has been evident is that nature will cloak the least promising of surfaces with greenery, although an absence of rabbits is certainly conducive to this process – as shown by the rabbit excluded enclosures (exclusures perhaps?).
But two hours of recording plants under a baking sun is quite enough until next spring. So I'm off home to put the results on my spreadsheet and sit in the cool shade cast by a rather nice Acer tree at the bottom of my garden.
Follow my wanderings along the coast of England at www.leggingroundbritain.com.