Heather beetle damage on Dartmoor 2019

I have been very surprised how much Heather Beetle damage there is on Dartmoor this year. The Heather Beetle larvae hatch in June and then feed on the young leaves and shoots. As a result the affected parts of the heather plant turn orange brown.

Heather Beetle damage. It is very characteristic and eye catching.

Last week I walked from Rowtor on Okehampton Common up the military road to Observation Post 15 and then down to Ockerton Court. All the way along the track there are signs of extensive damage to the heather plants – I would estimate that over 90% of plants are affected.

Work carried out in the north of England and in Scotland suggest that the larvae are active until the end of August when they drop down into the litter and pupate into adult beetles. Despite three separate searches on Okehampton Common, the Forest of Dartmoor and Headland Warren Common I only managed to find three larvae and one adult beetle.

Here is a Heather Beetle larvae on Okehampton Common eating the few remaining green leaves of the plant.

I suspect that the absence of larvae and adults during my searches in the first week of August means that the larvae have already dropped into the litter and are beginning to pupate – as a result larvae and adults are not visible. However the very extensive areas of damaged heather indicates that they have been very active in June and July.

It is possible for the heather to recover from this attack and I will be monitoring it to see if it does. However parts or all of the heather plant can be killed. When this happens the shoots turn from orange brown to grey.

This is mature heather at Ockerton Court which has been killed by Heather Beetle

In this image the areas of dead heather (darker brown bits) are being over run by Purple Moor Grass (Molinia caerulea) – the bright green shoots of this year’s growth and the light brown leaves from last year. Molinia is unable to replace heather whilst the heather is alive but can and does do so when it is dead.

Heather Beetle is a seriously under-recorded species on Dartmoor – the National Biodiversity Network database has just one record and the is from Fingle Woods and not from the high moor!

There is clearly a need to gather more records ….

There is anecdotal evidence nationally that Heather Beetle attacks are getting worse and it has been suggested (based on research from the Netherlands) that the severity and frequency of Heather Beetle outbreaks is linked to the levels of atmospheric pollution – particularly nitrogen levels.

Dartmoor receives high levels of nitrogen deposition as a result of its high rainfall – Natural England have reported that Dartmoor receives 24kg / ha / annum of nitrogen (as NOx) which is damaging the blanket bog and mires. This high level of nitrogen deposition may also be responsible for the high levels of Heather Beetle damage.

Heather Beetles are a natural part of the moorland wildlife community and historically damage to heather was limited except in the ‘outbreak’ years. Last year when I was walking the Commons in July I also noticed extensive areas of affected heather – at this point in time heavy attacks appear to be frequent – maybe even annual.

There are implications for wildlife, conservation and hill-farming as a result of these serious Heather Beetle attacks.

  1. The heather plants themselves are either killed or remain stunted
  2. The species of wildlife which feed on heather shoots are also impacted – this includes moth species such as the Emperor Moth and the Fox Moth, whose hairy caterpillars are important prey items for one of Dartmoor’s iconic and successful birds – the cuckoo.
  3. Heather has long been a conservation indicator for the condition of Dartmoor’s Commons and historically grazing levels were reduced significantly to reduce overgrazing pressures to conserve heather.
  4. Heather is also a winter food for sheep on the Commons, if the amount of heather generally is significantly reduced as a result of Heather Beetle attacks it put pressure of the remaining plants that have survived.

Ironically it is thought that the severity and frequency of Heather Beetle attacks has increased because the nitrogen has made the young shoots and leaves more nutritious, it is also reported that sheep preferentially graze the new shoots too for the same reason.

There is a dearth of information on Heather Beetle issues on Dartmoor but from my own observations this year and last it is a potentially serious and widespread problem. However it would also appear that the problem is not universal across the moor. I searched for it in the heather stands around the Warren House Inn  and found Heather Beetle attacks to be minor – perhaps this level of damage is the natural level – whereas the levels seen on Okehampton Common, the north part of the Forest and on Headland Warren Common are the outbreak levels.

It seems to me that there is a clear need to better understand the Heather Beetle situation on Dartmoor, this would be in the interests of Natural England, the Dartmoor National Park Authority and the Dartmoor Commoners Council. The time to survey for the impacts of Heather Beetle is July and August. Maybe a bit of ‘Citizen Science’ could come to the rescue?

I would also be interested to hear from people who have found the characteristic orange brown stands of heather this year on Dartmoor.

I’ve written before about Heather Beetles and this link takes you to my blog which contains further information and some references you can download.

A Black Fox Running

I was passing Waterstones in Exeter on Saturday and saw a window display for this book.

If you love Dartmoor and wildlife I suspect that this book is for you. I’m halfway through it and am spell bound.

Here is what Waterstones have to say about it – it will give you an idea of what to expect .

A beautiful lost classic of nature writing which sits alongside Tarka the Otter, Watership Down, War Horse and The Story of a Red Deer

This is the story of Wulfgar, the dark-furred fox of Dartmoor, and of his nemesis, Scoble the trapper, in the seasons leading up to the pitiless winter of 1947.

As breathtaking in its descriptions of the natural world as it is perceptive its portrayal of damaged humanity, it is both a portrait of place and a gripping story of survival.

Uniquely straddling the worlds of animals and men, Brian Carter’s A Black Fox Running is a masterpiece: lyrical, unforgiving and unforgettable.

The 25 year Environment Plan – the wait is over

After months of waiting the Plan has finally been published and launched by the Prime Minister. So ….. has the wait been worth it? Of course this is just a plan BUT if it is delivered an awful lot to do with the environment will change for the better. There will of course be those who say it doesn’t go far enough here and opportunities have been missed there – they will probably be right too. BUT, my goodness who would have thought a plan such as this would have been published during the Paterson or Leadsom eras? I’m not going to systematically review the document I’m just going to pull out a few bits and pieces that caught my attention and made me smile.

You can download and the the 25 year plan here and I recommend you do 

To start with I wonder whether the cover of the report contains a Defra joke? This is Mam Tor in the Peak District with the sun rising in the background (at least I assume it is rising). It is owned by the National Trust who are developing plans to encourage hen harriers and peregrines back into the area. A new dawn is breaking …. hang on …. that was somebody else.

Back to Gove, he repeats in his introduction this –

We will support farmers to turn over fields to meadows rich in herbs and wildflowers, plant more trees, restore habitats for endangered species, recover soil fertility and attract wildlife back. We will ensure broader landscapes are transformed by connecting habitats into larger corridors for wildlife, as recommended by Sir John Lawton in his official review.

In the main report we are told again that subsidies are on the way out.

£3.2bn is spent in the UK under the CAP. £2.59bn of this is spent under ‘Pillar 1’ – the ‘basic payment scheme’ (BPS). This pays farmers according to the amount of land they own, rather than the outcomes they achieve. It concentrates money in the hands of those who already have significant private wealth, without improving environmental outcomes.

And that the ‘greening’ measures have failed and that only a fraction of the money has been spent on things that make a difference.

There have been efforts to improve this by ‘greening’ one third of BPS payments – but scholars have recently found these to be largely ineffective. Just £0.64bn – 20% of the total – is spent on environmental stewardship programmes under ‘Pillar 2’.

The principle public good ….. that is progress!!

After a period of stability to ensure a smooth transition, we will move to a system of paying farmers public money for public goods. The principal public good we want to invest in is environmental enhancement.

OK nothing specifically about uplands, hill-farmers or Commons but Gove covered them in his OFC speech last week – see here. These topics will be specially covered in the Agriculture Command paper due in the Spring and all will be well! Hill-farmers will be supported and the uplands will be restored.

Incentives ….. and ….. the ‘polluter pays’ – I never thought that I would read that regarding fertiliser and pesticide usage

We will introduce a new environmental land management system to deliver this. It will incentivise and reward land managers to restore and improve our natural capital and rural heritage. It will also provide support for farmers and land managers as we move towards a more effective application of the ‘polluter pays’ principle (whereby for costs of pollution lie with those responsible for it).

Here is the strong influence on Government that the Natural Capital Committee has had. Before the NCC ‘externalities’ were just jargon from economists but now it looks like we will all be using the word to reduce pollution.

Farming can be a powerful force for environmental enhancement but it currently generates too many externalities such as emissions from livestock and pollution from fertilisers and pesticides. Overall, farming is now the most significant source of water pollution and of ammonia emissions into the atmosphere in the UK. It accounts for 25% phosphate, 50% nitrate and 75% sediment loadings in the water environment, which harms ecosystems.

Finally a clear and not tacit admission that atmospheric pollution harms soils and alters vegetation.

By ensuring fertilisers are used efficiently, we can cut the air and water pollution that harms public health and the environment, and reduce greenhouse gas emissions. Poor storage of manure and slurry can lead to the release of harmful chemicals and gases such as ammonia (in 2015, more than four-fifths of ammonia emissions in the UK stemmed from agriculture). This can cause acid rain, combine with pollution from traffic and industry to form smog, and harm soils and vegetation.

A clear indication that peat bogs will be conserved and managed better in the future.

Our peat bogs and fens are important habitats that provide food and shelter for wildlife, help with flood management, improve water quality and play a part in climate regulation. Most peat soils support ecosystems that are sensitive to human activities including drainage, grazing, liming and afforestation. This makes them susceptible to degradation if poorly managed.

If I were still working at Wicken Fen on the National Trust’s Vision or the Wildlife Trust’s Great Fen project I would be very excited about this – opportunities, opportunities, opportunities.

Over the last 200 years, we have lost 84% of our fertile peat topsoil in East Anglia. The fens there could lose the remainder in just 30-60 years given current land management practices and a changing climate. In view of this, we intend to create and deliver a new ambitious framework for peat restoration in England.

Habitat creation on a grand scale …

Through changes in the way we manage our land, we will develop a Nature Recovery Network providing 500,000 hectares of additional wildlife habitat, more effectively linking existing protected sites and landscapes, as well as urban green and blue infrastructure.

Five years ago commissioning a review into National Parks would have been a recipe for their further emasculation – this can only mean they are going to be strengthened and properly funded! Who to chair the review? Dame Fiona Reynolds would be a good choice in my view.

The UK’s first National Parks were created by an Act of Parliament in 1949 following the government’s 1947 Hobhouse Report, which remains the basis for most protected landscape designation in England today.

Now, 70 years on, the Government will commission a review for the 21st Century. This will consider coverage of designations, how designated areas deliver their responsibilities, how designated areas are financed, and whether there is scope for expansion. It will also consider opportunities to enhance the environment in existing designations, and expand on the existing eight-point plan for National Parks to connect more people with the natural environment.

To my eyes much of this plan looks excellent, of course it will only be effective if things happen – that is the next stage.

This tweet which I posted earlier sums up my feelings

There is also an annex which was published alongside the main report – this is also very good – it is full of useful data with url links to the sources. You can download the annex here.

I can’t see the Defra joke though in this image – can you?

Giant Horsefly in Exeter

Last night I found a Dark Giant Horsefly (Tabanus sudeticus) on the wall of the Devon and Exeter Squash Club. This is the largest horsefly in Britain and they don’t get any bigger anywhere else in the world including the tropics.

The body is 24mm long – the orange base to the antennae and dark markings on the abdomen are diagnostic. This is a female – they have gaps between their eyes. In the males their eyes touch.

I’m not sure what it was doing at the Squash Club, I’ve normally seen this species in wild remote places like the Highlands, the Lake District and Dartmoor. I wonder whether it had been affected by yesterday’s heavy rain and took shelter before setting off again in search of cattle and horses.

Here is a photograph of the same species – one I took on Dartmoor a few years ago with a pound coin for scale

This is the same individual showing its mouthparts – it is only the females that bite – little reassurance though as this is a female!

This is the national distribution of the Dark Giant Horsefly – not very common

A Western Bee-fly in my garden in Exeter

Yesterday in the warm sunshine I came across a very small bee-fly in my garden. I have regularly seen the larger Dark-edged Bee-fly (Bombylius major) but I have never seen a Western Bee-fly (Bombylius canescens) in the garden before. If I want to see one of these I normally go to Hembury Woods on Dartmoor.

Distinctive bee-fly with its long proboscis – the animal was around 8mm long

Feeding on Germander Speedwell flowers – gives a good indication of the size of the bee-fly

The dark core with the lighter fringing hairs is distinctive.

As you can see from this distribution map (courtesy of the NBN) it is not a common animal

The problem with Heather Beetles

The Heather Beetle (Lochmaea suturalis) is a native Chrysomelid leaf beetle which feeds almost exclusively on heather (Calluna vulgaris). It is common in areas whether heather grows from the south of England to Orkney in the north (Duff 2016).

Heather beetle populations are well known to fluctuate greatly from low numbers which have little over impact on heather plants to very high numbers which can lead to the widespread defoliation of heather and can cause its death.


Heather Beetle damage on Ryders Hill March 2016

Heather beetle outbreaks have historically been problematic for grouse moor owners and the issue of heather beetle and its control has been championed by the Heather Trust who have produced a short document on the species (Heather Trust undated).

In addition the Heather Trust commissioned a literature review of the species (Rosenburgh & Marrs 2010) which summarises the ecology of the beetle, its impact as a pest and strategies for control. This work has been updated (Gillingham et al 2015a and 2015b) and published as Natural England Evidence Reviews on its ecology and its management.

These reviews state the following regarding heather beetle outbreaks:-

  • ‘Considerable damage to heather can occur with complete death in the worst cases’.
  • ‘Large scale vegetation change can follow’ (heather outcompeted by invasive grass species).
  • ‘The occurrence and severity of heather beetle attacks appears to be made worse by increased levels of nitrogen in the soil and plant tissues, which has been blamed on high nitrogen pollutant inputs from the atmosphere in recent years’.
  • ‘The high nitrogen in the leaves provides the beetles with more high quality food to consume’
  • ‘Climate change is expected to lead to increased winter survival of heather beetles’

On Exmoor heather beetle is considered a major problem, and the National Park Authority report that outbreaks are common and are spreading from the south to the north of Park. They also suggest that in areas where Purple Moor Grass (Molinia caerulea) is absent the heather plants recover fully and rapidly but where Molinia is present this quickly swamps the heather and replaces it (ENPA 2015).

I have written before about the loss of heather that had occurred on the National Trust’s land in the Upper Plym valley on Dartmoor (see here). In 1995 there was a serious outbreak of heather beetle which killed off the heather in the area known as Hen Tor Fields. At the time it was assumed that overgrazing was the cause although no increase in stocking levels had taken place for a number of years.  In this specific instance the heathland communities (H12 Calluna vulgaris-Vaccinium myrtillus) were replaced by upland grass communities (U4 Festuca ovina-Agrostis capillaris-Galium saxatile) which do not naturally contain Molinia. On the wet heaths of the Upper Plym Estate there were numerous other outbreaks on heather beetle during the 1990s and 2000s (Helen Radmore NT tenant pers comm) and in these habitats Molinia now dominates (my observations).

There has been no systematic survey of heather beetle on Dartmoor and Goodfellow et al (1997) only briefly mention it “Outbreaks of heather beetle cause local declines in heather”, however my recent observations on the moor suggest that heather beetle damage is very widespread and extensive.


Heather Beetle damage on Ryders Hill – March 2016

I would be very interested to hear from anyone with information about heather beetles on Dartmoor in recent years – it is an issue which is begging for more research.

References
Duff A.G. (2016) Beetles of Britain and Ireland. Volume 4 Cerambycidae to Curculionidae. A.G. Duff (Publishing) West Runton.
ENPA (2015) Exmoor Swaling Review 2014/15. Seminar Notes ENPA. Dulverton. http://www.exmoor-nationalpark.gov.uk/__data/assets/pdf_file/0011/583454/Exmoor-Swaling-Review-2014-15.pdf
Gillingham P., Diaz A., Stillman R. & Pinder A.C. (2015a) A desk review of the ecology of the heather beetle. Natural England Evidence Review, Number 008. http://publications.naturalengland.org.uk/publication/6386866406293504
Gillingham P., Diaz A., Stillman R. & Pinder A.C. (2015b) Desk review of burning and other management options for the control for heather beetle. Natural England Evidence Review, Number 009. http://publications.naturalengland.org.uk/publication/4817807814426624
Goodfellow S., Wolton R. & Baldock N. (1997) The Nature of Dartmoor: a biodiversity profile. English Nature / Dartmoor National Park Authority publication. http://www.dartmoor.gov.uk/__data/assets/pdf_file/0014/42701/au-natureodp2.pdf
Heather Trust (undated) Heather Beetle. Download from Heather Trust Website http://media.wix.com/ugd/fdc287_2b9ec8fa073d4ca38baf4a754d7a77f4.pdf
Rosenburgh A. & Marrs R. (2010) The Heather Beetle: a review. Report to the Heather Trust. http://media.wix.com/ugd/111722_4370d9fb976442b2af6e678aa83c3663.pdf