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Maidenhair spleenwort near Orton Maidenhair spleenwort grows in the grykes (or 'gaps') of limestone pavement near Orton.

Mind what’s in the gap

Friday 21 February, 2020, by News Release

Local consultant ecologists spent last summer hunting out ‘priority habitats’ in the newest area of the Yorkshire Dales National Park.

Now a report on the ‘2019 Priority Habitat survey’ has been made publicly available – see here.

Among the priority habitats found was a ‘speciality of the Dales’, limestone pavement.

The job for Steve Heaton from Otley firm Haycock and Jay, on a cloudy September day, was to survey the Beacon Hill area just north of Orton in the Westmorland Dales.

Here he is, in his element:

Steve Heaton inputs the data onto a tablet

A few hundred metres southeast from Beacon Hill is Great Asby Scar Natural Nature Reserve.  Here you will find a stunning area of limestone pavement that is a site of special scientific interest (SSSI).   Such national sites are monitored by Natural England.  The Haycock and Jay ecologists were commissioned by the National Park Authority to look at areas of potential priority habitats outside these SSSIs. 

In fact, Steve was doing the first ever ‘condition assessment’ of the limestone pavement around Orton Scar, which runs north from Beacon Hill for half a kilometre.* 

Somewhat disappointingly, much of the limestone pavement along the scar was found to be far from pristine.

“All the rocks are broken up,” said Steve.  “Traditionally one of the threats to limestone pavement was rock extraction; the Victorians loved their rockeries.”

In a 2013 character assessment of the Orton Fells, Natural England acknowledged that in the past there was extensive quarrying and stone extraction from limestone pavements. However, the assessment says that these “unique geological features” have been protected by Limestone Pavement Orders since the 1980s.

On a brighter note, amid the broken up rocks there were some classic limestone-pavement-loving plants to look at.

Herb Robert may be a common flower but it’s a limestone pavement specialist

Steve explained how the condition assessment would be carried out:

“I look at an area of two square metres. First I need to record whether it is open or wooded. I need to look for signs of recent damage. Then I need to look for ‘undesirable species’ – which is quite an amusing term – such as creeping thistle, and record their percentage cover. We’re assessing whether the desirable plants are being outcompeted. Here, the creeping thistle is not dominating, so I think it’s a good one to have for wildlife; often it’s covered in moths.

Creeping thistle – an ‘undesirable’ plant on limestone pavement

“Then the last question is to record the ‘indicator species’, such as herb robert, the spleenworts, hart’s tongue and wall lettuce. Once I’ve recorded all the species it’s the end of the survey. Over the whole area I need to make 10 stops. I can’t just choose the best areas, as I don’t want to give a false image.

“Overall it’s not in great condition because of all the broken rocks, but it will pass the condition assessment because of the plant species found. Limestone pavement is a unique habitat, as well as a real speciality of the Dales. A big range of insects rely on it.”

As we moved off the beacon and moved a couple of hundred metres east of the scar to near an old quarry site, we came across a much more intact area. Here were plenty of limestone pavement indicator species.

Steve Heaton with shield fern, a species common to limestone pavement
Steve Heaton with shield fern, a species common to limestone pavement

One of the people working on the ‘2019 Priority Habitat survey’ at the National Park Authority is Wildlife Conservation Officer, Sue Thurley.

“This is part of a long-term programme to identify, map and assess the condition of priority habitats across the whole National Park,” she said.

“In 2019 we identified 20,000ha of land for survey and mapping. We estimated that around  4,000 ha of this might be priority habitat. All this land falls within the Westmorland Dales area that became part of the National Park in 2016 – so we’ve never surveyed these areas before. Accurate and up-to-date data on habitats and their condition is extremely important to have, as it will help us to fulfil the Yorkshire Dales National Park management plan ambition for the National Park to be home to the finest variety of wildlife in England. 

“The information from these surveys means we can enhance and protect existing habitats and identify areas for potential restoration. We do this by working alongside and supporting landowners and partners. This could mean helping farmers to get into the national agri-environment schemes. If we can show a particular piece of land is priority habitat,  then the application stand a better chance of succeeding. A good knowledge of habitats and species also helps us to bid for resources to carry out specific projects and work with partners on landscape restoration programmes, like the Ingleborough Dales and Westmorland Dales Landscape Partnership.”

The results of the ‘2019 Priority Habitat survey’ will feed in to the next National Park-wide Biodiversity ‘Trends and Status’ report, which will be published in early 2021

If you’ve read this far, then here’s a photographic reward: 

Hart’s tongue fern on Orton Scar.  Hart’s tongue is seen as a woodland plant, enjoying shady conditions, but it is also a key indicator species for limestone pavement, where it shelters in the grykes

This is the second blog post on the priority habitat survey.  Here’s an account from summer 2018 of how Haycock and Jay ecologists assessed the condition of a woodland near Sedbergh.


* The Orton Scar area is marked on the government’s ‘Magic’ map service and was surveyed in October 2009 for a Higher level Stewardship agri-environment scheme. So, a condition assessment may have been carried out at that time, but the data is not publicly accessible.

** The number of plant species emerging from the grykes is important. It  can be used to assess appropriate grazing levels; less emergent vegetation indicates high grazing pressure. 

Picture of News Release

News Release

Yorkshire Dales National Park Authority


4 Replies to “Mind what’s in the gap”

  1. dan says:

    informative thanks

  2. Paul Redshaw says:

    What great survey and a lovely explanation of work! I would love to help out with this kind of work in the future or any other similar work.
    Please contact me.

  3. Tom Davies says:

    Interesting article! Thanks for the read

  4. Paul Redshaw says:

    “Somewhat disappointingly, much of the limestone pavement along the scar was found to be far from pristine.”
    Come on I’m not naive, but it’s well known the scar is not pristine!
    On another point Herb Robert is far from being a limestone specialist plant, there are many limestone pavements from North Yorkshire to South Cumbria with little of this plant. In fact it can be said it is a common plant that given the opportunity will grow absolutely anywhere, including on acid soils!
    It is a weed of gardens and roadsides all over.
    If would have been good in this survey to stick with the issues it faces. The fact their seems to be a lot of Thistles and Herb Robert suggests that though they like the site the scar is being dominated by species that are undesirables to it and are a threat to wider areas!

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